Immunobiology of mesenchymal stem cells

Mesenchymal stem cells (MSCs) can be isolated from almost all tissues and effectively expanded in vitro. Although their true in situ properties and biological functions remain to be elucidated, these in vitro expanded cells have been shown to possess potential to differentiate into specific cell lineages. It is speculated that MSCs in situ have important roles in tissue cellular homeostasis by replacing dead or dysfunctional cells. Recent studies have demonstrated that in vitro expanded MSCs of various origins have great capacity to modulate immune responses and change the progression of different inflammatory diseases. As tissue injuries are often accompanied by inflammation, inflammatory factors may provide cues to mobilize MSCs to tissue sites with damage. Before carrying out tissue repair functions, MSCs first prepare the microenvironment by modulating inflammatory processes and releasing various growth factors in response to the inflammation status. In this review, we focus on the crosstalk between MSCs and immune responses and their potential clinical applications, especially in inflammatory diseases.

The specific role of FAM20C in amelogenesis

Previously, we showed that Sox2-Cre;Fam20C(fl/fl) mice in which Fam20C was ubiquitously inactivated had severe defects in dentin, enamel, and bone, along with hypophosphatemia. It remains to be determined if the enamel defects in the mice with universal inactivation of Family with sequence similarity 20-C (FAM20C) were associated with the dentin defects and whether hypophosphatemia in the knockout mice contributed to the enamel defects. In this study, we crossed Fam20C(fl/fl) mice with keratin 14-Cre (K14-Cre) transgenic mice to specifically inactivate Fam20C in the epithelial cells, including the dental epithelial cells that are responsible for forming tooth enamel. X-ray, backscattered scanning electron microscopic, and histological analyses showed that the K14-Cre;Fam20C(fl/fl) mice had severe enamel and ameloblast defects, while their dentin and alveolar bone were not significantly affected. Accordingly, serum biochemistry of the K14-Cre;Fam20C(fl/fl) mice showed normal phosphate and FGF23 levels in the circulation. Analysis of these data indicates that, while FAM20C is a molecule essential to amelogenesis, its inactivation in the dental epithelium does not significantly affect dentinogenesis. Hypophosphatemia makes no significant contribution to the enamel defects in the mice with the ubiquitous deletion of Fam20C.

Effect of insulin in combination with selenium on Irs/PI3K-mediated GLUT4 expression in cardiac muscle of diabetic rats

BACKGROUND

Oral administration of selenium is an effective treatment for diabetes in animal models. However, selenium exerts these effects at high doses and several toxic effects are produced. Low doses of selenium are relatively safe but are unable to elicit any antidiabetic effect.

OBJECTIVES

The present study explored the prospect of using low doses of insulin in combination with selenium to evaluate their antidiabetic effect, and to evaluate their effect on IRS-1, PI3K and GLUT4 levels in cardiac muscle of diabetic rats.

MATERIALS AND METHODS

Diabetic rats were treated with insulin, selenium, and insulin and selenium in combination for four weeks. The effect of these antidiabetic compounds was examined on general physiological parameters and distribution of IRS-1, PI3K and GLUT4 in cardiac muscle by immunoblotting and immunohistochemistry.

RESULTS

Insulin in combination with selenium could significantly revive normoglycemia, and restore the disturbances in IRS-1, PI3K and GLUT4 levels in cardiac muscle. Treatment with insulin was only partially effective in the restoration of diabetic alterations.

CONCLUSION

The treatment of diabetic rats with combined doses of insulin and selenium was most effective in controlling glycaemia, and remarkably restored GLUT4 distribution by IRS-1/PI3K-dependent pathway in cardiac muscle of diabetic rat.

A vacuum pressure sensor based on ZnO nanobelt film

A vacuum pressure sensor was fabricated by assembling ZnO nanobelt film on the interdigital electrodes, and the current–voltage characteristics were measured with an Agilent semiconductor parameter tester. Under different pressures of 1.0 × 10(3), 6.7 × 10(−3), 8.2 × 10(−4) and 9.5 × 10(−5) mbar, the currents are 8.71, 28.1, 46.1 and 89.6 nA, and the pressure sensitive resistances are 1150, 356, 217 and 112 MΩ, respectively. In the range of 10(−5)–10(3) mbar the smaller the pressure is, the higher the current is. The pressure sensitive resistance of the vacuum pressure sensor increases linearly with the logarithmic pressure, and the measurement range is at least one order of magnitude wider than that of the previous sensors. Under the final pressure, the vacuum pressure sensor has maximum sensitivity (9.29) and power consumption of 0.9 μW. The sensitivity is larger than that of the previous sensor based on a ZnO single nanowire at that pressure, and the power consumption is much lower than that for the sensor based on a ZnO nanowire array. The pressure sensitive mechanism is reasonably explained by using oxygen chemisorption and energy band theory.

