scholarly journals Relationship Between Ex Vivo Tissue Diffusion Tensor Indexes and Material Properties in Posterior Tibialis Tendon

2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0045
Author(s):  
Jennifer A. Zellers ◽  
Masoud Edalati ◽  
Jeremy Eekhoff ◽  
Spencer P. Lake ◽  
Jie Zheng ◽  
...  
Keyword(s):  
Diffusion Tensor ◽  
Ex Vivo ◽  
Water Displacement ◽  
Tendon Tissue ◽  
Tract Length ◽  
Tissue Organization ◽  
Scan Time ◽  
Relationship Of ◽  
The Relationship

Category: Ankle, tendon imaging Introduction/Purpose: Posterior tibialis tendon is of clinical importance in the development and progression of acquired flatfoot and other midfoot deformity. The ability to quantitatively evaluate tendon tissue non-invasively would enable assessment of tendon health status and tracking of recovery from injury. Magnetic resonance diffusion tensor imaging (DTI) has been used to examine tendon tissue organization in healing tendon tissue. However, the relationship of DTI-based measures to tendon mechanical function has not been established. The purpose of this pilot study was to quantitatively evaluate posterior tibialis tendon using DTI and determine the relationship of these parameters to tendon function assessed via ex vivo mechanical testing. Methods: Posterior tibialis tendons from individuals undergoing amputation were positioned vertically in an agarose mold filled with saline for imaging. High resolution diffusion imaging parameters were optimized for tendon on a 3 T MRI to acquire 13 6-mm transverse slices covering the length: 1mm2 isotropic resolution, 2 signal averaging, repetition/echo times of 5000/58 ms, diffusion strength of 500s/mm2 with 30 gradient directions, scan time 5 min. Diffusion images had sufficient quality and were corrected for motion and image distortion. DTI parametric maps including fractional anisotropy (FA), mean, axial, and radial diffusivities (MD, AD, and RD; mm2/s) were calculated along with fiber tracking indexes of fiber length (mm) and density. After imaging, specimens were preloaded to 10 Newtons, preconditioned 10 cycles at 6% strain, subjected to stress-relaxation at 6% strain (10 minutes), then loaded to a maximum of 10% strain. Relationships between DTI indexes and mechanical properties (stiffness and hysteresis) were evaluated using Spearman correlation. Results: Six individuals (4 male, mean(SD) age: 56(5)years, body mass index: 30(6) kg/m2) were included. Reason for amputation was diabetes-related complications in 5 participants and failed orthopaedic surgery in 1 participant. In DTI (Figure 1A), tendons had a tract length of 11.5(11.3)mm and tract density of 23.9(2.4) per ROI. FA, MD, AD, and RD quantify how freely a water molecule is able to move within the tissue, and the directionality of that movement. Tendons had an FA of 0.26(0.25), MD of 1.25(1.28), AD of 1.54(1.57), and RD of 1.11(1.14). Tract length was positively related to linear stiffness (rho=0.829, p=0.04) and hysteresis at 10% strain (rho=0.886, p=0.019) (Figure 1B-D). AD was positively related to hysteresis at 10% strain (rho=0.812, p=0.05). Conclusion: This is the first study to describe posterior tibialis tendon appearance on DTI. Tract length and AD are both related to tendon mechanics. Tract length is based on quantity and directionality of water displacement and may indicate degree of collagen organization given its relationship to stiffness. Tract length and AD related positively to hysteresis, which will require additional research to identify the mechanisms behind this relationship. This study is limited by sample size and specimens that likely do not represent healthy tissue. Regardless, these findings support continued investigation into in vivo imaging of tendon with DTI for quantitative tendon assessment.

scholarly journals Combination of histochemical analyses and micro-MRI reveals regional changes of the murine cervix in preparation for labor

