Effect of ceftriaxone on the intestinal epithelium and microbiota in neonatal mice / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the effect of ceftriaxone on the intestinal epithelium and microbiota in mice in the early-life stage, as well as the recovery of the intestinal epithelium and reconstruction of intestinal microbiota in adult mice.</p><p><b>METHODS</b>A total of 36 BALB/C neonatal mice were randomly divided into control group and experimental group, with 18 mice in each group. The mice in the experimental group were given ceftriaxone 100 mg/kg every day by gavage within 21 days after birth. Those in the control group were given an equal volume of normal saline by gavage. Immunohistochemistry was used to measure the expression of Ki67, Muc2, and ZO-1 in the intestinal epithelium. qPCR and next-generation sequencing were used to analyze the overall concentration and composition of fecal bacteria.</p><p><b>RESULTS</b>After 21 days of ceftriaxone intervention, the experimental group had a significant reduction in body weight, a significant reduction in the expression of Ki67 and ZO-1 and a significant increase in the expression of Muc2 in intestinal epithelial cells, a significant reduction in the overall concentration of fecal bacteria, and a significant increase in the diversity of fecal bacteria compared with the control group (P<0.05). Firmicutes was the most common type of fecal bacteria in the experimental group, and there were large amounts of Staphylococcus and Enterococcus. The experimental group had a certain degree of recovery of the intestinal epithelium, but there were still significant differences in body weight and the structure of intestinal microbiota between the two groups at 56 days after birth (P<0.05).</p><p><b>CONCLUSIONS</b>Early ceftriaxone intervention significantly affects the development of the intestinal epithelium and the construction of intestinal microbiota in the early-life stage. The injury of the intestinal microbiota in the early-life stage may continue to the adult stage and affect growth and development and physiological metabolism.</p>

Biomechanics and rehabilitation technical aids / 医用生物力学

The effect and significance of rehabilitation technical aids are growing with the population aging. Recently, the State Council of China has released several documents about the industrial development of Chinese rehabilitation technical aids, and proposed new requirements on the innovation in this field. Biomechanics plays an important role in rehabilitation technical aids, including exercise rehabilitation training system, orthotic device, artificial limb, walking aid, etc. In this special issue, several biomechanical papers about rehabilitation and rehabilitation technical aids are included，to provide references for rehabilitation engineering and rehabilitation technical aids.

The First Switched Time of PML/RARα Fusion Gene in Patients with Acute Promyelocytic Leukemia and Its Clinical Significance / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To investigate the first switched time of PML/RARα fusion gene in patients with acute promyelocytic leukemia (APL) and its clinical significance.</p><p><b>METHODS</b>sixty cases of newly diagnosed APL were enrolled in this study. They received standard remission induction, consolidation and maintenance treatments according to the clinical pathway for APL, and were followed up. During the same time the PML/RARα fusion gene mRNA expression of all cases was detected by multi-nested PCR.</p><p><b>RESULTS</b>except for 3 death cases and 1 case failed to follow-up, the PML/RARα fusion genes in the remaining 56 cases were firstly found to be negative from 24 to 381 days respectively, the mean value of the first switched time was 131 ± 90 days. There was no statistically significant difference in age, sex and risk stratification between different groups. However, the cases with L-type PML/RARα gene had shorter time compared with the patients with S-type PML/RARα gene (P = 0.032); then, for the above-mentimed 56 cases, the follow-up duration ranged from 25-1979 days (median 946 days), long-term molecular remissions had been observed in most cases, but 1 case with the first switched time of 133 days unfortunately recurred to be positive and followed by clinical relapse.</p><p><b>CONCLUSION</b>The PML/RARα fusion gene in newly diagnosed APL patients was first switched to be negative in about 4 months after treatment. The first switched time of PML/RARα fusion gene can objectively reflect the reduction of leukemia cells, and the differences among different subtypes of PML/RARα fusion gene may have some suggestions for the treatment, but without important significance for the evaluation of prognosis and recurrence for APL patients. In addition, minimal residual disease (MRD) can be dynamically monitored by detecting PML/RARα fusion gene, thus having an important clinical significance for analysis of APL recurrence.</p>

