Risk factors for collisions attributed to microsleep-related behaviors while driving in professional truck drivers

Sleep-disordered breathing (SDB) is prevalent among professional drivers. Although SDB is a known risk factor for truck collisions attributed to microsleep-related behaviors at the wheel (TC-MRBs), the usefulness of overnight pulse oximetry for predicting TC-MRBs is debatable. This retrospective study assessed the association between overnight pulse oximetry parameters, the Epworth Sleepiness Scale (ESS), and TC-MRBs, confirmed by dashcam footage. This study included 108 matched professional truck drivers (TC-MRBs: N = 54; non-TC-MRBs: N = 54), with a mean age and body mass index of 41.9 ± 11.3 years and 23.0 ± 3.7 kg/m2, respectively. Night-time drivers, 4% oxygen desaturation index (ODI), and nadir oxygen saturation (SpO2) were associated with TC-MRBs (odds ratio [95% confidence interval]: 25.63 [5.88-111.77], p < 0.0001; 2.74 [1.02-7.33], p = 0.045; and 3.87 [1.04-14.39], p = 0.04, respectively). The area under the curve of 4% ODI and nadir SpO2 for TC-MRBs were 0.50 and 0.57, respectively. In conclusion, night-time driving, 4% ODI, and nadir SpO2 were significantly associated with TC-MRBs in professional truck drivers. However, the sensitivity of overnight pulse oximetry parameters to predict TC-MRBs in a real-world application was poor. Therefore, combining subjective and objective assessments such as dashcam video footage may be needed to achieve high accuracy for predicting TC-MRBs among professional truck drivers.

Local distribution of manganese to leaf sheath is mediated by OsNramp5 in rice

To play essential roles of manganese (Mn) in plant growth and development, it needs to be transported to different organs and tissues after uptake. However, the molecular mechanisms underlying Mn distribution between different tissues are poorly understood. We functionally characterized a member of rice natural resistance-associated macrophage protein (NRAMP) family, OsNramp5 in terms of its tissue specificity of gene expression, cell-specificity of protein localization, phenotypic analysis of leaf growth and response to Mn fluctuations. OsNramp5 is highly expressed in the leaf sheath. Immunostaining revealed that OsNramp5 is polarly localized at the proximal side of xylem parenchyma cells of the leaf sheath. Both the gene expression and protein abundance of OsNramp5 are unaffected by different Mn concentrations. Knockout of OsNramp5 decreased the distribution of Mn to the leaf sheath, but increased the distribution to the leaf blade at both low and high Mn supplies, resulting in reduced growth of leaf sheath. Furthermore, expression of OsNramp5 under the control of root-specific promoter in osnramp5 mutant complemented Mn uptake, but could not complement Mn distribution to the leaf sheath. These results indicate that OsNramp5 expressed in the leaf sheath plays an important role in unloading Mn from the xylem for the local distribution in rice.

Truck collisions attributed to falling asleep at the wheel in two commercial drivers prescribed oral appliance therapy for obstructive sleep apnea

Falling asleep at the wheel is attributed to sleepiness, and obstructive sleep apnea is a significant cause of sleepiness that increases the risk of motor vehicle collisions due to falling asleep at the wheel. Although continuous positive airway pressure therapy for obstructive sleep apnea reduces the risk of motor vehicle collisions, similar evidence for alternatives such as oral appliance therapy is lacking. We discuss two truck collisions attributed to microsleep confirmed with dashcam video footage of commercial drivers with obstructive sleep apnea. Our results highlight the current situation where there is insufficient evidence for the prevention and reduction of the risk of motor vehicle collisions by oral appliance therapy, objective adherence monitoring of oral appliance therapy, and effectiveness confirmation tests. Therefore, it is suggested that for commercial truck drivers who require a high level of driving safety, careful selection for oral appliance therapy, systematic follow-up, and monitoring of the driver and truck status with dashcam video footage are crucial.

CITATION

Kumagai H, Tsuda H, Kawaguchi K, et al. Truck collisions attributed to falling asleep at the wheel in two commercial drivers prescribed oral appliance therapy for obstructive sleep apnea. J Clin Sleep Med. 2023;19(12):2117-2122.

Polar localization of a rice silicon transporter requires isoleucine at both C- and N-termini as well as positively charged residues

Silicon (Si) is important for stable and high yields in rice (Oryza sativa), a typical Si hyperaccumulator. The high Si accumulation is achieved by the cooperation of 2 Si transporters, LOW SILICON 1 (OsLsi1) and OsLsi2, which are polarly localized in cells of the root exodermis and endodermis. However, the mechanism underlying their polar localization is unknown. Here, we identified amino acid residues critical for the polar localization of OsLsi1. Deletion of both N- and C-terminal regions resulted in the loss of its polar localization. Furthermore, the deletion of the C-terminus inhibited its trafficking from the endoplasmic reticulum to the plasma membrane. Detailed site-directed mutagenesis analysis showed that Ile18 at the N-terminal region and Ile285 at the C-terminal region were essential for the polar localization of OsLsi1. Moreover, a cluster of positively charged residues at the C-terminal region is also required for polar localization. Phosphorylation and Lys modifications of OsLsi1 are unlikely to be involved in its polar localization. Finally, we showed that the polar localization of OsLsi1 is required for the efficient uptake of Si. Our study not only identified critical residues required for the polar localization of OsLsi1, but also provided experimental evidence for the importance of transporter polarity for efficient nutrient uptake.

Advanced emergency braking system reduces the risk of motor vehicle collisions caused by falling asleep while driving in patients with untreated obstructive sleep apnea

Obstructive sleep apnea leads to excessive daytime sleepiness and cognitive dysfunction, which are risk factors for motor vehicle collisions. We aimed to clarify if vehicles with an advanced emergency braking system could reduce motor vehicle collisions caused by falling asleep while driving among patients with untreated obstructive sleep apnea. We enrolled patients with untreated obstructive sleep apnea who underwent polysomnography. The questionnaires included the Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, history of drowsy driving accidents, and use of an advanced emergency braking system. Multivariate analysis was performed, and odds ratios and 95% confidence intervals were calculated. This study included 1097 patients (mean age, 51.2 ± 12.9 years). Collisions caused by falling asleep while driving were recorded in 59 (5.4%) patients, and were more frequently observed in vehicles without an advanced emergency braking system (p = 0.045). Multivariate analysis showed that these collisions were associated with use of an advanced emergency braking system (odds ratio [95% confidence interval]: 0.39 [0.16-0.97], p = 0.04), length of driving (2.79 [1.19-6.50], p = 0.02), total sleep time (2.40 [1.62-3.55], p < 0.0001), sleep efficiency (0.94 [0.90-0.98], p = 0.003) and periodic limb movement index (1.02 [1.01-1.03], p = 0.004). The collision risk caused by falling asleep while driving in vehicles with an advanced emergency braking system was significantly lower. This study indicates that advanced emergency braking systems may be a preventive measure to reduce motor vehicle collisions among patients with untreated obstructive sleep apnea.

Nocturnal hypoxemia is related to morning negative affectivity in untreated patients with severe obstructive sleep apnea

The relationship between sleep apnea and morning affectivity remains unclear. We aimed to clarify how sleep disturbance in patients with obstructive sleep apnea (OSA) influences their affectivity. The enrolled participants underwent the Positive and Negative Affect Schedule on their beds immediately before and after overnight polysomnography. Thirty patients with OSA were divided into two groups according to the apnea-hypopnea index (AHI): mild to moderate OSA (5 ≤ AHI < 30/h) and severe OSA (AHI ≥ 30/h) groups. Additionally, 11 healthy participants (AHI < 5/h) were included as the control group. No independent association was found between affectivity and OSA severity markers in the whole population; however, the severe OSA group had a significantly higher cumulative percentage of sleep time at saturations < 90% (CT90) and worsened morning negative affectivity. Multiple regression analysis showed that CT90 was an independent factor for increasing negative affectivity in the severe OSA group (p = 0.0422). In patients with OSA, the receiver operating characteristic curve analysis showed that the best cutoff value for CT90 for predicting no decrease in negative affectivity after sleep was 1.0% (sensitivity = 0.56, specificity = 0.86); the corresponding area under the curve was 0.71. Worsening of negative affectivity in the morning was influenced by nocturnal hypoxemia in patients with severe OSA.

