Efficiency and Rolling Resistance in Manual Wheelchair Propulsion.

The efficiency and the rolling resistance in wheelchair propulsion play an important role in the comfort and the health of wheelchair users in daily life. Here we identify these fundamental interactions of wheelchair-user system on treadmill and on track. We measured the oxygen uptake (input) and the propelling torque (output) as the parameters with velocity and tire pressure. The efficiency increased about 9-13% as the velocity increased on treadmill and it increased around 11-12% as the tire pressure reduced on track. The mean coefficient of rolling resistance was 0.012 on treadmill and that were 0.016 (200 kPa) and 0.026 (30 kPa) on track. Our experimental results indicated that the efficiency and the rolling resistance were strongly dependent on the velocity and tire pressure.

Advantages of Unstable Manual Wheelchair.

In this study, many test runs were conducted using experimental manual wheelchair on various floor surface conditions. In the result, operability of manual wheelchair would be improved by shifting the position of drive wheels forward.

Hypothalamic dopamine is required for salsolinol-induced prolactin secretion in goats.

The aim of the present study was to clarify the relationship between hypothalamic dopamine (DA) and salsolinol (SAL) for the secretion of prolactin (PRL) in goats. SAL or thyrotropin-releasing hormone (TRH) was intravenously injected into female goats treated with or without the D2 DA receptor antagonist haloperidol (Hal), which crosses the blood-brain barrier, and the PRL-releasing response to SAL was compared with that to TRH. PRL-releasing responses to SAL, Hal, and Hal plus SAL were also examined after a pretreatment to augment central DA using carbidopa (Carbi) and L-dopa. The PRL-releasing response to Hal alone was greater than that to SAL or TRH alone. The PRL-releasing response to Hal plus SAL was similar to that of Hal alone. In contrast, the PRL-releasing response to Hal plus TRH was greater than that to TRH or Hal alone. The treatment with Carbi plus L-dopa inhibited SAL- and Hal-induced PRL secretion. The inhibition of the PRL-releasing response to SAL disappeared when SAL was injected with Hal. These results indicate that the mechanisms underlying the SAL-induced PRL response differ from those of TRH, and suggest that hypothalamic DA and its synthesis is associated in part with SAL-induced PRL secretion in goats.

Effects of downregulating TEAD4 transcripts by RNA interference on early development of bovine embryos.

Transcription factor TEA domain family transcription factor 4 (Tead4) is one of the key factors involved in the differentiation of the trophectoderm (TE) in murine embryos. However, knowledge on the roles of TEAD4 in preimplantation development during bovine embryos is currently limited. This study examined the transcript and protein expression patterns of TEAD4 and attempted to elucidate the functions of TEAD4 during bovine preimplantation development using RNA interference. TEAD4 mRNA was found to be upregulated between the 16-cell and morula stages, and nuclear localization of the TEAD4 protein was detected at the morula stage, as well as in subsequent developmental stages. TEAD4 downregulation did not affect embryonic development until the blastocyst stage, and TEAD4-downregulated embryos were capable of forming the TE under both 5% and 21% O2 conditions. Results of gene expression analysis showed that TEAD4 downregulation did not affect the expression levels of POU class 5 transcription factor 1 (OCT-4), NANOG, caudal-type homeobox 2 (CDX2), GATA binding protein 3 (GATA3), and interferon-tau (IFNT). In conclusion, TEAD4 might be dispensable for development until the blastocyst stage and TE differentiation in bovine embryos.

The Necessity of OCT-4 and CDX2 for Early Development and Gene Expression Involved in Differentiation of Inner Cell Mass and Trophectoderm Lineages in Bovine Embryos.

