RESUMO
BACKGROUND: Reconstruction of surgical defects located close to eyelid edges, nostrils, or the mouth is challenging, as tension generated by direct closure or skin flaps in these sensitive regions tends to cause distortion. New repair techniques that prevent retraction may significantly improve outcomes. PATIENTS AND METHODS: Retrospective study of the use of 2 novel flap designs-the nautilus flap and the bullfighter crutch flap-to repair surgical defects in the peripalpebral, perivestibular, nasal, and perioral areas. The nautilus flap was used to repair 4 peripalpebral defects and 2 perioral defects, and the bullfighter crutch flap to repair 14 nasal ala defects. RESULTS: Cosmetic and functional outcomes were very satisfactory in all 20 patients, with no cases of ectropion, nasal vestibule collapse, or labial asymmetry. Necrosis did not occur in any of the cases. CONCLUSIONS: The nautilus and bullfighter crutch flaps appear to be excellent choices for reconstructing surgical defects in periorificial areas.
Assuntos
Nautilus , Procedimentos de Cirurgia Plástica , Humanos , Animais , Estudos Retrospectivos , Retalhos Cirúrgicos , NarizRESUMO
BACKGROUND: Reconstruction of surgical defects located close to eyelid edges, nostrils, or the mouth is challenging, as tension generated by direct closure or skin flaps in these sensitive regions tends to cause distortion. New repair techniques that prevent retraction may significantly improve outcomes. PATIENTS AND METHODS: Retrospective study of the use of 2 novel flap designs-the nautilus flap and the bullfighter crutch flap-to repair surgical defects in the peripalpebral, perivestibular, nasal, and perioral areas. The nautilus flap was used to repair 4 peripalpebral defects and 2 perioral defects, and the bullfighter crutch flap to repair 14 nasal ala defects. RESULTS: Cosmetic and functional outcomes were very satisfactory in all 20 patients, with no cases of ectropion, nasal vestibule collapse, or labial asymmetry. Necrosis did not occur in any of the cases. CONCLUSIONS: The nautilus and bullfighter crutch flaps appear to be excellent choices for reconstructing surgical defects in periorificial areas.
Assuntos
Nautilus , Procedimentos de Cirurgia Plástica , Humanos , Animais , Estudos Retrospectivos , Retalhos Cirúrgicos , NarizRESUMO
Hemocyanins present in the hemolymph of invertebrates are multifunctional proteins that are responsible for oxygen transport and play crucial roles in the immune system. They have also been identified as a source of antimicrobial peptides during infection in mollusks. Hemocyanin has also been identified in the cephalopod ancestor Nautilus, but antimicrobial peptides derived from the hemocyanin of Nautilus pompilius have not been reported. Here, the bactericidal activity of six predicted peptides from N. pompilius hemocyanin and seven mutant peptides was analyzed. Among those peptides, a mutant peptide with 15 amino acids (1RVFAGFLRHGIKRSR15), NpHM4, showed relatively high antibacterial activity. NpHM4 was determined to have typical antimicrobial peptide characteristics, including a positive charge (+5.25) and a high hydrophobic residue ratio (40%), and it was predicted to form an alpha-helical structure. In addition, NpHM4 exhibited significant antibacterial activity against Gram-negative bacteria (MBC = 30 µM for Vibrio alginolyticus), with no cytotoxicity to mammalian cells even at a high concentration of 180 µM. Upon contact with V. alginolyticus cells, we confirmed that the bactericidal activity of NpHM4 was coupled with membrane permeabilization, which was further confirmed via ultrastructural images using a scanning electron microscope. Therefore, our study provides a rationalization for the development and optimization of antimicrobial peptide from the cephalopod ancestor Nautilus, paving the way for future novel AMP development with broad applications.
Assuntos
Hemocianinas , Nautilus , Animais , Antibacterianos/farmacologia , Hemocianinas/química , Hemocianinas/metabolismo , Hemocianinas/farmacologia , Mamíferos/metabolismo , Moluscos/metabolismo , Nautilus/química , Nautilus/metabolismo , Peptídeos/químicaRESUMO
We report a 71-year-old woman who presented with unilateral flank pain and sepsis. A computed tomographic (CT) scan demonstrated left-sided hydronephrosis. Subsequent percutaneous nephrotomy drainage showed pus-like material, confirming the diagnosis of pyonephrosis. The ureteral stricture was caused by previous radiation injury for cervical cancer in this ESRD patient who was on chronic dialysis for years. In our case, the grade IVB hydronephrosis is a result of an extremely atrophic kidney, pyonephrosis, and ureteral stricture. The CT section of pyonephrosis in an extremely atrophic kidney resembles a sagittal section of a Nautilus shell, as the shell corresponds to the diffusely thinned renal cortex.
