Aldosterone-to-renin ratio as a predictor of stroke under conditions of high sodium intake: the Ohasama study

BACKGROUND

Aldosterone is thought to have deleterious effects on the cardiovascular system. The aldosterone-to-renin ratio (ARR) is more reproducible than aldosterone levels alone and could be an index for inappropriate aldosterone secretion or activity. We previously reported the apparent relation between ARR and hypertension in subjects with high sodium intake. This prospective study investigated the risk of ARR for a first stroke in a general population stratified by sodium intake.

METHODS

We obtained plasma renin activity (PRA) and plasma aldosterone concentrations (PAC) for 883 participants aged ≥ 35 years not receiving antihypertensive treatment in the general population of Ohasama (mean age: 59.0 ± 11.3 years; 65.6% women).

RESULTS

Over a mean of 10.9 follow-up years, 45 strokes occurred. The median PRA, PAC, and ARR were 1.2 ng/ml/h, 6.4 ng/dl, and 5.3 ng/dl per ng/ml/h, respectively. Using Cox regression, we computed hazard ratios adjusted for sex, age, body mass index (BMI), and systolic blood pressure. No association between logARR and stroke was observed in subjects overall. However, in subjects with high sodium intake (≥ median of 4,058 mg/day (salt equivalent, 10.5 g/day)), each 1 s.d. increase in logARR was associated with an increased hazard ratio for stroke (hazard ratio: 1.49, P = 0.04). No significant association was observed in subjects with low sodium intake (P = 0.7). When we repeated all the analyses using logPRA or logPAC, no significant associations were found.

CONCLUSION

These results suggest that high ARR, that is, relative aldosterone excess, is a predictor for stroke under conditions of high sodium intake.

Overexpression of a rice TIFY gene increases grain size through enhanced accumulation of carbohydrates in the stem

Screening of rice full-length cDNA overexpressing (FOX) lines allowed the identification of a TIFY gene, TIFY11b, as a growth-promoting gene whose overexpression increased plant height and seed size. The grains of TIFY11b-overexpressing plants exceeded those of non-transformants in length, width and thickness, resulting in 9-21% increases in grain weight. The increase was achieved by overexpressing the gene in the whole plant body, but not by seed-restricted expression, indicating that seed enlargement is attributable to overexpression in vegetative organs such as the leaf. The whole-body overexpressing plants developed longer leaves along with higher levels of starch and sucrose in the leaf sheath and culm at the heading stage than the non-transformants. Although overexpression of TIFY11b did not alter the photosynthetic rate per leaf area before and after heading, it caused an accumulation of higher levels of the carbohydrate assimilate, probably due to increased photosynthesis per plant, suggesting that the increase in grain size and weight is attained by enhanced accumulation and translocation of the carbohydrate in the culms and leaf sheaths of the transgenic plants. Thus, TIFY11b is a novel grain-size increasing gene.

Evaluation of the efficacy and safety of the combination of gemcitabine and nedaplatin for elderly patients with advanced non-small-cell lung cancer

OBJECTIVE

The aim of the present study was to retrospectively assess the safety and efficacy of the combination of gemcitabine and nedaplatin in elderly patients with advanced non-small-cell lung cancer (NSCLC).

METHODS

Patients ≥75 years with previously untreated NSCLC who underwent chemotherapy consisting of gemcitabine (800 mg/m(2) on days 1 and 8) and nedaplatin (80 mg/m(2) on day 1) every 3 weeks were retrospectively analyzed.

RESULTS

Of the 35 patients, 28 were men and 7 were women, with a mean age of 78 years (range 75-87); 10 patients had stage IIIB disease and 25 patients had stage IV disease. The overall response rate was 45.7% (95% confidence interval 28.8-63.4). The median survival time was 14 months (range 3-44). Grade 3-4 toxicities included neutropenia in 74.3%, thrombocytopenia in 48.6%, anemia in 34.3%, hepatic dysfunction in 11.4%, and infection in 2.9%. There were no treatment-related deaths. There were no differences in response rate and survival between patients aged 75-79 years and patients ≥80 years, although grade 3-4 thrombocytopenia and anemia were significantly more frequent in patients ≥80 years.

CONCLUSION

Our results suggest that the combination of gemcitabine and nedaplatin is effective and well tolerated for selected elderly patients with advanced NSCLC.

