Mandibular distraction in temporomandibular joint ankylosis

Condylar damage during childhood can produce ankylosis and alteration of the mandibular growth. In case of unilateral ankylosis occurring in early childhood, a mandibular hypoplasia of the affected side may develop. The patients have limitation of mouth opening, facial asymmetry, and chin deviation toward the affected side. The aims of this study are to show the use of distraction osteogenesis in mandibular hypoplasia associated with ankylosis and to present our experience with a new therapeutic option for the treatment of mandibular hypoplasia with unilateral ankylosis in the childhood consisting of the association of arthroplasty to treat the ankylosis and mandibular distraction to correct the facial asymmetry, both accomplished in the same surgical procedure. From November of 1996 to November of 1997, three male patients aged 2, 7, and 13 years with mandibular hypoplasia and ankylosis were treated by distraction osteogenesis. An arthroplasty consisting of the resection of the ankylotic block and interposition of a temporalis muscle flap, plus coronoidectomy was done in two of them and mandibular distraction was done in all three patients. Articular functional rehabilitation began on the first postoperative day. Mandibular distraction began on the fifth postoperative day with a rate of 1 mm per day, ending when the facial symmetry was achieved. From the first postoperative day, an increase in the mouth opening was achieved; this increase continued until ending the distraction. The average duration of distraction was 22 days. Average duration of consolidation was 6 weeks. Oral opening increased from 10 mm to 35 mm in the 7-year-old patient, from 9 mm to 27 mm in the 2-year-old patient, and from 14 mm to 38 mm in the 13-year-old patient. To date, oral opening and facial symmetry persist. Osseous mandibular distraction together with arthroplasty offers an excellent new alternative for treatment of patients with mandibular hypoplasia and associated ankylosis, with minimal morbidity and complications.     

Mandibular distraction osteogenesis in very young patients to correct airway obstruction

The purpose of this study was to measure changes in the airway cross-sectional area of pediatric patients with micrognathia and obstructive airway symptoms after treatment by mandibular distraction. The measurements obtained were correlated with the clinical outcomes.Ten patients, ranging in age from 3 months to 8 years, underwent measurement and distraction. Eight patients were under 30 months of age. Six were diagnosed with Pierre Robin sequence, two with Treacher Collins syndrome, and two with Nager syndrome. All patients had retrognathia of greater than 8 mm and obstructive airway symptoms while awake that had resulted in tracheostomy (3), repeated apnea monitor triggering (5), or abnormal sleep study (2). Cephalometric analysis was performed pretreatment and posttreatment by distraction. The effective airway space was defined with the following boundaries: a horizontal line from the tip of the odontoid to the velum, the uvula tip to the tongue base along the shortest line, the tongue base down to the base of the epiglottis, and the horizontal line to the posterior pharynx. These lines were traced for each cephalogram, the outline was digitized, and the area was calculated by computer. An analysis of the square area change was done by paired t test. The range of distraction was 8 to 22 mm; the mean effective airway increase was 67.5 percent, with a range of 26 to 120 percent. Measurable airway increase occurred in all patients who underwent distraction, and all patients showed clinical improvement. Six patients with Pierre Robin sequence became asymptomatic, with normal sleep, feeding, and weight gain. Two patients with Nager syndrome and tracheostomies were decannulated and were asymptomatic postdistraction. One patient with Treacher Collins syndrome without tracheostomy became asymptomatic after mandibular distraction; one patient failed to distract because of premature consolidation and continued to require a cannula.Mandibular distraction seems to provide a consistent change in tongue base position that improves obstructive airway symptoms by increasing measured effective airway space. The potential for mandibular distraction exceeds the simple correction of malocclusion also by eliminating soft-tissue obstruction of the micrognathic airway. Airway improvement is independent of the syndrome diagnosed. Mandibular distraction osteogenesis may be useful to avoid or decannulate existing tracheostomy in infants with micrognathia.     

