A transpositional skin flap for release of volar contractures of a finger at the MP joint.

We describe a finger flap which, in properly selected patients, and with careful planning of the incision design, has been useful for covering small defects over the volar aspects of the MP joint. The donor site can be closed without skin grafting.     

Autogenous vein graft repair of digital nerve defects in the finger: a retrospective clinical study

Twenty-two digital nerve repairs were performed in the finger using autogenous vein grafts. Eighty-two percent of the repairs were available for follow-up. Results of sensibility return were assessed using moving two-point discrimination, Semmes-Weinstein monofilaments, and vibratory testing. Two-point discrimination averaged 4.6 mm for 11 acute digital nerve repairs using vein conduits 1 to 3 cm in length. Delayed digital nerve repair with vein conduits yielded poor results. Semmes-Weinstein values demonstrated comparable levels of return of slowly adapting fiber/receptors to the quickly adapting fiber/receptors, as evidenced by moving two-point discrimination tests. Vibratory sensibility was present in all. A review of previous experiences with end-to-end digital neurorrhaphies and digital nerve grafting suggests that repair of 1- to 3-cm gaps in digital nerves with segments of autologous vein grafts appears to give comparable results to nerve grafting. Further laboratory and clinical research is necessary to better define the role of interpositional vein conduits for repair of peripheral nerves.     

Importance of the ribbon sign, indicating unsuitability of the vessel, in replanting a finger

A marked tortuosity of the digital arteries ("ribbon" sign) at the site of a digit amputation is a sign of a severe avulsion injury to the neurovascular bundles. When this finding is present, the artery should be resected and the gap bridged by a vein graft, if revascularization is attempted.     

A report from Australia: when a human life has not yet begun--according to the law

Victoria, Australia's Infertility (Medical Procedures) Act 1984, the first legislation to regulate reproductive technologies, permits research on surplus embryos fertilized in vitro but prohibits the creation of embryos for research purposes. The failure to define when an embryo has come into existence or when fertilization has occurred has prevented the continuation of potentially valuable research directed at overcoming infertility. The Standing Review and Advisory Committee on Infertility must now consider the debate over when fertilization occurs, an event that is no longer regarded as a discrete or instantaneous act but as a process revealing no clear point at which a human individual begins to exist. Because the law requires a clear line of demarcation, any legislation in this area will face the problem of defining this point. Interpretation of a 1987 amendment to the 1984 Act may allow the fertilization of ova for purposes other than implantation.     

Standardizing digital photography: it's not all in the eye of the beholder

Advances in digital photography have made it an efficient and economically appealing alternative to conventional photography. Nevertheless, as objective observers and clinical photographers, we must realize that all digital cameras are not created equal. Different digital cameras frequently used in plastic surgery practices (Olympus 600DL, Olympus 2500, Sony DSC-D700, Nikon Coolpix 950, and Nikon D1) were evaluated, using a subject photographed with each camera in the identical lighting conditions, to determine inherent differences in quality, color, and contrast of the resultant photographs. Three different lighting conditions were examined: single soft-box lighting, dual studio flash boxes, and operating room lighting with on-camera flash. The same digital settings (program mode, ISO camera default setting, high quality setting with JPEG compression) were used. Each camera was digitally color balanced using an 18 percent gray card. Raw and color-balanced images were viewed side-by-side. The macro-image capabilities of each camera were also examined. Conventional 35-mm photographs using a 105 macro-lens on Kodachrome and Ektachrome slide film were obtained for comparison. All of the digital cameras performed with noticeable differences, but they maintained consistency in the three different lighting conditions. Digital photographs differed most greatly with respect to quality and contrast, which was especially obvious once color balancing was performed. Marked differences in quality and ability were observed with respect to macro-image capabilities. Inherent differences in features among digital cameras produce dramatically different photographic results with regard to color, contrast, focus, and overall quality. With the increasing use of digital photography in plastic surgery journals and presentations, it must be recognized that digital cameras do not all display photographs of similar quality, especially when used to evaluate skin appearance. To standardize digital photography, the surgeon must realize that switching digital cameras is akin to switching film types. Standardization of digital photographs should include image resolution between 1.5 and 2.7 million pixels, ISO default setting, color balancing with an 18 percent gray card and software, consistency in focal distance, JPEG compression of medium-to-high quality, and backgrounds of medium blue or 18 percent gray.     

S-flap: a method for reconstruction of sensibility on the finger pulp

A two-staged procedure for reconstruction of sensibility on the critically important areas of the finger pulp is described. Sensation on the radial side of the index finger was reestablished by this method in five patients. Two of the patients regained normal sensation and three almost normal sensation on the contact area for pinch grip. The disadvantages of this operation are scars and some deformity of the natural contour of the pulp.     

