The septal chondromucosal island pedicle flap: anatomic study and clinical application

A study was made of the facial regions of 10 fresh cadavers. The vascular anatomy of the perinasal region and the septum consistently confirmed the existence of a nasal alar basal artery and a nasal alar basal nerve to the septum. A new septal chondromucosal flap, supplied by the nasal alar basal artery and nerve, is proposed in this article. The composite flap can be used safely to restore partial or entire tarsoconjunctival defects of the upper or lower eyelid or combined defects of the upper and lower eyelid.     

Repairing defects of the lower eyelid with a free chondromucosal graft.

A method is presented for the repair of full-thickness defects of the eyelid. The lining and tarsal plate are replaced by a free chondromucosal graft from the nasal septum, in which the cartilage is thinned and perforated. Cover is provided by a compound, bipedicled flap of skin and muscle from the opposite lid.     

Surgical correction of the nose and midface in maxillonasal dysplasia (Binder's syndrome)

In 48 patients with maxillonasal dysplasia the retruded nasal base was corrected with onlay cancellous bone grafts after subperiosteal dissection using an oral vestibular approach. Support for the nasal dorsum was achieved in 39 patients with an L-shaped bone graft from the iliac crest introduced through the same approach. The advancement of the nose was found stable on lateral cephalograms; i.e., resorption did not occur. However, the grafts showed considerable remodeling. Half the patients found the stiffness of the nose to be disturbing. In nine patients, the cartilaginous septum was used instead as a support for the nasal dorsum and tip. At operation, the entire cartilaginous septum was mobilized after subperichondrial dissection and rotated forward either pedicled at the nasal dorsum or completely released. Cartilage regenerated in the periochondrial pocket left behind the advanced septum. The anterior transfer of the nose was 6 to 10 mm. The use of septal advancement is preferred over bone implants in the correction of maxillonasal dysplasia in patients in whom the bony nasal dorsum is of adequate height because it results in a soft and flexible nose and the risk of traumatic fracture and resorption is eliminated. The technique has been used in adolescents with promising results.     

Reconstruction of both eyelids following electrical burn

A case of severe electrical burn of the unilateral upper and lower eyelids is reported, together with the surgical technique of reconstruction. A 25-year-old man suffered an electrical burn on his left eyelids. On admission, his left upper and lower eyelids were subtotally necrotic. Total eyelid reconstruction was performed 2 1/2 months later. A chondromucosal graft taken from the nasal septum was utilized as the deep layer of the upper eyelid, which was covered by sliding down the remaining levator muscle and connective tissues to maintain the blood supply to the composite graft. The outer layer of the upper lid was reconstructed with a free split-thickness skin graft. The lower lid was reconstructed with a local flap lined with a free mucosal graft. This sandwich method using the levator muscle as a core was found useful for reconstructing both the upper and lower eyelids.     

Lower eyelid reconstruction with a cheek flap supported by fascia lata.

The use of a cheek rotation flap is a well-known method for reconstruction of a large defect of the lower eyelid. In this technique, a separate lining tissue supporting the cheek flap is required for full-thickness reconstruction. Previously, a chondromucosal graft or conchal cartilage has been used to support this flap. Recently, we have used a homologous or autologous fascia lata as support for the cheek flap instead of rigid tissues like cartilages. A fascia lata strip is fixed with tolerable tension to the medial canthal tendon and lateral orbital rim. The inner surface of the fascia and the cheek flap is lined with a buccal mucosa graft to decrease irritation of the conjunctiva and cornea. We present here seven patients in whom this procedure was used for lower eyelid reconstruction following resection of a malignant skin tumor. Based on follow-ups of 7 to 22 months, the functional and aesthetic results have been good in all cases. This procedure may be applicable for total or subtotal reconstruction of the lower eyelid.     

