A Methodology for Quantifying Cell Density and Distribution in Multidimensional Bioprinted Gelatin–Alginate Constructs

Author(s):  
Houzhu Ding ◽  
Filippos Tourlomousis ◽  
Robert C. Chang

Bioprinted tissue constructs can be produced by microextrusion-based materials processing or coprinting of cells and hydrogel materials. In this paper, a gelatin–alginate hydrogel material formulation is implemented as the bio-ink toward a three-dimensional (3D) cell-laden tissue construct. However, of fundamental importance during the printing process is the interplay between the various parameters that yield the final cell distribution and cell density at different dimensional scales. To investigate these effects, this study advances a multidimensional analytical framework to determine both the spatial variations and temporal evolution of cell distribution and cell density within a bioprinted cell-laden construct. In the one-dimensional (1D) analysis, the cell distribution and single printed fiber shape in the circular cross-sectional view are observed to be dependent on the process temperature and material concentration parameters, along with the initial bio-ink cell densities. This is illustrated by reliable fabrication verified by image line profile analyses of structural fiber prints. Round fiber prints with width 809.5 ± 52.3 μm maintain dispersive cells with a degree of dispersion (Dd) at 96.8 ± 6.27% that can be achieved at high relative material viscosities under low temperature conditions (21 °C) or high material concentrations (10% w/v gelatin). On the other hand, flat fiber prints with width 1102.2 ± 63.66 μm coalesce cells toward the fiber midline with Dd = 76.3 ± 4.58% that can be fabricated at low relative material viscosities under high temperature (24 °C) or low material concentrations (7.5% w/v gelatin). A gradual decrement of Dd (from 80.34% to 52.05%) is observed to be a function of increased initial bio-ink cell densities (1.15 × 106–16.0 × 106 cells/ml). In the two-dimensional (2D) analysis, a printed grid structure yields differential cell distribution, whereby differences in localized cell densities are observed between the strut and cross regions within the printed structure. At low relative viscosities, cells aggregate at the cross regions where two overlapping filaments fuse together, yielding a cell density ratio of 2.06 ± 0.44 between the cross region and the strut region. However, at high relative viscosities, the cell density ratio decreases to 0.96 ± 0.03. In the 3D analysis, the cell density attributed to the different layers is studied as a function of printing time elapsed from the initial bio-ink formulation. Due to identifiable cell sedimentation, the dynamics of cell distribution within the original bio-ink cartridge or material reservoir yield initial quantitative increases in the cell density for the first several printed layers, followed by quantitative decreases in the subsequent printed layers. Finally, during incubation, the evolution of cell density and the emergence of material degradation effects are studied in a time course study. Variable initial cell densities (0.6 × 106 cells/mL, 1.0 × 106 cells/mL, and acellular control group) printed and cross-linked into cell-laden constructs for a 48 h time course study exhibit a time-dependent increase in cell density owing to proliferation within the constructs that are presumed to affect the rate of bio-ink material degradation.

Author(s):  
Houzhu Ding ◽  
Enyan Dai ◽  
Filippos Tourlomousis ◽  
Robert C. Chang

Bioprinted tissue constructs are enabled by microextrusion-based co-printing of cells and hydrogel materials. In this paper, a gelatin-alginate hydrogel material formulation is implemented as the bio-ink towards a 3D cell-laden tissue construct. However, of fundamental importance during the printing process is the interplay between the various parameters that yield the final cell distribution and cell density at different dimensional scales. To investigate these effects, this study advances a multidimensional analytical framework to determine the spatial variations and temporal evolution of cell distribution and cell density within a bioprinted cell-laden construct. In the one dimensional (1D) analysis, the cell distribution and cross-sectional shape for a single printed fiber are observed to be dependent on the process temperature and material concentration parameters. This is illustrated by the reliable fabrication and image line profile analysis of the fiber prints. Round fiber prints with a measured width of 809.5±52.3 μm maintain dispersive cells with a degree of dispersion (Dd) at 96.8 % that can be achieved at high relative material viscosities under low temperature conditions (21 °C) or high material concentrations (10 % w/v gelatin). On the other hand, flat fiber prints with a measured width of 1102.2±63.6 μm coalesce cells towards the fiber midline with Dd = 76.3% that can be fabricated at low relative material viscosities under high temperature (24 °C) or low material concentrations (7.5 % w/v gelatin). In the 2D analysis, a printed grid structure yields differential cell distribution whereby differences in localized cell densities are observed between the strut and cross regions within the printed structure. At low relative viscosities, cells aggregate at the cross regions where two overlapping filaments fuse together, yielding a cell density ratio of 2.06±0.44 between the cross region and strut region. However, at high relative viscosities, the cell density ratio decreases to 0.96±0.03. In the 3D analysis, the cell density attributed to the different layers is studied as a function of printing time elapsed from the initial bio-ink formulation. Due to identifiable gravity and extrusion process-induced effects, the cell distribution within the original bio-ink cartridge or material reservoir is altered over time to yield initial quantitative increases in the cell density over the first several printed layers, followed by quantitative decreases in the subsequent printed layers. Finally, in the time-dependent analysis, the evolution of cell density and the emergence of material degradation effects is studied over a time course study. Variable initial cell densities (0.6 × 106 cells/ml, 1.0 × 106 cells/ml, and acellular control group) printed and cross-linked into cell-laden constructs for the 48 hr time course study exhibit a time-dependent increase in cell density owing to proliferation within the constructs that are presumed to accelerate the degradation rate.


