Influence of pump laser fluence on ultrafast myoglobin structural dynamics

High-intensity femtosecond pulses from an X-ray free-electron laser enable pump-probe experiments for the investigation of electronic and nuclear changes during light-induced reactions. On timescales ranging from femtoseconds to milliseconds and for a variety of biological systems, time-resolved serial femtosecond crystallography (TR-SFX) has provided detailed structural data for light-induced isomerization, breakage or formation of chemical bonds and electron transfer1,2. However, all ultrafast TR-SFX studies to date have employed such high pump laser energies that nominally several photons were absorbed per chromophore3-17. As multiphoton absorption may force the protein response into non-physiological pathways, it is of great concern18,19 whether this experimental approach20 allows valid conclusions to be drawn vis-à-vis biologically relevant single-photon-induced reactions18,19. Here we describe ultrafast pump-probe SFX experiments on the photodissociation of carboxymyoglobin, showing that different pump laser fluences yield markedly different results. In particular, the dynamics of structural changes and observed indicators of the mechanistically important coherent oscillations of the Fe-CO bond distance (predicted by recent quantum wavepacket dynamics21) are seen to depend strongly on pump laser energy, in line with quantum chemical analysis. Our results confirm both the feasibility and necessity of performing ultrafast TR-SFX pump-probe experiments in the linear photoexcitation regime. We consider this to be a starting point for reassessing both the design and the interpretation of ultrafast TR-SFX pump-probe experiments20 such that mechanistically relevant insight emerges.

Genome-wide classification of epigenetic activity reveals regions of enriched heritability in immune-related traits

Epigenetics underpins the regulation of genes known to play a key role in the adaptive and innate immune system (AIIS). We developed a method, EpiNN, that leverages epigenetic data to detect AIIS-relevant genomic regions and used it to detect 2,765 putative AIIS loci. Experimental validation of one of these loci, DNMT1, provided evidence for a novel AIIS-specific transcription start site. We built a genome-wide AIIS annotation and used linkage disequilibrium (LD) score regression to test whether it predicts regional heritability using association statistics for 176 traits. We detected significant heritability effects (average |τ∗|=1.65) for 20 out of 26 immune-relevant traits. In a meta-analysis, immune-relevant traits and diseases were 4.45× more enriched for heritability than other traits. The EpiNN annotation was also depleted of trans-ancestry genetic correlation, indicating ancestry-specific effects. These results underscore the effectiveness of leveraging supervised learning algorithms and epigenetic data to detect loci implicated in specific classes of traits and diseases.

Inference of Coalescence Times and Variant Ages Using Convolutional Neural Networks

Accurate inference of the time to the most recent common ancestor (TMRCA) between pairs of individuals and of the age of genomic variants is key in several population genetic analyses. We developed a likelihood-free approach, called CoalNN, which uses a convolutional neural network to predict pairwise TMRCAs and allele ages from sequencing or SNP array data. CoalNN is trained through simulation and can be adapted to varying parameters, such as demographic history, using transfer learning. Across several simulated scenarios, CoalNN matched or outperformed the accuracy of model-based approaches for pairwise TMRCA and allele age prediction. We applied CoalNN to settings for which model-based approaches are under-developed and performed analyses to gain insights into the set of features it uses to perform TMRCA prediction. We next used CoalNN to analyze 2,504 samples from 26 populations in the 1,000 Genome Project data set, inferring the age of ∼80 million variants. We observed substantial variation across populations and for variants predicted to be pathogenic, reflecting heterogeneous demographic histories and the action of negative selection. We used CoalNN's predicted allele ages to construct genome-wide annotations capturing the signature of past negative selection. We performed LD-score regression analysis of heritability using summary association statistics from 63 independent complex traits and diseases (average N=314k), observing increased annotation-specific effects on heritability compared to a previous allele age annotation. These results highlight the effectiveness of using likelihood-free, simulation-trained models to infer properties of gene genealogies in large genomic data sets.