Contribution of the aortopulmonary septum to the muscular outlet septum in the human heart

The development of the outlet septum has been studied microscopically in 14 human embryos, ranging from 9 to 28 mm crown-rump length. Three tissue components are involved in the septation process: condensed mesenchyme of extracardiac origin, myocardium and endocardial cushion tissue. At the stage of 9 1/2 mm the condensed mesenchyme, which is embedded in the endocardial cushion tissue, is in contact with the myocardium at two sites. Graphic reconstructions of a 16 mm embryo show that at these sites of contact the myocardium is "drawn inwards" to form two bulges interconnected by the condensed mesenchyme. With further development the two myocardial bulges become the main mass of what then can be called the outlet septum. Thus the sites of contact between condensed mesenchyme and myocardium can be considered to represent the sites of attachment of the muscular outlet septum. This has important implications for the elucidation of the development of outlet malformations.     

Function of intracoelomic septa in lung ventilation of amniotes: lessons from lizards

Aspiration breathing is the dominant mechanism of lung inflation among extant amniotes. However, aspiration has two fundamental problems associated with it: paradoxical visceral translation and partial lung collapse. These can constrain the inspiratory tidal volume, reduce the effective lung ventilation, and ultimately curtail the aerobic capacity of an animal. Separation of the pleural and peritoneal cavities by an intracoelomic septum can restrict the cranial shift of abdominal viscera and provide structural support to the caudal lung surface. A muscular septum, such as the diaphragm of mammals or the diaphragmaticus of crocodilians, can exert active control over visceral translation and the degree of lung inflation. To a lesser degree, a nonmuscular septum can also function as a passive barrier when stretched taut by rib rotation. Studies of the posthepatic septum in teiid lizards and the postpulmonary septum in varanid lizards underscore the importance of nonmuscular septa in aspiration. These septa provide plausible functional models that help us infer the evolution of mammalian and avian lung ventilatory systems, respectively.     

Compressive and tensile mechanical properties of the porcine nasal septum

The expanding nasal septal cartilage is believed to create a force that powers midfacial growth. In addition, the nasal septum is postulated to act as a mechanical strut that prevents the structural collapse of the face under masticatory loads. Both roles imply that the septum is subject to complex biomechanical loads during growth and mastication. The purpose of this study was to measure the mechanical properties of the nasal septum to determine (1) whether the cartilage is mechanically capable of playing an active role in midfacial growth and in maintaining facial structural integrity and (2) if regional variation in mechanical properties is present that could support any of the postulated loading regimens. Porcine septal samples were loaded along the horizontal or vertical axes in compression and tension, using different loading rates that approximate the in vivo situation. Samples were loaded in random order to predefined strain points (2–10%) and strain was held for 30 or 120 seconds while relaxation stress was measured. Subsequently, samples were loaded until failure. Stiffness, relaxation stress and ultimate stress and strain were recorded. Results showed that the septum was stiffer, stronger and displayed a greater drop in relaxation stress in compression compared to tension. Under compression, the septum displayed non-linear behavior with greater stiffness and stress relaxation under faster loading rates and higher strain levels. Under tension, stiffness was not affected by strain level. Although regional variation was present, it did not strongly support any of the suggested loading patterns. Overall, results suggest that the septum might be mechanically capable of playing an active role in midfacial growth as evidenced by increased compressive residual stress with decreased loading rates. However, the low stiffness of the septum compared to surrounding bone does not support a strut role. The relatively low stiffness combined with high stress relaxation under fast loading rates suggests that the nasal septum is a stress dampener, helping to absorb and dissipate loads generated during mastication.     

Combined conchal cartilage-ethmoid bone grafts in nasal surgery

Septal cartilage grafts are frequently required in rhinoplasties and nasal reconstructions. Unfortunately, sufficient septum is not always available for graft purposes. Conchal cartilage can serve as a substitute, but its usefulness is limited because of its soft, elastic nature. Applying thin sheets of pliable ethmoid bone to conchal cartilage gives the cartilage greater strength and, at the same time, allows it to retain some flexibility. This article examines the role of combined conchal cartilage-ethmoid bone grafts in nasal surgery. These grafts are simple to construct and are versatile in their application. By maintaining a free cartilage edge, they are readily sutured into place. The results seem to last long term.     