Effects of Continuous Positive Airway Pressure Therapy on Nocturnal Blood Pressure Fluctuation Patterns in Patients with Obstructive Sleep Apnea

This retrospective study was designed to evaluate the effects of continuous positive airway pressure (CPAP) therapy, a well-established treatment for obstructive sleep apnea (OSA), on nocturnal blood pressure fluctuations (NBPFs) during rapid eye movement (REM) and non-REM sleep, and to evaluate the NBPF patterns in patients with OSA. We included 34 patients with moderate-to-severe OSA who underwent polysomnography using pulse transit time before and at 3−6 months after CPAP therapy. Nocturnal BP and NBPF frequency in REM and non-REM sleep were investigated, as well as NBPF pattern changes after receiving CPAP therapy. CPAP therapy resulted in significant reductions in the apnea−hypopnea index (AHI), arousal index, nocturnal systolic and diastolic BP, and NBPF frequency in REM and non-REM sleep (all p < 0.01). A higher AHI before CPAP resulted in lower nocturnal systolic BP (r = 0.40, p = 0.019) and NBPFs (r = 0.51, p = 0.002) after CPAP. However, 58.8% of patients showed no change in NBPF patterns with CPAP therapy. CPAP therapy significantly improved almost all sleep-related parameters, nocturnal BP, and NBPF frequency in REM and non-REM sleep periods, but NBPF patterns showed various changes post-CPAP therapy. These results suggest that factors other than OSA influence changes in NBPF patterns.

Efficacy of a Combination Therapy for Difficulties Waking Up in Non-School-Attending Students

School non-attendance due to difficulties waking up is increasing in Japan, and affected students are commonly diagnosed with orthostatic dysregulation (OD); however, OD-associated sleep problems are overlooked. To date, no sleep-medicine-based treatment for wake-up difficulties in non-school-attending students has been established. This study aimed to assess the efficacy of a novel combination therapy for these students. We assessed the combined effect of sleep hygiene guidance, low-dose aripiprazole administration (3 mg/day), and blue-light exposure on wake-up difficulty in 21 non-school-attending teenage patients. The patients were evaluated using sleep studies and questionnaires before and after treatment. The average subjective total sleep time calculated from sleep diaries before treatment in the patients was 10.3 h. The therapy improved wake-up difficulty by 85.7% and further improved school non-attendance by 66.7%. The subjective sleep time significantly decreased by 9.5 h after treatment (p = 0.0004). The self-rating Depression Scale and mental component summary of the 36-item Short-Form Health Survey significantly improved after treatment (p = 0.002 and p = 0.01, respectively). Wake-up difficulties were caused by the addition of a delayed sleep phase to the patients’ long sleep times. The novel combination therapy was effective in improving wake-up difficulty and mental quality of life in non-school-attending teenage students.

Cell-Type-Dependent but CME-Independent Polar Localization of Silicon Transporters in Rice

Silicon (Si) is an important nutrient required for sustainable and high production of rice and its uptake is mediated by a pair of influx (OsLsi1)-efflux (OsLsi2) transporters showing polar localization. However, the mechanisms underlying their polarity are unknown. Here, we revealed that the polarity of the Si transporters depends on cell types. The polar localization of both OsLsi1 and OsLsi2 was not altered by Si supply, but their protein abundance was reduced. Double immunostaining showed that localization of OsLsi1 and OsLsi2 was separated at the edge of the lateral polar domain by Casparian strips in the endodermis, whereas they were slightly overlapped at the transversal side of the exodermis. When OsLsi1 was ectopically expressed in the shoots, it showed polar localization at the xylem parenchyma cells of the basal node and leaf sheath, but not at the phloem companion cells. Ectopic expression of non-polar Si transporters, barley HvLsi2 and maize ZmLsi2 in rice, resulted in their polar localization at the proximal side. The polar localization of OsLsi1 and OsLsi2 was not altered by inhibition of clathrin-mediated endocytosis (CME) by dominant-negative induction of dynamin-related protein1A and knockout of mu subunit of adaptor protein 2 complex, although the knockout mutants of OsAP2M gene showed dwarf phenotype. These results indicate that CME is not required for the polar localization of Si transporters. Taken together, our results indicate that CME-independent machinery controls the polar localization of Si transporters in exodermis, endodermis of root cells and xylem parenchyma cells.

Pathophysiological Analysis of Uninephrectomized db/db Mice as a Model of Severe Diabetic Kidney Disease

Diabetic nephropathy, included in diabetic kidney disease (DKD), is the primary disease leading to end-stage renal disease (ESRD) or dialysis treatment, accounting for more than 40% of all patients with ESRD or receiving dialysis. Developing new therapeutics to prevent the transition to ESRD or dialysis treatment requires an understanding of the pathophysiology of DKD and an appropriate animal model for drug efficacy studies. In this study, we investigated the pathophysiology of diabetic kidney disease with type 2 diabetes in uninephrectomized db/db mice. In addition, the nephrectomized db/db mice from 10 weeks to 42 weeks were used to assess the efficacy of long-term administration of the angiotensin-II–receptor antagonist losartan. The blood and urinary biochemical parameters and the blood pressure which is a main pharmacological endpoint of the losartan therapy, were periodically measured. And at the end, histopathological analysis was performed. Uninephrectomized db/db mice clearly developed obesity and hyperglycemia from young age. Furthermore, they showed renal pathophysiological changes, such as increased urinary albumin-creatinine ratio (UACR) (the peak value 3104±986 in 40-week-old mice), glomerular hypertrophy and increased fibrotic areas in the tubulointerstitial tubules. The blood pressure in the losartan group was significantly low compared to the normotensive Vehicle group. However, as expected, Losartan suppressed the increase in UACR (829±500) indicating the medication was sufficient, but the histopathological abnormalities including tubular interstitial fibrosis did not improve. These results suggest that the uninephrectomized db/db mice are useful as an animal model of the severe DKD indicated by the comparison of the efficacy of losartan in this model with the efficacy of losartan in clinical practice.

A pericycle-localized silicon transporter for efficient xylem loading in rice

Rice is able to accumulate high concentrations of silicon (Si) in the shoots, and this ability is required for the mitigation of abiotic and biotic stresses. Although transporters for Si uptake have been identified, a transporter for the xylem loading of Si has not been found. We functionally characterized a Si transporter, OsLsi3, in terms of tissue-specific localization, knockout line phenotype and mathematic simulation. OsLsi3 was shown to be an efflux Si transporter. OsLsi3 was mainly expressed in the mature root region, and its expression was downregulated by Si. Immunostaining with a specific antibody showed that OsLsi3 was localized to the pericycle in the roots, without polarity. However, when it was expressed under the control of the OsLsi2 promoter, OsLsi3 became polarly localized to the proximal side of both the exodermis and endodermis. Knockout of this gene resulted in decreased Si uptake and concentration in the xylem sap under low Si supply, but not under high Si supply. Mathematical modeling showed that localization of OsLsi3 to the pericycle accounts for c. 30% of the total Si loading to the xylem under low Si concentrations. In summary, OsLsi3 was involved in the xylem loading of Si in rice roots, which is required for the efficient root-to-shoot translocation of Si.

