ABSTRACT
The evolutionary shift from a single-element ear, multi-element jaw to a multi-element ear, single-element jaw during the transition to crown mammals marks one of the most dramatic structural transformations in vertebrates. Research on this transformation has focused on mammalian middle-ear evolution, but a mandible comprising only the dentary is equally emblematic of this evolutionary radiation. Here, we show that the remarkably diverse jaw shapes of crown mammals are coupled with surprisingly stereotyped jaw stiffness. This strength-based morphofunctional regime has a genetic basis and allowed mammalian jaws to effectively resist deformation as they radiated into highly disparate forms with markedly distinct diets. The main functional consequences for the mandible of decoupling hearing and mastication were a trade-off between higher jaw stiffness versus decreased mechanical efficiency and speed compared with non-mammals. This fundamental and consequential shift in jaw form-function underpins the ecological and taxonomic diversification of crown mammals. This article is part of the theme issue 'The mammalian skull: development, structure and function'.
Subject(s)
Biological Evolution , Jaw , Animals , Mandible , Skull , Ear, Middle , Mammals/geneticsABSTRACT
BACKGROUND: Pancreatic cell destruction causing type 1 diabetes is associated to diverse autoantibodies. Antibodies against glutamic acid decarboxylase have been found in type 1 (DM1) and type 2 diabetic patients (DM2). Their presence in siblings is unknown. OBJECTIVE: To determine the presence of anti-GAD65 autoantibodies in diabetic patients and their siblings. PARTICIPANTS AND METHOD: Sixty-eight individuals were included and distributed in four groups: group 1 DM1, group 2 DM2, group 3 and 4 healthy siblings of patients from groups 1 and 2. Anti-GAD65, peptide C, serum glucose, total cholesterol and triglycerides were obtained. Body mass index and hip-waist ratio were measured. RESULTS: Anti-GAD65 antibodies were positive in 23% of DM1, in 14% of DM2, and in 7.7% and 9.5% in siblings of both groups, respectively. Using Mann-Whitney's U the mean of anti-GAD65 in diabetic type 1 and 2 patients was p = 0.022; between DM1 and their siblings and between DM2 and their siblings there was no statistical significance. C peptide was low in cases of positive anti-GAD65 of DM1 and DM2; and it was normal in patients with negative anti-GAD65. CONCLUSIONS: Anti-GAD65 autoantibodies are more frequent in type 1 diabetic patients. There were no meaningful differences regarding the presence of anti-GAD65 in patients and their siblings.
Subject(s)
Autoantibodies , Siblings , Adult , C-Peptide , Diabetes Mellitus, Type 1 , Glutamate Decarboxylase , HumansABSTRACT
BACKGROUND: The primary immunodeficiency diseases cause a deficit in the production of antibodies. The chronic sinopulmonary disease is common and their clinic symptoms are diverse (pneumonia, bronchiectasis). OBJECTIVE: To know the frequency and type of pulmonary abnormalities in patients with primary immunodeficiency in treatment with intravenous immunoglobulin. MATERIAL AND METHODS: 24 files of patients with primary immunodeficiency were selected. Age, sex, primary immunodeficiency type, time of immunoglobulin treatment, chest X-ray finding, pulmonary computed tomography of high resolution (HRCT) and pulmonary function tests were registered. Measures of central tendency were calculated. RESULTS: There was no predominance of gender; the average age was 14 years old. The common variable immunodeficiency and the Bruton's hypogammaglobulinemia represented 91% of the patients. The X-ray of thorax was abnormal in 33%, although there were not bronchiectasis. The high-resolution computed tomography scan (HRCT) was abnormal in 67%, and 75% had bronchiectasis. CONCLUSIONS: The pulmonary complications are common despite therapy with intravenous immunoglobulin. The HRCT is better than X-ray in these patients.
