Development of the evaluation system for barrier functions of engineered epithelial lumens

We have investigated the effects of a diameter of engineered epithelial lumen on cellar architectures and a barrier function. For this investigation, we have developed a system to evaluate the barrier function of engineered epithelial lumens. To test the utility of our system, we constructed the engineered epithelial lumens by culturing Madin-Darby Canine Kidney cells (MDCK) on the gold wires with different diameters ranging from 50 μm-200 μm. Confocal laser scanning microscopy revealed that long actin stress fibers and a low focal adhesion density were observed at the gold wire diameter of 200 μm, whereas the mesh-like morphology consisted of short actin stress fibers and high focal adhesion densities were found at the gold wire diameters of 50 μm and 100 μm. The expression pattern of ZO-1 that localizes at the tight junction was independent on the gold wire diameter. The electrical impedance measurement indicates that the barrier function for the samples constructed at the gold wire diameter of 200 μm was significantly higher than those at the gold wire diameters of 50 μm and 100 μm. The difference in the barrier functions of epithelial lumens might be attributed to the changes in cellular architectures with increasing the curvature of gold wire.

Three-dimensional morphogenesis of MDCK cells induced by cellular contractile forces on a viscous substrate

Substrate physical properties are essential for many physiological events such as embryonic development and 3D tissue formation. Physical properties of the extracellular matrix such as viscoelasticity and geometrical constraints are understood as factors that affect cell behaviour. In this study, we focused on the relationship between epithelial cell 3D morphogenesis and the substrate viscosity. We observed that Madin-Darby Canine Kidney (MDCK) cells formed 3D structures on a viscous substrate (Matrigel). The structures appear as a tulip hat. We then changed the substrate viscosity by genipin (GP) treatment. GP is a cross-linker of amino groups. Cells cultured on GP-treated-matrigel changed their 3D morphology in a substrate viscosity-dependent manner. Furthermore, to elucidate the spatial distribution of the cellular contractile force, localization of mono-phosphorylated and di-phosphorylated myosin regulatory light chain (P-MRLCs) was visualized by immunofluorescence. P-MRLCs localized along the periphery of epithelial sheets. Treatment with Y-27632, a Rho-kinase inhibitor, blocked the P-MRLCs localization at the edge of epithelial sheets and halted 3D morphogenesis. Our results indicate that the substrate viscosity, the substrate deformation, and the cellular contractile forces induced by P-MRLCs play crucial roles in 3D morphogenesis.

Establishment of a new cell line susceptible to Cyprinid herpesvirus 3 (CyHV-3) and possible latency of CyHV-3 by temperature shift in the cells

A new cell line named CCF-K104 predominantly consisting of fibroblastic cells showed optimal growth at temperatures from 25 °C to 30 °C. Serial morphological changes in the cells induced by Cyprinid herpesvirus 3 (CyHV-3) included cytoplasmic vacuolar formation, cell rounding and detachment. Mature virions were purified from CyHV-3-infected CCF-K104 cells by sucrose gradient ultracentrifugation and had a typical herpesvirus structure on electron microscopy. Infectious CyHV-3 was produced stably in CCF-K104 cells over 30 viral passages. Our findings showed that CCF-K104 is a useful cell line for isolation and productive replication of CyHV-3. A temperature shift from 25 °C to 15 °C or 35 °C did not allow serial morphological changes as observed at 25 °C for 14 days. Under the same conditions, real-time PCR showed that CyHV-3 was present with low viral DNA loads, suggesting that CyHV-3 may establish latent infection in CCF-K104 cells. Amplification of the left and right terminal repeat sequences of the CyHV-3 genome arranged in a head-to-tail manner was detected by nested PCR following an upshift in temperature from 25 °C to 35 °C. The PCR results suggested that the circular genome may represent a latent form of CyHV-3.