Tissue specificity and diurnal change in gene expression of the sucrose phosphate synthase gene family in rice

The rice genome contains 5 isogenes for sucrose phosphate synthase (SPS), the key enzyme in sucrose synthesis; however, little is known about their transcriptional regulation. In order to determine the expression patterns of the SPS gene family in rice plants, we conducted an expression analysis in various tissues and developmental stages by real-time quantitative RT-PCR. At the transcript level, the rice SPS genes, particularly SPS1, were preferentially expressed in source tissues, whereas SPS2, SPS6, and SPS8 were expressed equally in source and sink tissues. We also investigated diurnal changes in SPS gene expression, SPS activity, and soluble sugar content in leaf blades. Interestingly, the expression of all the SPS genes, particularly that of SPS1 and SPS11, tended to be higher at night when the activation state of the SPS proteins was low, and the mRNA levels of SPS1 and SPS6 were negatively correlated with sucrose content. Furthermore, the temporal patterns of SPS gene expression and sugar content under continuous light conditions suggested the involvement of endogenous rhythm and/or sucrose sensing in the transcriptional regulation of SPS genes. Our data revealed differential expression patterns in the rice SPS gene family and part of the complex mechanisms of their transcriptional control.

Repetitive hypoglycaemia increases serum adrenaline and induces monocyte adhesion to the endothelium in rat thoracic aorta

AIMS/HYPOTHESIS

Severe hypoglycaemia associated with diabetes management is a potential risk for cardiovascular diseases. However, the effect and mechanism of hypoglycaemia on the progression of atherosclerosis remains largely unknown. As a first step towards elucidating the above, we investigated the effect of hypoglycaemia on monocyte-endothelial interaction.

METHODS

Insulin was injected intraperitoneally once every 3 days for 5 weeks in Goto-Kakizaki rats, a non-obese rat model of type 2 diabetes. We counted the number of monocytes adherent to the endothelium of thoracic aorta as an index of early atherosclerogenesis. Cultured HUVEC were used to investigate the mechanism of action.

RESULTS

Insulin treatment increased the number of monocytes adherent to the vascular endothelium. This increase was abrogated by injection of glucose with insulin. Amosulalol, an α-1 and β-adrenoreceptor antagonist, suppressed monocyte adhesion to endothelium and levels of adhesion molecules (intercellular adhesion molecule-1 and vascular cell adhesion molecule-1) in the endothelial surface, which had been enhanced by insulin-induced hypoglycaemia. In HUVEC, adrenaline (epinephrine) significantly increased nuclear translocation of nuclear factor-κB (NF-κB) p65 and levels of adhesion molecules, effects that were abrogated following addition of SQ22536, a specific adenyl cyclase inhibitor.

CONCLUSIONS/INTERPRETATION

Our data indicate that repetitive hypoglycaemia induced by insulin enhanced monocyte adhesion to endothelial cells in Goto-Kakizaki rat aorta through enhanced adrenaline activity and that the latter stimulated intracellular cAMP, leading to nuclear translocation of NF-κB with subsequent production of adhesion molecules in endothelial cells.

Patching retinal breaks with Seprafilm in experimental rhegmatogenous retinal detachment of rabbit eyes

PURPOSE

To examine the short-term effect of Seprafilm for patching retinal breaks in experimental rhegmatogenous retinal detachment of rabbit eyes.

METHODS

Experimental retinal detachment with a break was made and repaired by fluid-gas exchange during vitreous surgery in 10 rabbit eyes. In seven eyes, Seprafilm was applied to cover iatrogenic retinal breaks entirely (study group) and in other three eyes operations were finished without Seprafilm application (control group). Funduscopic examination was carried out in both groups and in study group optical coherence tomography (OCT) was performed to observe Seprafilm on the retinal break. Eyes of study group were enucleated on 7th and 14th postoperative day for histological evaluation.

RESULTS

The funduscopic examination showed that the retina was reattached in all eyes of study group. Meanwhile all three eyes of control group resulted in proliferative vitreoretinopathy. OCT showed that Seprafilm adhered to the retina tightly. Funduscopic examination and OCT showed Seprafilm dissolved within 14 days. Histological examination revealed that Seprafilm adhered tightly to the retina and there was no inflammatory change at the Seprafilm application sites.

CONCLUSIONS

In our small number of this study, Seprafilm was found to be beneficial to patch small and posteriorly located retinal breaks in vitreous surgery for rhegmatogenous retinal detachment.