The functions of POU class 5 transcription factor 1 (Oct-4) and caudal-type homeobox 2 (Cdx2) in the differentiation of the murine inner cell mass (ICM) and trophectoderm (TE) have been described in detail. However, little is known about the roles of OCT-4 and CDX2 in preimplantation bovine embryos. To elucidate their functions during early development in bovine embryos, we performed OCT-4 and CDX2 downregulation using RNA interference. We injected OCT-4- or CDX2-specific short interfering RNAs (siRNAs) into bovine zygotes. The rate of blastocyst development of OCT-4-downregulated embryos was lower compared with uninjected or control siRNA-injected embryos. Gene expression analysis revealed decreased CDX2 and fibroblast growth factor 4 expression in OCT-4-downregulated embryos. CDX2-downregulated embryos developed to the blastocyst stage; however, in most cases, blastocoel formation was delayed. Gene expression analysis revealed decreased GATA3 expression and elevated NANOG expression in CDX2-downregulated embryos. In conclusion, OCT-4 and CDX2 are essential for early development and gene expression involved in differentiation of ICM and TE lineages in bovine embryos.

OCT-4 expression is essential for the segregation of trophectoderm lineages in porcine preimplantation embryos.

Oct-4, a member of the POU family of transcription factors, is a key factor that regulates the segregation of the inner cell mass (ICM) and the trophectoderm (TE) during the transition from morula to blastocyst in mice. However, little is known about its role in porcine early embryogenesis. To determine the function of OCT-4 in the ICM and TE segregation of porcine embryos, we studied the developmental morphology of porcine embryos using RNA interference technology. Our experiments demonstrated that when 1-cell stage embryos were co-injected with the small interfering RNA (siRNA)for targeted knockdown of OCT-4 (OCT-4-siRNA) and tetramethylrhodamine isothiocyanate (TRITC)-dextran conjugate (Dx), they failed to form blastocysts. Therefore, in this study, we constructed chimeric embryos comprising blastomeres that either expressed OCT-4 normally or showed downregulated OCT-4 expression by co-injection of OCT-4-siRNA and Dx into one blastomere in 2- to 4-cell stage embryos. In control embryos, which were co-injected with control siRNA and Dx, Dx-positive cells contributed to the TE lineage in almost all the blastocysts examined. In contrast, Dx-positive cells derived from a blastomere co-injected with OCT-4-siRNA and Dx were degenerated in almost half the blastocysts. This was probably due to the inability of these cells to differentiate into the TE lineage. Real-time RT-PCR analysis revealed no difference in the levels of SOX2, TEAD4, FGF4 and FGFR1-IIIc, all of which are known to be regulated by OCT-4, between the OCT-4-siRNA-injected morulae and the control ones. However, the level of CDX2, a molecule specifically expressed in the TE lineage, was significantly higher in the former than in the latter. Our results indicate that continuous expression of OCT-4 in blastomeres is essential for TE formation of porcine embryos.

Effects of extracerebral dopamine on salsolinol- or thyrotropin-releasing hormone-induced prolactin (PRL) secretion in goats.

The aim of the present study was to clarify the effect of extracerebral dopamine (DA) on salsolinol (SAL)-induced prolactin (PRL) secretion in goats. An intravenous injection of SAL or thyrotropin-releasing hormone (TRH) was given to female goats before and after treatment with an extracerebral DA receptor antagonist, domperidone (DOM), and the PRL-releasing response to SAL was compared with that to TRH. DOM alone increased plasma PRL concentrations and the PRL-releasing response to DOM alone was greater than that to either SAL alone or TRH alone. The PRL-releasing response to DOM plus SAL was similar to that to DOM alone, and no additive effect of DOM and SAL on the secretion of PRL was observed. In contrast, the PRL-releasing response to DOM plus TRH was greater than that to either TRH alone or DOM alone and DOM synergistically increased TRH-induced PRL secretion. The present results demonstrate that the mechanism involved in PRL secretion by SAL differs from that by TRH, and suggest that the extracerebral DA might be associated in part with the modulation of SAL-induced PRL secretion in goats.

Biomechanics and Physiology for Propelling Wheelchair Uphill Slope.