Bias in phylogenetic reconstruction of vertebrate rhodopsin sequences

Two spurious nodes were found in phylogenetic analyses of vertebrate rhodopsin sequences in comparison with well-established vertebrate relationships. These spurious reconstructions were well supported in bootstrap analyses and occurred independently of the method of phylogenetic analysis used (parsimony, distance, or likelihood). Use of this data set of vertebrate rhodopsin sequences allowed us to exploit established vertebrate relationships, as well as the considerable amount known about the molecular evolution of this gene, in order to identify important factors contributing to the spurious reconstructions. Simulation studies using parametric bootstrapping indicate that it is unlikely that the spurious nodes in the parsimony analyses are due to long branches or other topological effects. Rather, they appear to be due to base compositional bias at third positions, codon bias, and convergent evolution at nucleotide positions encoding the hydrophobic residues isoleucine, leucine, and valine. LogDet distance methods, as well as maximum-likelihood methods which allow for nonstationary changes in base composition, reduce but do not entirely eliminate support for the spurious resolutions. Inclusion of five additional rhodopsin sequences in the phylogenetic analyses largely corrected one of the spurious reconstructions while leaving the other unaffected. The additional sequences not only were more proximal to the corrected node, but were also found to have intermediate levels of base composition and codon bias as compared with neighboring sequences on the tree. This study shows that the spurious reconstructions can be corrected either by excluding third positions, as well as those encoding the amino acids Ile, Val, and Leu (which may not be ideal, as these sites can contain useful phylogenetic signal for other parts of the tree), or by the addition of sequences that reduce problems associated with convergent evolution.     

L-shaped structure from two alpha-helices with a proline residue between them]

L-shaped structures formed by two consecutive alpha-helices joined by short connections are considered. The L-structures with the alpha m gamma beta/delta alpha n-conformations are of particular value since they usually have Pro residues in the second positions of the second alpha-helices. These structures can be divided into two classes, the right-turned and left-turned L-structures, depending on whether the second alpha-helix is located on the right or the left, relative to the first one when viewed from the hydrophobic core. Stereochemical analysis shows that in an ideal case the left- and right-turned L-structures should have different sequence patterns of hydrophobic, hydrophilic and proline residues. These sequence patterns can be used in the prediction of the L-shaped structures as well as in protein design and engineering.     

Observation of Woronin bodies in Arthrinium aureum by scanning electron microscopy

Woronin bodies are cytoplasmic organelles of filamentous fungi that can be observed on one, or both sides of each septum. The goal of this paper is to illustrate the presence of them in hyphae of Arthrinium aureum by means of scanning electron microscopy and to show that they act as a safety plug to close septa pores in hypha. Results show that Woronin bodies as an immediate response to prevent a cytoplasm loss. Results support hypothesis proposed previously in literature. This revised version was published online in June 2006 with corrections to the Cover Date.     

Vascularized rib for facial reconstruction

The reconstruction of maxillectomy defects is a complex problem encountered in plastic surgery. Defects can range in size and complexity from small defects requiring only soft tissue to complete maxillectomies requiring large tissue bulk, bone, and one or more skin paddles. The most difficult defects involve the skull base and orbit. The reconstructive surgeon is faced with the challenge of isolating the nasopharynx from the dura and globe while simultaneously restoring the bony framework of the maxilla and orbit to support the soft tissue of the cheek. The authors present a series of six reconstructions using a rectus abdominis muscle flap with associated vascularized rib for reconstruction of complex maxillectomy defects. This flap provides large soft-tissue bulk as well as bony support and a long vascular pedicle. A skin island can be taken with the flap, and the donor-site morbidity is comparable to that seen with a vertical rectus abdominis myocutaneous flap. Six flaps were used in five patients over a 20-month period. All patients had stable support of the orbit at follow-up with adequate soft-tissue coverage, and there were no incidences of visual changes.     