Serum magnesium, ambulatory blood pressure, and carotid artery alteration: the Ohasama study

BACKGROUND

To investigate the associations of 24-h ambulatory blood pressure (ABP) and serum magnesium level (sMg) with risk of carotid artery alteration in a general population.

METHODS

sMg and ABP, monitored every 30 min, were measured in 728 subjects (mean age, 67 years) from the Japanese general population. The extent of carotid artery alteration was evaluated according to mean common carotid intima-media thickness (IMT) and the presence of focal carotid plaque. To determine the association of sMg and carotid artery alteration, analysis of covariance (ANCOVA) (for adjusted mean IMT) or multiple logistic regression analysis (for odds ratio (OR) for the presence of carotid plaques) was used.

RESULTS

Lower sMg was significantly associated with mean IMT (P = 0.004) and risk of ≥2 carotid plaques (P = 0.03) after adjusting for possible confounding factors, including 24-h ABP (systolic), creatinine clearance (Ccr) (estimated using the Cockcroft-Gault equation), and serum minerals (sodium, potassium, calcium, and inorganic phosphorus). Even when 24-h ABP values were within normal range (<130/80 mm Hg), lower sMg levels (<2.2 mg/dl) were significantly associated with mean IMT (P = 0.007) and risk of ≥2 carotid plaques (OR, 2.14; 95% confidence interval, 1.18-3.85; P = 0.01).

CONCLUSIONS

Both 24-h ABP and lower sMg were closely and independently associated with risk of carotid artery alteration. Further investigations are needed to examine the relationship between sMg levels and the incidence of cardiovascular disease.

Disruption of a gene for rice sucrose transporter, OsSUT1, impairs pollen function but pollen maturation is unaffected

Sucrose transporters (SUTs) are known to play critical roles in the uptake of sucrose from the apoplast in various steps of sugar translocation. Because developing pollen is symplastically isolated from anther tissues, it is hypothesized that SUTs are active in the uptake of apoplastic sucrose into pollen. To investigate this possibility, a comprehensive expression analysis was performed for members of the SUT gene family in the developing pollen of rice (Oryza sativa L.) using real-time RT-PCR combined with a laser microdissection technique. Among the five SUT genes, OsSUT1 and OsSUT3 were found to be preferentially expressed and had temporal expression patterns that were distinct from each other. Expression of OsSUT1 in pollen was confirmed by a promoter-GUS fusion assay. The physiological function of OsSUT1 in pollen was further investigated using retrotransposon insertion mutant lines. While the homozygote of disrupted OsSUT1 (SUT1-/-) could not be obtained, heterozygote plants (SUT1+/-) showed normal grain filling. Their progeny segregated into SUT1+/- and SUT1+/+ with the ratio of 1:1, suggesting that the pollen disrupted for OsSUT1 is dysfunctional. This hypothesis was reinforced in vivo by a backcross of SUT1+/- plants with wild-type plants and also by in vitro pollen germination on the artificial media. However, starch accumulation during pollen development was not affected by disruption of OsSUT1, suggesting that the sugar(s) required for starch biosynthesis is supplied by other sugar transporters.

Rice metal-nicotianamine transporter, OsYSL2, is required for the long-distance transport of iron and manganese

Rice (Oryza sativa) is indispensable in the diet of most of the world's population. Thus, it is an important target in which to alter iron (Fe) uptake and homeostasis, so as to increase Fe accumulation in the grain. We previously isolated OsYSL2, a functional iron [Fe(II)]- and manganese [Mn(II)]-nicotianamine complex transporter that is expressed in phloem cells and developing seeds. We produced RNAi (OsYSL2i) and overexpression lines (OXOsYSL2) of OsYSL2. At the vegetative stage in an OsYSL2i line, the Fe and Mn concentrations were decreased in the shoots, and the Fe concentration was increased in the roots. At the reproductive stage, positron-emitting tracer imaging system analysis revealed that Fe translocation to the shoots and seeds was suppressed in OsYSL2i. The Fe and Mn concentrations were decreased in the seeds of OsYSL2i, especially in the endosperm. Moreover, the Fe concentration in OXOsYSL2 was lower in the seeds and shoots, but higher in the roots, compared with the wild type. Furthermore, when OsYSL2 expression was driven by the sucrose transporter promoter, the Fe concentration in the polished rice was up to 4.4-fold higher compared with the wild type. These results indicate that the altered expression of OsYSL2 changes the localization of Fe, and that OsYSL2 is a critical Fe-nicotianamine transporter important for Fe translocation, especially in the shoots and endosperm.

