Light and focused ion beam microscopy workflow for resin-embedded tissues.

Although the automated image acquisition with the focused ion beam scanning electron microscope (FIB-SEM) provides volume reconstructions, volume analysis of large samples remains challenging. Here, we present a workflow that combines a modified sample protocol of the classical transmission electron microscope with FIB-SEM volume imaging. The proposed workflow enables efficient 3D structural surveys of rabbit ovaries collected at consecutive developmental stages. The precise trimming of the region of interest adds the time dimension to the volume, constructing a virtual 4D electron microscopy. We found filopodia-like processes emitted by oocyte cysts allowing contact between oocytes not previously observed.

Structure-function relationships of TMJ lateral capsule-ligament complex.

The human temporomandibular joint (TMJ) lateral capsule ligament (LCL) complex is debated as a fibrous capsule with distinct ligaments or ligamentous thickening, necessitating further evaluation of the complex and its role in TMJ anatomy and mechanics. This study explores the ultrastructural arrangement, biomechanical tensile properties, and biochemical composition of the human LCL complex including region-specific differences to explore the presence of a distinct temporomandibular ligament and sex-specific differences to inform evaluations of potential etiological mechanisms. LCL complex ultrastructural arrangement, biomechanical properties, and biochemical composition were determined using cadaveric samples. Statistical modeling assessed sex- and region-specific effects on LCL complex tissue properties. Collagen fiber coherency, collagen fiber bundle size, and elastin fiber count did not differ between sexes, but females trended higher in elastin fiber count. LCL complex water and sGAG content did not differ between sexes or regions, but collagen content was higher in the anterior region (311.0 ± 185.6 µg/mg) compared to the posterior region (221.0 ± 124.9 µg/mg) (p = 0.045) across sexes and in males (339.6 ± 170.6 µg/mg) compared to females (204.5 ± 130.7 µg/mg) (p = 0.006) across regions. Anterior failure stress (1.1 ± 0.7 MPa) was larger than posterior failure stress (0.6 ± 0.4 MPa) (p = 0.024). Regional differences confirm the presence of a mechanically and compositionally distinct temporomandibular ligament. Baseline sex-specific differences are critical for etiological investigations of sex disparities in TMJ disorders. These results have important biomechanical and clinical ramifications, providing critical baseline tissue material properties, informing the development of TMJ musculoskeletal models, and identifying new areas for etiologic investigations for temporomandibular disorders.

Effects of hyperbaric oxygen treatment on ultrastructure of rats with plateau deacclimatization / 重庆医学

Objective To research the effects of hyperbaric oxygen (HBO) on the ultrastructure of heart,brain and lung in rats with plateau deacclimatization.Methods Forty-mine SD rats were selected.Fortyfour SD rats were routinely fed in a hypobaric hypoxia chamber at the simulated altitude of 5 000 m for 3 months.Nine rats died in the hypobaric hypoxia chamber.After coming out from the chamber,35 survival rats were randomly divided into the high altitude control group (instantly after out of the hypobaric hypoxia chamber),HBO group Ⅰ,Ⅱ and Ⅲ (7 days,1 months and 2 months after HBO treatment) and control groups Ⅰ,Ⅱ and Ⅲ according to the body mass,5 cases in each group;the HBO groups were treated by HBO for 7 d.The control group Ⅰ,Ⅱ and Ⅲ were synchronously fed in normal pressure and oxygen environment after HBO treatment.The rats in all groups were synchnonously sacrificed,the other 5 SD rats as the plain control group were fed in hormal pressure oxygen environment.The frontal cortex,heart and lung tissues were taken out for observing the ultrastructure changes by optical microscopy and electron microscopy.Results Hypoxia induced mitochondria swelling and ridge breakage in cranial nerves cells,swelling of mitochondria and peripheral structures,myocardial cells cloudy swelling,vacuolar degeneration,muscle fibers irregular arrangement,inflammatory cell infiltration and vasodilatation.The alveolar septm was broadened,blood capillaries were dilated and congestive,alveolar space was filled with pink transudation,inflammatory cells were infiltrated,and alveolar wall was incrassated.After HBO treatment,the tissue ultrastructure injurys were significantly improved compared with the control group,the recovery in the HBO group Ⅱ was significantly better than that in the HBO group Ⅰ,and the HBO group Ⅲ was significantly better than the HBO group Ⅱ,which recovered to plain level after 2 months.Conclusion HBO treatment has the effects for improving cranial nerves injury in hypoxia rat,promotes cellular function recovery,decreases hypoxia induced pulmonary hypertension,and has the protective effect on ischemic myocardium.

Structure-Function Relationships of Temporomandibular Retrodiscal Tissue.

It is estimated that 2% to 4% of the US population will seek treatment for temporomandibular joint (TMJ) symptoms, typically occurring with anterior disc displacement. The temporomandibular retrodiscal tissue (RDT) has been postulated to restrict pathologic disc displacement. To elucidate RDT function, understanding regional RDT biomechanics and ultrastructure is required. No prior biomechanical analysis has determined regional variations in RDT properties or associated biomechanical outcomes with regional variations in collagen and elastin organization. The purpose of this study was to determine direction- and region-dependent tensile biomechanical characteristics and regional fibrillar arrangement of porcine RDT. Incremental stress relaxation experiments were performed on 20 porcine RDT specimens, with strain increments from 5% to 50%, a ramp-strain rate of 2% per second, and relaxation periods of 2.5 min. Tensile characteristics were determined between temporal and condylar regions and anteroposterior and mediolateral directions. RDT preparations were imaged using second-harmonic generation (SHG) microscopy for both collagen and elastin. Young's modulus showed significant differences by region ( P < 0.001) and strain ( P < 0.001). Young's modulus was <1 MPa from 5% to 20% strain, before increasing from 20% to 50% strain to a maximum of 2.9 MPa. Young's modulus trended higher in the temporal region and mediolateral direction. Instantaneous and relaxed moduli showed no significant difference by region or direction. Collagen arrangement was most organized near the disc boundary, with disorganization increasing posteriorly. Elastin was present at the disc boundary and RDT mid-body. Porcine RDT demonstrated region- and strain-dependent variations in tensile moduli, associated with regional differences in collagen and elastin. The small tensile moduli suggest that the RDT is not resistive to pathologic disc displacement. Further biomechanical analysis of the RDT is required to fully define RDT functional roles. Understanding regional variations in tissue stiffness and ultrastructure for TMJ components is critical to understanding joint function and for the long-term goal of improving TMJ disorder treatment strategies.

Effect of Acupuncture of Stomach-meridian Acupoints on Brown Adipocytes in Extraweight Rats / 广州中医药大学学报

[ Objective ] To observe the effects of acupuncture in treating extraweight rats and on morphology of brown adipocytes. [ Methods ] Sixty SD rats were randomized into normal group ( group A), model group ( group B) and acupuncture group (group C). Group A was fed with common forage and groups B and C with high-fat diet for 12 weeks. After then group C was given acupuncture of Zusanli (ST36) and Neiting (ST44) points for 15 days. Body weight, body length and Lee's index were compared before and after treatment in the three groups; wet weight of perirenal fat was detected and the ultrastructure of interscapular brown adipose tissue was observed under transmission electron microscope after treatment. [Results] After treatment, body weight, Lee's index and wet weight of perirenal fat were decreased in group C (P