Assuntos
Rim/diagnóstico por imagem , Pionefrose/diagnóstico por imagem , Idoso , Animais , Atrofia/complicações , Feminino , Dor no Flanco/etiologia , Humanos , Hidronefrose/etiologia , Rim/patologia , Nautilus , Pionefrose/complicações , Sepse/etiologia , Tomografia Computadorizada por Raios X , Obstrução Ureteral/complicaçõesRESUMO
The correct diagnosis and treatment of disease in chambered nautiluses Nautilus pompilius are difficult. The basic morphology and natural behaviors of the species tend to mask the initial onset of a disease or infection, and by the time it is observable, mortality usually occurs. A single specimen of chambered nautilus at the Museum of Nature South Tyrol, Italy, exhibited symptoms of an infection, including mucus production, abnormal buoyancy, irregular hood appearance, and inconsistent tentacle movement. Soon after, tetracycline hydrochloride was administered in bath form at 25 mg/L in seawater daily for 30 min over six consecutive days. The specimen regained normal buoyancy after the fifth day. After the 6-d treatment, the specimen regained all normal behaviors and appearance within 2 weeks. More than 1 year after treatment, the specimen was exhibiting normal behaviors with no adverse reactions. When administered soon after symptoms of an infection were observed, tetracycline was effective at halting the progression of symptoms and led to the full recovery of the chambered nautilus.
Assuntos
Antibacterianos/uso terapêutico , Nautilus/efeitos dos fármacos , Tetraciclina/uso terapêutico , Animais , Feminino , Nautilus/microbiologiaRESUMO
Living fossils are survivors of previously more diverse lineages that originated millions of years ago and persisted with little morphological change. Therefore, living fossils are model organisms to study both long-term and ongoing adaptation and speciation processes. However, many aspects of living fossil evolution and their persistence in the modern world remain unclear. Here, we investigate three major aspects of the evolutionary history of living fossils: cryptic speciation, population genetics and effective population sizes, using members of the genera Nautilus and Allonautilus as classic examples of true living fossils. For this, we analysed genomewide ddRAD-Seq data for all six currently recognized nautiloid species throughout their distribution range. Our analyses identified three major allopatric Nautilus clades: a South Pacific clade, subdivided into three subclades with no signs of admixture between them; a Coral Sea clade, consisting of two genetically distinct populations with significant admixture; and a widespread Indo-Pacific clade, devoid of significant genetic substructure. Within these major clades, we detected five Nautilus groups, which likely correspond to five distinct species. With the exception of Nautilus macromphalus, all previously described species are at odds with genomewide data, testifying to the prevalence of cryptic species among living fossils. Detailed FST analyses further revealed significant genome-wide and locus-specific signatures of selection between species and differentiated populations, which is demonstrated here for the first time in a living fossil. Finally, approximate Bayesian computation (ABC) simulations suggest large effective population sizes, which may explain the low levels of population differentiation commonly observed in living fossils.
Assuntos
Especiação Genética , Genética Populacional , Nautilus/classificação , Animais , Teorema de Bayes , Nautilus/genética , Filogenia , Densidade Demográfica , TranscriptomaRESUMO
In this paper, we describe worked and pigment-stained Nautilus shell artefacts recovered from Jerimalai, Timor-Leste. Two of these artefacts come from contexts dating to between 38,000 and 42,000 cal. BP (calibrated years before present), and exhibit manufacturing traces (drilling, pressure flaking, grinding), as well as red colourant staining. Through describing more complete Nautilus shell ornaments from younger levels from this same site (>15,900, 9500, and 5000 cal. BP), we demonstrate that those dating to the initial occupation period of Jerimalai are of anthropogenic origin. The identification of such early shell working examples of pelagic shell in Island Southeast Asia not only adds to our growing understanding of the importance of marine resources to the earliest modern human communities in this region, but also indicates that a remarkably enduring shell working tradition was enacted in this area of the globe. Additionally, these artefacts provide the first material culture evidence that the inhabitants of Jerimalai were not only exploiting coastal resources for their nutritional requirements, but also incorporating these materials into their social technologies, and by extension, their social systems. In other words, we argue that the people of Jerimalai were already practicing a developed coastal adaptation by at least 42,000 cal. BP.
