Jaw musculature of the Meiglyptini (Aves: Piciformes: Picidae)

The Meiglyptini comprise eight species of woodpeckers grouped into three genera, two of which contain three species ( Meiglyptes and Mulleripicus), while one genus includes two species ( Hemicircus). The purpose of this study is to describe the mandibular apparatus found in six species of Meiglyptini and to compare them with each other and with other woodpecker species. The results reveal a number of structures that are worth mentioning: (i) the components of the external mandibular adductor system of Hemicircus concretus, particularly the M. adductor mandibulae externus caudalis medialis, are underdeveloped compared with the other investigated species; (ii) the muscles of the internal mandibular system are structurally different among Meiglyptes species and are less developed, both in size and in structure, in H. concretus; (iii) the M protractor quadrati is vestigial in Meiglyptes species; (iv) the muscles of the protractor system of the quadrate are relatively undeveloped in H. concretus; (v) most of the muscles of the pterygoideus system are structurally differentiated in Meiglyptes species. It appears that the complexity of the mandibular apparatus is associated with the type of food consumed, as the apparatus of the frugivorous species H. concretus is markedly different from that of the insectivorous species. © 2012 The Royal Swedish Academy of Sciences.

Jaw musculature of the Picini (Aves: Piciformes: Picidae)

The Picini tribe comprises 25 Old World woodpecker species grouped into seven genera that are widely distributed in Asia and include several representatives from the Eurasian region. Given the absence of detailed anatomical studies of Picini in the literature, the purposes of this study were to describe the jaw musculature of 14 species of Picini in detail and to compare the musculature patterns of these species. The results of this analysis indicate the following: (1) there is a clear association between the ventralis lateralis and dorsalis lateralis muscles through fleshy fibers that are connected in all species, (2) the jaw musculature of the genus Picus differs from that of other Picini genera in terms of the poor development of the protractor muscle system of the quadrate (M. protractor quadrati and M. protractor pterygoidei), (3) generally, the M. pseudotemporalis superficialis originates in the ventrocaudal region of the laterosphenoid (the lower part of the orbit), with the only noteworthy exception being an origin in the upper part of the orbit in Dinopium javanense, and (4) the protractor pterygoidei muscle is more developed in Blythipicus rubiginosus, Dinopium rafflesii, and D. javanense than in the other species. © 2012 Reginaldo José Donatelli.

Copaiba oil effect on experimental jaw defect in Wistar rats

PURPOSE: To evaluate the effects of copaiba oil on jaw defects repair in Wistar rats treated with bioglass or adipose tissue. METHODS: A jaw defect was randomly created in forty-two rats and filled with bioglass or adipose tissue. The two groups (Gbio and Gcell) were subdivided in three subgroups with seven animals each according to gavage administration: control (distillated water), oil (copaiba oil) and melox (meloxicam). Euthanasia was performed after forty post-operative days. The bone formation was analyzed regarding the histological aspects. RESULTS: The osteoclasts activity was observed only in four subgroups (p=0.78). Regarding the osteoblasts presence, it was very similar between the subgroups, the difference was due to Gcell-melox (p=0.009) that presented less osteoblastic activity. The inflammatory cells were more evident in Gcell-melox subgroup, however, there was no difference in comparison with the other subgroups (p=0.52). Bone formation was observed in all subgroups, just two animals showed no bone formation even after 40 days. More than 50% of bone matrix mineralization was observed in 56% (23 animals) of the analyzed areas. The bone matrix mineralization was not different between subgroups (p=0.60). CONCLUSIONS: The subgroups that received copaiba oil showed bone repair, although not statistically significant in comparison to subgroups treated whit meloxicam or controls. Copaiba oil administered by gavage had no effect on bone repair in this experimental model.

