Life-threatening respiratory failure due to cranial dystonia after dental procedure in a patient with multiple system atrophy.

We report on a woman with a an 8-year history of multiple system atrophy with predominance of parkinsonism who developed jaw-locking oromandibular dystonia within hours after insertion of ill-fitting dentures. Dystonia spread rapidly to involve other facial muscles and the larynx causing stridor with respiratory failure necessitating crush intubation.     

Predicting Skull Loading: Applying Multibody Dynamics Analysis to a Macaque Skull

Evaluating stress and strain fields in anatomical structures is a way to test hypotheses that relate specific features of facial and skeletal morphology to mechanical loading. Engineering techniques such as finite element analysis are now commonly used to calculate stress and strain fields, but if we are to fully accept these methods we must be confident that the applied loading regimens are reasonable. Multibody dynamics analysis (MDA) is a relatively new three dimensional computer modeling technique that can be used to apply varying muscle forces to predict joint and bite forces during static and dynamic motions. The method ensures that equilibrium of the structure is maintained at all times, even for complex statically indeterminate problems, eliminating nonphysiological constraint conditions often seen with other approaches. This study describes the novel use of MDA to investigate the influence of different muscle representations on a macaque skull model (Macaca fascicularis), where muscle groups were represented by either a single, multiple, or wrapped muscle fibers. The impact of varying muscle representation on stress fields was assessed through additional finite element simulations. The MDA models highlighted that muscle forces varied with gape and that forces within individual muscle groups also varied; for example, the anterior strands of the superficial masseter were loaded to a greater extent than the posterior strands. The direction of the muscle force was altered when temporalis muscle wrapping was modeled, and was coupled with compressive contact forces applied to the frontal, parietal and temporal bones of the cranium during biting. Anat Rec, 291:491–501, 2008. © 2008 Wiley‐Liss, Inc.     

Role of neoadjuvant chemotherapy in congenital intracranial haemangiopericytoma

Infantile haemangiopericytoma of the CNS is a rare entity. We report the first case of a congenital haemangiopericytoma successfully treated by preoperative chemotherapy. The patient presented shortly after birth with the diagnosis of a haemangiopericytoma. As neurosurgery was too risky due to size, location and age of the patient an anthracycline‐based chemotherapeutic regimen was applied and resulted in a significant decrease in tumour size, making a postchemotherapy complete surgical resection possible. Chemotherapy may benefit patients with congenital haemangiopericytoma especially if the tumour cannot initially be treated by complete neurosurgical resection. Pediatr Blood Cancer. 2010;56:161–163. © 2010 Wiley‐Liss, Inc.     

Structure–function relations of primate lower incisors: a study of the deformation of Macaca mulatta dentition using electronic speckle pattern interferometry (ESPI)

Teeth adopt a variety of different morphologies, each of which is presumably optimized for performing specific functions during feeding. It is generally agreed that the enamel cap is a crucial element in controlling the mechanical behavior of mammalian teeth under load. Incisors are particularly interesting in terms of structure–function relations, as their role in feeding is that of the ‘first bite’. However, little is known how incisor cap morphology is related to tooth deformation. In the present paper we examine the mechanical behavior of mandibular central incisors in the cercopithecine primate Macaca mulatta under loads similar to those encountered during ingestion. We map three‐dimensional displacements on the labial surface of the crown as it is compressed, using electronic speckle pattern interferometry (ESPI), an optical metrology method. In addition, micro‐computed tomography is used to obtain data regarding the morphology of the enamel cap, which in the M. mulatta lower incisors exhibits missing or very little enamel on the lingual face. The results showed that although compressed along a longitudinal axis, deformation in the incisors mostly occurred in the lingual direction and orthogonal to the direction of the applied load. Both isolated, embedded teeth and teeth in the mandible showed considerable lingual deformation. Incisor deformation in the mandible was generally greater, reflecting the additional freedom of movement enabled by the supporting structures. We show that the association with adjacent teeth in the arch is significant for the behavior of the tooth under load. Finally, loading two teeth simultaneously in the mandible showed that they work as one functional unit. We suggest that these results demonstrate the importance of enamel cap morphology in directing deformation behavior; an ability stemming from the stiffness of the enamel cap overlying the more pliable dentin.     