Cranial morphology of Aegyptopithecus and Tarsius and the question of the tarsier-anthropoidean clade

New crania of the Oligocene anthropoidean Aegyptopithecus provide a test of the hypothesized tarsier-anthropoidean clade. Three cranial characters shared by Tarsius and some modern anthropoideans (apical interorbital septum, postorbital septum, "perbullar" carotid pathway) were examined. 1) An apical interorbital septum is absent in Aegyptopithecus. A septum does occur in Galago senegalensis (Lorisidae) and Microcebus murinus (Cheirogaleidae), so the presence of a septum is not strong evidence favoring a tarsiiform-anthropoidean clade. 2) In Aegyptopithecus and other anthropoideans, the postorbital septum is formed mainly by a periorbital flange of the zygomatic that extends medially from the lateral orbital margin onto or near the braincase. The postorbital plate of Tarsius is formed by frontal and alisphenoid flanges that extend laterally from the braincase to the zygomatic's frontal process, which is not broader than the postorbital bars of other prosimians. Periorbital flanges evolved in Tarsius for support or protection of the enormous eyes, as suggested by the occurrence of maxillary and frontal flanges that cup portions of the eye but do not separate it from temporal muscles. 3) The internal carotid artery of Aegyptopithecus enters the bulla posteriorly and crosses the anteroventral part of the promontorium. The tympanic cavity was probably separated from the anteromedial cavity by a septum stretching from the carotid channel to the ventrolateral bullar wall. In Tarsius, the carotid pathway is prepromontorial, and a septum stretches from the carotid channel to the posteromedial bullar wall. Quantitative analyses indicate that anterior carotid position has evolved because of erect head posture. The cranium of Oligocene anthropoideans thus provides no support for the hypothesized tarsier-anthropoidean clade.     

The slow road to the eukaryotic genome

The eukaryotic genome is a mosaic of eubacterial and archaeal genes in addition to those unique to itself. The mosaic may have arisen as the result of two prokaryotes merging their genomes, or from genes acquired from an endosymbiont of eubacterial origin. A third possibility is that the eukaryotic genome arose from successive events of lateral gene transfer over long periods of time. This theory does not exclude the endosymbiont, but questions whether it is necessary to explain the peculiar set of eukaryotic genes. We use phylogenetic studies and reconstructions of ancestral first appearances of genes on the prokaryotic phylogeny to assess evidence for the lateral gene transfer scenario. We find that phylogenies advanced to support fusion can also arise from a succession of lateral gene transfer events. Our reconstructions of ancestral first appearances of genes reveal that the various genes that make up the eukaryotic mosaic arose at different times and in diverse lineages on the prokaryotic tree, and were not available in a single lineage. Successive events of lateral gene transfer can explain the unusual mosaic structure of the eukaryotic genome, with its content linked to the immediate adaptive value of the genes its acquired. Progress in understanding eukaryotes may come from identifying ancestral features such as the eukaryotic splicesome that could explain why this lineage invaded, or created, the eukaryotic niche.     

Characterization and evolutionary dynamics of complex regions in eukaryotic genomes

Complex regions in eukaryotic genomes are typically characterized by duplications of chromosomal stretches that often include one or more genes repeated in a tandem array or in relatively close proximity. Nevertheless, the repetitive nature of these regions,together with the often high sequence identity among repeats, have made complex regions particularly recalcitrant to proper molecular characterization, often being misassembled or completely absent in genome assemblies. This limitation has prevented accurate functional and evolutionary analyses of these regions. This is becoming increasingly relevant as evidence continues to support a central role for complex genomic regions in explaining human disease, developmental innovations, and ecological adaptations across phyla. With the advent of long-read sequencing technologies and suitable assemblers, the development of algorithms that can accommodate sample heterozygosity, and the adoption of a pangenomic-like view of these regions, accurate reconstructions of complex regions are now within reach. These reconstructions will finally allow for accurate functional and evolutionary studies of complex genomic regions, underlying the generation of genotype-phenotype maps of unprecedented resolution.     

Subwavelength Quarter-Waveplate Composed of L-Shaped Metal Nanoparticles

We propose a subwavelength quarter-waveplate composed of four L-shaped nanoparticles that act as optical nanoantennas and investigate its optical properties using the finite-difference time-domain method. When polarization of the incident beam is parallel to one arm of the antenna, polarization of the scattering light rotates 45° with respect to that of the incident beam due to the symmetry of the L-shaped nanoantennas. Phase retardation is generated by changing the arm length of the antennas. The influence of the distance between the L-shaped nanoantennas on the far-field radiation is also discussed.     

Lateral intermuscular septum of the thigh and short head of the biceps femoris muscle: an anatomic investigation with new clinical applications.