Patient Education and Self-Care for the Management of Jaw Pain upon Awakening: A Randomized Controlled Clinical Trial Comparing the Effectiveness of Adding Pharmacologic Treatment with Cyclobenzaprine or Tizanidine

Aims: To compare the effectiveness of adding cyclobenzaprine, tizanidine, or placebo to patient education and a self-care management program for patients with myofascial pain and specifically presenting with jaw pain upon awakening. Methods: Forty-five patients with a diagnosis of myofascial pain based on the guidelines of the American Academy of Orofacial Pain participated in this 3-week study. The subjects were randomly assigned into one of three groups: placebo group, TZA group (tizanidine 4 mg), or CYC group (cyclobenzaprine 10 mg). Patients were evaluated for changes in pain intensity, frequency, and duration by using the modified Severity Symptoms Index and changes in sleep quality with the use of the Pittsburgh Sleep Quality Index. Data were analyzed by ANOVA and post-hoc or nonparametric statistical tests as appropriate. Results: All three groups had a reduction in pain symptoms and improvement of sleep quality based on a comparison of pretreatment and treatment scores. However, no significant differences among the groups were observed at the posttreatment evaluation. Conclusion: The use of tizanidine or cyclobenzaprine in addition to self-care management and patient education was not more effective than placebo for the management of patients with myofascial jaw pain upon awakening.

Relationship Between Jaw Apparatus, Feeding Habit, and Food Source in Oriental Woodpeckers

Associations among feeding habit, beak type, and food source in birds have been widely studied and are well known to exist. The relationship between feeding habit and jaw apparatus in birds has not attracted attention from ornithologists, perhaps because of the complexity of the skeletal morphology of the feeding system of birds. The goal of this study was to compare the jaw apparatus and foraging strategies of various Oriental species of the Picidae (Meiglyptini and Picini tribes) using a morphofunctional analysis of the skeletal structure of the jaw apparatus. This study showed that there are at least three types of jaw apparatus in these woodpeckers, as follows: 1) robust, developed, and complex; 2) complexity and development intermediate, as observed in Meiglyptes tristis and Dinopium spp., whose main foraging method involves gleaning, probing, and tapping; and 3) poorly developed, as observed in Picus miniaceus and Hemicircus concretus. The success of woodpeckers as a natural group is due not only to their feeding diversity, but also their ability to explore a wide range of different resources, as appropriate to their jaw apparatus.

Influence of Estrogen Deficiency on Bone Around Osseointegrated Dental Implants: An Experimental Study in the Rat Jaw Model

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of Maternal Pb2+ poisoning during pregnancy on the development of the jaw (Meckel´s Cartilage) of rat fetus

The purpose of this study was to investigate the effects of maternal lead poisoning during pregnancy on the development of the jaw (Meckel's cartilage) of rat fetuses by histologic and morphometric methods. Pregnant rats received a single intraperitoneal injection of 2.5 mg of lead acetate/100g body weight on the 10th day of pregnancy. Meckel's cartilage of fetuses of the lead-treated group showed smaller volume density and size of the lacunae, as well as modification of the lacunae shape. Moreover, the number density of lacunae and the volume density of the matrix increased significantly in the Meckel's cartilage in treated group fetuses. The results suggest that lead poisoning during the period of organogenesis can induce disturbances in the development and differentiation of the fetal stomatognathic system. Reducing the consumption of alcoholic beberages and smoking cessation by women in childbearing age, along with a strict policy of control of the environmental lead exposure can bring great benefits to the future generations of children.

Time series analysis of jaw muscle contraction and tissue deformation during mastication in miniature pigs

Masticatory muscle contraction causes both jaw movement and tissue deformation during function. Natural chewing data from 25 adult miniature pigs were studied by means of time series analysis. The data set included simultaneous recordings of electromyography (EMG) from bilateral masseter (MA), zygomaticomandibularis (ZM) and lateral pterygoid muscles, bone surface strains from the left squamosal bone (SQ), condylar neck (CD) and mandibular corpus (MD), and linear deformation of the capsule of the jaw joint measured bilaterally using differential variable reluctance transducers. Pairwise comparisons were examined by calculating the cross-correlation functions. Jaw-adductor muscle activity of MA and ZM was found to be highly cross-correlated with CD and SQ strains and weakly with MD strain. No muscle’s activity was strongly linked to capsular deformation of the jaw joint, nor were bone strains and capsular deformation tightly linked. Homologous muscle pairs showed the greatest synchronization of signals, but the signals themselves were not significantly more correlated than those of non-homologous muscle pairs. These results suggested that bone strains and capsular deformation are driven by different mechanical regimes. Muscle contraction and ensuing reaction forces are probably responsible for bone strains, whereas capsular deformation is more likely a product of movement.