Expression of (pro)renin receptor in the human brain and pituitary, and co-localisation with arginine vasopressin and oxytocin in the hypothalamus

(Pro)renin receptor [(P)RR], a specific receptor for renin and prorenin, is a 350 amino acid protein with a single transmembrane domain. In the present study, the expression of (P)RR in the human brain and pituitary, and its co-localisation with arginine vasopressin and oxytocin in the human hypothalamus were studied by quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and immunocytochemistry. Human brain and pituitary tissues were obtained at autopsy from the subjects without neurological or endocrinological disorders. The antiserum against (P)RR was raised in a rabbit by injecting the peptide fragment of human (P)RR corresponding to 224-237 amino acids conjugated with bovine serum albumin. Quantitative RT-PCR showed that (P)RR mRNA was widely expressed in every region of brain examined and pituitary, with the highest expression levels found in the pituitary and frontal lobe. Immunocytochemistry showed that (P)RR was expressed in the paraventricular and supraoptic nuclei of human hypothalami, and in anterior pituitary cells. Immunostaining of serial sections showed that (P)RR was co-localised with arginine vasopressin and oxytocin in the magnocellular neurones of the paraventricular and supraoptic nuclei. The preabsorption of the antibody by the antigen peptide abolished the immunostaining of (P)RR in the human hypothalamus. The present study has shown that (P)RR mRNA is widely expressed in the human brain and pituitary, consistent with the hypothesis that (P)RR is related to the various brain functions, such as cognitive function and brain development. Co-localisation of (P)RR with vasopressin in the hypothalamus raised the possibility that (P)RR may be related to the central control of water-electrolyte metabolism and blood pressure.

Increases in discontinuous rib cartilage and fused carpal bone in rat fetuses exposed to the teratogens, busulfan, acetazolamide, vitamin A, and ketoconazole

Skeletal changes induced by treatment of pregnant rats with four potent teratogens, busulfan, acetazolamide, vitamin A palmitate, and ketoconazole, were evaluated using Alizarin Red S and Alcian Blue double-staining to investigate the relationship between drug-induced skeletal malformations and cartilaginous changes in the fetuses. Pregnant rats (N = 8/group) were treated once or twice between gestation days (GDs) 10 to 13 with busulfan at doses of 3, 10, or 30 mg/kg; acetazolamide at 200, 400, or 800 mg/kg; vitamin A palmitate at 100,000, 300,000, or 1,000,000 IU/kg; or ketoconazole at doses of 10, 30, or 100 mg/kg. Uterine evaluations and fetal external and skeletal examinations were conducted on GD 20. Marked skeletal abnormalities in ribs and hand/forelimb bones such as absent/ short/bent ribs, fused rib cartilage, absent/fused forepaw phalanx, and misshapen carpal bones were induced at the mid- and high-doses of busulfan and acetazolamide and at the high-dose of vitamin A palmitate and ketoconazole. Increased incidences of discontinuous rib cartilage (DRC) and fused carpal bone (FCB) were observed from the low- or mid-dose in the busulfan and acetazolamide groups, and incidences of FCB were increased from the mid-dose in the vitamin A palmitate and ketoconazole groups. Therefore, DRC and FCB were detected at lower doses than those at which ribs and hand/forelimb malformations were observed in the four potent teratogens.

Effect of tiotropium bromide on airway inflammation and remodelling in a mouse model of asthma

BACKGROUND

Tiotropium bromide, a long acting muscarinic receptor inhibitor, is a potent agent for patients with bronchial asthma as well as chronic obstructive pulmonary disease.

OBJECTIVE

The aim of this study was to evaluate whether tiotropium bromide can inhibit allergen-induced acute and chronic airway inflammation, T helper (Th)2 cytokine production, and airway remodelling in a murine model of asthma.

METHODS

Balb/c mice were sensitized and challenged acutely or chronically to ovalbumin (OVA). The impact of tiotropium bromide was assessed using these mice models by histologic, morphometric, and molecular techniques. Moreover, the effect of tiotropium bromide on Th2 cytokine production from purified human peripheral blood mononuclear cells (PBMCs) was assessed.

