Skull expansion in experimental craniosynostosis

Bilateral coronal suture immobilization was performed in 9-day-old rabbits to simulate the brachycephaly deformity characteristic of coronal synostosis. Growth abnormalities were documented by serial radiographic cephalometry. A "corrective" linear craniectomy procedure was performed on the rabbits with an immobilized coronal suture at 60 days of age. The degree of amelioration of the induced abnormalities by the surgery in these animals was compared with a similar group of animals that had the same surgery plus supplemental implantation of a spring expansion device at the coronal suture craniectomy site. The mean marker separation at the coronal suture was significantly greater (5.61 mm +/- 0.52 SE versus 2.53 mm +/- 0.38 SE; p less than 0.05) following spring expander implantation than with linear craniectomy alone. Similarly, induced anterior cranial base shortening and distortion of craniofacial cephalometrics were more significantly improved by the additional use of the spring expansion device.     

The use of intraoperative autotransfusion during cranial vault remodeling for craniosynostosis.

Intraoperative autotransfusion salvages blood shed during surgery for use in immediate resuscitation of the patient. The purpose of this study was to determine whether such autotransfusion decreases the volume of homologous blood transfused in patients undergoing primary cranial vault remodeling for craniosynostosis. The Cobe-Bret 2 autologous blood recovery system (Hemo Concepts, Union, N.J.) was used in 11 cases, and an equal number of consecutive cases did not receive intraoperative autotransfusion. There were no significant differences between the groups with respect to age, sex, and weight. Mean estimated blood loss was 43.2 ml/kg (range, 20.3 to 65.0 ml/kg) in the intraoperative autotransfusion group and 40.2 ml/kg (range, 6.8 to 72.3 ml/kg) in the control group (not statistically significant; p < 0.05). There was no significant difference in volume of homologous blood transfusion between the two groups. The autotransfusion group received 34.1 ml/kg of homologous blood (range, 0 to 60.7 ml/kg), and the control group received a mean of 32.7 ml/kg (range, 14.5 to 60.2 ml/kg). The autotransfusion group received a mean of 10.4 ml/kg of recovered autologous blood (range, 0 to 21.4 ml/kg). In four of the 11 autotransfusion patients, insufficient autologous blood was recovered intraoperatively to warrant transfusion. Results of this study suggest little benefit for the use of intraoperative autotransfusion in primary cranial vault remodeling for craniosynostosis in the young patient. It was hypothesized that this finding was a result of the following: (1) intraoperative autotransfusion blood was usually available only toward the end of the procedure, after homologous blood had already been administered, and (2) the volume of recovered intraoperative autotransfusion blood is minimal, compared with the homologous transfusion volume requirements during an extensive cranial vault remodeling and fronto-orbital advancement procedure. In the context of unproven cost benefit and increasing similar evidence from other comparative studies, emphasis should be directed to other medical and surgical strategies to minimize the need for perioperative blood transfusion.     

Palate vault morphology in Down syndrome

Moire topography was used to quantitatively determine the shape of the palatal vault in 57 Spanish patients with Down syndrome (DS) (38 males and 19 females; age range 18-36 years) and in 100 normal controls (N) (76 males and 24 females; age range 20-29 years). The topographic image for each palatal vault was analyzed and approximately 40 sets of coordinates (x, y, z) were recorded. Other parameters, including length, width and maximum height, were recorded from the palate vault images. No appreciable sexual dimorphism in palate dimensions was observed in DS subjects versus the situation in N subjects. Globally, the average N dimensions were significantly greater than those in the DS patients (P < 0.005). A special palatal morphology was found to be associated with DS, with different ratios for the three dimensions (mean factor 0.88 for length, 0.81 for width and 0.73 for height), versus the healthy palatal vaults. It is concluded that palatal morphology in DS fits an elliptic paraboloid. On the other hand, no lineal correlation was observed between height, width and length in the DS and N groups. The scatter plots of bivariate data exhibited a shapeless morphology. The lineal correlation coefficients ranged from 0.008 to 0.33 for the DS and N groups.     

