[Exploring the causality between intestinal flora and hyperplastic scars of human based on two-sample Mendelian randomization analysis].

Objective: To investigate the causality between intestinal flora and hypertrophic scars (HS) of human. Methods: This study was a study based on two-sample Mendelian randomization (TSMR) analysis. The data on intestinal flora (n=18 473) and HS (n=208 248) of human were obtained from the genome-wide association study database. Genetically variable genes at five levels (phylum, class, order, family, and genus) of known intestinal flora, i.e., single nucleotide polymorphisms (SNPs), were extracted as instrumental variables for linkage disequilibrium (LD) analysis. Human genotype-phenotype association analysis was performed using PhenoScanner V2 database to exclude SNPs unrelated to HS in intestinal flora and analyze whether the selected SNPs were weak instrumental variables. The causal relationship between intestinal flora SNPs and HS was analyzed through four methods of TSMR analysis, namely inverse variance weighted (IVW), MR-Egger regression, weighted median, and weighted mode. Scatter plots of significant results from the four aforementioned analysis methods were plotted to analyze the correlation between intestinal flora SNPs and HS. Both IVW test and MR-Egger regression test were used to assess the heterogeneity of intestinal flora SNPs, MR-Egger regression test and MR-PRESSO outlier test were used to assess the horizontal multiplicity of intestinal flora SNPs, and leave-one-out sensitivity analysis was used to determine whether HS was caused by a single SNP in the intestinal flora. Reverse TSMR analyses were performed for HS SNPs and genus Intestinimonas or genus Ruminococcus2, respectively, to detect whether there was reverse causality between them. Results: A total of 196 known intestinal flora, belonging to 9 phyla, 16 classes, 20 orders, 32 families, and 119 genera, were obtained, and multiple SNPs were obtained from each flora as instrumental variables. LD analysis showed that the SNPs of the intestinal flora were consistent with the hypothesis that genetic variation was strongly associated with exposure factors, except for rs1000888, rs12566247, and rs994794. Human genotype-phenotype association analysis showed that none of the selected SNPs after LD analysis was excluded and there were no weak instrumental variables. IVW, MR-Egger regression, weighted median, and weighted mode of TSMR analysis showed that both genus Intestinimonas and genus Ruminococcus2 were causally associated with HS. Among them, forest plots of IVW and MR-Egger regression analyses also showed that 16 SNPs (the same SNPs number of this genus below) of genus Intestinimonas and 15 SNPs (the same SNPs number of this genus below) of genus Ruminococcus2 were protective factors for HS. Further, IVW analysis showed that genus Intestinimonas SNPs (with odds ratio of 0.62, 95% confidence interval of 0.41-0.93, P<0.05) and genus Ruminococcus2 SNPs (with odds ratio of 0.62, 95% confidence interval of 0.40-0.97, P<0.05) were negatively correlated with the risk of HS. Scatter plots showed that SNPs of genus Intestinimonas and genus Ruminococcus2 were protective factors of HS. Both IVW test and MR-Egger regression test showed that SNPs of genus Intestinimonas (with Q values of 5.73 and 5.76, respectively, P>0.05) and genus Ruminococcus2 (with Q values of 13.67 and 15.61, respectively, P>0.05) were not heterogeneous. MR-Egger regression test showed that the SNPs of genus Intestinimonas and genus Ruminococcus2 had no horizontal multiplicity (with intercepts of 0.01 and 0.06, respectively, P>0.05); MR-PRESSO outlier test showed that the SNPs of genus Intestinimonas and genus Ruminococcus2 had no horizontal multiplicity (P>0.05). Leave-one-out sensitivity analysis showed that no single intestinal flora SNP drove the occurrence of HS. Reverse TSMR analysis showed no reverse causality between HS SNPs and genus Intestinimonas or genus Ruminococcus2 (with odds ratios of 1.01 and 0.99, respectively, 95% confidence intervals of 0.97-1.06 and 0.96-1.04, respectively, P>0.05). Conclusions: There is a causal relationship between intestinal flora and HS of human, in which genus Intestinimonas and genus Ruminococcus2 have a certain effect on inhibiting HS.