Boron uptake in rice is regulated post-translationally via a clathrin-independent pathway

Uptake of boron (B) in rice (Oryza sativa) is mediated by the Low silicon rice 1 (OsLsi1) channel, belonging to the NOD26-like intrinsic protein III subgroup, and the efflux transporter B transporter 1 (OsBOR1). However, it is unknown how these transporters cooperate for B uptake and how they are regulated in response to B fluctuations. Here, we examined the response of these two transporters to environmental B changes at the transcriptional and posttranslational level. OsBOR1 showed polar localization at the proximal side of both the exodermis and endodermis of mature root region, forming an efficient uptake system with OsLsi1 polarly localized at the distal side of the same cell layers. Expression of OsBOR1 and OsLsi1 was unaffected by B deficiency and excess. However, although OsLsi1 protein did not respond to high B at the protein level, OsBOR1 was degraded in response to high B within hours, which was accompanied with a significant decrease of total B uptake. The high B-induced degradation of OsBOR1 was inhibited in the presence of MG-132, a proteasome inhibitor, without disturbance of the polar localization. In contrast, neither the high B-induced degradation of OsBOR1 nor its polarity was affected by induced expression of dominant-negative mutated dynamin-related protein 1A (OsDRP1AK47A) or knockout of the mu subunit (AP2M) of adaptor protein-2 complex, suggesting that clathrin-mediated endocytosis is not involved in OsBOR1 degradation and polar localization. These results indicate that, in contrast to Arabidopsis thaliana, rice has a distinct regulatory mechanism for B uptake through clathrin-independent degradation of OsBOR1 in response to high B.

Three polarly localized ammonium transporter 1 members are cooperatively responsible for ammonium uptake in rice under low ammonium condition

Ammonium is a preferential nitrogen form for rice (Oryza sativa) grown in paddy field, but the molecular mechanisms for ammonium uptake have not been well understood. We functionally characterized three members belonging to ammonium transporter 1 (AMT1) and investigated their contributions to ammonium uptake. Spatial expression analysis showed that the upregulated expression of OsAMT1;1 and OsAMT1;2 and downregulated expression of OsAMT1;3 by ammonium were higher in the root mature region than in the root tips. All OsAMT1 members were polarly localized at the distal side of exodermis in the mature region of crown roots and lateral roots. Upon exposure to ammonium, localization of OsAMT1;1 and OsAMT1;2 was also observed in the endoplasmic reticulum, but their abundance in the plasma membrane was not changed. Single knockout of either gene did not affect ammonium uptake, but knockout of all three genes resulted in 95% reduction of ammonium uptake. However, the nitrogen uptake did not differ between the wild-type rice and triple mutants at high ammonium and nitrate supply. Our results indicate that three OsAMT1 members are cooperatively required for uptake of low ammonium in rice roots and that they undergo a distinct regulatory mechanism in response to ammonium.

AB0065 HGF/C-MET SIGNALING PROMOTE ANGIOGENESIS THROUGH CXCL16 IN RHEUMATOID ARTHRITIS

Background:

Hepatocyte growth factor (HGF) binds to the receptor tyrosine kinase c-Met and is a multifunctional cytokine that promotes processes such as cell proliferation, survival, differentiation, migration and angiogenesis [1]. We previously reported that HGF is produced by inflammation in the RA synovium, and activates monocyte migration to the synovium and promotes bone destruction through its own chemotactic effect and enhanced chemokine production in the synovium [2].

Objectives:

Therefore, we next aimed to determine the role of HGF in RA angiogenesis.

Methods:

The expression of HGF / c-Met in the serum and synovial tissues (STs) of RA patients and controls and human umbilical vein endothelial cells (HUVECs) was evaluated by ELISA and immunostaining. The effect of HGF/c-Met signaling on the promotion of CXCL16 production from HUVECs and RA fibroblast-like synoviocytes (FLSs) was determined by ELISA. To examine the role of HGF in angiogenesis, we performed in vitro Matrigel assays using HUVECs treated with HGF.

Results:

HGF in serum in treatment-naive RA patients was significantly higher than that in controls and HGF in serum in treatment-resistant RA showed a significant positive correlation with CXCL16. c-Met were expressed on vascular endothelial cells of RA STs and HUVECs. Stimulation of HUVECs with HGF dose-dependently increased CXCL16 production. c-Met signal inhibition by SU11274 suppressed TNF-α stimulation-enhanced CXCL16 production by RA FLSs in a dose-dependent manner. Furthermore, HGF induced HUVEC tube formation by 1.8-fold.

Conclusion:

HGF is produced by inflammation in the RA synovium, and activates angiogenesis through its own potent angiogenic effect and enhanced production of CXCL16 in the synovium. These results indicate that a strategy targeting c-Met signalling may be important for resolving treatment-resistant RA.

References:

[1]Nakamura T, Nishizawa T, Hagiya M, et al. Molecular cloning and expression of human hepatocyte growth factor. Nature. 1989 Nov 23;342(6248):440-3.

[2]Hosonuma M, Sakai N, Furuya H, et al. Inhibition of hepatocyte growth factor/c-Met signalling abrogates joint destruction by suppressing monocyte migration in rheumatoid arthritis. Rheumatology (Oxford). 2021 Jan 5;60(1):408-419.

Disclosure of Interests:

None declared

POS0429 INTERLEUKIN-4 ACTIVATES EOSINOPHILS AND CCR3-POSITIVE T HELPER CELLS MIGRATION TO FASCIA AND PROMOTES FIBROSIS IN EOSINOPHILIC FASCIITIS

Background:

Eosinophilic fasciitis (EF) is a rare disease that causes inflammation and fibrosis mainly in the fascia of the extremities with eosinophilia. It has been reported that the hypertrophied fascia in EF shows inflammatory cell infiltration by the lymphocytes and eosinophils and increased expression of fibrosis-related cytokines genes in fibroblast [1]. However, its pathophysiology in the fascia remains unresolved.

Objectives:

Therefore, we focused on fascial fibroblasts and aimed to determine the role of interleukin-4 (IL-4) in eosinophil and helper T cell infiltration and fibrosis in fascial fibroblast in EF.

Methods:

Fascial fibroblasts were obtained from fascia biopsy of a patient with EF, and were stimulated with pre- and post-treatment serum of a patient with EF and healthy control, followed by microarray to analyze gene expression. Fascial fibroblasts were stimulated with IL-4 10 ng/mL, and gene expression of IL-4 receptor and CCR3 ligands, CCL7 and CCL11 were measured by qPCR. Transforming growth factor (TGF) -β and periostin in the pre- and post-treatment serum of a patient with EF and conditioned medium of fascial fibroblasts stimulated with IL-4 were measured by ELISA. To examine the role of IL-4 in proliferation, we performed in proliferation assays using fascial fibroblasts treated with IL-4. CCR3-positive T cells in the fascial tissue of EF, dermatomyositis, and polymyositis patients were evaluated by immunostaining.

Results:

By microarray analysis, CCL7 and CCL11 expression of fascial fibroblasts stimulated with pre-treatment EF serum was higher than that in post-treatment EF serum and control serum. CCL7 and CCL11 mRNA in IL-4 stimulated facial fibroblasts were increased by 5.1-fold and 7.3-fold, respectively. TGF-β and periostin in IL-4 stimulated facial fibroblast conditioned medium were also increased. In addition, TGF-β and periostin in EF serum were gradually decreased by treatment for 4 and 10 weeks, compared to before treatment. Finally, fascial fibroblast proliferation was significantly increased by stimulation with IL-4. Furthermore, infiltration of CCR3-positive T cells was specific to the fascial tissue of EF.

Conclusion:

In EF, IL-4 enhances the production of CCR3 ligands, TGF-β, and periostin from fascial fibroblasts. As a result, it promotes the migration of eosinophils and CCR3-positive T helper cells to the fascia and fibrosis. These results suggest that inhibition of IL-4 pathway could be a novel strategy for eosinophilic fasciitis.

References:

[1]Igarashi A, Nashiro K, Kikuchi K, et al. Connective tissue growth factor gene expression in tissue sections from localized scleroderma, keloid, and other fibrotic skin disorders. J Invest Dermatol. 1996 Apr;106(4):729-33.

Disclosure of Interests:

None declared

Estimated respiratory arousal threshold in patients with rapid eye movement obstructive sleep apnea

Purpose

Rapid eye movement (REM) obstructive sleep apnea (OSA) is a prevalent clinical phenotype. However, the literature focusing on the pathophysiology of REM OSA is limited. This study compared the proportion of individuals with a low respiratory arousal threshold between patients with REM and non-REM OSA.

