The effect of back muscle fatigue on EMG and kinematics based estimation of low-back loads and active moments during manual lifting tasks.

This study investigated the effects of back muscle fatigue on the estimation of low-back loads and active low-back moments during lifting, using an EMG and kinematics based model calibrated with data from an unfatigued state. Fourteen participants performed lifting tasks in unfatigued and fatigued states. Fatigue was induced through semi-static forward bending. EMG, kinematics, and ground reaction forces were measured, and low-back loads were estimated using inverse dynamics and EMG-driven muscle model. A regression model was developed using data from a set of calibration lifts, and its accuracy was evaluated for unfatigued and fatigued lifts. During the fatigue-inducing task, the EMG amplitude increased by 2.8 %MVC, representing a 38% increase relative to the initial value. However, during the fatigued lifts, the peak EMG amplitude was found to be 1.6 %MVC higher than that observed during the unfatigued lifts, representing a mere 4% increase relative to the baseline unfatigued peak EMG amplitude. Kinematics and low-back load estimates remained unaffected. Regression model estimation errors remained unaffected for 5 kg lifts, but increased by no more than 5% of the peak active low-back moment for 15 kg lifts. We conclude that the regression-based estimation quality of active low-back moments can be maintained during periods of muscle fatigue, although errors may slightly increase for heavier loads.

Fast electro-plasmonic detection of heart signal in Balb/C cells onto one-dimensional plasmonic grating.

The heart is a vital and complex organ in the human body that forms with most organs between the second week of pregnancy, and fetal heart rate is an important indicator or biological index to know the condition of fetal well-being. In general, long-term measurement of fetal heart rate is the most widely used method of providing information about fetal health. In addition to fetal life, growth, and maturity, information such as congenital heart disease, often due to structural or functional defects in heart structure that often occur during the first trimester of pregnancy during fetal development, can be detected by continuous monitoring of fetal heart rate. The gold standard for monitoring the fetus's health is the use of non-invasive methods and portable devices so that while maintaining the health of the mother and fetus, it provides the possibility of continuous monitoring, especially for mothers who have a high-risk pregnancy. Therefore, the present study aimed to propose a low-cost, compact, and portable device for recording the heart rate of 18-day-old fetal mouse heart cells. Introduced device allows non-invasive heart rate monitoring instantly and without side effects for mouse fetal heart cells. One-dimensional gold-plated plasmonic specimens as a physiological signal recorder are mainly chips with nanoarray of resonant nanowire patterns perform in an integrated platform. Here the surface plasmon waves generated in a one-dimensional plasmonic sample are paired with an electrical wave from the heart pulse, and this two-wave pairing is used to record and detect the heart rate of fetal heart cells with high accuracy and good sensitivity. This measurement was performed in normal mode and two different stimulation modes. Stimulation of cells was performed once using adrenaline and again with electrical stimulation. Our results show that our sensor is sensitive enough to detect heart rate in both standard and excitatory states and is also well able to detect and distinguish between changes in heart rate caused by different excitatory conditions.

Comparative characteristics of mesenchymal stem cells derived from reamer-irrigator-aspirator, iliac crest bone marrow, and adipose tissue.