2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Yuanyuan Guo ◽  
Shouxiang Ni ◽  
Weiyan Zhou ◽  
Jiangping Hou ◽  
Jiaquan Shen

Purpose. To evaluate the role of SPARC in the antiproliferation effect of MMC on human Tenon’s fibroblasts (HTF). Method. Sixteen PACG patients aged 59 ± 10 years (31–72 years), including 6 males and 10 females, were recruited. Tenon tissue was harvested during filtering surgery. Cell density was evaluated after MMC application with different concentrations and application times, by which the optimized MMC application modality was determined. MMC, si-SPARC, or SPARC protein was used when needed to evaluate the cell densities under different conditions, by which the role of SPARC in MMC-mediated antifibrotic process was identified. Results. Considering that the cell densities, as well as SPARC expression on mRNA and protein levels, are relatively stable when the MMC concentration is higher than 0.02% and exposure time longer than 90 s, we chose the MMC application pattern with 0.02% and 90 s as an optimized pattern for the downstream work. Compared to control, the si-SPARC and MMC downregulated the SPARC protein by 91% (P<0.01) and 65% (P<0.01) and mRNA by 96% (P<0.01) and 64% (P<0.01), respectively. MMC decreases the cell densities by 53.50% compared to control. si-SPARC + MMC dramatically deceased the cell density no matter compared to the control group (P<0.01) or MMC group (P<0.01); correspondingly, the relative collagen gel area in the MMC + si-SPARC group was higher than that in the MMC group or si-SPARC group (P<0.05). The reactive oxygen species expression in the MMC + si-SPARC group is higher than that in the MMC group (P<0.05). Conclusion. This study demonstrates that in HTF, (1) MMC downregulates the expression of SPARC in protein and mRNA levels; (2) SPARC depletion has synergistic effect on the antifibrotic effect of MMC; and (3) reactive oxygen species are the possible mediator in the antifibrotic effect of MMC and si-SPARC.


Author(s):  
Danyelle Cristina Silva Pelet ◽  
Fábio Lera Orsatti

The objectives of this study were 1) to compare the extent of cross-transfer of high- versus low-load unilateral resistance training performed with external pacing of the movement (URTEP) and 2) to compare the time course of the two approaches. Fifty subjects were randomized to one of the following three groups: G80 [two sets at 80% and two sets at 40% of one maximum repetition (1RM), 1 concentric second and 3 eccentric seconds controlled by a metronome]; G40 (four sets at 40% of 1 RM, 1s and 3s controlled by a metronome); or CG (control group). At week 1, the G80 increased the elbow flexion 1RM (P<0.05) in contralateral arm. At week 4, both G80 and G40 increased the elbow flexion 1RM (P<0.05) in contralateral arm. However, a greater 1RM gain was observed in the G80 than in the G40 (P< .05). Thus, although higher-load URTEP seems to enhance the cross-education effect when compared to lower-load URTEP, the cross-education of dynamic strength can be achieved in the two approaches after four weeks. Many patients would benefit from cross-education of muscle strength through URPEP, even who are unable to exercise with high loads and in short periods of immobilization. Novelty bullets: (1) Unilateral resistance training promotes cross-education of dynamic muscle strength. (2) However, higher-load resistance training enhances the effects of cross-education of muscle strength.