Protein engineering as a strategy to avoid formation of amyloid fibrils

The activation domain of human procarboxypeptidase A2 (ADA2h) aggregates following thermal or chemical denaturation at acidic pH. The aggregated material contains well-defined ordered structures with all the characteristics of the fibrils associated with amyloidotic diseases. Variants of ADA2h containing a series of mutations designed to increase the local stability of each of the two helical regions of the protein have been found to have a substantially reduced propensity to form fibrils. This arises from a reduced tendency of the denatured species to aggregate rather than from a change in the overall stability of the native state. The reduction in aggregation propensity may result from an increase in the stability of local relative to longer range interactions within the polypeptide chain. These findings show that the intrinsic ability of a protein to form amyloid can be altered substantially by protein engineering methods without perturbing significantly its overall stability or activity. This suggests new strategies for combating diseases associated with the formation of aggregated proteins and for the design of novel protein or peptide therapeutics.     

When to copy or avoid an opponent's strategy

Models of two-player games are analyzed in which contestants strive to maximize relative success (market share). Each contestant divides its resources among a set of investment strategies. For a particular investment strategy the contestants may receive different expected rates of return. Each strategy also returns to both contestants an additional payoff that is unpredictable. Depending on particular assumptions, a contestant may maximize relative success by copying or avoiding its opponent's allocation pattern. In other cases a contestant may be favored to diversify its investments equally among strategies and minimize its total variance in returns, or to invest only in one strategy and maximize its total variance in returns.     

Mandibular distraction osteogenesis in Pierre Robin sequence: application of a new internal single-stage resorbable device

Pierre Robin sequence may result in physiologically significant obstructive apnea in the neonatal and infant period. This may be life threatening and is most often treated by tracheostomy. To avoid tracheostomy or allow for early decannulation in severely affected infants and children, the authors have developed a new class of neonatal and infant mandibular bone distraction devices. These devices require a single operative procedure for placement and no operative removal is necessary. Fifteen infants (aged 7 days to 11 months; mean age, 3 months) and five children (aged 2 to 8 years; mean age, 5.5 years), 10 boys and 10 girls, with severe obstructive apnea and Pierre Robin sequence were treated with the mandibular infant devices over a 24-month period. Tracheostomy was avoided in 14 patients, whereas five of six patients who had previous tracheostomy were decannulated after mandibular distraction. The final tracheostomy status in one patient will be determined after surgery for gastroesophageal reflux. There were no major complications and no structural device failures.     

Extended culture up to the blastocyst stage: a strategy to avoid multiple pregnancies in assisted reproductive technologies

The aim of this study was to review the experience and outcomes of assisted reproduction cycles with embryos grown up to day 5 of development, comparing different parameters according to the ages of the patients. We retrospectively studied 1,874 assisted reproduction cycles where embryo culture was extended up to the fifth or sixth day of development. All IVF and ICSI cycles were included, comparing, according to patient age, the following rates: blastocyst formation, pregnancy, implantation and abortion. As control, we analyzed cycles with donated oocytes from young donors (OD). The number of embryos reaching the blastocyst stage is similar in all groups of patients. Only the OD group was different in terms of blastocyst formation, pregnancy and implantation rates. Patients over 39 years of age had an abortion rate of 59.1 %, which is significantly higher than the other groups. Extended embryo culture up to the blastocyst stage can be implemented in programs of assisted reproduction in order to increase the pregnancy rate. The potential of blastocyst implantation is high, allowing us to transfer fewer embryos and reduce the probability of multiple pregnancies.     

Recruitment of the major vault protein by InlK: a Listeria monocytogenes strategy to avoid autophagy

L. monocytogenes is a facultative intracellular bacterium responsible for listeriosis. It is able to invade, survive and replicate in phagocytic and non-phagocytic cells. The infectious process at the cellular level has been extensively studied and many virulence factors have been identified. Yet, the role of InlK, a member of the internalin family specific to L. monocytogenes, remains unknown. Here, we first show using deletion analysis and in vivo infection, that InlK is a bona fide virulence factor, poorly expressed in vitro and well expressed in vivo, and that it is anchored to the bacterial surface by sortase A. We then demonstrate by a yeast two hybrid screen using InlK as a bait, validated by pulldown experiments and immunofluorescence analysis that intracytosolic bacteria via an interaction with the protein InlK interact with the Major Vault Protein (MVP), the main component of cytoplasmic ribonucleoproteic particules named vaults. Although vaults have been implicated in several cellular processes, their role has remained elusive. Our analysis demonstrates that MVP recruitment disguises intracytosolic bacteria from autophagic recognition, leading to an increased survival rate of InlK over-expressing bacteria compared to InlK(-) bacteria. Together these results reveal that MVP is hijacked by L. monocytogenes in order to counteract the autophagy process, a finding that could have major implications in deciphering the cellular role of vault particles.     