Assuntos
Arqueologia , Nautilus , Animais , Fósseis , Humanos , Tecnologia , Timor-LesteRESUMO
Understanding the distribution of genetic diversity in exploited species is fundamental to successful conservation. Genetic structure and the degree of gene flow among populations must be assessed to design appropriate strategies to prevent the loss of distinct populations. The cephalopod Nautilus pompilius is fished unsustainably in the Philippines for the ornamental shell trade and has limited legislative protection, despite the species' recent dramatic decline in the region. Here, we use 14 microsatellite markers to evaluate the population structure of N. pompilius around Australia and the Philippines. Despite their relative geographical proximity, Great Barrier Reef individuals are genetically isolated from Osprey Reef and Shark Reef in the Coral Sea (FST = 0.312, 0.229, respectively). Conversely, despite the larger geographical distances between the Philippines and west Australian reefs, samples display a small degree of genetic structure (FST = 0.015). Demographic scenarios modelled using approximate Bayesian computation analysis indicate that this limited divergence is not due to contemporary gene flow between the Philippines and west Australia. Instead, present-day genetic similarity can be explained by very limited genetic drift that has occurred due to large average effective population sizes that persisted at both locations following their separation. The lack of connectivity among populations suggests that immigrants from west Australia would not facilitate natural recolonization if Philippine populations were fished to extinction. These data help to rectify the paucity of information on the species' biology currently inhibiting their conservation classification. Understanding population structure can allow us to facilitate sustainable harvesting, thereby preserving the diversity of genetically distinct stocks.
Assuntos
Genética Populacional , Nautilus/genética , Animais , Austrália , Teorema de Bayes , Conservação dos Recursos Naturais , Recifes de Corais , Fluxo Gênico , Deriva Genética , Genótipo , Repetições de Microssatélites , Modelos Genéticos , Dados de Sequência Molecular , Filipinas , Densidade DemográficaRESUMO
Irregular shell formation and black lines on the outside of live chambered nautilus shells have been observed in all adult specimens at aquariums and zoos soon after the organisms enter aquaria. Black lines have also been observed in wild animals at sites of broken shell, but continued growth from that point returns to a normal, smooth structure. In contrast, rough irregular deposition of shell continues throughout residence in aquaria. The composition and reasons for deposition of the black material and mitigation of this irregular shell formation is the subject of the current study. A variety of analytical techniques were used, including stable isotope mass spectrometry (SI-MS), inductively coupled plasma mass spectrometry (ICP-MS), micro x-ray fluorescence (µXRF), X-ray diffraction (XRD), and scanning electron microscopy (SEM) based X-ray microanalysis. Results indicate that the black material contains excess amounts of copper, zinc, and bromine which are unrelated to the Nautilus diet. The combination of these elements and proteins plays an important role in shell formation, growth, and strengthening. Further study will be needed to compare the proteomics of the shell under aquaria versus natural wild environments. The question remains as to whether the occurrence of the black lines indicates normal healing followed by growth irregularities that are caused by stress from chemical or environmental conditions. In this paper we begin to address this question by examining elemental and isotopic differences of Nautilus diet and salt water. The atomic composition and light stable isotopic ratios of the Nautilus shell formed in aquaria verses wild conditions are presented.
Assuntos
Exoesqueleto/química , Exoesqueleto/crescimento & desenvolvimento , Animais de Zoológico , Dieta , Nautilus/crescimento & desenvolvimento , Animais , Bromo/análise , Cobre/análise , Espectrometria de Massas/veterinária , Microscopia Eletrônica de Varredura/veterinária , Água do Mar/química , Espectrometria por Raios X/veterinária , Difração de Raios X/veterinária , Zinco/análiseRESUMO
Authors present the X-ray radiography as a method useful for the visualization internal structure of the shells for the conchiology and malacology.
