Atrial conduction times and left atrial mechanical functions and their relation with diastolic function in prediabetic patients

BACKGROUND/AIMS: The aim of this study was to investigate atrial conduction times and left atrial mechanical functions, the noninvasive predictors of atrial fibrillation, in prediabetic patients with impaired fasting glucose (IFG) and impaired glucose tolerance (IGT). METHODS: Study included 59 patients (23 males, 36 females; mean age 52.5 ± 10.6 years) diagnosed with IFG or IGT by the American Diabetes Association criteria, and 43 healthy adults (22 males, 21 females; mean age 48.5 ± 12.1 years). Conventional and tissue Doppler echocardiography were performed. The electromechanical delay parameters were measured from the onset of the P wave on the surface electrocardiogram to the onset of the atrial systolic wave on tissue Doppler imaging from septum, lateral, and right ventricular annuli. The left atrial volumes were calculated by the disk method. Left atrial mechanical functions were calculated. RESULTS: The mitral E/A and E′/A′ ratios measured from the lateral and septal annuli were significantly lower in the prediabetics compared to the controls. The interatrial and left atrial electromechanical delay were significantly longer in prediabetic group compared to the controls. Left atrial active emptying volume (LAAEV) and fraction (LAAEF) were significantly higher in the prediabetics than the controls. LAAEV and LAAEF were significantly correlated with E/A, lateral and septal E′/A′. CONCLUSIONS: In the prediabetic patients, the atrial conduction times and P wave dispersion on surface electrocardiographic were longer before the development of overt diabetes. In addition, the left atrial mechanical functions were impaired secondary to a deterioration in the diastolic functions in the prediabetic patients.

Morphologic effects of filiform papilla root on the lingual mechanical functions of Chinese yellow cattle / Efectos morfológicos de las raíces de las papilas filiformes sobre la función mecánica lingual del ganado amarillo chino

The morphology of filiform papilla root in the tongue of Chinese yellow cattle were studied by scanning electron microscopy, and several geometric models were established to analyze the possible effects of such structures on lingual mechanical functions. Conical and tongue-like filiform papillae were detected in different locations on the lingual surface, along with six types of root structures. A lingual groove surrounded the papillae in five of these structures. To date, such grooves have not been discussed in studies on bovine lingual morphology, and those distributed on the dorsal surface of the lingual apex can limit the motion ranges of filiform papillae. Two secondary papillae emerged from a groove on the dorsal surface of the lingual apex's caudal half; these papillae can protect a filiform papilla root from damage. The grooves and the flat orientation of such papillae on the dorsal surface of the lingual body can reduce energy expenditure during forage transportation. A lingual rib that can strengthen the filiform papilla root emerged from a groove on the dorsal surface of the rostral half of the lingual body. On the dorsal surface of the lingual body's caudal half, all filiform papillae emerged from a groove to form low lingual walls that can protect the roots from being crushed by forage. High lingual walls were generated on the lateral surface of the lingual apex; these walls enable filiform papillae to adapt to harsh food environments effectively. The root structures on the lingual body's lateral surface were adequately simple and did not exhibit lingual grooves; thus, hydraulic resistance may decrease during mastication. Diverse root structures can optimize the lingual mechanical functions and improve self-protection capability in combination with the appearance and distributions of these papillae. All the aforementioned features may be the result of environmental adaption and cattle evolution.

La morfología de las papilas filiformes ubicadas en la raíz lingual del ganado amarillo chino fue estudiada mediante microscopía electrónica de barrido, estableciendo varios modelos geométricos para analizar los posibles efectos de estas estructuras sobre las funciones mecánicas linguales. Se detectaron papilas filiformes cónicas en diversas localizaciones de la superficie lingual, junto con seis tipos de estructuras en la raíz de la misma. Un surco lingual rodeado de las papilas se observó en cinco de estas estructuras. Hasta la fecha, dichos surcos no se han discutido en los estudios sobre la morfología lingual bovina, y aquellas distribuidas en la superficie dorsal de la cúspide lingual pueden limitar los rangos de movimientos en las papilas filiformes. Dos papilas secundarias surgieron de una ranura en la superficie dorsal de la mitad caudal de la cúspide lingual; estas papilas pueden proteger de los daños a una papila filiforme. Las ranuras y la orientación plana de tales papilas en la superficie dorsal del cuerpo lingual pueden reducir el gasto de energía durante el transporte de forraje. Un nervio lingual que puede fortalecer la raíz y las papilas filiformes se observó en una de las ranuras en la superficie dorsal, de la mitad rostral del cuerpo lingual. En la superficie dorsal de la mitad caudal del cuerpo lingual, todas las papilas filiformes generaron una ranura para formar un tipo de paredes linguales que pueden proteger las raíces. Las paredes linguales altas se generaron en la superficie lateral del ápice lingual; estas paredes permiten que las papilas filiformes se adapten a entornos inhóspitos de alimentos. Las estructuras de la raíz en la superficie lateral del cuerpo lingual fueron simples y no mostraron surcos linguales, lo que puede disminuir la resistencia hidráulica durante la masticación. Diversas estructuras de la raíz pueden optimizar las funciones mecánicas linguales y mejorar la capacidad de autoprotección en combinación con el aspecto y las distribuciones de estas papilas. Todas las características antes mencionadas pueden ser el resultado de la adaptación ambiental y la evolución de ganado.

