The use of Teflon in orbital floor reconstruction following blunt facial trauma: a 20-year experience

A myriad of materials have been used for reestablishing continuity of the orbital floor following blunt facial trauma. Traditionally, autogenous grafts have been the material of choice for orbital floor reconstruction; however, alloplastic materials have gained popularity because of their availability and ease of use. A large clinical experience with long-term treatment results has never been reported for any substance used in orbital floor reconstruction. The purpose of this study was to review our long-term treatment results using Teflon for orbital floor reconstruction following blunt trauma, with emphasis on the incidence of infection, extrusion, and implant displacement. This report presents a 20-year review of 230 Teflon implants for reconstruction of traumatic orbital floor defects. With a mean follow-up period of 30 months, there was only one implant infection and no complications of extrusion or implant displacement. These findings support the use of Teflon as a safe and effective material for the reconstruction of orbital floor defects following blunt facial trauma.     

Autologous fat graft in nipple reconstruction

Reconstruction of the nipple is the penultimate step in breast reconstruction after mastectomy. A number of reconstructive techniques have been described for nipple reconstruction including skin grafts, composite grafts, and various local flaps. The authors' preferred reconstructive technique is the local C-V or modified star flap. This flap produces an excellent reconstruction, but it is dependent on underlying subcutaneous fat to provide bulk to the reconstructed nipple. In most instances, the subcutaneous tissue is adequate. However, under certain circumstances, the subcutaneous fat may be insufficient to produce a nipple of adequate projection. Two cases of bilateral nipple reconstruction after soft-tissue expansion and implant placement and subsequent nipple reconstruction with local flaps provided inadequate nipple projection. These instances, as well as a retrospective review of reconstructed nipples after mound restoration using a variety of techniques, led the authors to conclude that a more predictable alternative to sustain nipple projection was necessary. The authors identified two broad categories of breast reconstruction patients in whom this new technique would be beneficial. In the first category of patients, breast mounds are reconstructed with tissue expansion and implant insertion, and in the second category, breast mounds are reconstructed by any technique in which the nipple reconstruction subsequently flattens. This article describes the indications, techniques, and experience in 13 patients treated over a 10-month period with fat grafting for nipple reconstruction.     

Image analysis reveals that Escherichia coli RecA protein consists of two domains.

The Escherichia coli RecA protein catalyzes homologous genetic recombination by forming helical polymers around DNA molecules. These polymers have an ATPase activity, which is essential for the movement of strands between two DNA molecules. One obstacle to structural studies of the RecA filament has been that the ATPase results in a dynamical polymer containing a mixture of states with respect to the bound ATP and its hydrolytic products. We have formed filaments which are trapped in the ADP-Pi state by substituting AIF4- for the Pi, and have used these stable filaments to generate a three-dimensional reconstruction from electron micrographs. The resolution of the reconstruction is sufficient to resolve the 38-k RecA subunit into two nearly equal domains. This reconstruction provides the most detailed view yet of the RecA protein, and serves as a framework within which existing biochemical data on RecA can be understood.     

Breast reconstruction with the DIEP flap or the muscle-sparing (MS-2) free TRAM flap: is there a difference?