Asymmetry in host and parasitoid diffuse coevolution: when the red queen has to keep a finger in more than one pie

BACKGROUND: Coevolution between pairs of antagonistic species is generally considered an endless "arms race" between attack and defense traits to counteract the adaptive responses of the other species. PRESENTATION OF THE HYPOTHESIS: When more than two species are involved, diffuse coevolution of hosts and parasitoids could be asymmetric because consumers can choose their prey whereas preys do not choose their predator. This asymmetry may lead to differences in the rate of evolution of the antagonistic species in response to selection. The more long-standing the coevolution of a given pair of antagonistic populations, the higher should be the fitness advantage for the consumer. Therefore, the main prediction of the hypothesis is that the consumer trophic level is more likely to win the coevolution race. TESTING THE HYPOTHESIS: We propose testing the asymmetry hypothesis by focusing on the tritrophic system plant/aphid/aphid parasitoid. The analysis of the genetic variability in the virulence of several parasitoid populations and in the defenses of several aphid species or several clones of the same aphid species could be compared. Moreover, the analysis of the neutral population genetic structure of the parasitoid as a function of the aphid host, the plant host and geographic isolation may complement the detection of differences between host and parasitoid trophic specialization. IMPLICATIONS OF THE HYPOTHESIS: Genetic structures induced by the arms race between antagonistic species may be disturbed by asymmetry in coevolution, producing neither rare genotype advantages nor coevolutionary hotspots. Thus this hypothesis profoundly changes our understanding of coevolution and may have important implications in terms of pest management.     

A comprehensive review of epinephrine in the finger: to do or not to do.

The prohibition against the use of local anesthetics with epinephrine for digital blocks or infiltration is an established surgical tradition. The present article provides a comprehensive review of all reported digital necrotic and ischemic complications with epinephrine in the digits in an effort to understand whether the current prohibition is based on documented reports. A comprehensive review of articles showing the successful use of local anesthetic with epinephrine in the digits is presented.A review of Index Medicus from 1880 to 1966 and a computer review of the National Library of Medicine database from 1966 to 2000 were performed using multiple keywords. Selected major textbooks from 1900 to 2000 were also reviewed.A total of 48 cases of digital gangrene after anesthetic blocks (mostly using cocaine or procaine) have been reported in the world literature. Only 21 cases involved the use of epinephrine; 17 involved an unknown concentration based on manual dilution. Multiple other concurrent conditions (hot soaks, tight tourniquets, and infection) existed in these case reports, making it difficult to determine the exact cause of the tissue insult. There have been no case reports of digital gangrene using commercial lidocaine with epinephrine (introduced in 1948). Multiple studies involving thousands of patients support the premise that the use of lidocaine with epinephrine is safe in the digits.An extensive literature review failed to provide consistent evidence that our current preparations of local anesthesia with epinephrine cause digital necrosis, although not all complications are necessarily reported. However, as with all techniques, caution is necessary to balance the risks of this technique with the dangers of mechanical tourniquets and upper extremity block anesthesia.     

Importance of a flanking AT-rich region in target site recognition by the GC box-binding zinc finger protein MIG1.

MIG1 is a zinc finger protein that mediates glucose repression in the yeast Saccharomyces cerevisiae. MIG1 is related to the mammalian Krox/Egr, Wilms' tumor, and Sp1 finger proteins. It has two fingers and binds to a GCGGGG motif that resembles the GC boxes recognized by these mammalian proteins. We have performed a complete saturation mutagenesis of a natural MIG1 site in order to elucidate its binding specificity. We found that only three mutations within the GC box retain the ability to bind MIG1: G1 to C, C2 to T, and G5 to A. This result is consistent with current models for zinc finger-DNA binding, which assume that the sequence specificity is determined by base triplet recognition within the GC box. Surprisingly, we found that an AT-rich region 5' to the GC box also is important for MIG1 binding. This AT box is present in all natural MIG1 sites, and it is protected by MIG1 in DNase I footprints. However, the AT box differs from the GC box in that no single base within it is essential for binding. Instead, the AT-rich nature of this sequence seems to be crucial. The fact that AT-rich sequences are known to increase DNA flexibility prompted us to test whether MIG1 bends DNA. We found that binding of MIG1 is associated with bending within the AT box. We conclude that DNA binding by a simple zinc finger protein such as MIG1 can involve both recognition of the GC box and flanking sequence preferences that may reflect local DNA bendability.     

The importance of assessing parameter sensitivity when using biophysical models: a case study using plethodontid salamanders

Landscapes are continually changing due to numerous assaults, including habitat alteration, anthropogenic disturbances, and climate change. Understanding how species will respond to these changes is of critical importance for conservation and management. Mechanistic models, such as biophysical models (BPMs), are an increasingly popular tool to predict how local population dynamics or species’ distributions may be altered in response to environmental and climate changes. By mechanistically modeling relationships between environmental conditions, physiology and behavior, it is possible to make accurate predictions about how species may respond. However, BPMs are often difficult to implement due to lack of appropriate, species-specific data that is biologically realistic or relevant. In this study, we present a BPM for the salamander Plethodon jordani and assess how adding more biological realism has potential to alter model predictions about annual energy budgets. Additionally, we conducted local and global sensitivity analyses to evaluate the importance of accurately specifying model parameter values and functional relationships. We found that the addition of biological realism resulted in greater model complexity as well as substantially different estimates of energy balance. Correct parameterization of biophysical models is also critical, as small changes in parameter values can result in disproportionately large changes in downstream model estimates. Our model highlights the overall importance of using ecologically relevant and specific data for input parameters, as well as careful assessment of parameter sensitivity. We encourage researchers to be aware of the data they are using to parameterize BPMs, and urge the collection of system-specific data that is relevant in spatial and temporal scale. We also recommend greater and more transparent use of sensitivity analyses to provide a better understanding of the model, as well as greater confidence in model predictions.