The effect of the acupuncture intervention of dredging Governor Vessel and regulating mentality for the medication treatment of post-stroke depression / 中国针灸

<p><b>OBJECTIVE</b>To observe the differences in onset time and the overall efficacy of the acupuncture therapy of dredging Governor Vessel and regulating mentality combined with fluoxetine and the fluoxetine for post-stroke depression(PSD).</p><p><b>METHODS</b>Sixty-three patients were randomly divided into an acupuncture intervention of dredging Governor Vessel and regulating mentality group(acupuncture and medication group, 33 cases) and a control group (medication group, 30 cases). In the medication group, 20 mg fluoxetine was used by oral administration, once a day at 7:00 in the morning, continuously for 4 weeks. In the acupuncture and medication group, based on the oral administration of fluoxetine, the acupuncture intervention of dredging Governor Vessel and regulating mentality was applied mainly at Baihui(GV 20), Fengfu(GV 16), Shenting(GV 24), Shuigou(GV 26), Dazhui(GV 14) and Shendao(GV 11), once a day, 6 times a week, continuously for 4 weeks. Twenty-four items in Hamilton Depression Scale(HAMD), modified Edinburgh Scandinavia Stroke Scale(MESSS) and activity of daily life scale(ADL, Barthel index, BI) were used before and after 2-week and 4-week treatment. The efficacy was compared between the two groups.</p><p><b>RESULTS</b>After 2-week treatment, the HAMD score and the MESSS score in the acupuncture and medication group were obviously decreased and the BI score was apparently increased(all P<0. 01). In the medication group, however, the score of every scale was not statistically different from that before treatment(P'>0. 05). After 4-week treatment, HAMD scores and MESSS scores in the two groups were obviously decreased and the BI scores I were apparently increased(all P<0. 01). After 2-week and 4-week treatment, the HAMD scores and the MESSS scores in the acupuncture and medication group were lower than those in the medication group and the BI scores were higher than those in the medication group(P<0. 01, P<0. 05). The total effective rate of anti-depression (97. 0%, 32/33) the total effective rate of nerve function impairment(90. 9%, 30/33) and the total effective rate of daily life activity(97. 0% 32/33) in the acupuncture and medication group were better than 80. 0% (24/30), 80. 0%(24/30), 83. 3%(25/30) in the medication group(all P<0. 05).</p><p><b>CONCLUSION</b>The acupuncture therapy of dredging Governor Vessel and regulating mentality could reduce the onset time of anti-depression medicine treatment of PSD and enhance the overall efficacy. Therefore, it enhances the clinical compliance.</p>

Biomechanical research for design of rehabilitation technical aids / 医用生物力学

Rehabilitation technical aids have great significance in improving life quality of people with disability and reducing burdens of care for family and society. Nowadays, the policy, research funding and industrial environment in China all provide a good chance for rehabilitation technical aids research, which has already made great progress. Biomechanics plays an important role in design of rehabilitation technical aids. On the one hand, biomechanics can provide important references for measurement and evaluation on biomechanical characteristics of physical disabilities, so the design of rehabilitation technical aids can meet the requirements of maintaining or improving biomechanical functional capabilities of individuals with disabilities. On the other hand, the biomechanical interaction between human body and rehabilitation technical aids should also be considered carefully during the optimization of design. As an introduction to this special issue on rehabilitation, this paper will briefly review the progress of rehabilitation technical aids research in recent years in China, and then introduce some biomechanical researches in development of rehabilitation technical aids.

Numerical and experimental study on steady flow in the model of internal carotid artery siphon / 医用生物力学

Objective To investigate the hemodynamic factors in internal carotid arteries (ICA) with different shapes, and analyze the relationship between the arterial geometry and atherosclerotic stenosis to provide the hemodyanmic basis for the risk prediction and early diagnosis of ICA stenosis. Methods The flow field in the most two common types of ICAs, U and V-shaped ICA, were investigated by numerical simulation and particle image velocimetry (PIV) experiment under the condition of steady flow. Results At the upstream bend of ICA, the hemodynamic factors were monotonically associated with the curvature of the bend. As a result, the risk for stenosis here was smaller in the V-shaped ICA, as compared to U-shaped ICA. But at the downstream bend, such monotonic relationship didn’t exist due to the synergistic effect of the two bends. ConclusionsThe curvature of the artery is positively related to the risk for stenosis, but the synergistic effect of bends needs to be considered for studying arteries with the serial bends. The research on the synergistic effect may explain why the stenosis is frequently observed in arteries with multiple bends.