Rational Control of Off-State Heterogeneity in a Photoswitchable Fluorescent Protein Provides Switching Contrast Enhancement

Reversibly photoswitchable fluorescent proteins are essential markers for advanced biological imaging, and optimization of their photophysical properties underlies improved performance and novel applications. Here we establish a link between photoswitching contrast, one of the key parameters that dictate the achievable resolution in nanoscopy applications, and chromophore conformation in the non-fluorescent state of rsEGFP2, a widely employed label in REversible Saturable OpticaL Fluorescence Transitions (RESOLFT) microscopy. Upon illumination, the cis chromophore of rsEGFP2 isomerizes to two distinct off-state conformations, trans1 and trans2, located on either side of the V151 side chain. Reducing or enlarging the side chain at this position (V151A and V151L variants) leads to single off-state conformations that exhibit higher and lower switching contrast, respectively, compared to the rsEGFP2 parent. The combination of structural information obtained by serial femtosecond crystallography with high-level quantum chemical calculations and with spectroscopic and photophysical data determined in vitro suggests that the changes in switching contrast arise from blue- and red-shifts of the absorption bands associated to trans1 and trans2, respectively. Thus, due to elimination of trans2, the V151A variants of rsEGFP2 and its superfolding variant rsFolder2 display a more than two-fold higher switching contrast than their respective parent proteins, both in vitro and in E. coli cells. The application of the rsFolder2-V151A variant is demonstrated in RESOLFT nanoscopy. Our study rationalizes the connection between structural and photophysical chromophore properties and suggests a means to rationally improve fluorescent proteins for nanoscopy applications.

Effect of X-ray free-electron laser-induced shockwaves on haemoglobin microcrystals delivered in a liquid jet

X-ray free-electron lasers (XFELs) enable obtaining novel insights in structural biology. The recently available MHz repetition rate XFELs allow full data sets to be collected in shorter time and can also decrease sample consumption. However, the microsecond spacing of MHz XFEL pulses raises new challenges, including possible sample damage induced by shock waves that are launched by preceding pulses in the sample-carrying jet. We explored this matter with an X-ray-pump/X-ray-probe experiment employing haemoglobin microcrystals transported via a liquid jet into the XFEL beam. Diffraction data were collected using a shock-wave-free single-pulse scheme as well as the dual-pulse pump-probe scheme. The latter, relative to the former, reveals significant degradation of crystal hit rate, diffraction resolution and data quality. Crystal structures extracted from the two data sets also differ. Since our pump-probe attributes were chosen to emulate EuXFEL operation at its 4.5 MHz maximum pulse rate, this prompts concern about such data collection.

Three-dimensional view of ultrafast dynamics in photoexcited bacteriorhodopsin

Bacteriorhodopsin (bR) is a light-driven proton pump. The primary photochemical event upon light absorption is isomerization of the retinal chromophore. Here we used time-resolved crystallography at an X-ray free-electron laser to follow the structural changes in multiphoton-excited bR from 250 femtoseconds to 10 picoseconds. Quantum chemistry and ultrafast spectroscopy were used to identify a sequential two-photon absorption process, leading to excitation of a tryptophan residue flanking the retinal chromophore, as a first manifestation of multiphoton effects. We resolve distinct stages in the structural dynamics of the all-trans retinal in photoexcited bR to a highly twisted 13-cis conformation. Other active site sub-picosecond rearrangements include correlated vibrational motions of the electronically excited retinal chromophore, the surrounding amino acids and water molecules as well as their hydrogen bonding network. These results show that this extended photo-active network forms an electronically and vibrationally coupled system in bR, and most likely in all retinal proteins.

Bacteriorhodopsin (bR) is a light-driven proton pump. Here the authors combine time-resolved crystallography at a free-electron laser, ultrafast spectroscopy and quantum chemistry to study the structural changes following multiphoton photoexcitation of bR and find that they occur within 300 fs not only in the light-absorbing chromophore but also in the surrounding protein.