Methods

REM OSA was defined as having an apnea–hypopnea index (AHI) ≥ 5 and AHI during REM (AHI-REM)/AHI during NREM (AHI-NREM) ≥ 2. REM OSA was sub-divided into REM-predominant OSA and REM-isolated OSA. REM-predominant OSA was defined as satisfying the definition of REM OSA and having an AHI-NREM ≥ 5. REM-isolated OSA was defined as satisfying the definition of REM OSA and having an AHI-NREM < 5. Patients with an AHI-REM/AHI-NREM < 2 were defined as having non-REM OSA. A low respiratory arousal threshold was defined as having 2 or more of the following conditions: AHI < 30 events/h, proportion of hypopnea > 58.3%, and nadir SpO₂ > 82.5%.

Results

The proportions of individuals with low respiratory arousal thresholds among individuals with REM-predominant OSA and REM-isolated OSA were significantly higher (77.2% and 93.7%, respectively) than that of patients with non-REM OSA (48.6%). This was also true when the analysis was performed according to sex.

Conclusion

These results indicate that a low respiratory arousal threshold might be an important endotype that contributes to the pathogenesis of REM OSA, especially in REM-isolated OSA.

Overexpression of the manganese/cadmium transporter OsNRAMP5 reduces cadmium accumulation in rice grain

Rice is a major dietary source of the toxic metal cadmium (Cd), and reducing its accumulation in the grain is therefore important for food safety. We selected two cultivars with contrasting Cd accumulation and generated transgenic lines overexpressing OsNRAMP5, which encodes a major influx transporter for manganese (Mn) and Cd. We used two different promoters to control the expression, namely OsActin1 and maize Ubiquitin. Overexpression of OsNRAMP5 increased Cd and Mn uptake into the roots, but markedly decreased Cd accumulation in the shoots, whilst having a relatively small effect on Mn accumulation in the shoots. The overexpressed OsNRAMP5 protein was localized to the plasma membrane of all cell types in the root tips and lateral root primordia without polarity. Synchrotron X-ray fluorescence mapping showed that the overexpression lines accumulated more Cd in the root tips and lateral root primordia compared with the wild-type. When grown in three Cd-contaminated paddy soils, overexpression of OsNRAMP5 decreased concentration of Cd in the grain by 49-94% compared with the wild type. OsNRAMP5-overexpression plants had decreased Cd translocation from roots to shoots as a result of disruption of its radial transport into the stele for xylem loading, demonstrating the effect of transporter localization and polarity on ion homeostasis.

The urea transporter DUR3 contributes to rice production under nitrogen-deficient and field conditions

Nitrogen is one of the most important elements for plant growth, and urea is one of the most frequently used nitrogen fertilizers worldwide. Besides the exogenously-supplied urea to the soil, urea is endogenously synthesized during secondary nitrogen metabolism. Here, we investigated the contribution of a urea transporter, DUR3, to rice production using a reverse genetic approach combined with localization studies. Tos17 insertion lines for DUR3 showed a 50% yield reduction in hydroponic culture, and a 26.2% yield reduction in a paddy field, because of decreased grain filling. Because shoot biomass production and shoot total N was not reduced, insertion lines were disordered not only in nitrogen acquisition but also in nitrogen allocation. During seed development, DUR3 insertion lines accumulated nitrogen in leaves and could not sufficiently develop their panicles, although shoot and root dry weights were not significantly different from the wild-type. The urea concentration in old leaf harvested from DUR3 insertion lines was lower than that in wild-type. DUR3 promoter-dependent β-glucuronidase (GUS) activity was localized in vascular tissue and the midribs of old leaves. These results indicate that DUR3 contributes to nitrogen translocation and rice yield under nitrogen-deficient and field conditions.

Impact of Gender and Age on Rapid Eye Movement-Related Obstructive Sleep Apnea: A Clinical Study of 3234 Japanese OSA Patients

Rapid eye movement (REM)-related obstructive sleep apnea (OSA) is characterized by apnea and hypopnea events due to airway collapse occurring predominantly or exclusively during REM sleep. Previous studies have reported that REM-related OSA occurs more commonly in women and younger individuals. However, external validity of this tendency has not been confirmed in a large clinical sample. The objective of this study was to evaluate the effect of gender and age on REM-related OSA after adjustment for several covariates based on their established clinical relationships to gender difference in OSA. A total of 3234 Japanese patients with OSA were enrolled in this study. We confirmed that female sex is an important risk factor for REM-related OSA, as reported by previous studies. Moreover, we showed that women aged over 50 years were at a greater risk than those aged under 50 years. These results suggest that hormonal changes in women might play an important role in REM-related OSA and might reflect its unknown pathophysiological characteristics.

Decreasing arsenic accumulation in rice by overexpressing OsNIP1;1 and OsNIP3;3 through disrupting arsenite radial transport in roots

Rice is a major dietary source of the toxic metalloid arsenic. Reducing arsenic accumulation in rice grain is important for food safety. We generated transgenic rice overexpressing two aquaporin genes, OsNIP1;1 and OsNIP3;3, under the control of a maize ubiquitin promoter or the rice OsLsi1 promoter, and tested the effect on arsenite uptake and translocation. OsNIP1;1 and OsNIP3;3 were highly permeable to arsenite in Xenopus oocyte assays. Both transporters were localized at the plasma membrane. Knockout of either gene had little effect on arsenite uptake or translocation. Overexpression of OsNIP1;1 or OsNIP3;3 in rice did not affect arsenite uptake but decreased root-to-shoot translocation of arsenite and shoot arsenic concentration markedly. The overexpressed OsNIP1;1 and OsNIP3;3 proteins were localized in all root cells without polarity. Expression of OsNIP1;1 driven by the OsLsi1 promoter produced similar effects. When grown in two arsenic-contaminated paddy soils, overexpressing lines contained significantly lower arsenic concentration in rice grain than the wild-type without compromising plant growth or the accumulation of essential nutrients. Overexpression of OsNIP1;1 or OsNIP3;3 provides a route for arsenite to leak out of the stele, thus restricting arsenite loading into the xylem. This strategy is effective in reducing arsenic accumulation in rice grain.

Outgrowth of Rice Tillers Requires Availability of Glutamine in the Basal Portions of Shoots

BACKGROUND

Our previous studies concluded that metabolic disorder in the basal portions of rice shoots caused by a lack of cytosolic glutamine synthetase1;2 (GS1;2) resulted in a severe reduction in the outgrowth of tillers. Rice mutants lacking GS1;2 (gs1;2 mutants) showed a remarkable reduction in the contents of both glutamine and asparagine in the basal portions of shoots. In the current study, we attempted to reveal the mechanisms for this decrease in asparagine content using rice mutants lacking either GS1;2 or asparagine synthetase 1 (AS1). The contributions of the availability of glutamine and asparagine to the outgrowth of rice tillers were investigated.

RESULTS

Rice has two AS genes, and the enzymes catalyse asparagine synthesis from glutamine. In the basal portions of rice shoots, expression of OsAS1, the major species in this tissue, was reduced in gs1;2 mutants, whereas OsAS2 expression was relatively constant. OsAS1 was expressed in phloem companion cells of the nodal vascular anastomoses connected to the axillary bud vasculatures in the basal portions of wild-type shoots, whereas cell-specific expression was markedly reduced in gs1;2 mutants. OsAS1 was up-regulated significantly by NH₄⁺ supply in the wild type but not in gs1;2 mutants. When GS reactions were inhibited by methionine sulfoximine, OsAS1 was up-regulated by glutamine but not by NH₄⁺. The rice mutants lacking AS1 (as1 mutants) showed a decrease in asparagine content in the basal portions of shoots. However, glutamine content and tiller number were less affected by the lack of AS1.