Expression of xSDF-1α, xCXCR4, and xCXCR7 during gastrulation in Xenopus laevis

Chemokines play a crucial role in developmental processes and recent studies have revealed that they also control gastrulation movements. In this paper, we report the expression patterns of xSDF-1α, xCXCR4 and xCXCR7 and regulation of the expression of xSDF-1α and xCXCR4 during gastrulation. We performed whole mount in situ hybridization (WISH) and quantitative real-time RT-PCR (qRT-PCR) analyses to examine the distribution of transcripts. The effect of activin/nodal signaling on the expression of xSDF-1α and its receptors was examined by animal cap assay and microinjection of cer-s mRNA. We have demonstrated that the xSDF-1αtranscript is increased in the blastocoel roof during gastrulation, but not in the involuted mesoderm. xCXCR4 was expressed in the mesendoderm at late blastula and was retained throughout gastrulation. xCXCR7 was found in the dorsal lip around the blastopore in the early gastrula stage and became localized in the presumptive notochord later. We also show that the expression of xCXCR4 and xSDF-1transcript is increased in the blastocoel roof during gastrulation, but not in the involuted mesoderm. xCXCR4 was expressed in the mesendoderm at late blastula and was retained throughout gastrulation. xCXCR7 was found in the dorsal lip around the blastopore in the early gastrula stage and became localized in the presumptive notochord later. We also show that the expression of xCXCR4 and xSDF-1α were reciprocally regulated by activin/nodal signaling. These results suggest that xSDF-1α and its receptors contribute to the cell arrangement of mesoderm cells and their expression patterns are partially regulated by activin/nodal signaling.

Multiscale analysis of changes in an anisotropic collagen gel structure by culturing osteoblasts

Mimicking the complicated anisotropic structures of a native tissue is extremely important in tissue engineering. In a previous study, we developed an anisotropic collagen gel scaffold (ACGS) having a hierarchical structure and a properties gradient. In this study, our objective was to see how cells remodel the scaffolds through the cells-ACGS interaction. For this purpose, we cultured osteoblastic cells on ACGS, which we regarded as a model system for the cells-extracellular matrix (cell-ECM) interaction. Changes in the ACGS-cell composites structure by cell-ECM interactions was investigated from a macroscopic level to a microscopic level. Osteoblastic cells were also cultured on an isotropic collagen gel (ICGS) as a control. During the cultivation, mechanical stimuli were applied to collagen-cell composites for adequate matrix remodeling. Confocal laser scanning microscope (CLSM) was used to observe macroscopic changes in the ACGS-cell composite structure by osteoblastic cells. Small-angle X-ray scattering (SAXS) measurements were performed to characterize microscopic structural changes in the composites. Macroscopic observations using CLSM revealed that osteoblastic cells remained only in the diluted phase in ACGS and they collected collagen fibrils or formed a toroidal structure, depending on the depth from the ACGS surface in the tubular diluted phase. The cells were uniformly distributed in ICGS. SAXS analysis suggests that collagen fibrils were remodeled by osteoblastic cells, and this remodeling process would be affected by the structure difference between ACGS and ICGS. These results suggest that we directly regulate cell-ECM interaction by the unique anisotropic and hierarchical structure of ACGS. The cell-gel composite presented in this study would promise an efficient scaffold material in tissue engineering.

Nanometric locking of the tight focus for optical microscopy and tip-enhanced microscopy

We have successfully stabilized the tight focus onto the sample surface of an optical microscope within ±1.0 nm for a virtually unlimited time duration. The time-dependent thermal drift of the tight focus and the mechanical tilt of the sample surface were simultaneously sensed by a non-optical means based on a capacitive sensor and were compensated for in real-time. This non-optical scheme is promising for the suppression of background light sources for optical microscopy. The focus stabilization is crucial for microscopic measurement at an interface, particularly when scanning a large surface area, because there is always a certain amount of mechanical tilt of the sample substrate, which degrades the contrast of the image. When imaging nanoscopic materials such as carbon nanotubes or silicon nanowires, more stringent nanometric stabilization of the focus position relative to such samples is required, otherwise it is often difficult to interpret the results from the observations. Moreover, the smaller the sample volume is, the smaller the signal becomes, resulting in a long exposure time at each position. In this sense, long-term stability of the tight focus is essential for both microscopic large area scanning and nanosized sample scanning (high-resolution/large-area imaging). In addition, the recently developed tip-enhanced microscopy requires long-term stability of the relative position of the tip, sample and focus position. We were able to successfully demonstrate a stability improvement for tip-enhanced microscopy in the same manner. The stabilization of the tight focus enables us to perform long-term and robust measurements without any degradation of optical signal, resulting in the capability of true nanometric optical imaging with good reproducibility and high precision. The technique presented is a simple add-on for any kind of optical microscope.

Incidence of symptomatic autonomic dysreflexia varies according to the bowel and bladder management techniques in patients with spinal cord injury

STUDY DESIGN

A retrospective, multicenter study.

OBJECTIVES

To investigate the relationship between bowel and bladder management methods and symptomatic autonomic dysreflexia (AD) during hospitalization in patients with spinal cord injury (SCI).

SETTING

Twenty-eight Rosai hospitals in Japan.