Crystallography on a chip - without the chip: sheet-on-sheet sandwich

Crystallography chips are fixed-target supports consisting of a film (for example Kapton) or wafer (for example silicon) that is processed using semiconductor-microfabrication techniques to yield an array of wells or through-holes in which single microcrystals can be lodged for raster-scan probing. Although relatively expensive to fabricate, chips offer an efficient means of high-throughput sample presentation for serial diffraction data collection at synchrotron or X-ray free-electron laser (XFEL) sources. Truly efficient loading of a chip (one microcrystal per well and no wastage during loading) is nonetheless challenging. The wells or holes must match the microcrystal size of interest, requiring that a large stock of chips be maintained. Raster scanning requires special mechanical drives to step the chip rapidly and with micrometre precision from well to well. Here, a `chip-less' adaptation is described that essentially eliminates the challenges of loading and precision scanning, albeit with increased, yet still relatively frugal, sample usage. The device consists simply of two sheets of Mylar with the crystal solution sandwiched between them. This sheet-on-sheet (SOS) sandwich structure has been employed for serial femtosecond crystallography data collection with micrometre-sized crystals at an XFEL. The approach is also well suited to time-resolved pump-probe experiments, in particular for long time delays. The SOS sandwich enables measurements under XFEL beam conditions that would damage conventional chips, as documented here. The SOS sheets hermetically seal the sample, avoiding desiccation of the sample provided that the X-ray beam does not puncture the sheets. This is the case with a synchrotron beam but not with an XFEL beam. In the latter case, desiccation, setting radially outwards from each punched hole, sets lower limits on the speed and line spacing of the raster scan. It is shown that these constraints are easily accommodated.

Elevated Cytosolic Cl- Concentrations in Dendritic Knobs of Mouse Vomeronasal Sensory Neurons

In rodents, the vomeronasal system controls social and sexual behavior. However, several mechanistic aspects of sensory signaling in the vomeronasal organ remain unclear. Here, we investigate the biophysical basis of a recently proposed vomeronasal signal transduction component-a Ca(2+)-activated Cl(-) current. As the physiological role of such a current is a direct function of the Cl(-) equilibrium potential, we determined the intracellular Cl(-) concentration in dendritic knobs of vomeronasal neurons. Quantitative fluorescence lifetime imaging of a Cl(-)-sensitive dye at the apical surface of the intact vomeronasal neuroepithelium revealed increased cytosolic Cl(-) levels in dendritic knobs, a substantially lower Cl(-) concentration in vomeronasal sustentacular cells, and an apparent Cl(-) gradient in vomeronasal neurons along their dendritic apicobasal axis. Together, our data provide a biophysical basis for sensory signal amplification in vomeronasal neuron microvilli by opening Ca(2+)-activated Cl(-) channels.

Equivalent plastic strain gradient plasticity with grain boundary hardening and comparison to discrete dislocation dynamics

The gradient crystal plasticity framework of Wulfinghoff et al. (Wulfinghoff et al. 2013 Int. J. Plasticity 51, 33–46. ( doi:10.1016/j.ijplas.2013.07.001 )), incorporating an equivalent plastic strain γ eq and grain boundary (GB) yielding, is extended with GB hardening. By comparison to averaged results from many discrete dislocation dynamics (DDD) simulations of an aluminium-type tricrystal under tensile loading, the new hardening parameter of the continuum model is calibrated. Although the GBs in the discrete simulations are impenetrable, an infinite GB yield strength, corresponding to microhard GB conditions, is not applicable in the continuum model. A combination of a finite GB yield strength with an isotropic bulk Voce hardening relation alone also fails to model the plastic strain profiles obtained by DDD. Instead, a finite GB yield strength in combination with GB hardening depending on the equivalent plastic strain at the GBs is shown to give a better agreement to DDD results. The differences in the plastic strain profiles obtained in DDD simulations by using different orientations of the central grain could not be captured. This indicates that the misorientation-dependent elastic interaction of dislocations reaching over the GBs should also be included in the continuum model.

[Orbital reconstruction in children]

The orbital cavity, covering the globe and basement of the lids, is partially or totally impaired by tumors arising from inside or outside. In childhood, the reduction of contents jeopardizes the size of the orbit. Reconstruction is always difficult, particularly after exenteration, and a well-made prosthesis is much better than a poor reconstruction.

[Controversies regarding the orbital septum]

The orbital septum, a well-known structure since a long time ago, is a controversy object anyway. Its physiological, anatomical and pathological importance is undeniable. However, it will be difficult not to consider it as a part of the whole structure which organizes the general system of the soft tissues of the face, in which the orbital frame is one of the pivots.

[Avatars in face transplants]

Avatar carries a pejorative connotation often related to an unfortunate hazard. In face transplants, incarnations were numerous. The analysis of their evolution through time and increasing sophistication of procedures turn out to be informative regarding the wide disrepairs in the craniofacial area. The authors report the principal constraints of face transplant and the evolution in minds to deal with it.