Mandibular growth after distraction in patients under 48 months of age

Distraction osteogenesis is an effective technique for reconstruction of the congenitally deficient mandible. However, the age at which it is best performed remains under discussion. Distraction performed at an early age, while possibly allowing the face to develop with a more normal functional matrix, may entail a higher rate of complications. Additionally, it is possible that subsequent asymmetric growth of the mandible may necessitate serial distraction. To address this issue, the clinical records and cephalometric radiographs of all patients less than 48 months of age undergoing mandibular distraction at New York University Medical Center between August of 1989 and August of 1997 were examined. There was a total of 14 patients ranging in age from 19 months to 43 months. Nine patients had a diagnosis of unilateral craniofacial microsomia, three had Treacher Collins syndrome, one had Nager syndrome, and one had bilateral developmental micrognathia. The average amount of distraction was 27 mm (range, 23 to 39 mm) in unilateral cases and 24 mm in bilateral cases (range, 15 to 31 mm). The period of clinical follow-up averaged 32.6 months (range, 12 to 92 months). All patients showed significant improvement in craniofacial appearance, and in four patients, long-term tracheostomy tubes were removed. There were two major complications. In one patient with craniofacial microsomia, there was a relapse in the early postretention phase related to the presence of a dentigerous cyst. This required removal of the cyst and repeat distraction. In the patient with Nager syndrome, a coronoid ankylosis developed requiring surgical release. There were no other major complications. The scars required revision in only two of the patients. Cephalometric analysis of the patients in the study revealed a differential in the rate of growth between the affected and the unaffected side in all cases of craniofacial microsomia. The affected side always grew at a slower rate than the contralateral side after the distraction process was complete. This led to a progressive asymmetry of the rami, clinically expressed by some degree of facial asymmetry and an occlusal cant. For this reason, secondary distraction was required in one patient and is planned in a second. Initial overcorrection of the patient would seem to minimize the likelihood that secondary distraction will be necessary. Distraction osteogenesis for reconstruction of the mandible in this subset of young patients was a safe and effective technique for improving the craniofacial skeletal form and appearance, with minimal associated morbidity. Longer follow-up is necessary to assess the full impact of growth in these cases.     

Food aversion learning in Japanese monkeys (Macaca fuscata). A strategy to avoid a noxious food

Japanese monkeys consumed two kinds of food, the novel almonds and the familiar sweet potatoes, simultaneously, and then received a cyclophosphamide injection (20 mg/kg) intravenously. As the food-poison pairing was repeated, they first avoided the novel food completely, and then came to suppress eating the familiar one. During the subsequent extinction tests, the aversion to the familiar food was extinguished rapidly, whereas the aversion to the novel one was retained more than 2 months. In food aversion learning in a mixed situation, monkeys have a strategy to avoid a noxious food on the basis of the novelty of the food.     

PCR-based community structure studies of bacteria associated with eukaryotic organisms: a simple PCR strategy to avoid co-amplification of eukaryotic DNA

PCR primers targeting conserved regions of the SSU rRNA gene are commonly used in bacterial community studies. For microbes associated with eukaryotes, co-amplification of eukaryotic DNA may preclude the analysis. We present a simple and efficient PCR strategy to obtain pure bacterial rDNA amplicons from samples predominated by eukaryotic DNA.     

sofsog: a suite of programs to avoid inbreeding in plantation designs

Cost-effective ways of controlling inbreeding in conservation or productive plantations imply the allocation of individuals reducing the possibility of close relatives' mating and, consequently, limiting inbreeding. sofsog is a suite of programs, which helps to design plantation sites. First, if the plantation scheme involves several plots, it allows distribution of individuals available among different sites minimizing within-site global coancestry. Then, it yields a plantation design for each site, either following the classical permutated neighbourhood strategy or the recently developed method by Fernández and González-Martínez. This new method allows the implementation of different pollen dispersion kernels, and to include in the designing strategy any available information on individual relationships, reproductive success, differences in phenology, etc., via weighting or penalization matrices. Additionally, the package includes a tool for calculating the molecular coancestry (Identity By State) from codominant marker data.     