An anatomic study was performed to reappraise the vasculature of the lateral intermuscular septum of the thigh and muscles associated with it using 12 preserved cadaver legs. Several possible new clinical applications of the lateral intermuscular septum and the short head of the biceps femoris were identified as follows: (1) short head of biceps femoris muscle or musculoseptal flap based on the second and/or third profunda perforating vessels, or based on the superior lateral genicular vessels, with or without the iliotibial tract and the deep fascia, and with or without the motor nerve of the short head; (2) transverse extension of the fascial portion of the tensor fasciae latae muscle or musculocutaneous flap to include the lateral intermuscular septum; (3) combination use of items 1 and 2, above; and (4) free septofascial graft using the lateral intermuscular septum and iliotibial tract.It is anticipated that the distally based short head of the biceps femoris muscle flap will be an additional option for repairing defects around the knee, and that a free short head of the biceps femoris muscle flap based on the profunda femoris perforating vessels will be useful in functional reconstruction such as reanimation of the paralyzed face. The lateral intermuscular septum can be incorporated into the short head of biceps femoris muscle flap or into the tensor fasciae latae flap, and it also can be used as a free fascial graft. Functional deficit resulting from harvesting the short head of the biceps femoris and the lateral intermuscular septum is minimal, and donor wound at the lateral lower thigh seems to be acceptable.     

Concordance analysis in mitogenomic phylogenetics

Here I advocate the utility of Bayesian concordance analysis as a mechanism for exploring the magnitude and source of phylogenetic signal in concatenated mitogenomic phylogenetic studies. While typically applied to the study of independently evolving gene trees, Bayesian concordance analysis can also be applied to linked, but individually analyzed, gene regions using a prior probability that reflects the expectation of similar phylogenetic reconstructions. For true branches in the mitogenomic tree, concordance factors should represent the number of gene regions that contain phylogenetic signal for a particular clade. As a demonstration of the application of Bayesian concordance analysis to empirical data, I analyzed two different salamander (Hynobiidae and Plethodontidae) mitogenomic data sets using a gene-based partitioning strategy. The results revealed many strongly supported clades in the concatenated trees that have high concordance factors, permitting the inference that these are robustly resolved through phylogenetic signal distributed across the mitogenome. In contrast, a number of strongly supported clades in the concatenated tree received low concordance factors, indicating that their reconstruction is either driven primarily by phylogenetic signal in a small number of gene regions, or that they are inconsistent reconstructions influenced by properties of the data that can produce inaccurate trees (e.g., compositional bias, selection, etc.). Exploration of the Bayesian joint posterior distribution of trees highlighted partitions that contribute phylogenetic information to similar clade reconstructions. This approach was particularly insightful in the hynobiid data, where different combinations of genes were identified that support alternative tree reconstructions. Concatenated analysis of these different subsets of genes highlighted through Bayesian concordance analysis produced strongly supported and contrasting trees, demonstrating the potential for inconsistency in concatenated mitogenomic phylogenetics. The overall results presented here suggest that Bayesian concordance analysis can serve as an effective exploration of the influence of different gene regions in mitogenomic (and other organellar genomic) phylogenetic studies.     

Fission yeast Ags1 confers the essential septum strength needed for safe gradual cell abscission

Fungal cytokinesis requires the assembly of a dividing septum wall. In yeast, the septum has to be selectively digested during the critical cell separation process. Fission yeast cell wall α(1-3)glucan is essential, but nothing is known about its localization and function in the cell wall or about cooperation between the α- and β(1-3)glucan synthases Ags1 and Bgs for cell wall and septum assembly. Here, we generate a physiological Ags1-GFP variant and demonstrate a tight colocalization with Bgs1, suggesting a cooperation in the important early steps of septum construction. Moreover, we define the essential functions of α(1-3)glucan in septation and cell separation. We show that α(1-3)glucan is essential for both secondary septum formation and the primary septum structural strength needed to support the physical forces of the cell turgor pressure during cell separation. Consequently, the absence of Ags1 and therefore α(1-3)glucan generates a special and unique side-explosive cell separation due to an instantaneous primary septum tearing caused by the turgor pressure.