Analyse des implications du tissu graisseux dans la morphologie faciale, à partir d'une revue de la littérature et de dissections de dix hémifaces

The morphological implications of the fatty tissue of the face are unequal. We study these with a review of the literature and an anatomical study with dissections of 10 half-faces. The sub-cutaneous fat, over the superficialis fascia, have got the most important implications on the morphology. These depend of the localisations on the face and the age and the weight of each subject. We can observe modifications of the positions of this fatty layer on old subjects, but also a diminution of its volume. The sub-fascial fatty tissue, above the SMAS is represented by few fat pads and seems ,to bee less concerned by modifications of its volumes.

[Uni-axial tissular extension for covering skin defects of the limbs. A 31 cases review]

INTRODUCTION

The skin property to adapt to external constraints is widely used in plastic surgery. Tissue expansion is the most known and codified application. Tissue extension appears to be an attractive alternative. The authors propose the usage of a simplified procedure to deal with skin loss in the superior or inferior members.

MATERIAL AND METHOD

Thirty-one patients underwent uni-axial traction between February 2000 and October 2003.

RESULTS

Closure of skin loss on the upper member has been obtained in 6 days and in 8 days on the inferior member.

DISCUSSION

Efficiency, reliability and no subsequent aftermaths are strong arguments in favor of the development of a simplified extension procedure.

CONCLUSION

The tissue extension procedure, although scarcely used is an attractive procedure for the coverage of skin losses.

La graisse de la face : anatomie descriptive et fonctionnelle à partir d'une revue de la littérature et de dissections de dix hémifaces

The aim of this study is to describe the anatomy of the fat in the face, based on a review of the literature and dissections of 10 half-faces. The facial fat can be divided in two layers. The first-one is superficial, between the skin and the superficialis fascia. Its function is essentially protective and its morphological implications are major, especially according to the facial aging. The other layer is deep, under the superficialis fascia. Its principal function is mechanical and its morphological implications are less important. This layer is made of several fat pads in continuity, excepted the buccal fat pad which is separated from the others by its own capsula. The other fat pads are the intra orbialis fat pad, the sub orbicularis oculi fat pad (SOOF), the retro orbicularis oculi fat pad (ROOF), the galeal fat pad and the temporal fat pad.

[Hypertrophic diseases of facial fatty tissue]

Based on our own experience and a review of the literature, we des-cribe hypertrophic diseases concerning the fatty tissue of the face. Pathological patterns are numerous and polymporphous. Fatty localizations involving the face may be associated or not with specific histological presentation.

[Contribution of the pathology examination in the operating theatre in patients with skin cancer: retrospective analysis of 388 patients]

INTRODUCTION

Pathological examination in the operating theatre in patients undergoing resection of a skin cancer is one of the most adapted therapeutic approaches. We present our experience with 388 patients, comparing the rate of recurrence with or without operating-theatre pathological examination.

MATERIAL AND METHOD

The study population included 388 patients, mean age 69.5 years (28-98 years) who underwent resection of 544 skin tumors (520 primary and 36 recurrent), 76.6% unique tumors. The pathological examination of the surgical specimen was performed immediately after removal. This method was systematic procedure for spinocellular carcinomas, was not performed for basocellular carcinomas measuring less than 1 cm when well circumscribed and not peri-orifice, and when reconstruction was not planned.

RESULTS

The pathological examination was not performed in the operative theatre for 76 tumors; for 470 examinations performed in the operative theatre, at least one surgical margin was positive in 93 (19.8%). Anatomic regions concerned most were the tip of the nose and the eyelids. Recurrent tumors (5.0% of resections) accounted for 27% of the positive pathological results. Thirty-one patients had to have revision surgery, four after a false negative on the pathological examination performed in the operative theatre, four patients for a healing problem and 23 because of tumor recurrence (4%).

DISCUSSION

Pathological examination in the operative theatre can help decrease the rate of recurrence in comparison with classical surgery using empiric margins. This method is reliable if performed by an experienced pathologist so that reconstruction can be undertaken before the definitive pathological results are obtained, improving patient comfort. These therapeutic options have a cost however in terms of equipment and personnel. Indications should be well chosen and balanced against the advantages of a two-phase classical procedure.