Differential activation of canonical Wnt signaling determines cranial sutures fate: A novel mechanism for sagittal suture craniosynostosis

Premature closure of cranial sutures, which serve as growth centers for the skull vault, result in craniosynostosis. In the mouse posterior frontal (PF) suture closes by endochondral ossification, whereas sagittal (SAG) remain patent life time, although both are neural crest tissue derived. We therefore, investigated why cranial sutures of same tissue origin adopt a different fate. We demonstrated that closure of the PF suture is tightly regulated by canonical Wnt signaling, whereas patency of the SAG suture is achieved by constantly activated canonical Wnt signaling. Importantly, the fate of PF and SAG sutures can be reversed by manipulating Wnt signaling. Continuous activation of canonical Wnt signaling in the PF suture inhibits endochondral ossification and therefore, suture closure, In contrast, inhibition of canonical Wnt signaling in the SAG suture, upon treatment with Wnt antagonists results in endochondral ossification and suture closure. Thus, inhibition of canonical Wnt signaling in the SAG suture phenocopies craniosynostosis. Moreover, mice haploinsufficient for Twist1, a target gene of canonical Wnt signaling which inhibits chondrogenesis, have sagittal craniosynostosis. We propose that regulation of canonical Wnt signaling is of crucial importance during the physiological patterning of PF and SAG sutures. Importantly, dysregulation of this pathway may lead to craniosynostosis.     

Comparative morphology of the sagittal otolith in Serranus spp.

Variations in the morphology of saccular otoliths (sagittae) among three sympatric species of the genus Serranus ( S. atricauda , S. cabrilla and S. scriba ) from the Canary Islands were investigated. Although the otolith gross morphology was similar among species, S. scriba was distinct in having a rostrum which had a slight turning at the tip and a more funnel‐like ostium. The shallower water species ( S. scriba ) had otolith and sulcus areas which were smaller than the deeper water species ( S. cabrilla and S. atricauda ). The sulcus acusticus and ostium size were correlated with the habit depth of the species, with the highest values in the deepest species, S. cabrilla . The otolith outline shape indices changed with size (total length) of the species, and allowed the separation of the species by means of a discriminate function.     

Delayed cranial vault reconstruction for sagittal synostosis in older children: an algorithm for tailoring the reconstructive approach to the craniofacial deformity

An algorithm for the management of sagittal synostosis in older children who underwent delayed cranial vault reconstruction is presented. This algorithm tailors the surgical approach to the specific craniofacial deformity present in each case. The scaphocephalic deformity characteristic of sagittal synostosis varies significantly when presentation is delayed beyond the first year of life, the time during which reconstruction is usually performed. Sixteen patients with sagittal synostosis who presented after 12 months of age, and were a mean of 3.2 years of age at the time of cranial vault reconstruction, were reviewed. Four patients demonstrated preoperative symptoms and objective findings indicative of increased intracranial pressure, including frequent headaches and emesis, papilledema, or digital markings on computed tomographic scan. Each of the 16 patients underwent either (1) single-stage total vault reconstruction with or without concomitant fronto-orbital expansion; (2) two-stage total vault reconstruction with anterior two-thirds vault expansion followed by transverse occipital expansion and recession a mean of 8.7 months later; or (3) anterior two-thirds vault reconstruction with or without fronto-orbital expansion. In each case, the extent of the scaphocephalic deformity determined the procedure used. The presence of severe frontal bossing associated with transverse restriction of the orbitotemporal region was an indication for fronto-orbital expansion in addition to vault reconstruction, whereas significant occipital protrusion was an indication for transverse posterior vault expansion and recession in addition to anterior two-thirds vault reconstruction. Excellent aesthetic results were obtained in all cases regardless of the type of reconstruction performed. However, it is essential that the extent of the deformity be carefully evaluated preoperatively to permit selection of the appropriate technique for reconstruction.     

