Bionanocomposite scaffolds based on chitosan-gelatin and nanodimensional bioactive glass particles: In vitro properties and in vivo bone regeneration.

Bone repair bionanocomposite scaffolds were produced by incorporating dense bioactive glass nanoparticles or mesoporous bioactive glass nanospheres into a chitosan-gelatin polymer blend. The in vitro bioactivity of the scaffolds was assessed in simulated body fluid, and cell viability and osteogenic differentiation assays were performed with dental pulp stem cells. Bone regeneration properties of the scaffold materials were in vivo assessed by using a critical-sized femoral defect model in rat. The scaffold nanocomposites showed excellent cytocompatibility and ability to accelerate the crystallization of bone-like apatite in vitro. Bionanocomposites prepared with bioactive glass nanoparticles were particularly more active to promote the osteogenic differentiation of dental pulp stem cells as judged by the higher activity of alkaline phosphatase. This result is attributed to the faster dissolution of bioactive glass nanoparticles into osteogenic ionic products compared to mesoporous bioactive glass nanospheres. In vivo experiments demonstrated that bioactive glass nanoparticles (5%)/chitosan-gelatin bionanocomposite significantly produces the highest amount of new bone (∼80%) in the defect area after eight weeks of implantation. The bone regeneration capacity exhibited by the scaffolds formulated with nanodimensional bioactive glass particles make them attractive for bone reconstruction applications.

Effects of breathing type on electromyographic activity of respiratory muscles at different body positions.

AIM: To compare the effect of breathing type on the activity of respiratory muscles at different body positions. METHODOLOGY: Two groups of 20 subjects each, one with upper costal and the other with costodiaphragmatic breathing, were studied. Electromyographic activity of sternocleidomastoid (SCM), diaphragm (DIA), external intercostal (EIC), and latissimus dorsi (LAT) muscles was recorded at standing and lateral decubitus positions during swallowing and maximal voluntary clenching. RESULTS: All muscles showed higher activity during standing in upper costal breathing subjects except the SCM muscle. EIC activity was higher during standing in the costodiaphragmatic breathing group. Subjects with upper costal breathing showed higher DIA activity than subjects with costodiaphragmatic breathing at both body positions and higher SCM activity at lateral decubitus position, whereas, EIC activity was only higher during swallowing. CONCLUSIONS: Subjects with upper costal breathing presented higher respiratory effort than subjects with costodiaphragmatic breathing, being most prominent at the lateral decubitus position.

Effect of upper costal and costo-diaphragmatic breathing types on electromyographic activity of respiratory muscles.

AIM: To compare electromyographic (EMG) activity in young-adult subjects with different breathing types. METHODOLOGY: This study included 50 healthy male subjects with complete natural dentition, and no history of orofacial pain or craniomandibular-cervical-spinal disorders. Subjects were classified into two groups: upper costal breathing type, and costo-diaphragmatic breathing. Bipolar surface electrodes were located on sternocleidomastoid, diaphragm, external intercostal, and latissimus dorsi muscles. Electromyographic activity was recorded during the following tasks: (1) normal quiet breathing; (2) speaking the word 'Mississippi'; (3) swallowing saliva; and (4) forced deep breathing. RESULTS: Sternocleidomastoid and latissimus dorsi EMG activity was not significantly different between breathing types, whereas diaphragm and external intercostal EMG activity was significantly higher in the upper costal than costo-diaphragmatic breathing type in all tasks (P<0·05; Wilcoxon signed rank-sum test). CONCLUSION: Diaphragm and external intercostal EMG activity suggests that there could be differences in motor unit recruitment strategies depending on the breathing type.

[Clinical differences between suicide and non suicide attempter hospitalized adolescents]. / Diferencias clínicas entre adolescentes hospitalizados por intento suicida y adolescentes hospitalizados por otra causa psiquiátrica.

BACKGROUND: Suicide is the third cause of death among adolescents in United States and between 5 to 12% of teenagers have a history of suicide attempt. Therefore, suicide is a public health problem in this age group. AIM: To compare the clinical characteristics of hospitalized adolescents who attempted suicide with those without a history of suicide attempt. MATERIAL AND METHODS: The clinical records of adolescents aged less than 18 years, hospitalized in a psychiatric clinic, were analyzed. Forty six patients aged 15 +/-2 years (72% females) had a history of suicide attempt and were considered cases and 81 patients aged 15 +/-2 years (52% females) did not have a history of suicide attempt and were considered controls. Demographical and clinical characteristics of both groups were compared. Psychiatric diagnoses were based on the Diagnostic and Statistical Manual of Mental Disorders IV (DSMIV). RESULTS: No significant differences were found between groups in the length of hospital stay. The most common psychiatric diagnosis was depressive disorder, found in 71 and 35% of suicide and non-suicide attempters, respectively (p < 0.01). Personality diagnosis was deferred in most studied cases. CONCLUSIONS: Depression is more common among hospitalized adolescents who attempt suicide.