Fracture Tests Of Polysilicon Film

A new test approach is presented to measure the fracture toughness of thin films. The polysilicon specimen is a center-cracked panel that is 3.5 μm thick and 3 mm wide with a 100 μm long slot in the center. It is subjected to tensile loading, and the crack-opening displacement is measured by interferometry. The average toughness is 1.4 ± 0.65 MPa-m1/2.

Zinc intake and the risk of hyperglycemia among Chinese adults: the prospective Jiangsu Nutrition Study (JIN)

OBJECTIVE

To prospectively examine the associations between zinc intake, the zinc to heme iron ratio and the incidence of hyperglycemia in Chinese.

METHODS

We followed 1056 healthy adults aged 20 and older from 2002 to 2007. Dietary data were collected using 3-day food record and food frequency questionnaire. Hyperglycemia was defined as fasting plasma glucose > 5.6 mmol/l.

RESULTS

During the 5 years of follow-up, we documented 125 incident cases of hyperglycemia. Zinc intake alone was not associated with the risk of hyperglycemia. The zinc to heme iron ratio was inversely associated with the risk of hyperglycemia: odds ratios (OR, 95% CI) across increasing quartiles of the zinc to heme iron ratio were 1.00, 0.78(0.44-1.37), 0.40(0.19-0.83), and 0.21(0.08-0.54)(p for trend= 0.001). Adjustment for lifestyle covariates did not significantly change the associations.

CONCLUSIONS

This cohort study suggests that the zinc to heme iron intake ratio was significantly associated with a decreased risk of hyperglycemia in Chinese adults.

Comparison of anatomical shoulder prostheses and the proximal humeri of Chinese people

Reconstruction of normal anatomy is important to a successful proximal humeral arthroplasty, in which the surgeon needs to know multiple measured anatomical parameters during the surgery. Based on three-dimensional computed tomography scanning data, computer models of the proximal humeri of 180 Chinese people were built. They came from 77 males and 103 females; their ages ranged from 19 to 86 years. Anatomical parameters including the curvature diameter of the head, the head height, the inclination, and the retroversion were measured using the software in these three-dimensional proximal humerus models. The methodology was valid and the measured results showed marked variations in all those parameters. On average, the curvature diameter of the head was 44.6 mm, ranging from 36.4 to 55.5 mm. The head height was located at 16.7 +/- 1.9 mm (minimum, 12.4 mm; maximum, 22.0 mm). The inclination angle ranged from 122.35 degrees to 147.09 degrees (mean, 132.4 +/- 4.7 degrees). The proximal humeral retroversion was found to be extremely variable, ranging from -4.71 degrees to 52.46 degrees, and has a mean of 21.11 degrees. Then these measured results were compared with four commonly used anatomical prostheses. The wide range of variation in the normal values makes it difficult to restore anatomical characteristics individually. Thus, the use of an accurate three-dimensional model to guide surgery preoperatively can improve the outcome of some serious cases, such as gross degenerative change and large-bone-loss surgery.

Sex differences in the responses of spinal wide-dynamic range neurons to subcutaneous formalin and in the effects of different frequencies of conditioning electrical stimulation

The purpose of this study was to investigate sex-related differences in nociception elicited by s.c. injection of different concentrations (1-5%) of formalin. S.c. formalin-induced biphasic (early and late phases) persistent nociception was assessed by extracellularly recording the spontaneous activities of single spinal dorsal horn wide-dynamic range neurons in anesthetized male and female rats. The nociceptive responses of the dorsal horn wide-dynamic range neurons following s.c. injection of 5%, but not 1% and 2.5%, formalin in female rats were significantly stronger than the responses obtained in male rats. However, these concentration-dependent differences with respect to different sexes existed only in the late, but not the early, phase of formalin-induced nociception in intact, not spinal rats. The 5% formalin-induced late phase nociception in male rats was significantly depressed by 15 min of repeated conditioning electrical stimulation at a frequency of 5 Hz as well as 50 Hz during and after the period of conditioning electrical stimulation (intensity: 1 mA; pulse duration: 1 ms). In contrast, the inhibitory effect of 50 Hz conditioning electrical stimulation on the 5% formalin-elicited late phase response in female rats was markedly greater in magnitude and longer in duration than that of 5 Hz conditioning electrical stimulation. No significant depressive effects of 5 Hz conditioning electrical stimulation on formalin-induced nociception were found in female rats, indicating that the distinct effects of conditioning electrical stimulation at different frequencies are different in animals of opposite sexes. In conclusion, s.c. administration of different concentrations of formalin shows a distinct sex-related difference in its late tonic nociception of spinal nociceptive sensory neurons. Sex differences in formalin-induced tonic nociception are stimulus intensity dependent and related to the modulation from the supraspinal regions. S.c. formalin-induced late phase nociception in female rats is only sensitive to depression at a frequency of 50 Hz, but not 5 Hz, of conditioning electrical stimulation. This suggests that the involvement of the central mechanisms in the antinociceptive effects of conditioning electrical stimulation may be different at various frequencies of stimulation.