Comparison of the atrial electro-mechanical function after successful cardioversion as a result of radiofrequency ablation and drug therapy for paroxysmal atrial fibrillation / 解放军医学杂志

Objective To compare the change in atrial electro-mechanical function after successful cardioversion treated by radiofrequency ablation or antiarrhythmic drug therapy in paroxysmal atrial fibrillation (PAF). Methods Sixty patients with PAF and 20 patients with sinus rhythm (control group), admitted or receiving physical examination at the Air Force General Hospital from Jan. 2011 to Jul. 2014, were consecutively enrolled in the present study. Thirty PAF patients were assigned to either the ablation group or drug treatment group according to their own intention. All the subjects received the baseline electrocardiogram and echocardiography, and the same examinations were repeated in all PAF patients in follow up period. P wave duration and amplitude, atrial volume and strain rate were analyzed, and these parameters were compared between the two treatment groups at follow-up. Results No significant difference was detected in baseline parameters of the P wave duration and amplitude, atrial volume, and the strain rate between two PAF groups (P>0.05). However, these parameters were significantly lower than those in control group (P<0.05). Three months after treatment, these atrial parameters were found to be improved, and atrial mechanical parameters including the strain rate was improved obviously (P<0.05). At six-month follow up, atrial parameters of the two PAF groups were further improved. Compared with patients of drug treatment group, the results in patients of ablation group were significantly better (P<0.05). Conclusions The P wave duration and amplitude, atrial volume and strain rate can be used as suitable parameters to evaluate the atrial electro-mechanical function. The atrial conduction and mechanical function of PAF patients can be improved by radiofrequency ablation or by drug therapy. Compared with drug therapy, ablation is more effective in improving the atrial parameters. The improvement of mechanical parameters is earlier than that of electrical conductivity, and it can be used as a sensitive parameter to evaluate atrial function improvement after cardioversion in patients with PAF.

To improve the mechanical function of bovine jugular vein by external stent / 中华胸心血管外科杂志

Objective To increase the mechanic characteristic of bovine jugular veins conduit (BJVC) by combined knitted stent outside made of nylon fiber. Methods Get rid of the cells of BJVC by enzymolysis, then combined a fabric stent with a acellular bovine jugular vein conduit that cross-linked dealed by photooxidation method to improve the mechanic function of BJVC. To compare the mechanical function and histology change of BJVC combined with fiber stent outside with that of BJVC only without stent. BJVC combined with fiber stent outside was divided into experiment group and the latter into control group. Two roller pumps on cardiopulmonary bypass unit were designed to simulate the pulmonary circulation. One produce the stream, and the other assist to bring a certain pressure by regulating a degree of tightness. The pressure of forward stream was used in messuring extension rate and leakage volume of two BJVC groups, and the pressure of backward stream was used in messuring the regurgitation volume. Results Set the formula to calculate the rate of variation of BJVC diameter under a certain pressure or not. The experiment group extension rate was zero under pressure of 10-20 mm Hg, about ( 7.7 ± 2.3 ) % under pressure of 40 mm Hg, until 60 mm Hg to ( 11.4 ± 3.1 ) %. While the control group reached about ( 14.8 ± 4.7 ) % at 20mm Hg already. There was no regurgitation volume of the experiment group under pressure of 30 mm Hg vs. the control group' s reached 34ml/min at 30 mm Hg while the two groups were same under pressure that lower than 20 mm Hg. When the pressure higher, the difference between the two groups more notable. There was no leakage of the BJVCs with fabric stent till pressure from 40 mmHg to 60mmHg, vs. the control group 1,5, 13 ml/min at pressure 30, 40, 60 mm Hg. Except the regurgitation and leakage volumes under pressure at 10 -20 mm Hg, as the two numerical values were both zero that can not be caculated by the statistic software, the differences of the two groups above had statistics significance. In vivo, 9 dogs received bovine jugular vein conduit transplant procedure to observe the mechanic fnction and tissue reaction. Five adopted B.JVC with stent and four just BJVC only. Six month later after the transplant procedure, there was no significant difference between the two groups but more inflaming cells than the former group, especially at the location round the nylon fibers. Through the observation in HE stain, that was considered as foreign body reaction. Conclusion Fabric stent can improve the mechanical function of BJVC and relatively easy to get.

Three / 대한정형외과학회잡지

Since the finite element method(FEM) was introduced to the orthopaedic biomechanics, it has been applied with increasing intrest to investigate bone, bone-prosthesis, and fracture fixation device, etc., in terms of stress, strain, force, and displacement. The authors implemented the FEM for the "intact" and the "fractured long bone models respectively to observe the mechanical behaviors of the plate fixation for the long bone fractures, and we observed the followings;l. In the intact model, stresses are evenly distributed and smoothly changed. 2. The maximum equivalent von-Mises stress in the fracture model is higher than that in the intact one. 3. Stresses on the plate are much higher than those on the bony surface in the fracture model. 4. Stresses for the bony surface beneath the plate in the fracture model are much lower than those in the intact model;however, stresses are highly concentrated around the screws. 5. Although two-thirds of total compressive load is transmitted through the fracture site area, maximum von-Mises stress in the fracture site is much lower than that in the plate. 6. High stresses are found at the areas between the plate holes and the screw heads. 7. Shearing forces of the screws are higher at the near and end screws from the fracture site.

ORIENTATION AND MECHANICAL ANALYSIS OF THE LUMBAR ZYGAPOPHYSEAL JOINTS / 解剖学报

The stereoscopic orientation of the lumbar zygapophyseal joints and the stability triangle of the motion segments were studied on 56 sets of adult lumbosacral skeletons. The orientation of the lumbar zygapophyseal joints changed gradually from about sagittal plane in upper segment to about coronal in lower. The gravity center of the stability triangle of the motion segments moved backward from upper to ower progressively. Therefore, the stability of lumbar spine decreases and the mobility increases successively from upper downward.