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Antara Chatterjee ◽  
Rojan Saghian ◽  
Anna Dorogin ◽  
Lindsay S. Cahill ◽  
John G. Sled ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Diffusion Tensor ◽  
Ex Vivo ◽  
Muscle Cells ◽  
Pregnant Mouse ◽  
Collagen Fibers ◽  
Muscular Layer ◽  
Tissue Organization ◽  
Picrosirius Red

AbstractThe cervix is responsible for maintaining pregnancy, and its timely remodeling is essential for the proper delivery of a baby. Cervical insufficiency, or “weakness”, may lead to preterm birth, which causes infant morbidities and mortalities worldwide. We used a mouse model of pregnancy and term labor, to examine the cervical structure by histology (Masson Trichome and Picrosirius Red staining), immunohistochemistry (Hyaluronic Acid Binding Protein/HABP), and ex-vivo MRI (T2-weighted and diffusion tensor imaging), focusing on two regions of the cervix (i.e., endocervix and ectocervix). Our results show that mouse endocervix has a higher proportion of smooth muscle cells and collagen fibers per area, with more compact tissue structure, than the ectocervix. With advanced gestation, endocervical changes, indicative of impending delivery, are manifested in fewer smooth muscle cells, expansion of the extracellular space, and lower presence of collagen fibers. MRI detected three distinctive zones in pregnant mouse endocervix: (1) inner collagenous layer, (2) middle circular muscular layer, and (3) outer longitudinal muscular layer. Diffusion MRI images detected changes in tissue organization as gestation progressed suggesting the potential application of this technique to non-invasively monitor cervical changes that precede the onset of labor in women at risk for preterm delivery.

scholarly journals Actin and Microtubules Differently Contribute to Vacuolar Targeting Specificity during the Export from the ER

Membranes ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 299
Author(s):  
Monica De Caroli ◽  
Fabrizio Barozzi ◽  
Luciana Renna ◽  
Gabriella Piro ◽  
Gian-Pietro Di Sansebastiano
Keyword(s):  
Spatial Targeting ◽  
Traffic Regulation ◽  
Emergent Features ◽  
Vacuolar Sorting ◽  
Er Export ◽  
Golgi Network ◽  
Relationship Of ◽  
The Relationship ◽  
Fine Tune

Plants rely on both actin and microtubule cytoskeletons to fine-tune sorting and spatial targeting of membranes during cell growth and stress adaptation. Considerable advances have been made in recent years in the comprehension of the relationship between the trans-Golgi network/early endosome (TGN/EE) and cytoskeletons, but studies have mainly focused on the transport to and from the plasma membrane. We address here the relationship of the cytoskeleton with different endoplasmic reticulum (ER) export mechanisms toward vacuoles. These emergent features of the plant endomembrane traffic are explored with an in vivo approach, providing clues on the traffic regulation at different levels beyond known proteins’ functions and interactions. We show how traffic of vacuolar markers, characterized by different vacuolar sorting determinants, diverges at the export from the ER, clearly involving different components of the cytoskeleton.

Genetic variation and relationship of ultrasonic measures and carcass composition in Suffolk cross lambs

1996 ◽  
Vol 1996 ◽  
pp. 111-111
Author(s):  
V.C. Flamarique ◽  
R.M. Lewis ◽  
G. Simm
Keyword(s):  
Genetic Variation ◽  
Selection Criteria ◽  
Live Weight ◽  
Ultrasonic Measurement ◽  
Carcass Composition ◽  
Selection Indices ◽  
Terminal Sire ◽  
Relationship Of ◽  
The Relationship

Excess fat in lamb is regarded as an important reason for less lamb meat being purchased by consumers. This has encouraged the development and use (particularly in Terminal Sire breeds) of selection indices that can identify animals that will sire leaner progeny. These indices usually include live weight and in vivo predictors of body composition, such as an ultrasonic measurement of muscle and fat depth, as selection criteria (Simm and Dingwall, 1989). But the usefulness of such in vivo measurements as predictors of carcass composition depends on the correlation between, and the variation in, live and carcass measures. The objectives of this study were to determine the strength of the relationship between ultrasound and dissection measures of carcass composition, and the degree of genetic variation in these measures, in crossbred progeny of Suffolk rams.