Effect of helmet mass and mass center on neck muscle strength in military pilots / 医用生物力学

Objective To investigate the effect from helmet mass and deviation of mass center on neck muscle activity in military pilots. Methods Based on AnyBody software platform, a musculoskeletal model of head neck complex was established including C0, C1-C7, T1 and 136 muscles. Concentrated loads were applied to simulate the role of helmet. Strength from seven main muscle groups under different helmet mass, mass center and +Gz acceleration loads were simulated and calculated.Results When mass center of the helmet and the head coincided with each other, the muscle groups (such as semispinalis, levator scapulae, splenius capitis and cervicis) which took charge of extension were activated. Muscle strength increased with helmet mass linearly and +Gz acceleration loads would make this increase multiplied. Flexion muscle began to work when mass center of the helmet moved backward, so did the lateral bending muscles when mass center of helmet moved in the right-and-left direction. Conclusions Helmet mass and its center have an obvious influence on neck muscle activity in military pilots. The musculoskeletal model established in this paper can be used to calculate the change in muscle strength under different situations and conduct a quantitative analysis for helmet design and validation.

Neck muscle activity during head flexion / 医用生物力学

Objective To analyze the neck muscle activity during head flexion and explore the cause of muscle fatigue in human head and neck. Methods A musculoskeletal model of head neck complex was established based on AnyBody software platform, and the muscle strengths during head flexion were simulated according to the input data measured by Vicon motion capture system, which were validated with the literature data. Results The neck muscles played a major role during head flexion. The force assignment mode among muscles was different during 45% and 75% flexion process. The integral of muscle strengths on flexion angle WM could reflect the muscle fatigue to some extent. Since the largest WM was found in the semispinalis cervicis and multifidus muscles during head flexion, it may indicate that those muscles have the easy tendency to be fatigue. Conclusions The musculoskeletal model established in this paper can provide a technical support for the exploration of neck fatigue mechanism.

Real-time plantar pressure measurement for monitoring exercise load in daily life activities / 医用生物力学

Objective To monitor the exercise load in daily life activities, a reliable method to estimate the real-time plantar pressure based only on a few sensors was presented. Methods Pedar-X pressure insoles were applied to collect plantar pressures from 10 healthy young adults performing 5 typical motions (vertical jump-landing, level walking, level running, stair ascending and stair descending). Stepwise linear regression was performed to reconstruct a mathematic model of calculating the foot force for each style of the motion based on 99 individual pressure data. Then these models were validated by comparing the plantar pressures measured by Pedar-X system and the estimated values by these models when other 4 subjects conducted the same 5 motions and the continuous motion composed of the 5 motions. Results Regardless of the single motion or continuous motion, the foot force calculated by each model for each motion, as well as that calculated by level walking model for each motion were almost the same as the data measured by Pedar-X system. In addition, there was no significant difference between the estimated values by each motion model and level walking model. Conclusions The foot force in daily life activities can be monitored effectively by level walking model with only 5 pressure sensors placed under T1, M2, M3, HM and HL region of the foot.

Effects of location training and orientation training on the visual-motor coordination under up-down reversed vision / 医用生物力学

Objective To compare the effects of location and orientation training on the improvement of visual motor coordination under up down reversed vision, provide reference for the preventation of space motion sickness and the design of adaptation training for sensory conflict. Method Sixteen subjects were instructed to complete the maze task wearing the up down reversing prism spectacle before and after the location training and the orientation training. Both trainings lasted 30 minutes respectively. The error rate and the executing time during the maze test were analyzed and compared. Results Both trainings significantly decreased the error rate and the executing time. In addition, the results of different training methods had significant difference, and the effects of the orientation training was better than that of the location training under up-down reversed vision. Conclusions Under the sensory conflict environment arising from the visual change, the adaptation induced by some task training could also be of benefit to some other task training so as to improve the ability of visual-motor coordination and the adaption to the sensory conflict. However, different trainings could have various degrees of improvement.