A vertical slope of sidewalks significantly inhibits to the mobility of manual wheelchair users in their daily life. International guidelines of the vertical slope are specified approximately 4% or 5% (1:20) gradient or less as preferred, and allow 8.3% (1:12) as its maximum when it is impossible. Relevant research of the physical strain for wheelchair users with pushing on slopes, and the validity assessment of slope guidelines have been investigated. However, the analysis for the effect of a slope distance and their transient performance are still remained. The purpose of this study is to clarify the physiological and biomechanical characteristics of manual wheelchair users that propelling a wheelchair on an uphill slope. We measured these data by a metabolic analysis system, a heart rate monitor system and an instrumented wheelchair wheel. Sixteen unimpaired subjects (non-wheelchair users) were examined to investigate the effect of a long slope with 120m distance and 8% gradient. And five wheelchair users with cervical cord injury were examined to evaluate the influence of different gradients (5%, 6.7%, 8.3%, 10% and 12.5%) with 3m length in laboratory. Our experimental results of the long slope showed that wheelchair propulsion velocity and power increased considerably at the beginning of the slope where the peak mean value of them were 0.96 m/s and 70.8W and they decreased linearly to 0.55m/s and 33.6W at final interval. A mean oxygen uptake and heart rate were increased as the distance increased and their results indicated the extremely high exercise intensity at a final interval that were 1.2liter /min and 152bpm. While wheelchair pushing cadence reduced after an initial interval, mean of strokes per10m increased to compensate the decrease of upper limb's power. The results of different gradients indicated that the normalized power of subjects with cervical cord injury was significant difference between each subject in the ability to climb a slope. Mean normalized power were 0.23W/kg on a 5% slope, 0.24W/kg on 6.7%, and 0.26W/kg on 8.3% respectively. Based on these findings, we examined the relationship between the theoretical normalized power and the lowest velocity to climb a slope, and we might indicate the ability to push on an uphill slope for the persons with manual wheelchair user.

Effect of Tire Pressure to Physical Workload at Operating a Manual Wheelchair.

It is often experienced that low tire pressure of the wheelchair not only increases running resistance, but also reduces parking brake performance. In this study, the required driving forces for different tire pressures were experimentally measured and evaluated. It was indicated from the result that the wheelchair with proper tire pressure could be run with less workload of wheelchair-user. Then it was also indicated that the wheelchair with a lower tire pressure needed more workload of wheelchair-user even on hard level surface.

Effects of downregulating GLIS1 transcript on preimplantation development and gene expression of bovine embryos.

Krüppel-like protein Gli-similar 1 (GLIS1) is known as a direct reprogramming factor for the generation of induced pluripotent stem cells. The objective of this study was to investigate the role of GLIS1 in the preimplantation development of bovine embryos. GLIS1 transcripts in in vitro-matured oocytes and 1-cell to 4-cell stage embryos were detected, but they were either absent or at trace levels at the 8-cell to blastocyst stages. We attempted GLIS1 downregulation of bovine early embryos by RNA interference and evaluated developmental competency and gene transcripts, which are involved in zygotic gene activation (ZGA) in GLIS1-downregulated embryos. Injection of specific siRNA resulted in a distinct decrease in GLIS1 transcript in bovine embryos at the 4-cell stage. Although the bovine embryos injected with GLIS1-siRNA could develop to the 16-cell stage, these embryos had difficulty in developing beyond the 32-cell stage. Gene transcripts of PDHA1 and HSPA8, which are transcribed after ZGA, showed lower level in GLIS1 downregulated embryos. It is possible that GLIS1-downregulated embryos fail to initiate ZGA. Our results indicated that GLIS1 is an important factor for the preimplantation development of bovine embryos.

Effects of hypothalamic dopamine on growth hormone-releasing hormone-induced growth hormone secretion and thyrotropin-releasing hormone-induced prolactin secretion in goats.

The aim of the present study was to clarify the effects of hypothalamic dopamine (DA) on the secretion of growth hormone (GH) in goats. The GH-releasing response to an intravenous (i.v.) injection of GH-releasing hormone (GHRH, 0.25 µg/kg body weight (BW)) was examined after treatments to augment central DA using carbidopa (carbi, 1 mg/kg BW) and L-dopa (1 mg/kg BW) in male and female goats under a 16-h photoperiod (16 h light, 8 h dark) condition. GHRH significantly and rapidly stimulated the release of GH after its i.v. administration to goats (P < 0.05). The carbi and L-dopa treatments completely suppressed GH-releasing responses to GHRH in both male and female goats (P < 0.05). The prolactin (PRL)-releasing response to an i.v. injection of thyrotropin-releasing hormone (TRH, 1 µg/kg BW) was additionally examined in male goats in this study to confirm modifications to central DA concentrations. The treatments with carbi and L-dopa significantly reduced TRH-induced PRL release in goats (P < 0.05). These results demonstrated that hypothalamic DA was involved in the regulatory mechanisms of GH, as well as PRL secretion in goats.