[Goal cell carcinoma: really a low malignancy tumor?]

Although basal cell carcinoma often presents as a fairly "benign" lesion early in its course, it remains the most frequent malignancy worldwide. Prevention, while possible, is not always optimal. We show that advanced basal cell carcinoma can be mutilating or even life threatening depending on location, type of lesion, or pre-existing co-morbidity. The consequences of this disease can be lessened if initial treatment does not underestimate its potential severity.

[Post-orthodontic rehabilitation of the sequellae of alveolar clefts: implantation or periodontal plastic surgery?]

Just as they do for many cranio-facial deformities, the treatment team begins the care of cleft palate patients early and continues treatment over a long period. Throughout the growth period, they perform well-timed interventions and re-evaluations according to the individual plan they have prepared. When growth is completed and the orthopedic and orthodontic corrections have contributed as much as possible to an esthetic and functional equilibrium, a final prosthetic replacement will frequently be required. When the correct edentulous space between the teeth on each side of the defect has been created, or maintained, practitioners can choose between two alternatives: implants or traditional fixed bridges. They should analyze any secondary anatomic discrepancies, severe or superficial, that may have developed, and prepare the best therapeutic pathway for a reconstruction of crestal gingival morphology by means of periodontal surgery.

[Coverage an irradiated wound of the lower lumbar area with a latissimus dorsi musculocutaneous free flap by lengthening the vascular pedicle with interpositional vein grafts]

Reconstruction of radionecrosis of the lower lumbar area is a challenging problem because of the difficulty of mobilization of the irradiated local tissues, absence of a reliable locoregional procedures and prolongation of the receiving vessels of the free flaps. The ideal treatment is a wide excision of the irradiated tissues and an immediate reconstruction in one step, which is better to be done by using a musculocutaneous flap. The latissimus dorsi musculocutaneous flap is ideal for this indication. The authors prefer to do the revascularization of the latissimus dorsi flap by its'thoracodorsal pedicle because of the possibility to have a high pressure blood flow which allow to use long venous bypass, the exposure of the recipient vessels at the same time of dissecting the flap and to have the anastamosis site away from the irradiated tissue. The authors are presenting their experience in treating a case of radionecrosis in the lower lumbar region with exposed vertebrae by a latissimus dorsi musculocutaneous free flap with exposed vertebrae by a latissimus dorsi musculocutaneous free flap with the lengthening of its'pedicle by two 30 cm interposition saphenous vein grafts.

[Principles of treatment of total unilateral cleft lip and palate. Suggested protocol]

Complete uni-lateral cleft palates resulting from failed union between internal and external nasal buds cause an imbalance of both superficial and deep nasal structures. After summarizing the principles that should guide the care of these anomalies, the authors present their therapeutic procedure, in which orthopaedic and surgical treatments are intimately associated. They conclude their presentation by emphasizing the difficulty of predicting the definitive result because of the extreme diversity of the sequellae that always accompany the treatment of cleft palates.

Unicoronal Suture Immobilization in the Fetal Rabbit

Pre-clinical evaluation of surgical procedures aimed to correct craniosynostosis is ideally performed in species of small animals characterized by perinatal brain development, early skeletal maturation, and genuine synostosis in all newborns. It would be nearly impossible to breed such a colony to homozygosity, so most researchers have resorted to artificial postnatal suture immobilization. Our aim was to test the hypothesis that artificial immobilization of a unicoronal suture in the fetal rabbit (25 days of gestation) would result in neurocranial growth alterations similar to those seen in the 9-day postnatally immobilized or congenital synostotic rabbit models. The advantages of prenatal immobilization are that rabbits can undergo the tested corrective procedure at postnatal day 9. This age corresponds to a human age of 6 months and allows the deformity and the effects of its correction to be more readily detected. The heads of 25-day-old fetuses of five time-dated pregnant New Zealand white rabbits were exposed by hysterotomy. The left unicoronal suture of 4 fetuses in each litter was immobilized with a polyglactin suture piercing the frontal and parietal bone plates. The remaining two fetuses were sham-operated. Nine days after spontaneous delivery, all rabbits were marked with four titanium screws close to the sagittal and coronal sutures. Growth was recorded with dorsoventral cephalograms at 9 and 90 days. The group with the immobilized suture showed a small increase in growth across the sagittal sutures. However, the decreases in growth at the unicoronal suture in both the immobilized (5.41-mm difference with sham-treated group) and nonimmobilized (1.17-mm difference with sham-treated group) were significant. Fetal immobilization results in growth alterations similar to those observed after postnatal immobilization.