Changes in morphology and in polyphosphoinositide turnover of human erythrocytes after cholesterol depletion

Human erythrocytes were cholesterol-depleted (5-25%) by incubation with phosphatidylcholine vesicles in media containing Ca2+ at different concentrations (0, 28 nM, 5 microM or 1 mM). After removal of the vesicles, the cells were reincubated with [32P]phosphate in the same media. Control (incubated in buffer alone) and cholesterol-maintained erythrocytes (incubated with cholesterol/phosphatidylcholine vesicles) were treated similarly. Cholesterol depletion induced the conversion of the cells into stomatocytes III and spherostomatocytes and decreased the turnover rate of phosphatidylinositol phosphate and of phosphatidylinositol bisphosphate. None of these effects were observed in cholesterol-maintained cells. In cholesterol-depleted cells, they occurred without changes in the ATP specific activity or in the polyphosphoinositide concentrations. Moreover, these modifications of shape and of lipid metabolism were proportional to the extent of the cholesterol depletion and were independent of the external Ca2+ concentration. In contrast, other effects of cholesterol depletion, a decrease in the turnover rate of phosphatidic acid, a decrease in diacylglycerol and in phosphatidic acid concentrations were dependent on the external Ca2+ concentration. Thus it appears that the shape change was not correlated with a change in the concentrations of these phospholipids or of diacylglycerol and therefore cannot be explained by a bilayer couple mechanism involving these phospholipids. However, the spherostomatocytic transformation was correlated with the decrease in the turnover rate of the polyphosphoinositides, but not with the turnover rate of phosphatidic acid, suggesting a role for the turnover of the polyphosphoinositides in the maintenance of the erythrocyte shape.     

Fine morphology of frontal filaments in nauplii of cirriped crustaceans

Fine morphology of the frontal filaments (FFs) at all nauplius stages of two barnacle species (Verruca stroemia and Hesperibalanus hesperius) has been investigated by scanning electron microscopy. FFs have been detected at the second nauplius stage and persist during all stages. FFs contain a wide proximal and a fine distal parts, but they are not actually separated as segments of the limbs, and the area between them looks like a single cuticular crease. Apical and subapical pores have been found at the top of each FF in the larvae of both species, which may indicate the chemoreceptor function of these organs.     

Changes in intervertebral disc morphology persist 5 mo after 21-day bed rest

As part of the nutrition-countermeasures (NUC) study in Cologne, Germany in 2010, seven healthy male subjects underwent 21 days of head-down tilt bed rest and returned 153 days later to undergo a second bout of 21-day bed rest. As part of this model, we aimed to examine the recovery of the lumbar intervertebral discs and muscle cross-sectional area (CSA) after bed rest using magnetic resonance imaging and conduct a pilot study on the effects of bed rest in lumbar muscle activation, as measured by signal intensity changes in T(2)-weighted images after a standardized isometric spinal extension loading task. The changes in intervertebral disc volume, anterior and posterior disc height, and intervertebral length seen after bed rest did not return to prebed-rest values 153 days later. While recovery of muscle CSA occurred after bed rest, increases (P ≤ 0.016) in multifidus, psoas, and quadratus lumborum muscle CSA were seen 153 days after bed rest. A trend was seen for greater activation of the erector spinae and multifidus muscles in the standardized loading task after bed rest. Greater reductions of multifidus and psoas CSA muscle and greater increases in multifidus signal intensity with loading were associated with incidence of low back pain in the first 28 days after bed rest (P ≤ 0.044). The current study contributes to our understanding of the recovery of the lumbar spine after 21-day bed rest, and the main finding was that a decrease in spinal extensor muscle CSA recovers within 5 mo after bed rest but that changes in the intervertebral discs persist.     

The relationship between trunk muscle electromyography and lifting moments in the sagittal and frontal planes