Effects of hypothalamic dopamine (DA) on salsolinol (SAL)-induced prolactin (PRL) secretion in male goats.

The aim of the present study was to clarify the effects of hypothalamic dopamine (DA) on salsolinol (SAL)-induced prolactin (PRL) release in goats. The PRL-releasing response to an intravenous (i.v.) injection of SAL was examined after treatment with augmentation of central DA using carbidopa (carbi) and L-dopa in male goats under 8-h (8 h light, 16 h dark) or 16-h (16 h light, 8 h dark) photoperiod conditions. The carbi and L-dopa treatments reduced basal PRL concentrations in the 16-h photoperiod group (P < 0.05), while a reduction was not observed in the 8-h photoperiod group. The mean basal plasma PRL concentration in the control group for the 8-h photoperiod was lower than that for the 16-h photoperiod (P < 0.05). SAL significantly stimulated the release of PRL promptly after the injection in both the 8- and 16-h photoperiod groups (P < 0.05). PRL-releasing responses for the 16-h photoperiod were greater than those for the 8-h photoperiod (P < 0.05). The carbi and L-dopa treatments blunted SAL-induced PRL release in both the 8- and 16-h photoperiods (P < 0.05). These results indicate that hypothalamic DA blunts the SAL-induced release of PRL in male goats, regardless of the photoperiod, which suggests that both SAL and DA are involved in regulating the secretion of PRL in goats.

Effects of downregulating oct-4 transcript by RNA interference on early development of porcine embryos.

The objective of this study was to investigate the role of the POU family transcription factor, Oct-4, in the early development of porcine embryos. We attempted Oct-4 downregulation of porcine early embryos by RNA interference, and evaluated Oct-4 suppression of developmental competencies and gene transcripts in porcine embryos. Injection of specific siRNA resulted in a distinct decrease in Oct-4 mRNA and protein expression in porcine embryos until at least the morula stage. Although the porcine embryos injected with Oct-4 siRNA were able to develop to the morula stage, these embryos failed to form blastocysts. Gene transcripts of caudal-like transcription factor (Cdx2) and fibroblast growth factor 4 (Fgf4), which were involved in segregation of the trophectderm and functionalization of the inner cell mass, were unchanged by Oct-4 siRNA injection. Our results indicated that Oct-4 is an important factor for porcine embryos and, in particular, for the regulation of porcine blastocyst formation.

Effects of photoperiod on secretory patterns of growth hormone in adult male goats.

The aim of the present study was to clarify the effect of photoperiod on secretory patterns of growth hormone (GH) in male goats. Adult male goats were kept at 20°C with an 8-h or 16-h light photoperiod, and secretory patterns of GH secretion were compared. In addition, plasma profiles of prolactin (PRL), insulin-like growth factor-I (IGF-I) and testosterone (T) were also examined to characterize GH secretion. GH was secreted in a pulsatile manner. There was no significant difference in pulse frequency between the 8-h and 16-h photoperiods. However, GH pulse amplitude tended to be greater in the group with the 16-h photoperiod (P = 0.1), and mean GH concentrations were significantly greater in the 16-h photoperiod (P < 0.05). The GH-releasing response to GH releasing hormone was greater in the 16-h than 8-h photoperiod (P < 0.05). Plasma PRL and IGF-I levels were higher in the 16-h than 8-h photoperiod (P < 0.05). In contrast, plasma T levels were lower in the 16-h photoperiod (P < 0.05). These results show that a long light photoperiod enhances the secretion of GH as well as PRL and IGF-I, but reduces plasma T concentrations in male goats.