CONCLUSION

These results indicate that in phloem companion cells of the nodal vascular anastomoses, asparagine synthesis is largely dependent on glutamine or its related metabolite-responsive AS1. Thus, the decrease in glutamine content caused by a lack of GS1;2 is suggested to result in low expression of OsAS1, decreasing asparagine content. However, the availability of asparagine generated from AS1 reactions is apparently less effective for the outgrowth of tillers. With respect to the tiller number and the contents of glutamine and asparagine in gs1;2 and as1 mutants, the availability of glutamine rather than asparagine in basal portions of rice shoots may be required for the outgrowth of rice tillers.

Cytosolic Glutamine Synthetase Isozymes Play Redundant Roles in Ammonium Assimilation Under Low-Ammonium Conditions in Roots of Arabidopsis thaliana

Ammonium is a major nitrogen source for plants; it is assimilated into glutamine via a reaction catalyzed by glutamine synthetase (GLN). Arabidopsis expresses four cytosolic GLN genes, GLN1; 1, GLN1; 2, GLN1; 3 and GLN1; 4, in roots. However, the function and organization of these GLN1 isozymes in ammonium assimilation in roots remain unclear. In this study, we aimed to characterize the four GLN1 isozymes. The levels of growth of the wild type and gln1 single and multiple knockout lines were compared in a hydroponic culture at ammonium concentrations of 0.1 and 3 mM. Under the low-ammonium concentration, in single mutants for each GLN1 gene, there was little effect on growth, whereas the triple mutant for GLN1; 1, GLN1; 2 and GLN1; 3 grew slowly and accumulated ammonium. Under the high-ammonium concentration, the single mutant for GLN1; 2 showed 50% decreases in fresh weight and glutamine, whereas the other gln1 single mutants did not show notable changes in the phenotype. The double mutant for GLN1; 1 and GLN1; 2 showed less growth and a lower glutamine concentration than the single mutant for GLN1; 2. Promoter analysis indicated an overlapping expression of GLN1; 1 with GLN1; 2 in the surface layers of the roots. We thus concluded that: (i) at a low concentration, ammonium was assimilated by GLN1; 1, GLN1; 2 and GLN1; 3, and they were redundant; (ii) low-affinity GLN1; 2 could contribute to ammonium assimilation at concentrations ranging from 0.1 to 3 mM; and (iii) GLN1; 1 supported GLN1; 2 within the outer cell layers of the root.

A temporal and spatial contribution of asparaginase to asparagine catabolism during development of rice grains

BACKGROUND

Asparagine is one of the most dominant organic nitrogen compounds in phloem and xylem sap in a wide range of plant species. Asparaginase (ASNase; EC, 3.5.1.1) catabolizes asparagine into aspartate and ammonium; therefore, it is suggested to play a key role in asparagine metabolism within legume sink organs. However, the metabolic fate of asparagine in source and sink organs during rice seed production remains to be elucidated. Therefore, the main objective of this study is to investigate the asparagine metabolism in a temporal and spatial manner during rice seed production.

RESULTS

For this purpose, the expression of genes involved in asparagine catabolism, such as asparaginase1 (OsASNase1) and 2 (OsASNase2), were quantitatively measured, and contents of asparagine, aspartate and ammonium ions were determined in sink and source organs during spikelet ripening. Quantitative real-time PCR and in situ localization studies determined that OsASNase2 is expressed in the dorsal vascular bundles and nucellar projection of developing grains, as well as in mesophyll and phloem companion cells of senescent flag leaves. Amino acid measurements revealed that the aspartate concentration is higher than asparagine in both source and sink organs.

CONCLUSION

This work suggests that asparaginase dependent asparagine catabolism occurred not only in sink but also in source organs.

Nitrate Supply-Dependent Shifts in Communities of Root-Associated Bacteria in Arabidopsis

Root-associated bacterial communities are necessary for healthy plant growth. Nitrate is a signal molecule as well as a major nitrogen source for plant growth. In this study, nitrate-dependent alterations in root-associated bacterial communities and the relationship between nitrate signaling and root-associated bacteria in Arabidopsis were examined. The bacterial community was analyzed by a ribosomal RNA intergenic spacer analysis (RISA) and 16S rRNA amplicon sequencing. The Arabidopsis root-associated bacterial community shifted depending on the nitrate amount and timing of nitrate application. The relative abundance of operational taxonomic units of 25.8% was significantly changed by the amount of nitrate supplied. Moreover, at the family level, the relative abundance of several major root-associated bacteria including Burkholderiaceae, Paenibacillaceae, Bradyrhizobiaceae, and Rhizobiaceae markedly fluctuated with the application of nitrate. These results suggest that the application of nitrate strongly affects root-associated bacterial ecosystems in Arabidopsis. Bulk soil bacterial communities were also affected by the application of nitrate; however, these changes were markedly different from those in root-associated bacteria. These results also suggest that nitrate-dependent alterations in root-associated bacterial communities are mainly affected by plant-derived factors in Arabidopsis. T-DNA insertion plant lines of the genes for two transcription factors involved in nitrate signaling in Arabidopsis roots, NLP7 and TCP20, showed similar nitrate-dependent shifts in root-associated bacterial communities from the wild-type, whereas minor differences were observed in root-associated bacteria. Thus, these results indicate that NLP7 and TCP20 are not major regulators of nitrate-dependent bacterial communities in Arabidopsis roots.

Contributions of two cytosolic glutamine synthetase isozymes to ammonium assimilation in Arabidopsis roots

Glutamine synthetase (GS) catalyzes a reaction that incorporates ammonium into glutamate and yields glutamine in the cytosol and chloroplasts. Although the enzymatic characteristics of the GS1 isozymes are well known, their physiological functions in ammonium assimilation and regulation in roots remain unclear. In this study we show evidence that two cytosolic GS1 isozymes (GLN1;2 and GLN1;3) contribute to ammonium assimilation in Arabidopsis roots. Arabidopsis T-DNA insertion lines for GLN1;2 and GLN1;3 (i.e. gln1;2 and gln1;3 single-mutants), the gln1;2:gln1;3 double-mutant, and the wild-type accession (Col-0) were grown in hydroponic culture with variable concentrations of ammonium to compare their growth, and their content of nitrogen, carbon, ammonium, and amino acids. GLN1;2 and GLN1;3 promoter-dependent green fluorescent protein was observed under conditions with or without ammonium supply. Loss of GLN1;2 caused significant suppression of plant growth and glutamine biosynthesis under ammonium-replete conditions. In contrast, loss of GLN1;3 caused slight defects in growth and Gln biosynthesis that were only visible based on a comparison of the gln1;2 single- and gln1;2:gln1;3 double-mutants. GLN1;2, being the most abundantly expressed GS1 isozyme, markedly increased following ammonium supply and its promoter activity was localized at the cortex and epidermis, while GLN1;3 showed only low expression at the pericycle, suggesting their different physiological contributions to ammonium assimilation in roots. The GLN1;2 promoter-deletion analysis identified regulatory sequences required for controlling ammonium-responsive gene expression of GLN1;2 in Arabidopsis roots. These results shed light on GLN1 isozyme-specific regulatory mechanisms in Arabidopsis that allow adaptation to an ammonium-replete environment.

Asparagine synthetase1, but not asparagine synthetase2, is responsible for the biosynthesis of asparagine following the supply of ammonium to rice roots

Asparagine is synthesized from glutamine by the reaction of asparagine synthetase (AS) and is the major nitrogen form in both xylem and phloem sap in rice (Oryza sativa L.). There are two genes encoding AS, OsAS1 and OsAS2, in rice, but the functions of individual AS isoenzymes are largely unknown. Cell type- and NH4(+)-inducible expression of OsAS1 as well as analyses of knockout mutants were carried out in this study to characterize AS1. OsAS1 was mainly expressed in the roots, with in situ hybridization showing that the corresponding mRNA was specifically accumulated in the three cell layers of the root surface (epidermis, exodermis and sclerenchyma) in an NH4(+)-dependent manner. Conversely, OsAS2 mRNA was abundant in leaf blades and sheathes of rice. Although OsAS2 mRNA was detectable in the roots, its content decreased when NH4(+) was supplied. Retrotransposon-mediated knockout mutants lacking AS1 showed slight stimulation of shoot length and slight reduction in root length at the seedling stage. On the other hand, the mutation caused an approximately 80-90% reduction in free asparagine content in both roots and xylem sap. These results suggest that AS1 is responsible for the synthesis of asparagine in rice roots following the supply of NH4(+). Characteristics of the NH4(+)-dependent increase and the root surface cell-specific expression of OsAS1 gene are very similar to our previous results on cytosolic glutamine synthetase1;2 and NADH-glutamate synthase1 in rice roots. Thus, AS1 is apparently coupled with the primary assimilation of NH4(+) in rice roots.