Assuntos
Exoesqueleto/diagnóstico por imagem , Moluscos , Animais , Nautilus , Intensificação de Imagem Radiográfica/métodosRESUMO
The use of intermittent hemodialysis (iHD), and continuous renal replacement therapy (CRRT), along with extracorporeal membrane oxygenation (ECMO) in patients with acute kidney injury (AKI) and end-stage renal disease (ESRD) is very common. In this technical report, we describe the methods to perform these dialytic therapies safely and effectively using the ECMO circuit in lieu of a separate dialysis catheter. Specifically, we describe in detail how to connect these kidney replacement therapy modalities to a Quadrox, Nautilus, and Cardiohelp HLS (combined oxygenator and pump) oxygenator. The dialysis (iHD or CRRT) inlet is attached to the post-oxygenators Luer-Lock, whereas the return is attached to the pre-oxygenator Luer-Lock, both with a dual lumen pigtail. We also discuss the technical aspects of performing plasmapheresis in conjunction with ECMO and iHD or CRRT. Finally, we highlight the fact that the reported technique does not require modifying the ECMO cannulas/tubing which helps maximize safety.
Assuntos
Terapia de Substituição Renal Contínua , Nautilus , Animais , Humanos , Oxigenadores de Membrana , Diálise Renal , Terapia de Substituição Renal/métodos , Plasmaferese , OxigenadoresRESUMO
BACKGROUND: Endovascular treatment of intracranial wide-necked and bifurcation aneurysms (WNBA) is technically challenging. The Nautilus Intrasaccular System is designed to provide a mechanical barrier at the aneurysm neck to support coil embolization. We report the results of a single-center series of patients treated for intracranial aneurysms with the Nautilus. METHODS: Clinical and radiological data were retrospectively collected for all patients treated with the Nautilus for an unruptured or ruptured intracranial aneurysm at our center between March 2021 and March 2022. Clinical outcomes (modified Rankin Scale (mRS) scores), Raymond-Roy angiographic occlusion, recanalization, and complications were measured immediately post-procedure and at 3-6-month follow-up. RESULTS: A total of 41 patients of mean age 56.7 years (range 37-83 years) were treated with the Nautilus, with 41 saccular aneurysms (18 (43.9%) unruptured and 23 (56.1%) ruptured). The majority of aneurysms (39/41 (95.1%)) were located in the anterior circulation. We experienced no technical complications. One patient had an asymptomatic post-procedural minor stroke related to the procedure. Immediate Class I occlusion was achieved in 30 (73.1%) patients. The rate of all-cause mortality was 7.3% (3/41). One patient was lost to follow-up. At follow-up, 94.5% (35/37) of patients achieved Class I occlusion and 94.5% (35/37) had an mRS score of 0. There were no procedural-related deaths or permanent morbidities at discharge or follow-up. CONCLUSION: This study demonstrates good safety and effectiveness using the Nautilus Intrasaccular System to treat both ruptured and unruptured intracranial aneurysms. Larger studies are needed to confirm these findings.
Assuntos
Aneurisma Roto , Embolização Terapêutica , Procedimentos Endovasculares , Aneurisma Intracraniano , Nautilus , Humanos , Animais , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/cirurgia , Resultado do Tratamento , Stents , Estudos Retrospectivos , Embolização Terapêutica/efeitos adversos , Embolização Terapêutica/métodos , Procedimentos Endovasculares/efeitos adversos , Procedimentos Endovasculares/métodos , Aneurisma Roto/diagnóstico por imagem , Aneurisma Roto/cirurgia , Angiografia CerebralRESUMO
A single Nautilus pompilius manifested a bacterial infection and nematode infestation soon after it was received from the wild, resulting in a significant buildup of mucus above the left eye and tentacles. This condition is known to lead to rapid mucodegeneration of the tentacles and epithelium, resulting in death. The specimen was quarantined 24 days after arrival. Initial topical treatments of 10% povidone solution were effective at slowing the progression of the mucus but did not eliminate it. After 26 days in quarantine, a new treatment regimen was developed that coupled a whole-animal dip in 25 mg/L oxytetracycline solution with the 10% povidone treatment on alternate days, for 5 days. After this treatment, mucus production ceased and nematodes were not present in tissue samples. The specimen was moved back to the original holding system after a quarantine period of 53 days.
Assuntos
Antibacterianos/farmacologia , Nautilus/microbiologia , Oxitetraciclina/farmacologia , Povidona-Iodo/farmacologia , Administração Tópica , Animais , Animais de Zoológico , Antibacterianos/administração & dosagem , Bactérias/efeitos dos fármacos , Esquema de Medicação , Nematoides/efeitos dos fármacos , Povidona-Iodo/administração & dosagemRESUMO
The nautilus, commonly known as a "living fossil," is endangered and may be at risk of extinction. The lack of genomic information hinders a thorough understanding of its biology and evolution, which can shed light on the conservation of this endangered species. Here, we report the first high-quality chromosome-level genome assembly of Nautilus pompilius. The assembled genome size comprised 785.15 Mb. Comparative genomic analyses indicated that transposable elements (TEs) and large-scale genome reorganizations may have driven lineage-specific evolution in the cephalopods. Remarkably, evolving conserved genes and recent TE insertion activities were identified in N. pompilius, and we speculate that these findings reflect the strong adaptability and long-term survival of the nautilus. We also identified gene families that are potentially responsible for specific adaptation and evolution events. Our study provides unprecedented insights into the specialized biology and evolution of N. pompilius, and the results serve as an important resource for future conservation genomics of the nautilus and closely related species.