Effects of melatonin on salsolinol-induced prolactin secretion in goats.

The aim of the present study was to clarify the effect of melatonin (MEL) on the salsolinol (SAL)-induced release of prolactin (PRL) in goats. Female goats were kept at 20°C with 16 h of light, 8 h of darkness, and orally administered saline or MEL for 5 weeks. A single intravenous (i.v.) injection of saline (controls), SAL, thyrotropin-releasing hormone (TRH) or a dopamine receptor antagonist, sulpiride, was given to the goats 3 weeks after the first oral administrations of saline or MEL, and the responses were compared. The mean basal plasma PRL concentrations in the control group were higher for the saline treatments than MEL treatments (P < 0.05). SAL as well as TRH and sulpiride stimulated the release of PRL promptly after each injection in both the saline- and MEL-treated groups (P < 0.05). The area under the response curve of PRL for the 60-min period after the i.v. injection of SAL, TRH and sulpiride in the saline-treated group was greater than each corresponding value in the MEL-treated group (P < 0.05). These results show that daily exposure to MEL under a long day length reduces the PRL-releasing response to SAL as well as TRH and sulpiride in goats.

Transcript abundance and apoptosis in day-7 porcine blastocyst cultured with exogenous insulin-like growth factor-I.

Exogenous growth factors may increase the efficiency of embryo development in vitro. The aim of the present study was to examine the effects of insulin-like growth factor (IGF)-I on porcine embryo development. Porcine embryos obtained by in vitro fertilization were cultured for seven days in the presence of IGF-I (50, 100 or 150ng/ml). Subsequently, relative transcript abundance (RA) of IGF-related genes (IGFR1, IGFBP2, and IGFBP3), glucose transporter genes (SLC2A4 and SLC2A8), and apoptosis-related genes (BAX and BCL-XL) was analyzed. No differences were observed in the cleavage rate on day 2 post insemination (pi) and blastocysts rate on day 7pi between IGF-treated and control embryos. IGF-I treatment did not affect RA of IGFR1, IGFBP3, and SLC2A4 genes, but decreased RA of IGFBP2 and SLC2A8 genes. The percentage of TUNEL-positive nuclei in blastocysts did not differ between the experimental groups. However, RA of BAX and BCL-XL genes decreased in response to all IGF-I concentrations, whereas the BCL-XL/BAX RA ratio was enhanced when embryos were cultured in medium containing 150ng/ml of IGF-I. These results indicate that IGF-I did not stimulate in vitro development of porcine embryos through the IGF signaling system, nor did IGF-I stimulate RA of glucose transporter genes. However, IGF-I at the highest dose was able to increase the BCL-XL/BAX transcript expression ratio. This may indicate that the primary role of IGF-I during the first days of embryo development in the pig is associated with anti-apoptotic actions rather than with growth stimulation.

Effects of photoperiod on the secretion of growth hormone and prolactin during nighttime in female goats.

The aim of the present study was to clarify the effect of photoperiod on nighttime secretion of growth hormone (GH) in goats. Adult female goats were kept at 20°C with an 8 h or 16 h dark photoperiod, and secretory patterns of GH for 8 h in the dark period were examined with the profile of prolactin (PRL) secretion. GH was secreted in a pulsatile manner in the dark period. There were no significant differences in pulse frequency between the 8- and 16-h dark photoperiods; however, pulse amplitude tended to be greater in the group with the 16-h dark photoperiod (P = 0.1), and mean GH concentrations were significantly greater in the same photoperiod (P < 0.05). PRL secretion increased quickly after lights off under both photoperiods. The PRL-releasing responses were weaker in the 8-h than 16-h dark photoperiod. The secretory response to photoperiod was more obvious for PRL than GH. The present results show that a long dark photoperiod enhances the nighttime secretion of GH in female goats, although the response is not as obvious as that for PRL.

Changes in the expression patterns of the genes involved in the segregation and function of inner cell mass and trophectoderm lineages during porcine preimplantation development.