METHODS

The study subjects were 571 patients with SCI who had been admitted to 28 Rosai hospitals between April 1997 and March 2007 for rehabilitation therapy and fulfilled the following criteria: (1) SCI at or above sixth thoracic level, (2) discharged from hospital after more than 4 months of admission for initial injury and (3) lack of pressure ulcers, deep venous thrombosis, ureteral and renal stones or heterotopic ossification throughout hospitalization to exclude possible influence of these complications on cardiovascular reflexes. The study subjects were examined for the incidence of symptomatic AD according to age, sex, ASIA Impairment Scale, injury level, bowel and bladder management techniques at discharge.

RESULTS

The Rosai Hospital registry included 3006 persons with SCI during 1997-2007, and 571 patients fulfilled the above criteria. The highest incidence of symptomatic AD was diagnosed in subjects using reflex voiding and in those using manual removal of stool. By contrast, the lowest incidence of symptomatic AD was in those on continent spontaneous voiding and continent spontaneous defecation.

CONCLUSION

Medical staff should evaluate the presence of AD in patients with SCI at or above the T6 level under bladder and bowel management such as reflex voiding and manual removal of stool.

Inorganic Polyphosphate Induces Osteoblastic Differentiation

Inorganic polyphosphate [Poly(P)] is especially prevalent in osteoblasts. We tested the hypothesis that Poly(P) stimulates osteoblastic differentiation and polyphosphate metabolism for bone formation. The osteoblast-like cell line, MC 3T3-E1, was cultured with Poly(P), and gene expression was evaluated by real-time reverse-transcription polymerase chain-reaction. Phosphatase activity and extracellular matrix mineralization were also determined. The role of Poly(P) was assessed in a beagle dog alveolar bone regeneration model. Poly(P) increased osteocalcin, osterix, bone sialoprotein, and tissue non-specific alkaline phosphatase gene expression, with a high level of end-polyphosphatase activity, resulting in low-chain-length Poly(P), inorganic pyrophosphate, and inorganic phosphate production. MC3T3-E1 cells differentiated into mature osteoblasts and showed expression of ectonucleotide pyrophosphatase phosphodiesterase 1, while mouse progressive ankylosis gene expression remained unchanged. Promotion of alveolar bone regeneration was observed in Poly(P)-treated beagle dogs. These findings suggest that Poly(P) induces osteoblastic differentiation and bone mineralization, and acts as a resource for mineralization.

Carcinogen adsorbent prepared from DNA complex by gamma-ray irradiation

The effects of gamma-ray irradiation on aqueous solutions of chub mackerel chromatin, salmon milt DNA with CoCl(2), mixtures of DNA with Type A gelatin, bovine serum albumin (BSA), CM-chitosan, carboxymethyl cellulose (CMC) and Catinal (hydroxyethyl-cellulose, O-[2-hydroxy-3-(trimethyl ammonio)-propyl], chloride) and DNA in the presence of polyfunctional monomers with the aim to insolubilize DNA for preparing a novel carcinogen adsorbent have been studied. Among those, precipitates or inhomogeneous gel consisting of cross-linked DNA were prepared from the samples of aqueous DNA in the presence of CoCl(2) at low irradiation dose, around 10 Gy, and bulk homogeneous gels were successfully prepared from aqueous mixtures of DNA with gelatin, BSA, CMC and Catinal in a limited range of irradiation doses. Gel fraction and swelling ratio of the gels were measured. Adsorption of a carcinogen, acridine orange, was also examined for the gels. From the experimental results, the optimum conditions for preparing insolubilized homogeneous DNA gels were determined.

Inorganic polyphosphate: a possible stimulant of bone formation

Inorganic polyphosphates [Poly(P)] are often distributed in osteoblasts. We undertook the present study to verify the hypothesis that Poly(P) stimulates osteoblasts and facilitates bone formation. The osteoblast-like cell line MC 3T3-E1 was cultured with Poly(P), and gene expression and potential mineralization were evaluated by reverse-transcription polymerase chain-reaction. Alkaline phosphatase activity, von Kossa staining, and resorption pit formation analyses were also determined. The potential role of Poly(P) in bone formation was assessed in a rat alveolar bone regeneration model. Poly(P) induced osteopontin, osteocalcin, collagen 1alpha, and osteoprotegerin expression and increased alkaline phosphatase activity in MC 3T3-E1 cells. Dentin slice pit formation decreased with mouse osteoblast and bone marrow macrophage co-cultivation in the presence of Poly(P). Promotion of alveolar bone regeneration was observed locally in Poly(P)-treated rats. These findings suggest that Poly(P) plays a role in osteoblastic differentiation, activation, and bone mineralization. Thus, local poly(P) delivery may have a therapeutic benefit in periodontal disease.