Assuntos
Nautilus , Animais , Fósseis , Genômica , HumanosRESUMO
Modern nautilids (Nautilus and Allonautilus) have often been studied by paleontologists to better understand the anatomy and ecology of fossil relatives. Because direct observations of these animals are difficult, the analysis of light stable isotopes (C, O) preserved in their shells has been employed to reveal their habitat and life history. We aim to (1) reconstruct the habitat depth of Nautilus macromphalus and (2) decipher the fraction of metabolic carbon in its shell by analyzing oxygen and carbon isotopes (δ18O, δ13C) in the septa of two specimens in combination with analyses of water samples from the area. Additionally, we investigate whether morphological changes during ontogeny are reflected in the isotopic values of the shells. Results reveal that the patterns of change of δ18O and δ13C in the septa of N. macromphalus pre- and post-hatching are consistent with previous studies. Values of δ18Owater range from 0.7 to 1.4 (VSMOW), with a maximum value coincident with a salinity maximum at ~150 m. We use the temperature and δ18Owater profiles to calculate equilibrium values of δ18Oaragonite with depth. Comparing these values with the measured δ18O of the septa shows that the habitat depth of N. macromphalus is ~140 m pre-hatching and ~370 m post-hatching. Using δ13C of shell carbonate and published data on metabolic carbon, the fraction of metabolic carbon is reconstructed as ~21% and 14% pre- and post-hatching, respectively. The reconstructed depth pre-hatching is slightly shallower than in N. pompilius from the Philippines and Fiji, but the post-hatching depth is similar. However, it is important to emphasize that these estimates represent average over time and space because nautilus is a mobile animal. Lastly, the changes in morphological parameters and the changes in δ13C and δ18O during ontogeny do not coincide except at hatching and at the onset of maturity.
Assuntos
Nautilus , Animais , Carbono , Isótopos de Carbono , Ecossistema , Nova Caledônia , Isótopos de OxigênioRESUMO
Cephalopod carbonate geochemistry underpins studies ranging from Phanerozoic, global-scale change to outcrop-scale paleoecological reconstructions. Interpreting these data hinges on assumed similarity to model organisms, such as Nautilus, and generalization from other molluscan biomineralization processes. Aquarium rearing and capture of wild Nautilus suggest shell carbonate precipitates quickly (35 µm/day) in oxygen isotope equilibrium with seawater. Other components of Nautilus shell chemistry are less well-studied but have potential to serve as proxies for paleobiology and paleoceanography. To calibrate the geochemical response of cephalopod δ15Norg, δ13Corg, δ13Ccarb, δ18Ocarb, and δ44/40Cacarb to modern anthropogenic environmental change, we analyzed modern, historical, and subfossil Nautilus macromphalus from New Caledonia. Samples span initial human habitation, colonialization, and industrial pCO2 increase. This sampling strategy is advantageous because it avoids the shock response that can affect geochemical change in aquarium experiments. Given the range of living depths and more complex ecology of Nautilus, however, some anthropogenic signals, such as ocean acidification, may not have propagated to their living depths. Our data suggest some environmental changes are more easily preserved than others given variability in cephalopod average living depth. Calculation of the percent respired carbon incorporated into the shell using δ13Corg, δ13Ccarb, and Suess-effect corrected δ13CDIC suggests an increase in the last 130 years that may have been caused by increasing carbon dioxide concentration or decreasing oxygen concentration at the depths these individuals inhabited. This pattern is consistent with increasing atmospheric CO2 and/or eutrophication offshore of New Caledonia. We find that δ44/40Ca remains stable across the last 130 years. The subfossil shell from a cenote may exhibit early δ44/40Ca diagenesis. Questions remain about the proportion of dietary vs ambient seawater calcium incorporation into the Nautilus shell. Values of δ15N do not indicate trophic level change in the last 130 years, and the subfossil shell may show diagenetic alteration of δ15N toward lower values. Future work using historical collections of Sepia and Spirula may provide additional calibration of fossil cephalopod geochemistry.