NADH-dependent glutamate synthase plays a crucial role in assimilating ammonium in the Arabidopsis root

Plant roots under nitrogen deficient conditions with access to both ammonium and nitrate ions, will take up ammonium first. This preference for ammonium rather than nitrate emphasizes the importance of ammonium assimilation machinery in roots. Glutamine synthetase (GS) and glutamate synthase (GOGAT) catalyze the conversion of ammonium and 2-oxoglutarate to glutamine and glutamate. Higher plants have two GOGAT species, ferredoxin-dependent glutamate synthase (Fd-GOGAT) and nicotinamide adenine dinucleotide (NADH)-GOGAT. While Fd-GOGAT participates in the assimilation of ammonium, which is derived from photorespiration in leaves, NADH-GOGAT is highly expressed in roots and its importance needs to be elucidated. While ammonium as a minor nitrogen form in most soils is directly taken up, nitrate as the major nitrogen source needs to be converted to ammonium prior to uptake. The aim of this study was to investigate and quantify the contribution of NADH-GOGAT to the ammonium assimilation in Arabidopsis (Arabidopsis thaliana Columbia) roots. Quantitative real-time polymerase chain reaction (PCR) and protein gel blot analysis showed an accumulation of NADH-GOGAT in response to ammonium supplied to the roots. In addition the localization of NADH-GOGAT and Fd-GOGAT did not fully overlap. Promoter-β-glucuronidase (GUS) fusion analysis and immunohistochemistry showed that NADH-GOGAT was highly accumulated in non-green tissue like vascular bundles, shoot apical meristem, pollen, stigma and roots. Reverse genetic approaches suggested a reduction in glutamate production and biomass accumulation in NADH-GOGAT transfer DNA (T-DNA) insertion lines under normal CO2 condition. The data emphasize the importance of NADH-GOGAT in the ammonium assimilation in Arabidopsis roots.

NADH-dependent glutamate synthase participated in ammonium assimilation in Arabidopsis root

Higher plants have 2 GOGAT species, Fd-GOGAT and NADH-GOGAT. While Fd-GOGAT mainly assimilates ammonium in leaves, which is derived from photorespiration, the function of NADH-GOGAT, which is highly expressed in roots, (1) needs to be elucidated. The aim of this study was to clarify the role of NADH-GOGAT in Arabidopsis roots. The supply of ammonium to the roots caused an accumulation of NADH-GOGAT, while Fd-GOGAT 1 and Fd-GOGAT 2 showed no response. A promoter-GUS fusion analysis and immunohistochemistry showed that NADH-GOGAT was located in non-green tissues like vascular bundles, shoot apical meristem, pollen, stigma, and roots. The localization of NADH-GOGAT and Fd-GOGAT was not overlapped. NADH-GOGAT T-DNA insertion lines showed a reduction of glutamate and biomass under normal CO2 conditions. These data emphasizes the importance of NADH-GOGAT in the ammonium assimilation of Arabidopsis roots.

anti-tumor effect of AlkB homolog 3 knockdown in hormone- independent prostate cancer cells

Castrate resistant prostate cancer (CRPC) is a disease that is resistant to both hormone therapy and chemotherapy. At present, no curative therapy for CRPC has been established. Therefore, it is necessary to determine a novel molecular target for the development of therapeutic agents. We previously reported that AlkB homolog 3 (ALKBH3) is highly expressed in prostate cancer but not in benign prostatic hyperplasia or in normal prostate epithelium and that the expression levels of ALKBH3 protein are significantly correlated with the hormone-independent state of prostate cancer. Moreover, ALKBH3 regulates the invasion of prostate cancer cells via the regulation of matrix metalloproteinase 9. Here, we show that ALKBH3 gene silencing markedly induces apoptosis in hormone-independent prostate cancer cell line DU145 but not in the normal prostate epithelial cell line PNT2. Moreover, the in vivo tumorigenicity of DU145 cells was significantly inhibited by the administration of ALKBH3 siRNA. Furthermore, the anchorage-independent growth of DU145 cells was inhibited by ALKBH3 knockdown and promoted by ALKBH3 overexpression, significantly. ALKBH3 shRNA-expressing prostate cancer cells formed significantly smaller tumors than those of control shRNA transfectants in an in vivo xenograft model. These findings suggest that ALKBH3 is a promising target molecule for the development of CRPC therapeutic agents.

Detection of RB, p16/CDKN2 and p15(INK4B) gene alterations with immunohistochemical studies in human prostate carcinomas

To examine the status of cell cycle-inhibitory genes in human prostate carcinoma, we investigated alterations of RE (retinoblastoma), p16/CDKN2 and p15(INK4B) genes in 32 adenocarcinomas with immunohistochemistry. PCR-single-strand conformation polymorphism (SSCP) was used to examine all 27 exons of the RE gene, exons 1 to 3 of the p16/CDKN2 gene and exons 1 and 2 of the p15(INK4B) gene for mutations. Loss of heterozygosity (LOH) for the RE gene was probed by restriction fragment length polymorphism (RFLP) analysis. In addition, coordinate samples were subjected to immunohistochemical studies for reactivity to RE and p16 protein. The RE gene alterations were detected in 5 of the 32 tumors (16%); of these, only one mutation, a missense substitution, occurred within an exon. The remaining four single base insertions or deletions were found within introns of the RE gene and no mutational event was detected in its promoter region. LOH involving intron 17 of RB was detected in three cases of 10 informative tumors (30%). Intragenic mutations were also present in 3 of the 32 tumors in the p16/CDKN2 gene. In contrast, no mutational events were found in the p15(INK4B) gene in the tumors. Only one tumor had both a p16/CDKN2 mutation and LOH of the RE gene. Expression of pRB was absent or reduced in 16 cancers, while p16 expression was present in all cases to varying degrees. The results suggest that p16/CDKN2 gene mutations occur rarely and intragenic mutation, but not LOH,of the RE gene is not required in prostatic tumorigenesis.

p53 tumor suppressor gene and ras oncogene mutations in hypopharyngeal squamous cell carcinomas

To examine the potential role of p53 and ras gene mutations in hypopharyngeal tumorigenesis, twenty-eight primary hypopharyngeal carcinomas, obtained at biopsy or total pharyngolaryngectomy, were investigated. Exons 5 through 9 of the p53 gene and exons 1 and 2 of the H-, K-, N-ras gene were screened using a combination of immunohistochemistry and single-strand conformation polymorphism analysis of polymerase chain reaction products (PCR-SSCP). The targeted DNA sequences coding for p53 and ras were confirmed by direct DNA sequencing. Point mutations of p53 were found in 9 (32.1%) of the 28 cases, including one with a double mutation, 3 in exon 5, 1 in exon 6, 2 in exon 7 and 4 in exon 8. Positive nuclear immunostaining for p53 was evident in 14 (50.0%) lesions. Seven (25.0%) of the 28 demonstrated point mutations in the H-rns gene, and 11 (39.3%) showed positive cytoplasmic staining for I as. The 5-year survival rate was worse with than without p53 overexpression (p <0.05). The present results suggest that gene mutations, although they occur at a relatively low incidence, are involved in hypopharyngeal tumorigenesis with p53 expression being a prognostic factor.