RESULTS

Treatment with tiotropium bromide significantly reduced airway inflammation and the Th2 cytokine production in bronchoalveolar lavage fluid (BALF) in both acute and chronic models of asthma. The levels of TGF-beta1 were also reduced by tiotropium bromide in BALF in a chronic model. The goblet cell metaplasia, thickness of airway smooth muscle, and airway fibrosis were all significantly decreased in tiotropium bromide-treated mice. Moreover, airway hyperresponsiveness (AHR) to serotonin was significantly abrogated by tiotropium bromide in a chronic model. Th2 cytokine production from spleen cells isolated from OVA-sensitized mice was also significantly inhibited by tiotropium bromide and 4-diphenylacetoxy-N-methylpiperidine methiodide, which is a selective antagonist to the M3 receptor. Finally, treatment with tiotropium bromide inhibited the Th2 cytokine production from PBMCs.

CONCLUSION

These results indicate that tiotropium bromide can inhibit Th2 cytokine production and airway inflammation, and thus may reduce airway remodelling and AHR in a murine model of asthma.

A gene controlling the number of primary rachis branches also controls the vascular bundle formation and hence is responsible to increase the harvest index and grain yield in rice

The quantitative trait locus controlling the number of primary rachis branches (PRBs) in rice was identified using backcrossed inbred lines of Sasanishiki/Habataki//Sasanishiki///Sasanishiki. The resultant gene was ABERRANT PANICLE ORGANIZATION 1 (APO1). Habataki-genotype segregated reciprocal recombinant lines for the APO1 locus increased both the number of PRB (12-13%) and the number of grains per panicle (9-12%), which increased the grain yield per plant (5-7%). Further recombination dividing this region revealed that different alleles regulated the number of PRB and the number of grains per panicle. The PRB1 allele, which includes the APO1 open reading frame (ORF) and the proximal promoter region, controlled only the number of PRB but not the number of grains per panicle. In contrast, the HI1 allele, which includes only the distal promoter region, increased the grain yield and harvest index in Habataki-genotype plants, nevertheless, the ORF expressed was Sasanishiki type. It also increased the number of large vascular bundles in the peduncle. APO1 expression occurred not only in developing panicles but also in the developing vascular bundle systems. In addition, Habataki plants displayed increased APO1 expression in comparison to Sasanishiki plants. It suggests that APO1 enhances the formation of vascular bundle systems which, consequently, promote carbohydrate translocation to panicles. The HI1 allele is suggested to regulate the amount of APO1 expression, and thereby control the development of vascular bundle systems. These findings may be useful to improve grain yield as well as quality through the improvement of translocation efficiency.

Elevation of myostatin and FOXOs in prolonged muscular impairment induced by eccentric contractions in rat medial gastrocnemius muscle

This study aimed to investigate torque deficit and activation of protein synthesis and/or protein degradation signaling pathways during the early and recovery phase after high- and low-velocity eccentric contractions (ECs). Male Wistar rats ( n = 36) were randomly divided into fast angular velocity ECs group (FAST; 180°/s; n = 12), slow ECs group (SLOW; 30°/s; n = 12), and control group (control; n = 12). ECs comprised four sets of five forced dorsiflexions combined with electrical stimulation of the plantar flexors. Isometric tetanic torque was measured before and after ECs. Tissue contents of Akt(P) (P, phosphorylated), mammalian target of rapamycin (mTOR)(P), 70-kDa ribosomal protein S6 kinase (P70S6k), P70S6k(P), forkhead transcription factor 1 of the O class (FOXO1), FOXO1(P), FOXO3, FOXO3(P), myostatin, and activin receptor type IIB (ActRIIB) were measured. The isometric tetanic torque after ECs was significantly lower in FAST than in SLOW ( days 1, 3, and 5, P < 0.05; day 2, P < 0.01). The ratio of P70S6k(P) against total P70S6k on days 2 and 7 was significantly higher in SLOW than in the control. The ratio of FOXO1 against total FOXO1, the ratio of FOXO3a against total FOXO3a, and myostatin on days 2 and 7 were significantly higher in FAST than in the control, while that of ActRIIB on day 7 was significantly lower in SLOW than in the other two groups. These results suggest that EC intensity plays a key role in impairment of muscular function and activation of protein synthesis and/or protein degradation signaling pathways.