Microsurgical lip replantation: Evaluation of functional and aesthetic results of three cases

Lip amputations are rare, and microsurgical replantation must be systematically tried to restore form and function in one step. The authors present a series of three cases. Revascularization of the amputated segment was obtained by arterial anastomosis with the corresponding labial coronary artery. No venous anastomosis was carried out, because no vein could be identified. Venous drainage was obtained by inducing bleeding and by postoperative application of leeches for 6 days. Anticoagulant therapy and antibiotherapy were used for 10 days. With this approach, two lip amputations were completely saved, and a third amputation only suffered partial necrosis. Aesthetic and functional results were evaluated as being good, with reestablishment of labial continence and recovery of protective sensitivity.

Diagnosis and treatment of vascular lesions of the lip

Many vascular lesions involve the lip. We present the clinical and imaging findings of vascular lesions, including haemangiomas and vascular malformations. We review the changing role of surgery and other treatments in the management of each type of lesion. Haemangiomas are treated surgically only when lip function is substantially impaired. Superselective embolisation is the treatment of choice for arteriovenous malformations, whereas capillary-venous malformations are best treated by operation together with intralesional injection of fibrosing agents. Capillary malformations are usually treated with laser.

[Morphologic disequilibrium of the lips]

The aetiologies of the labial desequilibrium are multiple. They respond to the anomalies of the position and the dimension. The authors will enumerate the different variety and their etiology.

[Full thickness defects of the lips. Reconstructive techniques and indications]

The full-thickness tissue loss of the lip leads to the loss of lip continuity. The classic principle is to repair a lip with a lip, giving the best results. Although the size of tissue lost can force to use local flaps, these could be naso-labio-jugal, labio-mental or submental. Even though the microsurgical labial replantation is the technique of choice, unfortunately, most of the time it cannot be done as a result of the situation and the conservation of the avulsed fragment.

[Labial aging. Composition and therapeutic principles]

Labial ageing process combining relaxation, distension and ptosis is aggravated by underlying structure modification: dental and bony. If the inferior lip moves back and collapses, the superior lip will go down and widen. The authors analyse the different ageing process components (intrinsic and extrinsic) as well as therapeutic principles.

[Red lip defects. Reconstructive techniques and indications]

The attractive color of the red lip must be the object of very meticulous reconstruction in their form and pigmentation. This can be done only by using the buccal mucosa. The graf is less indicated. There are multiple local flaps that have been proposed using the same lip, the jugal mucosa and the tongue. The authors will show the principal procedures found in the literature.

[Labial commissures. Reconstructive procedures and indications]

The commisures are the two extremities of the mouth. They make a big complex in their architecture and their function. Their repairing should have an important attention to their final shape and function. The frequency of the retraction of the scarring tissue imposes additional muscular exercise which has to be premature, intense, and prolonged.

[Labial balance]

The labial balance appreciated by statics and movement is the guarantee of morphology, bilabial competence and symmetry in function (ou bien in movement?). The restoration of the lips aims for this balance, the basic axiom is "to repair the lip by the lip". Three main technical forms meet these requirements: forward movement, rotation and transposition.

[Development of the maxilla in patients with complete unilateral cleft palate surgically treated by a periosteal transplantation technic. A retrospective study of 15 surgical cases with an 18 year follow-up]

PURPOSE

The aim of this study was to assess retrospectively the long-term growth of the maxilla in subjects with unilateral total cleft treated initially with the tibial periosteal graft technique.

PATIENTS AND METHODS

The study group included 15 patients with a mean 18 years follow-up (range 15-20 years). All patients had been operated on by the same surgeon. Only patients in stage DP3, one to two years after peak growth were retained for review. Delaire's architectural analysis was used to study anteroposterior and vertical growth of the maxilla. Transverse growth was studied with the Mars occlusal score. Bone generation induced by the periosteum was studied using the Björk Holmgren analysis. The quality of the palatine and nasal repair was studied using Pruzansky's criteria.