Assuntos
Nautilus , Animais , Humanos , Nautilus/metabolismo , Nova Caledônia , Concentração de Íons de Hidrogênio , Água do Mar , Isótopos de Oxigênio/metabolismoRESUMO
PURPOSE: Various adjunctive devices have been reported to be helpful during the endovascular coiling of complex, wide-necked cerebral aneurysms. This study aimed to describe the utilization of a recently introduced intrasaccular neck-bridging implant specifically designed to facilitate coil embolization. METHODS: We retrospectively reviewed eight consecutive patients who underwent treatment for intracranial aneurysms with the Nautilus intrasaccular bridging system between February 2022 to May 2022. We evaluated the angiographic appearances of treated aneurysms at the end of the procedure and early follow-up, the clinical status and complications. RESULTS: Eight patients with eight cerebral aneurysms (3 men and 5 women, mean age 52.8 years (range 39-66) were analyzed. Five of the treated aneurysms were managed in an acute case scenario. There were no technical difficulties while executing the technique. No other procedural adverse events were documented. Immediate complete occlusion of the aneurysm was seen in 6 patients, neck remnant in 1 and stable aneurysm reperfusion in one case. Early radiological follow-up was available in five patients, and the observed occlusion rates were - RR class I in all radiologically screened aneurysms. CONCLUSION: Nautilus-assisted coil embolization represents a rapid and safe solution for complex cerebral aneurysms. In our opinion this device symbolizes a significant step forward in treating intracranial aneurysms. We believe that the technique's actual value consists of the fact that the device is fully compatible with the modern low-profile microcatheter technology and does not involve the need for antiplatelet medications.
Assuntos
Embolização Terapêutica , Aneurisma Intracraniano , Nautilus , Masculino , Animais , Humanos , Feminino , Adulto , Pessoa de Meia-Idade , Idoso , Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/terapia , Aneurisma Intracraniano/complicações , Embolização Terapêutica/métodos , Estudos de Viabilidade , Estudos Retrospectivos , Stents/efeitos adversos , Resultado do Tratamento , Angiografia CerebralRESUMO
Numerous devices and sophisticated strategies have been developed to further increase the number of aneurysms amenable to endovascular treatment.1-4 Despite the superfluity of available neurovascular armamentarium, wide-necked bifurcation aneurysms can still pose a significant technical challenge to the treating clinician.5-7 Neck bridging is a conceptually new approach, which provides increased occlusion rates with lower recurrence and complications rates.8-10 The Nautilus (EndoStream Medical) is an intrasaccular bridging device intended to assist in coil embolization of wide-necked cerebral aneurysms. This CE-marked device, available in various sizes, consists of flexible-layers, and is a nitinol-based, detachable implant. The device is delivered through a standard microcatheter with a minimal 0.0165" inner diameter and is fully radiopaque and completely resheathable.Owing to its unique 'tornado' like shape the device entirely reconstructs the aneurysmal neck, which facilitates the following coil embolization. In this video 1, we demonstrate the use of Nautilus - assisted coil embolization for a complex anterior communicating artery (AcomA) wide-necked aneurysm in the setting of acute subarachnoid hemorrhage. neurintsurg;14/3/310/V1F1V1Video 1.
Assuntos
Embolização Terapêutica , Aneurisma Intracraniano , Nautilus , Hemorragia Subaracnóidea , Animais , Prótese Vascular , Humanos , Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/terapia , Stents , Hemorragia Subaracnóidea/diagnóstico por imagem , Hemorragia Subaracnóidea/terapiaRESUMO
We confirm with high-resolution techniques the existence of mineral bridges between superposed nacre tablets. In the towered nacre of both gastropods and the cephalopod Nautilus there are large bridges aligned along the tower axes, corresponding to gaps (150-200nm) in the interlamellar membranes. Gaps are produced by the interaction of the nascent tablets with a surface membrane that covers the nacre compartment. In the terraced nacre of bivalves bridges associated with elongated gaps in the interlamellar membrane (>100nm) have mainly been found at or close to the edges of superposed parental tablets. To explain this placement, we hypothesize that the interlamellar membrane breaks due to differences in osmotic pressure across it when the interlamellar space below becomes reduced at an advanced stage of calcification. In no cases are the minor connections between superimposed tablets (<60nm), earlier reported to be mineral bridges, found to be such.