The advantages of breast reconstruction using the deep inferior epigastric perforator (DIEP) flap and the muscle-sparing free transverse rectus abdominis musculocutaneous (TRAM) flap (MS-2) are well recognized. Both techniques optimize abdominal function by maintaining the vascularity, innervation, and continuity of the rectus abdominis muscle. The purpose of this study was to compare these two methods of breast reconstruction and determine whether there is a difference in outcome. The study considered 177 women who have had breast reconstruction using muscle-sparing flaps over a 4-year period. This includes 89 women who had an MS-2 free TRAM flap procedure, of which 65 were unilateral and 24 were bilateral, and 88 women who had a DIEP flap procedure, of which 66 were unilateral and 22 were bilateral. The total number of flaps was 223. Mean follow-up was 23 months (range, 3 to 49 months). For all MS-2 free TRAM flaps (n = 113), outcome included fat necrosis in eight (7.1 percent), venous congestion in three (2.7 percent), and total necrosis in two (1.8 percent). For the women who had an MS-2 free TRAM flap, an abdominal bulge occurred in three women (4.6 percent) after unilateral reconstruction and in five women (21 percent) after bilateral reconstruction. The ability to perform sit-ups was noted in 63 women (97 percent) after unilateral reconstruction and 20 women (83 percent) after bilateral reconstruction. For all DIEP flaps (n = 110), outcome included fat necrosis in seven (6.4 percent), venous congestion in five (4.5 percent), and total necrosis in three (2.7 percent) patients. For the women who had DIEP flap reconstruction, an abdominal bulge occurred in one woman (1.5 percent) after unilateral reconstruction and in one woman (4.5 percent) after bilateral reconstruction. The ability to perform sit-ups was noted in all women after unilateral reconstruction and in 21 women (95 percent) after bilateral reconstruction. These results demonstrate that there are no significant differences in fat necrosis, venous congestion, or flap necrosis after DIEP or MS-2 free TRAM flap reconstruction. The percentage of women who are able to perform sit-ups and the percentage of women who did not develop a postoperative abdominal bulge is increased after DIEP flap reconstruction; however, this difference is not statistically significant.     

Free microvascular muscle flaps with skin graft reconstruction of extensive defects of the foot: a clinical and gait analysis study

Over the past 4 years at the Massachusetts General Hospital 18 patients have been treated for extensive defects (mean size 130 cm2) of the foot at or below the medial and lateral malleoli. These patients have been treated with free muscle flaps covered with thick split-thickness skin grafts. Full muscle flap survival has been seen in each patient, and all patients are currently ambulatory. A subgroup of nine patients are weight-bearing directly upon their skin grafts covering transferred muscle. All patients are walking without chronic breakdown over a mean follow-up of over 19 months with the exception of a single patient who has had breakdown in a region of redundant improperly tailored muscle flap. None of the skin grafted muscles has significant cutaneous sensibility. Detailed gait analysis of these patients has confirmed the weight-bearing capabilities of free muscle flaps with skin grafts and has proven to be an excellent method of foot reconstruction evaluation. It would appear from this study that cutaneous sensibility may not be necessary for successful reconstruction of the weight-bearing surface of the foot. This method of reconstruction should be considered when local tissues are not suitable for plantar foot reconstruction.     

Reconstructing patterns of reticulate evolution in plants

Until recently, rigorously reconstructing the many hybrid speciation events in plants has not been practical because of the limited number of molecular markers available for plant phylogenetic reconstruction and the lack of good, biologically based methods for inferring reticulation (network) events. This situation should change rapidly with the development of multiple nuclear markers for phylogenetic reconstruction and new methods for reconstructing reticulate evolution. These developments will necessitate a much greater incorporation of population genetics into phylogenetic reconstruction than has been common. Population genetic events such as gene duplication coupled with lineage sorting and meiotic and sexual recombination have always had the potential to affect phylogenetic inference. For tree reconstruction, these problems are usually minimized by using uniparental markers and nuclear markers that undergo rapid concerted evolution. Because reconstruction of reticulate speciation events will require nuclear markers that lack these characteristics, effects of population genetics on phylogenetic inference will need to be addressed directly. Current models and methods that allow hybrid speciation to be detected and reconstructed are discussed, with a focus on how lineage sorting and meiotic and sexual recombination affect network reconstruction. Approaches that would allow inference of phylogenetic networks in their presence are suggested.     