Experimental study of the inhibition effect of CXCL12/CXCR4 in malignant pleural mesothelioma

2018 ◽  
Vol 67 (2) ◽  
pp. 338-345 ◽  
Author(s):  
Jianshuang Li ◽  
Tong Li ◽  
Shuo Li ◽  
Lipeng Xie ◽  
Yi-Lin Yang ◽  
...  
Keyword(s):  
Treatment Group ◽  
Malignant Pleural Mesothelioma ◽  
Synergistic Effects ◽  
Control Group ◽  
Pleural Mesothelioma ◽  
Gene Expressions ◽  
Relationship Of ◽  
The Relationship ◽  
Cxcr4 Axis

Previous studies have demonstrated that CXCL12/CXCR4 axis is closely related to tumors such as malignant pleural mesothelioma (MPM). This research was conducted in order to detect whether CXCL12/CXCR4 inhibitors could restrain MPM and have a synergistic effect with chemotherapy, also to investigate the relationship of CXCL12/CXCR4 with other gene expressions in MPM. Forty mice were injected MPM cells and randomly divided into four groups: the PBS (control group), AMD3100 (CXCR4-CXCL12 antagonist), pemetrexed and AMD3100 plus pemetrexed. The mice were treated respectively for duration of 3 weeks. The size, bioluminescence and weight of tumors were measured. The differences between gene expressions in each group were analyzed. The tumor weights of each treatment group were lower than that of the control group (p<0.05). The bioluminescence of the tumor of the AMD3100 treatment group and the AMD3100 plus pemetrexed treatment group were lower than that of the control group (p<0.05), and AMD3100 was shown to have synergistic effects with pemetrexed (p<0.05). Among the 2.5 billion genes, several hundreds of genes expressed differently between groups. Results show that AMD3100 and pemetrexed can inhibit the growth of MPM in vivo, also that there is a better result if both are used together. Our findings suggest that CXCL12/CXCR4 axis affects a certain amount of gene expression in MPM.

Adrenocortical function in aging exercise-trained rats

1977 ◽  
Vol 43 (5) ◽  
pp. 839-843 ◽  
Author(s):  
J. A. Severson ◽  
R. D. Fell ◽  
J. G. Tuig ◽  
D. R. Griffith
Keyword(s):  
Age Groups ◽  
Plasma Corticosterone ◽  
Treadmill Running ◽  
Adrenocortical Function ◽  
Elevated Plasma ◽  
Corticosterone Concentration ◽  
Relationship Of ◽  
The Relationship

Plasma corticosterone concentrations and in vitro adrenal secretion of corticosterone were determined in exercise-trained rats. Rats, 100, 200, and 300 days of age, were trained for a 10-wk period by treadmill running. Following the training program, rats were subjected to an acute bout of swimming. Acute swimming elevated plasma corticosterone concentrations in all age groups. At 170 days of age, the plasma corticosterone concentration following swimming was higher in exercise-trained rats than in controls. The opposite was true of acutely swum rats at 270 and 370 days of age. Acute swimming elevated the in vitro adrenal gland response to adrenocorticotropic hormone stimulation in control rats at all ages and in trained rats at 170 days of age. The in vivo relationship of epinephrine and the pituitary adrenal system is suggested as a mechanism which could have caused this response. The relationship of secretion rates to plasma corticosterone concentrations indicated that extra-adrenal mechanisms, such as decreased turnover, were also responsible for the elevated plasma corticosterone levels observed in response to acute swimming.

scholarly journals Determination of receptor occupancy in the presence of mass dose: [11C]GSK189254 PET imaging of histamine H3 receptor occupancy by PF-03654746