RESULTS

Anteroposterior and vertical growth led to a normal maxilla in 53.3% of the cases and a moderate to severe retromaxilla (> 5 mm) in 46.7%. Complete symmetry was achieved for the nasal fossae in 20% of the cases and marked asymmetry was noted in 26%. The height of the nasal fossae was symmetrical in 60% of the cases with marked asymmetry in 26%. Mean production of alveolar bone reached 58% of the height of the alveolar bone filling. It was good in 46.6% of the cases, fair in 26.7% and weak in 26.7%. The occlusal score evidenced crossed occlusion in 33.3% of the cases for a hemisection and in 46.7% of the cases for an anterior section. Normal occlusion was achieved in 20%. The quality of palatine repair was found to be good with a normal mucosa in 86.7% of the cases. A fistula was present in 13.3%.

CONCLUSION

The preoperative objectives of periosteal graft repair of unilateral complete clefts were achieved. This technique provides a closed scar-free palate. Nasal repair favored the development of an ample and functional airway. The periosteal graft produced bone in the anterior portion allowing a harmonious premaxillary region and stable nose support.

[Orthopedic treatment of labio-maxillo-palatal clefts: our approach]

Many authors use a preliminary orthopedic procedure before cleft lip and palate surgical closure in order to prevent possible bone distortion following the rupture of the muscle belts resulting from the cleft. Actually, this is generally not only an orthopedic treatment but rather a surgical orthopedic step which includes lip adhesion before the surgical closure of the clefts. Following the procedures proposed by Georgiade and Latham, we have used since 1996 a treatment based on traction applied with an elastic chain on splints attached by transmaxillary pins for certain types of clefts, namely unilateral complete clefts with endognathy of the small fragment, unilateral complete clefts larger than 7 mm, bilateral wide complete clefts with premaxilla protrusion, and bilateral wide complete clefts with collapsus and premaxillary protrusion. Technical procedures vary with the type of cleft. Standard procedures with or without jacks are used for the other types of complete clefts. These orthopedic procedures with elastic traction are performed between the 3rd and 6th week, before lip adhesion of the upper part of the lip (combined with release of skin and subcutaneous tissues from the underlying alar cartilage). A palatine plate with or without a jack, fitted most of the time with a spring for nostril support, is then inserted until surgical closure.

[Facial bone reconstruction. Review of particularities and procedures]

The authors report the particularities of the cranio-maxillofacial skeleton and the aims of the reconstruction procedures: osteogenesis, osteoconduction, osteoinduction. They review the various procedures, their abilities, some technical notes, their advantages and disadvantages. They analyse in order: classical bone autografts, pedicled bone flaps (arterio-osseous, fascio-osseous, myo-osseous flaps), free bone flaps, classical and pedicled periosteal transplantations. They also describe the mechanical and biological procedures of bone stimulation: bone distraction, guided bone regeneration, bone growth factors, and the biomaterials, especially coral and enosseous implants. They conclude that, in facial reconstruction, the best material is the autologous bone membranous and vascularized.

[The chondrocranium of an 18 mm human embryo. A 3-dimensional computer-assisted reconstruction]

INTRODUCTION

Three-dimensional reconstruction of histologic structures is still a real challenge. This is the reason why very few specimens are published, especially for the head.

MATERIAL AND METHODS

The chondrocranium of an 18-mm human embryo was reconstructed from serial histologic sections. The three-dimensional reconstruction was based on a software used in geology and adapted to medical applications. This software was able to smooth the reconstructed model, i.e. to correct the distortions due to the histologic preparation.

RESULTS

The chondrocranium model is presented. To facilitate spatial orientation, we added the reconstruction of Merkel cartilage, of Reichert cartilage, of the vertebrae, and of the cerebrum. The different portions of the chondrocranium are described.

DISCUSSION

The three-dimensional result is described and advantageously compared to the rare wax models available. The morphological differences are detailed.

CONCLUSION

This technique of three-dimensional reconstruction with its smoothing procedure is a very well adapted method for reconstruction of histologic structures. The results presented confirm the educational value of this tool, which is otherwise a powerful instrument of morphogenic study.