Swelling observation and modulus extraction of cartilage based on transient ultrasonic / 生物医学工程学杂志

Subtle changes in structure or composition can lead to degeneration of articular cartilage such as in osteoarthritis, so it is significant to study the materials attribute of the degenerating articular cartilage. A new transient ultrasonic technique was introduced into this study for measuring the swelling effects of the degenerated cartilage. The swelling-induced strain was calculated based on the measurement result, and then the uniaxial module of the articular cartilag was extracted using Narmoneva's triphasic model. The ultrasonic observation showed that the strains induced by the nonuniform swelling are depth-dependent, and the strains are small in the deep zone and big in the middle and surface zones. The uniaxial modulus also revealed that the cartilage in the deep zone (E1 = 12.20) is harder than that in surface zone (E2 = 0.15). These results suggest that the transient ultrasound technique accompanied by triphasic model provides a quantitative means to study the degeneration of articular cartilage.

A semi-automatic method for tooth segmentation in dental CT images / 生物医学工程学杂志

To reconstruct a tooth model from CT slices, we need to define the accurate contour of each tooth from CT slices. In this paper, we propose a semi-automatic method for drawing the contours of teeth in dental CT images. First of all, we select the reference slice from CT slices and carry out tooth segmentation interactively based on shape characteristic of each tooth. The dental CT images have the following distinct characteristic: in two neighboring CT slices, the size, location and intensity of corresponding tooth is very similar, so we can project the bounding box of the tooth whose contour has been drawn onto the next slice as the operation region of corresponding tooth. And then we perform segmentation operation tooth by tooth in the operation region based on the region growing algorithm using the information passed from the previous slice. With the reference slice as the starting slice, we carry out tooth segmentation slice by slice like this way automatically. The test result shows that the proposed method can detect the contours of teeth quickly and reliably with only little user intervention and it has practical value.

Regulation of endogenous cystathionine-gamma-lyase gene expression in high pulmonary flow by nitric oxide precursor / 中国应用生理学杂志

<p><b>AIM</b>Pulmonary hypertension is a common complication of congenital heart disease with a left-to right shunt. The mechanism of pulmonary hypertension induced by high pulmonary blood flow is still not fully understood. Recent studies showed that hydrogen sulfide (H2S) could relax vascular smooth muscle cells. But the change of the system of H2S in pulmonary hypertension induced by high pulmonary blood flow was not reported. We studied the influence on expression of CSE mRNA and production of hydrogen sulfide in rat lung tissues by L-Arginine, in order to demonstrate a regulating role of nitric oxide (NO) in the regulation of cystathionine-gamma-lyase/hydrogen sulfide system (CSE/H2S).</p><p><b>METHODS</b>Thirty male SD rats were randomly divided into shunting group, shunting with L-Arginine group, and control group. Abdominal aorta and inferior vena cava shunting was produced in rats of the later group. Pulmonary artery mean pressure (mPAP) and the hypertrophy of right ventricle of each rat were analyzed. The expression of lung tissue CSE mRNA was measured using quantitative reverse transcription-polymerase chain reaction and in situ hybridization. The activity of CSE in lung tissue was measured according to chemical analysis.</p><p><b>RESULTS</b>mPAP was significantly increased in shunted rats compared with normal control (P < 0.01), the expression of lung tissue CSE mRNA and the activity of CSE in lung tissue were decreased in shunt group (P < 0.01). However, L-arginine significantly attenuated pulmonary artery pressure, but augmented the expression of lung tissue CSE mRNA as well as the activity of CSE in lung tissue.</p><p><b>CONCLUSION</b>L-Arginine reverses the down-regulation of CSE/H2S system in high pulmonary blood flow-induced pulmonary hypertension.</p>

Estimation of Uniaxial Modulus of Articular Cartilage Based on Inhomogeneous 4 Parameters Triphasic Mode / 航天医学与医学工程

Objective To study the material attribute of articular cartilage.Methods An improved 4 parameters inhomogeneous triphasic model based on 3 parameters model was developed to estimate the uniaxial modulus Ha of cartilage and to predict the swelling pattern of cartilage.Results The results showed that more accurate uniaxial modulus can be extracted using 4 parameters inhomogeneous triphasic model,and the predicted results appeared to match the experimental strain data better than other models.Conclusion Inhomogeneous 4 parameters triphasic model can describe the depth-dependent material attribute of articular cartilage more exactly.