Author(s):  
М.М. САДЫКОВ ◽  
М.П. АЛИХАНОВ ◽  
А.Г. СИМОНОВ ◽  
Г.А. СИМОНОВ

Изучены рост и развитие бычков — помесей красной степной с казахской белоголовой породой в равнинной провинции Дагестана. Установлено, что помесный молодняк, по сравнению с чистопородным скотом красной степной породы, имеет более высокую живую массу при рождении на 1,8 кг, или 7,3%. При отъеме в 8-месячном возрасте помеси имели живую массу 210 кг против 187,6 кг у красного степного молодняка, что на 22,4 кг, или 11,9% выше. В 12-, 15- и 18-месячном возрасте живая масса помесных бычков равнялась 291,8 кг, 359,7 и 436,6 кг, соответственно, или на 28 кг, 36 и 45,8 кг больше по сравнению с красным степным скотом. Среднесуточные приросты помесных бычков за период выращивания и откорма составили 760 г, что выше на 12,1% по сравнению с чистопородным красным степным молодняком. После заключительного откорма и убоя помесные бычки дали тяжеловесные туши с хорошим поливом. По массе парной туши они превосходили чистопородных аналогов на 31,3 кг, или 15,6% с преимуществом выхода туши на 2,4%. Убойный выход у бычков опытной группы составил 58,7%, контрольной — 55,8%. От помесных бычков были получены тяжеловесные шкуры массой 27,1 кг, от чистопородных — 21,6 кг, преимущество по этому показателю имели помесные животные 5,5 кг, или 25,4%. Для увеличения производства говядины в равнинной провинции Дагестана рекомендуем скрещивание коров красной степной породы с быками казахской белоголовой породы. The growth and development of bulls of red steppe crossbreeds with the Kazakh white-headed breed in the flat province of Dagestan were studied. It was found that young crossbreed animals in comparison with purebred red steppe cattle have a higher live weight at birth by 1,8 kg or 7,3%. When weaning at 8 months of age, cross-bred bulls had a live weight of 210 kg against 187,6 kg in red steppe young, which is 22,4 kg, or 11,9% higher. At 12, 15 and 18 months of age, the live weight of crossbred bulls was 291,8 kg, 359,7 and 436,6 kg, respectively, or 28 kg, 36 and 45,8 kg more than the red steppe cattle. The average daily growth of cross-bred bulls during the growing and fattening period was 760 g compared to 678 g, that is, they were 12,1% higher compared to purebred red steppe young. After the final fattening and slaughter, the cross-bred bulls gave heavy carcasses with good watering. By weight of the paired carcass, they were superior to purebred counterparts by 31,3 kg or 15,6% with an advantage of 2,4% carcass yield. The slaughter yield of bulls in the experimental group was 58,7%, 55,8% in the control group, respectively, with an advantage in favor of crossbreeds of 2,9%. Heavy skins weighing 27,1 kg were obtained from crossbreed bulls, 21,6 kg from purebred ones, and crossbreed animals of 5,5 kg or 25,4% had an advantage in this indicator. Studies have shown that in order to increase beef production in the lowland province of Dagestan, it is necessary to use crossbreeding of the breeding stock of the red steppe breed with bulls of the Kazakh white-headed breed.


Hypertension ◽  
1980 ◽  
Vol 2 (4) ◽  
pp. 102-108 ◽  
Author(s):  
A. W. Voors ◽  
L. S. Webber ◽  
G. S. Berenson

2021 ◽  
Author(s):  
Przemysław Adamczyk ◽  
Martin Jáni ◽  
Tomasz S. Ligeza ◽  
Olga Płonka ◽  
Piotr Błądziński ◽  
...  

AbstractFigurative language processing (e.g. metaphors) is commonly impaired in schizophrenia. In the present study, we investigated the neural activity and propagation of information within neural circuits related to the figurative speech, as a neural substrate of impaired conventional metaphor processing in schizophrenia. The study included 30 schizophrenia outpatients and 30 healthy controls, all of whom were assessed with a functional Magnetic Resonance Imaging (fMRI) and electroencephalography (EEG) punchline-based metaphor comprehension task including literal (neutral), figurative (metaphorical) and nonsense (absurd) endings. The blood oxygenation level-dependent signal was recorded with 3T MRI scanner and direction and strength of cortical information flow in the time course of task processing was estimated with a 64-channel EEG input for directed transfer function. The presented results revealed that the behavioral manifestation of impaired figurative language in schizophrenia is related to the hypofunction in the bilateral fronto-temporo-parietal brain regions (fMRI) and various differences in effective connectivity in the fronto-temporo-parietal circuit (EEG). Schizophrenia outpatients showed an abnormal pattern of connectivity during metaphor processing which was related to bilateral (but more pronounced at the left hemisphere) hypoactivation of the brain. Moreover, we found reversed lateralization patterns, i.e. a rightward-shifted pattern during metaphor processing in schizophrenia compared to the control group. In conclusion, the presented findings revealed that the impairment of the conventional metaphor processing in schizophrenia is related to the bilateral brain hypofunction, which supports the evidence on reversed lateralization of the language neural network and the existence of compensatory recruitment of alternative neural circuits in schizophrenia.