Assessing mechanical function of the zygomatic region in macaques: validation and sensitivity testing of finite element models

Crucial to the interpretation of the results of any finite element analysis of a skeletal system is a test of the validity of the results and an assessment of the sensitivity of the model parameters. We have therefore developed finite element models of two crania of Macaca fascicularis and investigated their sensitivity to variations in bone material properties, the zygomatico-temporal suture and the loading regimen applied to the zygomatic arch. Maximum principal strains were validated against data derived from ex vivo strain gauge experiments using non-physiological loads applied to the macaque zygomatic arch. Elastic properties of the zygomatic arch bone and the zygomatico-temporal suture obtained by nanoindentation resulted in a high degree of congruence between experimental and simulated strains. The findings also indicated that the presence of a zygomatico-temporal suture in the model produced strains more similar to experimental values than a completely separated or fused arch. Strains were distinctly higher when the load was applied through the modelled superficial masseter compared with loading an array of nodes on the arch. This study demonstrates the importance of the accurate selection of the material properties involved in predicting strains in a finite element model. Furthermore, our findings strongly highlight the influence of the presence of craniofacial sutures on strains experienced in the face. This has implications when investigating craniofacial growth and masticatory function but should generally be taken into account in functional analyses of the craniofacial system of both extant and extinct species.     

Adherence to self‐care behavior and glycemic effects using structured education

Aims/Introduction

The purpose of the present study was to examine glycemic control in suboptimally controlled type 2 diabetes provided by a structured education group using the Diabetes Conversation Map™ (CM™) vs usual care in a university-based hospital primary care clinic.

Materials and Methods

This was a randomized, pragmatic clinical trial. Patients with type 2 diabetes were randomly assigned to structured education or usual care groups. The primary outcome was the difference in the mean change of glycated hemoglobin (HbA1c) from baseline to 12 months. Secondary outcomes included the percentage achieving therapeutic HbA1c goal and self-behavioral changes.

Results

A total of 245 patients were randomly assigned to two groups (CM™ group n = 121; usual care group, n = 116). The absolute reduction of HbA1c was significantly greater in the CM™ group at 3 and 6 months (Δ = −0.59% and Δ = −1.13%, P < 0.01), but the difference was no longer statistically significant at 9 and 12 months (Δ = −0.43% and Δ = −0.49%), based on an intention-to-treat analysis. A per-protocol analysis showed the significant change was maintained at 12 months (Δ = −0.67%). In the intervention group, greater percentages of patients achieved their American Association of Diabetes Educators Self-Care Behaviours™ framework (AADE7) behavioral goals at 3 months, in particular being active, problem-solving, reducing risk and health coping.

Conclusions

In type 2 diabetic patients with suboptimally controlled glucose, there were greater improvements in glucose control and self-care behavioral goals in those who underwent the CM™ education program compared with outcomes achieved in patients receiving usual care.     

A coiled-coil motif that sequesters ions to the hydrophobic core

Most core residues of coiled coils are hydrophobic. Occasional polar residues are thought to lower stability, but impart structural specificity. The coiled coils of trimeric autotransporter adhesins (TAAs) are conspicuous for their large number of polar residues in position d of the core, which often leads to their prediction as natively unstructured regions. The most frequent residue, asparagine (N@d), can occur in runs of up to 19 consecutive heptads, frequently in the motif [I/V]xxNTxx. In the Salmonella TAA, SadA, the core asparagines form rings of interacting residues with the following threonines, grouped around a central anion. This conformation is observed generally in N@d layers from trimeric coiled coils of known structure. Attempts to impose a different register on the motif show that the asparagines orient themselves specifically into the core, even against conflicting information from flanking domains. When engineered into the GCN4 leucine zipper, N@d layers progressively destabilized the structure, but zippers with 3 N@d layers still folded at high concentration. We propose that N@d layers maintain the coiled coils of TAAs in a soluble, export-competent state during autotransport through the outer membrane. More generally, we think that polar motifs that are both periodic and conserved may often reflect special folding requirements, rather than an unstructured state of the mature proteins.     

Torsade de pointes--a rare presentation of primary hyperaldosteronism

Primary aldosteronism was the most common form of endocrine hypertension resulting in hypertension, metabolic alkalosis, and hypokalemia. Ventricular arrhythmia in association with primary hyperaldosteronism is an uncommon presentation that has previously been described in literature. We presented one case of torsades de pointes due to primary hyperaldosteronism.