Nonaggressive behavior: A strategy employed by an obligate nest invader to avoid conflict with its host species

In addition to its builders, termite nests are known to house a variety of secondary opportunistic termite species so‐called inquilines, but little is known about the mechanisms governing the maintenance of these symbioses. In a single nest, host and inquiline colonies are likely to engage in conflict due to nestmate discrimination, and an intriguing question is how both species cope with each other in the long term. Evasive behaviour has been suggested as one of the mechanisms reducing the frequency of host‐inquiline encounters, yet, the confinement imposed by the nests' physical boundaries suggests that cohabiting species would eventually come across each other. Under these circumstances, it is plausible that inquilines would be required to behave accordingly to secure their housing. Here, we show that once inevitably exposed to hosts individuals, inquilines exhibit nonthreatening behaviours, displaying hence a less threatening profile and preventing conflict escalation with their hosts. By exploring the behavioural dynamics of the encounter between both cohabitants, we find empirical evidence for a lack of aggressiveness by inquilines towards their hosts. Such a nonaggressive behaviour, somewhat uncommon among termites, is characterised by evasive manoeuvres that include reversing direction, bypassing and a defensive mechanism using defecation to repel the host. The behavioural adaptations we describe may play an important role in the stability of cohabitations between host and inquiline termite species: by preventing conflict escalation, inquilines may improve considerably their chances of establishing a stable cohabitation with their hosts.     

Avian distraction displays: a review

Distraction displays are conspicuous behaviours functioning to distract a predator's attention away from the displayer's nest or young, thereby reducing the chance of offspring being discovered and predated. Distraction is one of the riskier parental care tactics, as its success derives from the displaying parent becoming the focus of a predator's attention. Such displays are prominent in birds, primarily shorebirds, but the last comprehensive review of distraction was in 1984. Our review aims to provide an updated synthesis of what is known about distraction displays in birds, and to open up new areas of study by highlighting some of the key avenues to explore and the broadened ecological perspectives that could be adopted in future research. We begin by drawing attention to the flexibility of form that distraction displays can take and providing an overview of the different avian taxa known to use anti-predator distraction displays, also examining species-specific sex differences in use. We then explore the adaptive value and evolution of distraction displays, before considering the variation seen in the timing of their use over a reproductive cycle. An evaluation of the efficacy of distraction compared with alternative anti-predator tactics is then conducted via a cost–benefit analysis. Distraction displays are also found in a handful of non-avian taxa, and we briefly consider these unusual cases. We conclude by postulating why distraction is primarily an avian behaviour and set out our suggestions for future research into the evolution and ecology of avian distraction displays.     

Options to avoid the second surgical site: a review of literature

As esthetics gain importance, periodontal plastic surgical procedures involving soft tissue grafts are becoming commoner both around natural teeth as well as around implants. Periodontal soft tissue grafts are primarily used for the purpose of root coverage and in pre-prosthetic surgery to thicken a gingival site or to improve the crestal volume. Soft tissue grafts are usually harvested from the palate. Periodontal plastic surgical procedures involving soft tissue grafts harvested from the palate have two surgical sites; a recipient site and another donor site. Many patients are apprehensive about the soft tissue graft procedures, especially the creation of the second/donor surgical site in the palate. In the past decade, newer techniques and products have emerged which provide an option for the periodontist/patient to avoid the second surgical site. MucoMatrixX, Alloderm^®, Platelet rich fibrin, Puros^® Dermis and Mucograft^® are the various options available to the practicing periodontist to avoid the second surgical site. Use of these soft tissue allografts in an apprehensive patient would decrease patient morbidity and increase patient’s acceptance towards periodontal plastic surgical procedures.