In this study, we explore the relationship between moments in the frontal and sagittal planes, generated by a lifting task, vs the electromyographic (EMG) activity of right and left trunk muscle groups. In particular, we postulate that the functional dependence between erector spinae muscle activity and the applied lifting moments about the spine is as follows: the sum of left and right erector spinae processed EMG depends on the sagittal plane moment, and the difference of left and right erector spinae processed EMG depends on the frontal plane moment. A simple out-of-sagittal plane physical model, treating the lumbar spine as a two degree-of-freedom pivot point is discussed to justify these hypotheses. To validate this model, we collected surface EMG and lifting moment data for ten males performing a grid of frontal and sagittal plane lifting tasks. A digital RMS-to-DC algorithm was developed for processing raw EMG. For these tests, we measured EMG for the left and right erector spinae and for the left and right external oblique muscles. The processed EMG signals of the left and right erector spinae muscles are summed and differenced for comparison to the measured sagittal and frontal plane moments. A linear correlation (r2) of 0.96 was obtained for the sum of erector spinae EMG vs the sagittal plane moment; a corresponding value of r2 = 0.95 was obtained for the difference vs the frontal plane moment. No correlations (r2 less than 0.004) was found for the sagittal plane moment and the difference of the left and right erector spinae EMG, and the frontal plane moment and the sum of the left and right erector spinae EMG.     

Knee joint passive stiffness and moment in sagittal and frontal planes markedly increase with compression

Knee joints are subject to large compression forces in daily activities. Due to artefact moments and instability under large compression loads, biomechanical studies impose additional constraints to circumvent the compression position–dependency in response. To quantify the effect of compression on passive knee moment resistance and stiffness, two validated finite element models of the tibiofemoral (TF) joint, one refined with depth-dependent fibril-reinforced cartilage and the other less refined with homogeneous isotropic cartilage, are used. The unconstrained TF joint response in sagittal and frontal planes is investigated at different flexion angles (0°, 15°, 30° and 45°) up to 1800 N compression preloads. The compression is applied at a novel joint mechanical balance point (MBP) identified as a point at which the compression does not cause any coupled rotations in sagittal and frontal planes. The MBP of the unconstrained joint is located at the lateral plateau in small compressions and shifts medially towards the inter-compartmental area at larger compression forces. The compression force substantially increases the joint moment-bearing capacities and instantaneous angular rigidities in both frontal and sagittal planes. The varus–valgus laxities diminish with compression preloads despite concomitant substantial reductions in collateral ligament forces. While the angular rigidity would enhance the joint stability, the augmented passive moment resistance under compression preloads plays a role in supporting external moments and should as such be considered in the knee joint musculoskeletal models.     

Patterning of geographic variation in Middle Pleistocene Homo frontal bone morphology

A quantitative assessment of the frontal bone morphology of a sample of Middle Pleistocene hominins was undertaken in order to address questions regarding their population structure and evolutionary history. Outline tracings of the frontal bones of forty-seven fossil crania were obtained, and size-standardized measurements were then computed using an Elliptical Fourier analysis of these tracings. Principal component scores of the Fourier harmonic amplitudes were derived and served as a quantitative representation of the morphology of the frontal bone. Morphological, geographical, and temporal distance matrices were then constructed between each pair of fossils. A partial Mantel matrix correlation test was performed between morphological and geographical distance matrices, controlling for temporal distance, in order to determine if the pattern of geographical differentiation in features of the frontal bone of mid-Pleistocene Homo followed that of an isolation-by-distance model of population structure. The results of the partial Mantel tests indicate that the overall patterning of differentiation in the features of the frontal bone cannot best be explained by a population structure shaped by isolation-by-distance. Additionally, various aspects of the frontal bone quantified here follow different patterns of geographical differentiation, suggesting that a mosaic pattern of evolution holds true for characters within one cranial region and not just for those between regions.     

Comparative morphology of the sagittal otolith in three species of south Caspian gobies

Sagittal otolith shapes were investigated in order to identify three sympatric species of south Caspian gobies (Caspian goby Neogobius caspius, deepwater goby Ponticola bathybius and bighead goby Ponticola gorlap). The sagittal otoliths in P. bathybius have a rectangular shape and are thick, whereas in N. caspius they are relatively round and thin. In P. gorlap, otoliths have an elongated shape and are relatively thick. The noticeable difference among the otoliths of the three species is the presence of one anterior and one posterior projection in the otoliths of N. caspius and P. gorlap. Among shape indices, form factor (irregularity of surface area), circularity, aspect ratio and rectangularity are the foremost that indicate interspecific variability. The canonical discriminant analysis correctly classifies 94·7% of the original group cases. The overall analyses show the relevance of applying otolith shape for interspecific distinction of the three species of Caspian gobies.