Breast augmentation with bilateral deepithelialized TRAM flaps: an alternative approach to breast augmentation with autologous tissue

Since the 1980s, many patients have benefited from the use of the transverse rectus abdominis musculocutaneous (TRAM) flap for postmastectomy reconstruction. In addition to cancer reconstruction, this technique has recently been used to treat patients with breast implant intolerance and for reconstruction after siliconoma resection. However, physicians and patients alike believe that such an extensive procedure should not be used for aesthetic purposes, and to the authors' knowledge, no study has been reported on the use of pedicled TRAM flaps for aesthetic augmentation mammaplasty. In the past several years, a number of the authors' patients have requested simultaneous breast augmentation and abdominoplasty. These patients objected to the use of prosthetic implants because of potential complications such as implant failure, capsular contracture, wrinkling, and palpability. Therefore, from 1995 to 2000, the authors performed 14 cases of bilateral breast augmentation with deepithelialized, pedicled TRAM flaps. In this series, the donor-site complication rate was similar to that of the traditional TRAM flap. Surprisingly, no cases of complete or partial flap loss were clinically detected. The only complaints were pedicle bulges at the costal margins. These patients were all extremely satisfied with the results. It was concluded that the TRAM flap is safe for augmentation in a subset of carefully selected women with hypoplastic or atrophic breasts. The authors discuss patient selection, technique, and their experience with this method of breast augmentation.     

The effects of femoral graft placement on cartilage thickness after anterior cruciate ligament reconstruction

Altered joint motion has been thought to be a contributing factor in the long-term development of osteoarthritis after ACL reconstruction. While many studies have quantified knee kinematics after ACL injury and reconstruction, there is limited in vivo data characterizing the effects of altered knee motion on cartilage thickness distributions. Thus, the objective of this study was to compare cartilage thickness distributions in two groups of patients with ACL reconstruction: one group in which subjects received a non-anatomic reconstruction that resulted in abnormal joint motion and another group in which subjects received an anatomically placed graft that more closely restored normal knee motion. Ten patients with anatomic graft placement (mean follow-up: 20 months) and 12 patients with non-anatomic graft placement (mean follow-up: 18 months) were scanned using high-resolution MR imaging. These images were used to generate 3D mesh models of both knees of each patient. The operative and contralateral knee models were registered to each other and a grid sampling system was used to make site-specific comparisons of cartilage thickness. Patients in the non-anatomic graft placement group demonstrated a significant decrease in cartilage thickness along the medial intercondylar notch in the operative knee relative to the intact knee (8%). In the anatomic graft placement group, no significant changes were observed. These findings suggest that restoring normal knee motion after ACL injury may help to slow the progression of degeneration. Therefore, graft placement may have important implications on the development of osteoarthritis after ACL reconstruction.     

Single particle macromolecular structure determination via electron microscopy

Three-dimensional structure determination of macromolecules and macromolecular complexes is an integral part of understanding biological functions. For large protein and macromolecular complexes structure determination is often performed using electron cryomicroscopy where projection images of individual macromolecular complexes are combined to produce a three-dimensional reconstruction. Single particle methods have been devised to perform this structure determination for macromolecular complexes with little or no underlying symmetry. These computational methods generally involve an iterative process of aligning unique views of the macromolecular images followed by determination of the angular components that define those views. In this review, this structure determination process is described with the aim of clarifying a seemingly complex structural method.     

What is in the black box? – A perspective on software in cryoelectron microscopy

This article bemoans the demise of truly modular open-source image processing systems, such as SPIDER, in recent years’ development of tools for three-dimensional reconstruction in cryo-electron microscopy. Instead, today’s users have to rely on the functionality of software systems that have little or no transparency. As a consequence, users of such packages no longer gain a conceptual understanding and intuitive grasp of the analytical routes leading from the stream of input data to the final density map. Possible remedies of this situation with free software are discussed.     