2021 ◽  
Vol 10 (8) ◽  
pp. 1786
Author(s):  
Valeria Pergola ◽  
Marco Previtero ◽  
Annagrazia Cecere ◽  
Vittorio Storer ◽  
Teresa Castiello ◽  
...  

The introduction of high-sensitivity cardiac troponin allowed identifying a proportion of subjects with chest pain and electrocardiographic changes suggestive of myocardial infarction showing <50% coronary artery stenosis. PFAI is a coronary CT marker proved to predict outcome in ischemic heart disease. Based on CMR findings, patients were divided into myocarditis (n = 15), MINOCA (n = 14) and TTS (n = 9) groups. The aim was to estimate the value of pFAI in these groups compared to 12 controls. To evaluate the coronary inflammation “time course,” 20 patients underwent CMR and coronary CT scan within 8 days from the onset, the others within 60 days. There were higher values of pFAI in myocarditis (−86.45 HU), MINOCA (−84.63 HU) and TTS (−84.79 HU) compared to controls (−96.02 HU; p = 0.0077). Among patients who underwent CT within 8 days from onset, the MINOCA had a significantly higher pFAI value (−76.91 HU) compared to the control group (−96.02 HU; p = 0.0001). In the group that underwent CT later than 8 days, elevated pFAI values persisted only in the myocarditis and TTS groups, and there was no difference between MINOCA and controls. Our study shows that in patients with a diagnosis of MINOCA, there is acute coronary inflammation, which is more evident within one week from the acute event but tends to disappear with time.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Gernot Seppel ◽  
Andreas Voss ◽  
Daniel J. H. Henderson ◽  
Simone Waldt ◽  
Bernhard Haller ◽  
...  

Abstract Background While supraspinatus atrophy can be described according to the system of Zanetti or Thomazeau there is still a lack of characterization of isolated subscapularis muscle atrophy. The aim of this study was to describe patterns of muscle atrophy following repair of isolated subscapularis (SSC) tendon. Methods Forty-nine control shoulder MRI scans, without rotator cuff pathology, atrophy or fatty infiltration, were prospectively evaluated and subscapularis diameters as well as cross sectional areas (complete and upper half) were assessed in a standardized oblique sagittal plane. Calculation of the ratio between the upper half of the cross sectional area (CSA) and the total CSA was performed. Eleven MRI scans of patients with subscapularis atrophy following isolated subscapularis tendon tears were analysed and cross sectional area ratio (upper half /total) determined. To guarantee reliable measurement of the CSA and its ratio, bony landmarks were also defined. All parameters were statistically compared for inter-rater reliability, reproducibility and capacity to quantify subscapularis atrophy. Results The mean age in the control group was 49.7 years (± 15.0). The mean cross sectional area (CSA) was 2367.0 mm2 (± 741.4) for the complete subscapularis muscle and 1048.2 mm2 (± 313.3) for the upper half, giving a mean ratio of 0.446 (± 0.046). In the subscapularis repair group the mean age was 56.7 years (± 9.3). With a mean cross sectional area of 1554.7 mm2 (± 419.9) for the complete and of 422.9 mm2 (± 173.6) for the upper half of the subscapularis muscle, giving a mean CSA ratio of 0.269 (± 0.065) which was seen to be significantly lower than that of the control group (p < 0.05). Conclusion Analysis of typical atrophy patterns of the subscapularis muscle demonstrates that the CSA ratio represents a reliable and reproducible assessment tool in quantifying subscapularis atrophy. We propose the classification of subscapularis atrophy as Stage I (mild atrophy) in case of reduction of the cross sectional area ratio < 0.4, Stage II (moderate atrophy) in case of < 0.35 and Stage III (severe atrophy) if < 0.3.


2012 ◽  
Vol 19 (6) ◽  
pp. 367-376 ◽  
Author(s):  
Viktoriya Golovatscka ◽  
Helena Ennes ◽  
Emeran A. Mayer ◽  
Sylvie Bradesi

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