Influence of mimic cardiac rate on hydrodynamics of different mechanical prosthetic cardiac valves in vitro / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To assess the influence of mimic cardiac rate on hydrodynamics of different mechanical prosthetic cardiac valves.</p><p><b>METHODS</b>US-made CarboMedics bileaflet valve, China-made Jiuling bileaflet valve and C-L tilting disc valve were tested via a pulsatile flow simulator in the aortic position. Testing conditions were set at mimic cardiac rates of 55 bpm, 75 bpm, 100 bpm with a constant mimic cardiac output of 4 L/min. The mean pressure differences (deltaP), leakage volumes (L(E)V) and closing volumes (C(L)V) across each valve, and effective orifice areas (EOA) were analyzed.</p><p><b>RESULTS</b>Within physiological range, deltaP, L(E)V, and C(L)V decreased as mimic cardiac rate increased, with a large extent of variance. EOA increased along with an increase in mimic cardiac rate. It was a different response in terms of cardiac rate alteration for different types of mechanical prosthetic cardiac valves.</p><p><b>CONCLUSION</b>Mimic cardiac rate change affects hydrodynamics of mechanical prosthetic cardiac valves. Within physiological range, the hydrodynamic of prosthetic bileaflet valve is better than that of tilting disc valve.</p>

Influence of wall thickness on the stress distribution within transtibial monolimb / 生物医学工程学杂志

Monolimb is a new type of lower-limb prostheses made of macromolecule polymer, in which the socket and prosthetic shank are integrative. Compared with traditional prosthesis, monolimb is more economical, good-looking and portable, so it indicates a possible direction in the future. Biomechanical research on trans-tibial monolimb is necessary and helpful just like traditional prosthesis. In this article, a 3D FE model based on real geometry shape of an endoskeletal trans-tibial monolimb is established. Keeping the same geometrical shape, three 3D FE models of transtibial monolimbs with different wall thickness are established. The influence of wall thickness on the stress distribution is analyzed under the load corresponding to the subphase of stance of Heel Off. The results indicate that stress within transtibial monolimb and pressure on the surface of soft tissue could be decreased with wall thickness of transtibial monolimb increased. This study will be helpful for the standard of wall thickness in designing transtibial monolimb.

A methodological study of measuring quantitatively turbulent shear stree downstream of mitral stenosis in vivo using Doppler echocardiography / 生物医学工程学杂志

In order to establish a method for measuring quantitatively turbulent shear stress (TSS) downstream of mitral stenosis in vivo based on Doppler echocardiography and computer-aided image analysis, we used doppler echocardiography to record the spectrum of flow velocity downstream of mitral valve at several locations in normal persons and in patients with mitral stenosis. With the computer-aided analysis of spectrum images, the magnitude of TSS was measured at the locations. The results demonstrate that no matter how severe the mitral stenosis is, the TSS and relative turbulent intensity(Irel) at the central locations of jet are lower than those at the marginal ones. A significant difference in the quantitative items of TSS, Irel and flow field uniformity between normal persons and patients with varying-degree of mitral stenosis was noticed (P < 0.05). There was a significant correlation between these items and effective orifice area (EOA), and we found that the smaller EOA is, the more severe the extent of stenosis is and the greater the magnitude of both TSS and Irel are, and that the highest magnitude of TSS is focused on the marginal area of jet. These results indicate that there is an obvious correlation between TSS(measured by Doppler echocardiography combined with computer-aided image analysis) and flow field uniformity. They can coincidently reveal the hemodynamic changes resulting from mitral stenosis of varied severeness, implying that our method could exactly depict the magnitude of TSS downstream of mitral stenosis in vivo and is non-invasive and good for anti-disturbance. The method can be used to analyze quantitatively TSS in the flow field of heart valve in patients with valvular diseases.