[Surgery of labio-maxillo-palatal clefts during humanitarian mission in the Philippines]

After describing the Philippines and the Comité de Soutien Enfance Philippines, a humanitarian association with a three-fold objective: to build, to educate and to treat, the authors present the organization and practical conduct of their missions abroad which have enabled them to treat almost 400 patients with cleft lip and palate between the ages of 3 months and 46 years.

A feasibility test of a brief educational intervention to increase fruit and vegetable consumption among callers to the Cancer Information Service

BACKGROUND

In this paper, results are reported from a pilot study designed to test the feasibility of a proactive educational intervention delivered to callers of the Cancer Information Service (CIS).

METHODS

The study used a randomized two-group design (intervention vs control). Callers assigned to the intervention condition received a brief educational intervention at the end of usual service to increase fruit and vegetable consumption. As part of the intervention, key education messages and materials drawn from the 5 A Day for Better Health program of the National Cancer Institute were provided to CIS callers over the telephone and then reinforced with two follow-up mailings.

RESULTS

Results from this pilot study indicated high levels of adherence to protocol by CIS Information Specialists who delivered the intervention to eligible CIS callers. Results obtained from the 4-week telephone follow-up interviews indicated that intervention subjects (n = 142) reported higher consumption of fruits and vegetables, averaging approximately 0.75 servings more per day (P < 0.01) than control subjects (n = 134).

CONCLUSION

Nearly 80% of CIS callers endorsed the strategy of providing 5 A Day information at the end of usual service, even if such information was not specifically requested by the caller (i.e., the information was provided to CIS callers proactively.

[Unusual facial clefts]

After briefly review facial morphogenesis, the authors define facial clefts, distinguishing primary clefts, secondary clefts, and residual clefts. They discuss the uncertainties surrounding the embryology and clinical features of palpebral colobomas. The various pathogenetic concepts are analysed: amniotic hypothesis, vascular hypothesis, fusion defect. The various classifications of rare facial clefts are reviewed, with particular emphasis on Tessier's classification and the so-called Milan classification. The general principles of surgical treatment are described together with the various skeletal and soft tissues procedures.

Distribution of physicians in Ontario. Where are there too few or too many family physicians and general practitioners?

OBJECTIVE

To assess the regional distribution of family physicians and general practitioners in Ontario after adjusting for practice intensity and the population's patterns of health care use.

DESIGN

Analysis of administrative data.

SETTING

Ontario.

MAIN OUTCOME MEASURES

Intensity of patient use of GP services, GP practice density, and physician density for each Ontario county (measured as the ratio of practice-intensity equivalent GPs to use-intensity equivalent inhabitants).

RESULTS

Despite adjustment for practice intensity and use patterns, wide variations exist in GP densities. chi 2 tests identified counties that consistently reported GP densities significantly different (P < 0.001) from the provincial average. Four of the five counties with health science teaching centres had densities significantly higher than the provincial average, while 10 other counties had significantly lower densities.

CONCLUSIONS

Results of this study provide useful information for physician resource planning and might inform debate concerning proposals to restrict physician billing numbers and practice locations to rectify perceived maldistribution of physicians.

[The coral orbital floor. Its value in traumatology. The results of a multicenter study of 83 cases]

A madreporic coral graft was used for orbital floor reconstruction following facial trauma. This report presents a multicentric study of 83 patients with a follow-up period of 15 to 24 months. The results of this study indicate no significant rejection or infection opposed to so many synthetic implants outcome. The radiological follow-up demonstrates a partially resorption of the implant within about 2 years and its replacements by new bone. Coral implant was used to correct enophthalmos or diplopia due to enlarged orbital dimensions. It was technically easy to insert and its anatomic shape does not require to be fashioned before use. Its inflexibility allows to bridge large bone defects and this implant should be considered as an attractive alternative to autogenous grafts, avoiding a second surgical site, in reconstructing orbital floor fractures.

[Temporomandibular joint luxation and Ehlers-Danlos disease. Apropos of a case]

First described by Tschernogobow in 1981, Ehlers-Danlos syndrome is usually observed in white males. Symptoms results from defective collagen synthesis. Diagnosis is based on clinical presentation. There are 9 different clinical groups. Maxillofacial manifestations are usually seen in type VIII Ehlers-Danlos syndrome. The clinical case presented here illustrates the problems involving the temporomandibular joints and focuses on an assessment of proposed therapeutic options.