Cysts Resembling Hydatids in a Chicken

Two large cysts recovered from the abdominal cavity of a domestic chicken superficially resembled hydatid cysts of Echinococcus spp. No protoscolices were present. Microscopic examination of the internal lining of one of the cysts revealed a single cuboidal to columnar, ciliated epithelium, leading to a diagnosis of oviduct cysts. Earlier records of hydatids of fowl are reviewed. Spanish abstract: Reporte de Caso--Quistes en un pollo semejantes a la hidatidosis. Se encontraron dos quistes grandes en la cavidad abdominal de un pollo doméstico. Superficialmente los quistes parecían quistes hidatidícos de Echinococcus spp. No se encontraron escólecis o cabezas de la tenia. El examen microscópico de la pared interna de uno de los quistes mostró un epitelio ciliado, variando de cuboidal a columnar, conduciendo a un diagnóstico de quiste en el oviducto. Se revisan otros casos de hidatidosis en aves.

Revisiting the Acanthamoeba species that form star-shaped cysts (genotypes T7, T8, T9, and T17): characterization of seven new Brazilian environmental isolates and phylogenetic inferences

Free-living amoebae of the genus Acanthamoeba are the agents of both opportunistic and non-opportunistic infections and are frequently isolated from the environment. Of the 17 genotypes (T1-T17) identified thus far, 4 (T7, T8, T9, and T17) accommodate the rarely investigated species of morphological group I, those that form large, star-shaped cysts. We report the isolation and characterization of 7 new Brazilian environmental Acanthamoeba isolates, all assigned to group I. Phylogenetic analyses based on partial (similar to 1200 bp) SSU rRNA gene sequences placed the new isolates in the robustly supported clade composed of the species of morphological group I. One of the Brazilian isolates is closely related to A. comandoni (genotype T9), while the other 6, together with 2 isolates recently assigned to genotype T17, form a homogeneous, well-supported group (2-0% sequence divergence) that likely represents a new Acanthamoeba species. Thermotolerance, osmotolerance, and cytophatic effects, features often associated with pathogenic potential, were also examined. The results indicated that all 7 Brazilian isolates grow at temperatures up to 40 degrees C, and resist under hvperosmotic conditions. Additionally, media conditioned by each of the new Acanthamoeba isolates induced the disruption of SIRC and HeLa cell monolayers.

Conservative Management of a Large Keratocystic Odontogenic Tumor in the Maxilla

Keratocystic odontogenic tumor is characterized by high recurrence rates. Conservative or aggressive management has been suggested as a method of treatment. Decompression is a conservative treatment that has been used in the treatment of large odontogenic cysts. The authors report a case of a 14-year-old patient with a keratocystic odontogenic tumor located in the right maxilla, which was treated by decompression followed by enucleation with curettage. The lesion did not recur on follow-up for 3 years after the enucleation surgery.

Combined pre- and subtemporal transtentorial approach for epidermoid cysts of the cerebellopontine angle

Objective Epidermoid cysts of the cerebellopontine angle (CPA) can be a surgical challenge for the pediatric neurosurgeon. Ideally, total removal must be achieved; however, occasional adhesions of these tumors to vital neurovascular structures and extension far beyond the midline may preclude their total removal. The aims of this article are to present an alternative surgical approach to these lesions and to provide the rationale for this technique. Material and methods A 16-year-old boy was admitted to our pediatric neurosurgery department with a 1-year history of nonspecific headaches. His neurological examination showed right-sided dysmetria and gait ataxia. Magnetic resonance scans showed a space-occupying lesion on the right CPA with low intensity on T-1-weighted images and high intensity on T-2-weighted images. Results Craniotomy for tumor excision via pre- and subtemporal transtentorial approach was performed disclosing a 3.5 x 3 x 2.8-cm(3) well-encapsulated tumor, which was confirmed to be an epidermoid cyst. The postoperative course was uneventful. Conclusions A combined pre- and subtemporal approach utilizes a wide opening of the tentorium and the option of supratentorial retraction of the cerebellum to provide an excellent angle of approach to CPA lesions involving the anterolateral aspect of the brain stem in children.