Mesenchymal stem cells (MSCs) have been considered promising tools for new clinical concepts in supporting cellular therapy and regenerative medicine. More recently, Ream/Irrigator/Aspirator (RIA) was introduced as a source of MSCs. In this study we compared MSCs derived from three different sources (iliac crest bone marrow (ICBM), adipose tissue (AT), and (RIA)) regarding the morphology, the success rate of isolating MSCs, colony frequency, expansion potential, osteogenic and chondrogenic differentiation capacity. MSCs were isolated from three different sources and flow cytometric analyses were performed for cell characterization. Colony-forming unit-fibroblast (CFU-F) assay and population doubling time (PDT) were evaluated for MSCs derived from three different sources and differentiation potential of RIA, ICBM-, and AT-MSCs were determined by staining. Additionally, gene expression profiles for tissue specific markers corresponding to osteogenesis and chondrogenesis were analyzed using real time polymerase chain reaction (RT-PCR). Cultured with the appropriate condition, osteogenic and chondrogenic differentiation could be confirmed in all MSC preparations. Flow cytometry analysis indicated that RIA- and AT-derived MSCs have more homogenous populations than ICBM-MSCs. A comparison of the colonogenic ability in different tissues by CFU-F assay after 10 days showed that more colonies are formed from RIA-MSCs than from ICBM-MSCs, and AT-MSCs. AT-MSCs, were dispersed with no obvious colonies. The RIA-MSCs underwent osteogenesis and chondrogenesis at a faster rate than ICBM and AT-MSCs. Direct comparisons of RIA- to ICBM- and AT-MSCs have shown the RIA-MSCs have higher differentiation toward osteoblast and chondrocytes compared to other sources of MSCs. Hence, RIA-MSCs may be recommended as a more suitable source for treating orthopedic disorders.

Hypoxia and laser enhance expression of SDF-1 in muscles cells.

Targeted homing of transplanted mesenchymal stem cells (MSCs) is a decades old discussion in regenerative medicine. It has been proved that stromal cell-derived factor-1 (SDF-1α) is a potent chemoattractant of MSCs. Therefore, different strategies have been used to increase secretion of SDF-1α in damaged tissues to elevate targeted homing of MSCs. Previous studies have revealed that increased SDF-1α expression in hypoxic necrotic tissues and also low-level laser exposure enhanced angiogenesis in injured tissues. Herein, human skeletal and cardiac muscle cells (HSKM and HCM) were treated with hypoxia and low level laser to see their effects on expression of SDF-1α and on MSCs migration towards these treated cells. The optimal treatment conditions were determined by investigating the cellular viability after treatment. Real-Time PCR and Western blot analysis were done to study the expression of SDF-1α in treated cells. Migration potential of MSCs toward hypoxic and laser treated cells was investigated via migration assay. MTT assay revealed that laser and hypoxia treatment had no effect on the viability of HCM, HSKM compared with Glioblastoma cells. Real-Time PCR showed 16- and 90-fold elevation in mRNA of SDF-1α in HSKM and HCM cells, respectively, in laser treated with 12 J/cm2 intensity. In these two groups, selected as optimal conditions, HIF-1α expression showed maximum fold changes that might be partly because of response to treatments help to SDF-1α expression. It can be concluded that hypoxia and laser treatments may recruit MSCs and applied as a useful strategy for the further targeted stem cell homing.

Adipose derived mesenchymal stem cells express keratinocyte lineage markers in a co-culture model.

Cutaneous wound healing is a complex type of biological event involving proliferation, differentiation, reprograming, trans/de-differentiation, recruitment, migration, and apoptosis of a number of cells (keratinocytes, fibroblasts, endothelial cells, nerve cells and stem cells) to regenerate a multi-layered tissue that is damaged by either internal or external factors. The exact regeneration mechanism of damaged skin is still unknown but the epithelial and other kinds of stem cells located in skin play crucial roles in the healing process. In this work, a co-culture model composed of adipose derived mesenchymal stem cells and keratinocytes was developed to understand the cellular differentiation behaviour in wound healing. Human mesenchymal stem cells were isolated from waste lipoaspirates. Keratinocytes were isolated from neonatal rats skin as well from human adult skin. Both types of cells were cultured and their culturing behaviour was observed microscopically under regular intervals of time. The identity of both cells was confirmed by flow cytometry and qRT-PCR. Cells were co-cultured under the proposed co-culturing model and the model was observed for 7, 14 and 21 days. The cellular behaviour was studied based on change in morphology, colonization, stratification, migration and expression of molecular markers. Expression of molecular markers was studied at transcriptional level and change in cellular morphology and migration capabilities was observed under the invert microscope regularly. Successfully isolated and characterized mesenchymal stem cells were found to express keratinocyte lineage markers i.e. K5, K10, K14, K18, K19 and Involucrin when co-cultured with keratinocytes after 14 and 21 days. Their expression was found to increase by increasing the time span of cell culturing. The keratinocyte colonies started to disappear after 10 days of culturing which might be due to stratification process initiated by possibly transdifferentiated stem cells. It can be concluded that mesenchymal stem cells can regenerate the damaged skin if transplanted to damaged area but for their successful differentiation and enhanced regeneration, they need a population of keratinocytes in situ which need further experiments for validation of co-culture model and its potential for being used in clinics.