A signal-to-noise analysis of phylogeny estimation by neighbor-joining: Insufficiency of polynomial length sequences

Phylogeny reconstruction is the process of inferring evolutionary relationships from molecular sequences, and methods that are expected to accurately reconstruct trees from sequences of reasonable length are highly desirable. To formalize this concept, the property of fast-convergence has been introduced to describe phylogeny reconstruction methods that, with high probability, recover the true tree from sequences that grow polynomially in the number of taxa n. While provably fast-converging methods have been developed, the neighbor-joining (NJ) algorithm of Saitou and Nei remains one of the most popular methods used in practice. This algorithm is known to converge for sequences that are exponential in n, but no lower bound for its convergence rate has been established. To address this theoretical question, we analyze the performance of the NJ algorithm on a type of phylogeny known as a 'caterpillar tree'. We find that, for sequences of polynomial length in the number of taxa n, the variability of the NJ criterion is sufficiently high that the algorithm is likely to fail even in the first step of the phylogeny reconstruction process, regardless of the degree of polynomial considered. This result demonstrates that, for general n-taxa trees, the exponential bound cannot be improved.     

Modern and fossil non-pollen palynomorphs from the Basque mountains (western Pyrenees, France): the use of coprophilous fungi to reconstruct pastoral activity

This paper presents results from a modern dataset of non-pollen palynomorphs and its application to a ca. 2,000 year peat record from the same area in the western Pyrenees (Basque Country, France). The modern dataset is composed of 35 surface samples (moss polsters) from a mountainous pasture-woodland landscape. Airborne fungal spores (ascospores and conidia), found dominant in the dataset, are linked to the degree of landscape openness and grazing pressure. The complete spectrum of 13 selected spore-types of dung-related Ascomycetes is positively linked with grazing pressure. However, different dung affinities between the spore-types have been identified. These are types clearly related to high grazing pressure and types with no or unclear dung indicative value. The modern dataset is used to aid interpretation of the local fossil pollen record as an independent ‘proxy’ to assess past pastoral dynamics. This study confirms the utility of modern non-pollen palynomorphs from terrestrial ecosystems in the reconstruction of historical local pastoral activities but also shows their limitation. It may be necessary to extend such study to wetland ecosystems and to investigate the spatial dimension of some fungal spores.     

Gene flow between species of Lake Victoria haplochromine fishes

The haplochromine cichlid fishes of Lake Victoria (LV), East Africa, are a textbook example of adaptive radiation-a rapid divergence of multiple morphologically distinguishable forms from a few founding lineages. The forms are generally believed to constitute a "flock" of several hundred reproductively isolated species in a dozen or so genera. This belief has, until now, not been subjected to a test, however. Here, we compare genetic variation at 11 loci in 10 haplochromine populations of 6 different species. Although the genetic diversity in the populations is quite high, using a variety of statistical tests, we find no evidence of genetic differentiation among the populations of LV haplochromines. On genetic distance trees, populations of the same species intermingle with those of different species. At the molecular level, the species are indistinguishable from one another. Genetic comparisons with closely related species in 2 crater lakes indicate that the species within LV continue exchanging genes. These observations have important implications for phylogenetic reconstruction. The approach used in this study is applicable to other instances of adaptive radiation.     

Immediate free TRAM reconstruction in lumpectomy and radiation failure patients

Local recurrence after lumpectomy and radiation therapy indicates failed breast conservation surgery. These patients often proceed to mastectomy and are candidates for autogenous breast reconstruction. Free transverse rectus abdominus muscle (TRAM) reconstruction in these patients is complicated by repeated axillary dissection and the use of irradiated tissue. Complication rates for pedicled TRAMs have been reported at 33 percent when used in irradiated tissue beds. We report our results using the free TRAM for breast reconstruction after lumpectomy and radiation failure. All patients within this study developed a local recurrence after lumpectomy and radiation therapy. All patients had undergone axillary dissection for staging at the time of their lumpectomy. Patient records were reviewed for patient age, total radiation dose, associated risk factors for TRAM failure, operative time, donor vessels used for anastomosis, status of the native thoracodorsal vessels at the time of surgery, and postoperative complications. Over a 7-year period, 16 TRAM patients had undergone previous breast conservation surgery. Of these 16 patients, 14 underwent reconstruction with a planned free TRAM after simple mastectomy. Average operating room time was 7 hours. There were no partial or total flap losses. Complications were seen in 14 percent of the overall group. Overall, we found that the free TRAM provided an excellent aesthetic result with a lower complication rate than previously reported for pedicled TRAM flaps in irradiated beds. The thoracodorsal vessels provided an adequate donor vessel in 93 percent of the cases. The free TRAM provides a superior alternative in immediate reconstruction in patients who have failed breast conservative surgery.     