Immunohistochemical detection of CDKN2, retinoblastoma and p53 gene products in primary astrocytic tumors

The expressions of p16(INK4), retinoblastoma (RB) and p53 protein were immunohistochemically examined in 70 primary astrocytic tumors. In 58 patients with high grade astrocytoma (18 anaplastic astrocytomas and 40 glioblastomas), 30 (51.1%) and 15 (25.9%) cases were undetectable for p16(INK4) and pRB, respectively, but their lack occurred infrequently in 12 low grade astrocytomas. The expression of p16(INK4) was inversely correlated with that of PRB, especially in glioblastomas. Accumulation of p53 was detected in 32 (45.7%) of 70 cases without any dependence on the grade. A deregulation of three tumor suppressor gene products most often occurs singly. Only patients with negative staining for pRB were significantly associated with a shorter survival time. Our findings suggest that loss of functional pRB at the G1/S check point may represent an important step in glioblastoma development and have a stronger negative impact on clinical outcome than p16(INK4) or p53 aberrations.

Prognostic significance of CD45RO+ memory T cells in renal cell carcinoma

Background:

Memory T cells are well known to have a critical role for host defense in humans. However, their role in actual human cancer remains largely unknown. In this study, we tried to reveal the clinical importance of tumour-infiltrating CD45RO+ memory T cells in renal cell carcinoma (RCC).

Methods:

We analysed 105 patients with RCC, who received radical or partial nephrectomy. Those were 65 in TNM stage I, 7 in stage II, 15 in stage III, and 18 in stage IV, respectively. CD45RO expression was evaluated by immunohistochemistry. CD4 and CD8 expressions were also systematically assessed in the same manner.

Results:

Patients with higher TNM stage or high nuclear grade were found to have higher densities of CD45RO. Furthermore, CD45RO status was positively correlated with preoperative C-reactive protein level. In prognostic analysis, CD45RO+lo patients had a significantly better prognosis than CD45RO+hi patients. There was also a significant difference between CD4+lo and CD4+hi groups, whereas no significant difference was observed in CD8 T-cell status. Finally, multivariate analysis revealed that CD45RO+ status was the independent prognostic factor for patient overall survival.

Conclusion:

CD45RO+ memory T-cell status has a significant independent prognostic value, indicating that the adaptive immune response is functionally critical in human RCC.

Clinical importance of B7-H3 expression in human pancreatic cancer

Background:

B7-H3 is a new member of the B7 ligand family and regulates T-cell responses in various conditions. However, the role of B7-H3 in tumour immunity is largely unknown. The purpose of this study was to evaluate the clinical significance of B7-H3 expression in human pancreatic cancer and the therapeutic potential for cancer immunotherapy.

Methods:

We investigated B7-H3 expression in 59 patients with pancreatic cancer by immunohistochemistry and real-time PCR. Furthermore, we examined the anti-tumour effect of B7-H3-blocking monoclonal antibody in vivo in a murine pancreatic cancer model.

Results:

Tumour-related B7-H3 expression was abundant in most human pancreatic cancer tissues and was significantly higher compared with that in non-cancer tissue or normal pancreas. Moreover, its expression was significantly more intense in cases with lymph node metastasis and advanced pathological stage. B7-H3 blockade promoted CD8⁺ T-cell infiltration into the tumour and induced a substantial anti-tumour effect on murine pancreatic cancer. In addition, the combination of gemcitabine with B7-H3 blockade showed a synergistic anti-tumour effect without overt toxicity.

Conclusion:

Our data show for the first time that B7-H3 may have a critical role in pancreatic cancer and provide the rationale for developing a novel cancer immunotherapy against this fatal disease.

Isoflurane exerts a short-term but not a long-term preconditioning effect in neonatal rats exposed to a hypoxic-ischaemic neuronal injury

BACKGROUND

Isoflurane has been shown to induce tolerance against ischaemic injury in adult rodents. Although the delayed preconditioning effect of isoflurane has been demonstrated in neonatal rat pups, the acute preconditioning effects of isoflurane remained undetermined. The present study was therefore conducted to evaluate the acute preconditioning efficacy of isoflurane in neonatal rats subjected to a hypoxic-ischaemic (HI) injury.

METHODS

Post-natal day 7 pups were exposed to 1 or 2% isoflurane in oxygen for either 30, 60 or 90 min. Fifteen minutes after isoflurane exposure, the pups were subjected to an HI injury induced by left common carotid artery ligation and exposure to 8% oxygen for 2 h. Pups not exposed to isoflurane or not subjected to HI served as controls. Histopathologic injury to the cortex and hippocampus was evaluated 7 and 49 days after HI.

RESULTS

Isoflurane 2% exposure for 60 or 90 min before HI induced tolerance in the hippocampus and the number of normal neurons in the CA1 sector 7 days after HI was significantly greater than in non-preconditioned animals. This protective efficacy of isoflurane preconditioning was not observed 49 days after HI.

CONCLUSIONS

Exposure of 2% isoflurane for at least 60 min is required to induce tolerance against HI injury in rat pups. However, this neuroprotective efficacy results in only transient neuroprotection.

Effect of continuous morphine infusion on hypoxic-ischaemic brain damage of neonatal rats

BACKGROUND

Opioids are commonly administered to critically ill neonates and infants for general anaesthesia and sedation. However, the clinical safety of these drugs, especially the effects on hypoxic-ischaemic damage of the developing brain, has not been well investigated. The present study was therefore conducted to investigate the effects of continuous morphine infusion on brain damage after hypoxic-ischaemic insults in neonatal rats.

METHODS

Seven-day-old Sprague-Dawley rats were subjected to left common carotid artery ligation followed by a 90-min exposure of 8% oxygen. The rats were administered morphine (0.1, 0.3 or 1 mg/kg/h) or saline continuously for 72 h using osmotic minipumps. Seven days later, the rats were weighed and their brains were morphologically categorized into groups based on the following grades: 0=normal, 1=mild atrophy, 2=moderate atrophy, 3=atrophy with cystic cavitation <3 mm and 4=cystic cavitation >3 mm. For histological assessment, the ratio of the surviving neurons (ipsilateral/contralateral) was calculated in the cornu ammonis fields, CA1 and CA3, and the dentate gyrus (DG).

RESULTS

One week after recovery (P14), the rats in the 1 mg/kg/h group showed significantly poorer weight gain compared with the other groups. However, the morphological score of the brains and the ratio of the surviving neurons in the CA1, CA3 and DG were similar among the groups.

CONCLUSION

Our results indicate that continuous administration of morphine does not worsen brain damage 7 days after hypoxic-ischaemic insults in neonatal rats.

Impact of a left-lobe graft without modulation of portal flow in adult-to-adult living donor liver transplantation

In adult-to-adult living donor liver transplantation (LDLT), left-lobe grafts can sometimes be small-for-size. Although attempts have been made to prevent graft overperfusion through modulation of portal inflow, the optimal portal venous circulation for a liver graft is still unclear. Hepatic hemodynamics were analyzed with reference to graft function and outcome in 19 consecutive adult-to-adult LDLTs using left-lobe grafts without modulation of graft portal inflow. Overall mean graft volume (GV) was 398 g, which was equivalent to 37.8% of the recipient standard liver volume (SV). The GV/SV ratio was less than 40% in 13 of the 19 recipients. Overall mean recipient portal vein flow (PVF) was much higher than the left PVF in the donors. The mean portal contribution to the graft was markedly increased to 89%. Average daily volume of ascites revealed a significant correlation with portal vein pressure, and not with PVF. When PVP exceeds 25 mmHg after transplantation, modulation of portal inflow might be required in order to improve the early postoperative outcome. Although the study population was small and contained several patients suffering from tumors or metabolic disease, all 19 patients made good progress and the 1-year graft and patient survival rate were 100%. A GV/SV ratio of less than 40% or PVF of more than 260 mL/min/100 g graft weight does not contraindicate transplantation, nor is it necessarily associated with a poor outcome. Left-lobe graft LDLT is still an important treatment option for adult patients.