Orbital Invasion by Squamous Cell Carcinoma Arising in Multiple Epidermoid Cysts

Epidermal or epidermoid cysts usually are benign, solitary-growing masses located in the mid- or lower dermis. They are believed to derive from pilosebaceous units and are lined with an epidermis-like epithelium including a granular cell layer.(1) The occurrence of multiple epidermal cysts on the scalp of nonsyndromic patients is extremely rare. Although the presence of squamous cell carcinoma in the wall of an isolated epidermoid cysts is well documented in the dermatological literature,(2,3) the authors are not aware of any article in the English literature describing orbital invasion by a carcinoma developed in isolated or multiple epidermoid cysts.

Jaw mechanics of the pterosaur skull construction and the evolution of toothlessness

In the present study, pterosaur skull constructions were analysed using a combined approach of finite element analysis (FEA), static investigations as well as applying classical beam theory and lever mechanics. The study concentrates on the operating regime „bite“, where loads are distributed via the dentition or a keratinous rhamphotheca into the skull during jaw occlusion. As a first step, pterosaur tooth constructions were analysed. The different morphologies of the tooth construction determine specific operational ranges, in which the teeth perform best (= greatest resistance against failure). The incomplete enamel-covering of the pterosaur tooth constructions thereby leads to a reduction of strain and stress and to a greater lateral elasticity than for a complete enamel cover. This permits the development of high and lateral compressed tooth constructions. Further stress-absorption occurs in the periodontal membrane, although its mechanical properties can not be clarified unambiguously. A three-dimensionally preserved skull of Anhanguera was chosen as a case-study for the investigation of the skull constructions. CT-scans were made to get information about the internal architecture, supplemented by thin-sections of a rostrum of a second Anhanguera specimen. These showed that the rostrum can be approximated as a double-walled triangular tube with a large central vacuity and an average wall-thickness of the bony layers of about 1 mm. On base of the CT-scans, a stereolithography of the skull of Anhanguera was made on which the jaw adductor and abductor muscles were modelled, permitting to determine muscular forces. The values were used for the lever mechanics, cantilever and space frame analysis. These studies and the FEA show, that the jaw reaction forces are critical for the stability of the skull construction. The large jugal area ventral to the orbita and the inclined occipital region act as buttresses against these loads. In contrast to the orbitotemporal region which is subject to varying loading conditions, the pattern in the rostrum is less complex. Here, mainly bending in dorsal direction and torsion occur. The hollow rostrum leads to a reduction of weight of the skull and to a high bending and torsional resistance. Similar to the Anhanguera skull construction, the skulls of those pterosaur taxa were analysed, from which enough skull material is know to permit a reliable reconstruction. Furthermore, FEA were made from five selected taxa. The comparison of the biomechanical behaviour of the different skull constructions results in major transformational processes: elongation of rostra, inclination of the occipital region, variation of tooth morphology, reduction of the dentition and replacement of teeth by a keratinous hook or rhamphotheca, fusion of naris and antorbital fenestra, and the development of bony and soft-tissue crests. These processes are discussed for their biomechanical effects during bite. Certain optional operational ranges for feeding are assigned to the different skull constructions and previous hypotheses (e.g. skimming) are verified. Using the principle of economisation, these processes help to establish irreversible transformations and to define possible evolutionary pathways. The resulting constructional levels and the structural variations within these levels are interpreted in light of a greater feeding efficiency and reduction of bony mass combined with an increased stability against the various loads. The biomechanical conclusive pathways are used for comparison and verification of recent hypothesis of the phylogenetic systematics of pterosaurs.