New insights into the phylogenetic relationships among the oceanic dolphins (Cetacea: Delphinidae)

The phylogenetic relationships of oceanic dolphins (family Delphinidae) remain unclear. Several works using mitochondrial and/or nuclear DNA on different genera and species have been published, though no consensus exists regarding even the subfamilies that conform the family. Here, a new phylogeny for the family Delphinidae, including 36 different complete mitochondrial genomes (plus two outgroups), was constructed under Bayesian and maximum likelihood approaches. Results indicate identical tree topology in both cases, with almost all nodes fully supported independently of the reconstruction approach. This topology is different from those previously published and proposes new phylogenetic relationships among subfamilies, genera and species of the family. These findings are critically important for the study of oceanic dolphin taxonomy, ecology, evolution and conservation, and highlight the importance of revisiting and resolving uncertain phylogenies.     

Composite reconstruction for chest wall and scalp using multiple ribs-latissimus dorsi osteomyocutaneous flaps as pedicled and free flaps

A composite flap is presented based on the latissimus dorsi myocutaneous unit together with the underlying ninth to eleventh ribs. Three patients are presented. In two, a full-thickness chest-wall defect was present. In one, a full-thickness scalp and cranial defect was present. Use of the composite osteomyocutaneous latissimus dorsi free flap as a pedicled flap in two patients and as a free flap in one patient resulted in successful definitive reconstruction in all with no complications. This procedure necessitates no transplantation of soft tissue prior to bone grafting to maintain local vascularity, so the simultaneous one-stage reconstruction of an osseous-soft-tissue defect becomes possible easily.     

Free vascularized appendix transfer for reconstruction of penile urethras with severe fibrosis

Despite the development of newer techniques with a free radial forearm tube flaps for phallus reconstruction, severe urethral strictures are still seen in such cases after irradiation or repeated infection because of the paucity of healthy, well-vascularized tissue. For urethral reconstruction in cases with poorly vascularized tissue as well as for total penile creation, a new technique involving a free vascularized appendix transfer combined with a radial forearm osteocutaneous flap was successfully used in two cases. The appendix provides a normal tube structure composed of a muscular tubular layer lined with mucosal epithelium. It has no hair and has rich vascularization. This results in little stricture at the junction with the original urethra, no occurrence of urethral stones, and possible postoperative enlargement of the diameter with changes in catheters. This method will allow a patient with severe fibrosis around the urethra to undergo one-stage phallus reconstruction with minimal complications.     

三维技术在古昆虫复原图制作中的应用

本文简单介绍了Autodesk Maya等软件以及利用三维技术制作古昆虫复原图所涉及到的三大方面知识,包括:三维昆虫制作、场景设计和艺术气氛。较为详细的介绍了利用三维软件制作昆虫的主要步骤。总结了在制作复原图时,将生物学、计算机技术、美术学三方面知识相结合的经验和技巧。为三维技术在古昆虫学研究工作中的推广和使用提供了更多思路。     

A Danish Photographer of Idaho Indians

New advances in spatial technology enable ethnographic data and Geographic Information Systems (GIS) to be integrated in innovative ways. These include mapping and virtual reconstruction of buildings no longer standing, of routes used for transportation and hunting, and other spatial ethnographic data, visualized in three dimensions (3D). Representation in 3D allows for a more complete understanding of landscape relationships, and can be used as a learning tool to convey information quickly. This article applies these techniques to the reconstruction of the now-abandoned village of Belkofski, Alaska, for presentation in a video ethnography produced by the Aleutian Pribilof Island Association in coordination with the Belkofski Tribe.