Automated quantification and reconstruction of collagen matrix from 3D confocal datasets

The geometrical structure of fibrous extracellular matrix (ECM) impacts on its biological function. In this report, we demonstrate a new algorithm designed to extract quantitative structural information about individual collagen fibres (orientation, length and diameter) from 3D backscattered-light confocal images of collagen gels. The computed quantitative data allowed us to create surface-rendered 3D images of the investigated sample.

Progressive apoptosis in chorion laeve trophoblast cells of human fetal membrane tissues during in vitro incubation is suppressed by antioxidative reagents

Previously, we demonstrated apoptotic cell death in the chorion laeve trophoblast layer of human fetal membrane tissues during the late stages of pregnancy, the progression of apoptosis during incubation in vitro, and its suppression by a low concentration of glucocorticoid hormones. We now report examination of mRNA expression of inflammatory cytokines [interleukin (IL)-1beta, IL-6, tumor necrosis factor-alpha] and antioxidative enzyme genes [heme oxygenase 1, catalase, Mn-superoxide dismutase (SOD), Cu/Zn-SOD, glutathione S-transferase, glutathione reductase and glutathione peroxidase] and apoptosis-related genes during in vitro progression of apoptosis with or without glucocorticoid by a reverse transcription/PCR method. It was shown that the mRNA levels increased in chorion laeve tissue for each cytokine examined and for catalase, heme oxygenase 1 and Mn-SOD in direct correlation with the in vitro incubation period. By Western blotting the existence of Mn-SOD protein, and its slight increase with incubation time, was also shown. The investigation of the influence of antioxidative reagents [pyrrolidine dithiocarbamate (PDTC), N-acetyl-l-cysteine (NAC) and nordihydroguaiaretic acid (NDGA)] on DNA fragmentation showed that DNA fragmentation in chorion laeve tissues was inhibited by approximately 50% in the presence of 1 mm PDTC, 30 mm NAC and 1 mm NDGA. These results suggest that apoptotic cell death of the trophoblast layer of chorion tissues may be induced through intracellular oxidative stress at the stage of parturition.

Isoproterenol-induced cardiac hypertrophy: role of circulatory versus cardiac renin-angiotensin system

To assess the possible contribution of the circulatory and cardiac renin-angiotensin system (RAS) to the cardiac hypertrophy induced by a beta-agonist, the present study evaluated the effects of isoproterenol, alone or combined with an angiotensin I-converting enzyme inhibitor or AT(1) receptor blocker, on plasma and LV renin activity, ANG I, and ANG II, as well as left ventricular (LV) and right ventricular (RV) weight. Male Wistar rats received isoproterenol by osmotic minipump subcutaneously and quinapril or losartan once daily by gavage. Plasma and LV ANGs were measured by radioimmunoassay after separation by HPLC. Isoproterenol alone decreased blood pressure, more markedly when combined with losartan or quinapril. Isoproterenol significantly increased LV and RV weight and total collagen. Neither losartan nor quinapril inhibited the increases in LV or RV weight. Losartan prevented the increase in RV collagen but enhanced the increase in LV collagen. Isoproterenol increased plasma renin, ANG I, and ANG II three- to fourfold. Isoproterenol combined with losartan or quinapril, caused marked further increases except for a significant decrease in plasma ANG II with quinapril. Isoproterenol alone did not increase LV ANG II and, combined with losartan or quinapril, actually decreased LV ANG II. These results indicate that isoproterenol-induced cardiac hypertrophy is associated with clear increases in plasma ANG II, but not in LV ANG II. Both losartan and quinapril lower LV ANG II below control levels, but do not prevent the isoproterenol-induced cardiac hypertrophy. These findings do not support a role for the circulatory or cardiac RAS in the cardiac trophic responses to beta-receptor stimulation.