In mouse embryos, segregation of the inner cell mass (ICM) and trophectoderm (TE) lineages is regulated by genes, such as OCT-4, CDX2 and TEAD4. However, the molecular mechanisms that regulate the segregation of the ICM and TE lineages in porcine embryos remain unknown. To obtain insights regarding the segregation of the ICM and TE lineages in porcine embryos, we examined the mRNA expression patterns of candidate genes, OCT-4, CDX2, TEAD4, GATA3, NANOG, FGF4, FGFR1-IIIc and FGFR2-IIIc, in blastocyst and elongated stage embryos. In blastocyst embryos, the expression levels of OCT-4, FGF4 and FGFR1-IIIc were significantly higher in the ICM than in the TE, while the CDX2, TEAD4 and GATA3 levels did not differ between the ICM and TE. The expression ratio of CDX2 to OCT-4 (CDX2/OCT-4) also did not differ between the ICM and TE at the blastocyst stage. In elongated embryos, OCT-4, NANOG, FGF4 and FGFR1-IIIc were abundantly expressed in the embryo disc (ED; ICM lineage), but their expression levels were very low in the TE. In contrast, the CDX2, TEAD4 and GATA3 levels were significantly higher in the TE than in the ED. In addition, the CDX2/OCT-4 ratio was markedly higher in the TE than in the ED. We demonstrated that differences in the expression levels of OCT-4, CDX2, TEAD4, GATA3, NANOG, FGF4, FGFR1-IIIc and FGFR2-IIIc genes between ICM and TE lineages cells become more clear during development from porcine blastocyst to elongated embryos, which indicates the possibility that in porcine embryos, functions of ICM and TE lineage cells depend on these gene expressions proceed as transition from blastocyst to elongated stage.

Effects of photoperiod on the secretion of growth hormone in female goats.

The aim of the present study was to clarify the effect of photoperiod on the secretion of growth hormone (GH) in goats. Adult female goats were kept at 20°C with an 8-h or 16-h photoperiod, and secretory patterns of GH for 4 h (12.00 to 16.00 hours) were compared. In addition, the goats were kept under a 16-h photoperiod and orally administered saline (controls) or melatonin, and the effects of melatonin on the secretion of GH were examined. GH was secreted in a pulsatile manner. There were no significant differences in pulse frequency between the 8- and 16-h photoperiods; however, GH pulse amplitude tended to be greater in the group with the 16-h photoperiod (P = 0.1), and mean GH concentrations were significantly greater in the 16-h photoperiod (P < 0.05). The GH-releasing response to GH-releasing hormone (GHRH) was also significantly greater for the 16-h photoperiod (P < 0.05). There were no significant differences in GH pulse frequency between the saline- and melatonin-treated groups. However, GH pulse amplitude and mean GH concentrations were significantly greater in the saline-treated group (P < 0.05). The present results show that a long photoperiod enhances the secretion of GH, and melatonin modifies GH secretion in female goats.

Kisspeptin-10 stimulates the release of luteinizing hormone and testosterone in pre- and post-pubertal male goats.

The aims of the present study were to clarify the effect of kisspeptin-10 (Kp10) on the secretion of luteinizing hormone (LH) and testosterone (T) in pre-pubertal and post-pubertal male ruminants. Four male goats (Shiba goats) were given an intravenous (i.v.) injection of Kp10 (5 µg/kg body weight (b.w.)), gonadotoropin-releasing hormone (GnRH, 1 µg/kg b.w.), or 2 mL of saline as a control at the ages of 3 (pre-pubertal) and 6 (post-pubertal) months. A single i.v. injection of Kp10 significantly stimulated the release of LH and T in both groups. The area under the response curve (AUC) of LH for a 60-min period after the i.v. injection of Kp10 was significantly greater in the pre-pubertal goats (P < 0.05). The AUC of T for a 120 min period post-injection did not differ between the two age groups. A single i.v. injection of GnRH also significantly stimulated the release of LH and T in both groups (P < 0.05). The secretory pattern of LH and T in response to GnRH resembled that in response to Kp10. These results show that the LH-releasing response to Kp10 is greater in pre-pubertal than post-pubertal male goats. They also show that Kp10, as well as GnRH, is able to stimulate the release of T in male goats.