Adsorption kinetics of carcinogens to DNA liquid crystalline gel beads

Adsorption behaviors of acridine orange (AO) and biphenyl (BP) to DNA liquid crystalline gel (LCG) beads in aqueous dispersing solution have been studied theoretically and experimentally. A theoretical consideration based on nonequilibrium thermodynamics predicted that the time course of the adsorption process is expressed with a scaled equation, and a scaled number of adsorbed carcinogen molecules ñ is expressed with the square root of a scaled immersion time t, ñ proportional, variant square root t at early stage, whereas it is expressed with a power law function 1 - ñ proportional, variant (te - t)3/2 for ñ0 > 1 and an exponential equation ñ0 - ñ proportional, variant e-t/alpha tau0 for ñ0 > 1 at later stages of adsorption. Here, ñ0 is the ratio of the initial number of carcinogen molecules in the dispersing solution to the number of the sites of adsorption of carcinogen molecules in the beads, te is the scaled equilibrium time of adsorption, tau0 is a time constant for adsorption, and alpha is a constant. Observed adsorption processes for AO were well expressed by the predicted ones, and the fitting parameters ñ0 and tau0 increased with increasing cobalt chloride concentration CCo used for preparation of the beads, and both saturated above CCo > or = 400 mM for the adsorption of AO, whereas the adsorption processes for BP were expressed with the square root function. These results indicate that (1) the adsorption process at early stage is explained by diffusion-limited binding of the carcinogen molecules to DNA beads, and the time range of the early stage depends on the solubility (the solubility of AO in water is high whereas that of BP is low); and (2) the process at later stages depends on the balance of the numbers of adsorption sites and carcinogen molecules.

Attenuation of natural killer cell activity during 2-h exercise in individuals with spinal cord injuries

DESIGN

Non-randomized study.

OBJECTIVE

To determine natural killer cell cytotoxic activity (NKCA) to 2-h arm ergometer exercise in persons with spinal cord injuries (SCI) and the underlying mechanism of such response.

SETTING

University of Occupational and Environmental Health, Japan.

METHODS

We examined NKCA response to 2-h arm crank ergometer exercise at 60% of maximum oxygen consumption (VO(2max)) in SCI and able-bodied persons. NKCA and plasma concentrations of prostaglandin E(2) (PGE(2)), adrenaline and cortisol were measured before, during and immediately after the exercise. The study included seven subjects with SCI between Th11 and L4 and six able-bodied persons.

RESULTS

NKCA in able-bodied subjects increased (P<0.05) at 60 min of exercise and immediately after the exercise, and remained elevated up to 2 h after exercise. However, NKCA in SCI decreased (P<0.05) immediately after exercise but recovered at 2 h after exercise. Plasma adrenaline in both groups increased significantly (P<0.05) immediately after exercise and returned to baseline level 2 h after the exercise. Plasma cortisol in both groups remained constant throughout the study. In SCI, PGE(2) significantly increased immediately after 2 h exercise and returned to the baseline level 2 h after exercise; however, it remained unchanged during the test in able-bodied subjects.

CONCLUSION

Our results suggested that increase of PGE(2) in SCI partially contributes to NKCA.

The incidence of post-race symptoms of upper respiratory tract infection in wheelchair marathon racers

STUDY DESIGN

Prospective analysis.

OBJECTIVES

To investigate the influence of exercise and major competition on infectious episodes in athletes with spinal cord injuries (SCI).

SETTING

Japan.

METHODS

We examined the self-reported infectious episodes of upper respiratory tract infection (URTI) in athletes with SCI during a 1-month period before the race and 2 weeks after the race. The study included 21 persons with SCI who participated in the 18th Oita International Wheelchair Marathon. Thirteen persons with SCI who did not participate in the race were studied as control subjects.

RESULTS

The number of URTI episodes in marathoners was 0.086+/-0.036/week during the 1-month period before the race and 0.089+/-0.040/week during the 2-week post-race period, whereas that of the controls was 0.139+/-0.046/week during the 1-month period before the race and 0.072+/-0.047/week during the 2-week post-race period. There were no significant differences between before and after the race in marathoners, or between marathoners and controls during each period. However, the number of URTI episodes 2 weeks after the race was significantly higher in subjects who trained more than 65 km/week compared to those who trained less than 65 km/week.

CONCLUSIONS

In subjects with SCI who completed a wheelchair full marathon race, the incidence of URTI after the race was not high compared to control subjects who did not participate in the race. According to the number of URTI episodes and the training data, it is recommended that wheelchair marathoners should consider their risk for URTI during excessive practice.