2016 ◽  
Vol 37 (3) ◽  
pp. 1095-1107 ◽  
Author(s):  
Jean-Dominique Gallezot ◽  
Beata Planeta ◽  
Nabeel Nabulsi ◽  
Donna Palumbo ◽  
Xiaoxi Li ◽  
...  
Keyword(s):  
Binding Sites ◽  
Human Subjects ◽  
Receptor Occupancy ◽  
Healthy Human ◽  
Positron Emission ◽  
Relationship Of ◽  
The Relationship ◽  
Pet Scans

Measurements of drug occupancies using positron emission tomography (PET) can be biased if the radioligand concentration exceeds “tracer” levels. Negative bias would also arise in successive PET scans if clearance of the radioligand is slow, resulting in a carryover effect. We developed a method to (1) estimate the in vivo dissociation constant Kd of a radioligand from PET studies displaying a non-tracer carryover (NTCO) effect and (2) correct the NTCO bias in occupancy studies taking into account the plasma concentration of the radioligand and its in vivo Kd. This method was applied in a study of healthy human subjects with the histamine H3 receptor radioligand [11C]GSK189254 to measure the PK-occupancy relationship of the H3 antagonist PF-03654746. From three test/retest studies, [11C]GSK189254 Kd was estimated to be 9.5 ± 5.9 pM. Oral administration of 0.1 to 4 mg of PF-03654746 resulted in occupancy estimates of 71%–97% and 30%–93% at 3 and 24 h post-drug, respectively. NTCO correction adjusted the occupancy estimates by 0%–15%. Analysis of the relationship between corrected occupancies and PF-03654746 plasma levels indicated that PF-03654746 can fully occupy H3 binding sites ( ROmax = 100%), and its IC50 was estimated to be 0.144 ± 0.010 ng/mL. The uncorrected IC50 was 26% higher.

IN VITRO INHIBITION OF UDP GLUCURONOSYLTRANSFERASES BY ATAZANAVIR AND OTHER HIV PROTEASE INHIBITORS AND THE RELATIONSHIP OF THIS PROPERTY TO IN VIVO BILIRUBIN GLUCURONIDATION

2005 ◽  
Vol 33 (11) ◽  
pp. 1729-1739 ◽  
Author(s):  
Donglu Zhang ◽  
Theodore J. Chando ◽  
Donald W. Everett ◽  
Christopher J. Patten ◽  
Shangara S. Dehal ◽  
...  
Keyword(s):  
Protease Inhibitors ◽  
Hiv Protease ◽  
Hiv Protease Inhibitors ◽  
In Vitro Inhibition ◽  
Relationship Of ◽  
The Relationship

scholarly journals Application of multishot diffusion tensor imaging in spinal cord tumors

2019 ◽  
Vol 5 (1) ◽  
pp. 59-64
Author(s):  
Jiefei Li ◽  
Le He ◽  
Yuqi Zhang
Keyword(s):  
Spinal Cord ◽  
Diffusion Tensor Imaging ◽  
Diffusion Tensor ◽  
Preoperative Imaging ◽  
Spinal Cord Tumors ◽  
Intramedullary Tumors ◽  
Routine Magnetic Resonance Imaging ◽  
Relationship Of ◽  
The Relationship ◽  
Diffusion Tensor Imaging Dti

Objective: To explore the usefulness of multishot diffusion tensor imaging (DTI) for evaluating the neurological function of patients with spinal cord tumors Methods: Routine magnetic resonance imaging and multishot DTI were performed in five patients with spinal cord tumors. The values of fractional anisotropy (FA) and radial diffusivity (RD) were analyzed. Results: Multishot DTI of spinal cord tumors allowed for defining the margins of tumors and determining the relationship of tumors with the adjacent white matter structures of the spinal cord. Multishot DTI demonstrated significantly increased RD and decreased FA of spinal cord tumors compared with those of the normal spinal cord. Conclusions: Multishot DTI is a potentially useful modality for differentiating resectable tumors from nonresectable ones based on preoperative imaging alone as well as for differentiating intramedullary tumors from extramedullary ones. Further prospective studies are warranted to confirm these results.

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