Role of Berberine on molecular markers involved in migration of esophageal cancer cells.

Berberine is an isoquinoline alkaloid found in several plant species like famous chinese herb, Rhizoma coptidis which has been used locally as a strong gastrointestinal remedy for thousands of years. The inhibitory effects of berberine on tumor progression properties have been reported before. In this study, we investigated the effect of berberine on an esophageal cancer cell line, KYSE-30 with emphasis on its effects on the expression of certain chemokine receptors. The cytotoxic effect of berberine on KYSE-30 cells was analyzed by MTT assay. In vitro cell migration assay was also applied to the treated cells and the expression levels of the selected chemokine receptors (CXCR4 and CCR7) was measured at mRNA level. A retarded growth, associated with increasing concentrations of berberine, was obvious. On the other hand, the migration rate of the cells was decreased when they were treated with different concentrations of berberine and the expression levels of the two chemokine receptors, involved in the migration and metastasis of esophageal cancer cells, were decreased following the same treatments. With these results, we tend to conclude that berberine might be a proper candidate for further investigations, by targeting the chemokine receptors, and possible applications as anti-metastatic agent in cancer studies.

Optic neuritis, multiple sclerosis and human leukocyte antigen: results of a 4-year follow-up study.

In the present study the relation between human leukocyte antigen (HLA), optic neuritis (ON) and multiple sclerosis (MS) has been investigated in 56 Iranian patients (46 females and 10 males). HLA-A and -B typing by microlymphocytotoxicity method and HLA-DRB, DQA and DQB by polymerase chain reaction based on sequence specific primers method was performed for the selected patients with ON. The diagnosis of clinically defined MS (CDMS) was confirmed in 15 of them (26.7%) during their follow-up. HLA-A24 was significantly higher in ON patients, whilst A23, A26, and A30 showed a significant decrease in these patients. HLA-A10 and A26 were absent in CDMS patients and A2 and A11 were significantly decreased in ON and CDMS patients. HLA-B5, B51, B38, B27, and B35 were significantly increased in ON patients compared with control subjects. HLA-B44, B16 and B38 alleles were not present in CDMS patients. Regarding DR locus, the frequency of HLA-DRB1*15 and DRB1*04 has been increased in CDMS patients, whilst the frequency of HLA-DRB1*07 and *11 was much higher in ON patients. In DQA region, the most frequent allele in the MS patients was DQA1*0102, which was significantly higher than ON patients, and control group. The frequency of DQA1*0103 was significantly increased in both patients group. In DQB1, the frequency of DQB1*0602 increased significantly in the MS patients. In conclusion existence of common genetic basis for early manifestations of MS could be suggested.

Leber's hereditary optic neuropathy: the spectrum of mitochondrial DNA mutations in Iranian patients.

We studied 14 patients with Leber's hereditary optic neuropathy (LHON) to investigate the mtDNA haplotypes associated with the primary mutation(s). Eleven patients carried the mitochondrial DNA (mtDNA) G11778A mutation, while one had the T14484C mutation; one patient had the G3460A mutation and one the G14459A mutation. The Iranian G11778A LHON mutation was not associated with two mtDNA haplogroups-M (0.0% compared with 3.2% in healthy controls) and J (7.7% compared with 10% in healthy controls). Our results showed a similarity in the pattern of LHON primary point mutations between Iranian families with LHON and those of Russian, European, and North American origin. Our results also do not support an association between mtDNA haplogroups J and M with LHON primary point mutations.