Effects of delta-opioid receptor stimulation and inhibition on hippocampal survival in a rat model of forebrain ischaemia

BACKGROUND

It has been reported that delta-opioid (DOP) receptor agonists may be neuroprotective in the central nervous system. However, the DOP agonist [d-Ala(2), d-Leu(5)]enkephalin (DADLE) does not produce neuroprotection in severe forebrain ischaemia. The aim of this study was to examine the effects of DADLE on hippocampal neurone survival against less severe forebrain ischaemia.

METHODS

Intraperitoneal injection of DADLE (0 or 16 mg kg(-1)) in male Sprague-Dawley rats was performed 30 min before ischaemia. Severe (10 min), moderate (8 min), or mild (6 min) forebrain ischaemia was produced by bilateral carotid occlusion combined with hypotension (35 mm Hg) under isoflurane (1.5%) anaesthesia. Naltrindole (10 mg kg(-1)) (DOP antagonist) was administered 30 min before DADLE in order to confirm DOP receptor activation in the neuroprotective efficacy of DADLE. Naltrindole alone was also administered 30 min before ischaemia to examine endogenous DOP agonism as a self-protecting mechanism against ischaemia. All animals were evaluated neurologically and histologically after a 1 week recovery period.

RESULTS

DADLE improved neurone survival in hippocampal CA3 and dentate gyrus (DG) sectors. CA1 neurones were not protected against moderate and mild ischaemia. Naltrindole abolished DADLE neuroprotection in the CA3 and DG after both moderate and mild ischaemia. Interestingly, regardless of co-administration of DADLE, naltrindole significantly worsened neuronal injury in the CA1 region after mild ischaemia.

CONCLUSIONS

These results suggest that DADLE provides limited neuroprotection to relatively ischaemia-resistant regions but not to selectively vulnerable regions. This was probably mediated by DOP stimulation. Pre-ischaemic treatment with a DOP antagonist, regardless of co-administration of DADLE, worsened neuronal damage at the selectively vulnerable regions only after mild forebrain ischaemia. These data suggest that DOP activation with endogenous DOP ligand may be involved in self-protecting ischaemia-sensitive regions of the brain.

A study for establishment of individualized chemotherapy for colorectal cancer based on the individual 50% inhibitory area under the concentration curve (AUCIR50) using the collagen gel droplet embedded culture-drug sensitivity test (CD- DST)

14553

Background: The drug sensitivity of tumor cells is one of the key issues to explore in individualized 5-fluorouracil (5-FU) based chemotherapy for colorectal cancer patients. We reported that growth inhibition rate (IR) and area under the concentration curve (AUC) approximated to a logarithmic curve using the collagen gel droplet embedded culture-drug sensitivity test (CD-DST) in ASCO 2003 (#1283). We also reported that the individual 50% inhibitory area under the concentration curve (AUC IR50) could be obtained using the individual AUC-IR curve in ASCO 2006 (#13560). The aim of this study was to evaluate the achievement of the individual AUCIR50 in 5-FU based adjuvant chemotherapy for the establishment of individualized chemotherapy. Methods: Surgical specimen was obtained from resectable 33 CRC patients without any preoperative chemotherapy during 2001 to 2005. 5-FU based adjuvant chemotherapy was administered in all patients. CD-DST was performed under 6–9 different conditions. The individual AUCIR50 was obtained from the individual AUC-IR curve. The patients were divided into 2 groups, the achieved group and the non-achieved group. In the achieved group, total administered AUC was more than the individual AUCIR50 and in non-achieved group, the total administered AUC was less than the individual AUCIR50. Recurrence rates were evaluated from the 2 groups. Results: In all patients, the recurrence rates were 6.7% (1/15) in the achieved group and 27.8% (5/18) in the non-achieved group. In the colon cancer patients, the recurrence rates were 8.3% (1/12) in the achieved group and 10.0% (1/10) in the non-achieved group. In the rectal cancer patients, the recurrence rates were 0% (0/3) in the achieved group and 50.0% (4/8) in the non-achieved group. Conclusions: The recurrence rate of the achieved group was lower than that of the non-achieved group. Therefore, this study demonstrated that the achievement of the individual AUCIR50 could be a prerequisite of individualized 5-FU based adjuvant chemotherapy.

No significant financial relationships to disclose.

Prostatic volume and volume-adjusted prostate-specific antigen as predictive parameters for prostate cancer patients with intermediate PSA levels

The object of the study was to examine the usefulness of volume-adjusted prostate-specific antigen (PSA) parameters for prediction of prostate cancer in the patients with intermediate PSA levels. The subjects were 235 patients with intermediate PSA levels (range: 4.1-10.0 ng/ml) whose prostate volume (PV) and prostate transition zone volume (TZV) were evaluated between August 1996 and April 2004. PSA, PV, TZV, PSA density (PSAD) (PSA/PV) and PSA transition zone density (PSATZD) (PSA/TZV) were assessed with the receiver operating characteristic (ROC) curve and the area under the curve (AUC). Simple and multivariate logistic regression analyses were used to analyze the odds ratios of age, PSA, PSAD, PSATZD, PV, TZV, digital rectal examination (DRE) and transrectal ultrasonography (TRUS) findings. Fifty-five patients (23.4%) of 235 patients had biopsy-proven prostate cancer. The univariate analysis revealed significant differences in the mean values of age, PSAD, PSATZD, PV, TZV and DRE between the patients with cancer and the non-cancer patients. The ROC curve analysis revealed that PV, TZV, PSAD and PSATZD had significant predictive values as compared with that of PSA. However, there was no difference in AUC between them. The stepwise logistic regression analysis showed that the age, PV, PSATZD and DRE had significant predictive values, and that PSATZD had the most predictive power. In conclusion, both PSAD and PSATZD had significant predictive values in discriminating prostate cancer. Furthermore, the stepwise logistic regression analysis showed that PSATZD had the strongest predictive value.

Frontal cerebral blood flow change associated with infant-directed speech

OBJECTIVE

To examine the auditory perception of maternal utterances by neonates using near-infrared spectroscopy (NIRS).

METHODS

Twenty full-term, healthy neonates were included in this study. The neonates were tested in their cribs while they slept in a silent room. First, two probe holders were placed on the left and right sides of the forehead over the eyebrows using double-sided adhesive tape. The neonates were then exposed to auditory stimuli in the form of infant-directed speech (IDS) or adult-directed speech (ADS), sampled from each of the mothers, through an external auditory speaker.

RESULTS

A 2 (stimulus: IDS and ADS) x 2 (recording site: channel 1 (right side) and channel 2 (left side)) analysis of variance for these relative oxygenated haemoglobin values showed that IDS (Mean = 0.25) increased brain function significantly (F = 3.51) more than ADS (Mean = -0.26).

CONCLUSIONS

IDS significantly increased brain function compared with ADS. These results suggest that the emotional tone of maternal utterances could have a role in activating the brains of neonates to attend to the utterances, even while sleeping.

Genetic analysis to complement histopathological diagnosis of brain tumors

Gliomas, the most frequent tumors originating in the human nervous system, are divided into various subtypes. Currently, microscopic examination alone is insufficient for classification and grading so that genetic profiles are increasingly being emphasized in recognition of the emerging role of molecular diagnostic approaches to glioma classification. Glioblastomas (WHO grade IV) may develop de novo (primary glioblastomas) or through progression from lower-grade astrocytomas (secondary glioblastomas), while both glioblastomas show similar histological features. In contrast, they do constitute distinct disease entities that evolve through different genetic pathways, and are likely to differ in prognosis and response to therapy. Oligodendrogliomas (WHO grade II) account for 2.7% of brain tumors and 5-18% of all gliomas. Since this tumor is recognized as a particular subtype of glioma that shows remarkable responses to chemotherapy, a correct diagnosis is of prime importance. The difficulty is that histological differentiation of oligodendrogliomas from diffuse astrocytomas is highly subjective in cases without typical morphological features and there is a lack of reliable immunohistochemical markers. While histological distinction of low-grade gliomas from reactive astrocytes is also often difficult, reactive astrocytes usually lack genetic alterations. More biological and molecular approaches to glioma classification thus appear warranted to provide improved means to achieve correct diagnoses.