Eicosapentaenoic acid reduces inflammation and apoptosis by SREBP1/TLR4/MYD88.

AIM: Podocytes dysfunction including the cell integrity, apoptosis and inflammation plays crucial role in diabetic nephropathy. Current exploration evaluated the protective role of eicosapentaenoic acid (EPA) in high glucose-treated podocytes and the underlying mechanisms. METHOD: MPC5 cell were stimulated by high glucose or treated by EPA of different concentrations. CCK8 assay was utilized to assess MPC5 cell viability, flow cytometry analyzed cell apoptosis. RESULTS: Data showed that EPA prominently alleviated the high glucose-induced apoptosis and inflammation. Besides, the disruption of the podocytes structure certifying by podocin and synaptopodin induced by hyperglycemia was hindered by EPA administration. In addition, overexpression of the sterol regulatory element-binding protein-1 (SREBP-1) reversed the protective effects of EPA in high glucose-treated podocytes. EPA inhibits the SREBP-1/TLR4/MYD88 signaling in high glucose treated cells. CONCLUSIONS: This study suggests that EPA protects against podocytes dysfunction by regulating SREBP-1 and these findings provide a better understanding for diabetic nephropathy and a novel therapeutic strategy (Fig. 7, Ref. 24).

Association of arterial stiffness in non-hypertensive offspring with parental hypertension: the Hanzhong adolescent hypertension cohort study.

OBJECTIVE: Arterial stiffness may be an early marker for vascular changes associated with hypertension in young adults. Individuals with a family history of hypertension are at high risk of developing hypertension. We investigated whether arterial stiffness measured, such as mean arterial pressure (MAP) and brachial to ankle pulse wave velocity (baPWV), were increased in normotensive offspring with a parental history of hypertension. PATIENTS AND METHODS: We compared MAP and baPWV in a sample of 1953 non-hypertensive participants (974 men, mean age 42±3 years) recruited in the previous Hanzhong adolescent hypertension cohort study. Standardized questionnaires, physical examinations and laboratory tests were used to obtain information, with a particular focus on family hypertension history, anthropometric, hemodynamic, and biochemical factors. RESULTS: A total of 1039, 759, 155 participants had 0, 1, and 2 parents with hypertension, respectively. Parental hypertension was associated with elevated offspring MAP (in multivariable-adjusted models, B=1.5 mm Hg, 95% CI 0.8-2.2 for 1 parent with hypertension; B=3.0 mm Hg, 95% CI 1.8-4.3, for 2 parents with hypertension; p<0.001 for each). A significant positive correlation was also observed between MAP and baPWV (r=0.543, p<0.001). BaPWV displayed a similar correlation with parental hypertension in age-adjusted, sex-adjusted and body mass index (BMI)-adjusted models (B=23.1 cm/s, 95% CI 8.0-38.1, for 1 parent with hypertension, p<0.01; B=53.0 cm/s, 95% CI 25.8-80.2, p<0.001 for 2 parents with hypertension), but associations were attenuated in multicovariate models after adjustment for MAP. In multivariable-adjusted models, logistic regression analysis showed that the risk of belonging to the upper quartile of MAP was significantly increased for offspring whose parents had hypertension (OR=1.5, 95% CI 1.2-1.9, for 1 parent with hypertension; OR=2.3, 95% CI 1.6-3.4, for 2 parents with hypertension; p<0.001 for each). Similarly, the odds ratios of belonging to the upper quartile of baPWV increased (OR=1.3, 95% CI 1.1-1.6, for 1 parent with hypertension, p<0.05; OR=2.1, 95% CI 1.5-3.0, for 2 parents with hypertension, p<0.001, in age-sex-BMI-adjusted models), and were then brought down in the fully adjusted models including MAP, but the increase remained significant for 2 parents with hypertension (OR=1.6, 95% CI 1.0-2.3, p<0.05). CONCLUSIONS: These findings provide evidence that arterial stiffness is higher in young-to middle-aged normotensive subjects with a family history of hypertension, suggesting that increased arterial stiffness may occur in the early stages during the pathogenesis of hypertension.

[The influence of apolipoprotein A1 on the prognosis of multiple myeloma].

Objective: In this study, we aimed to determine the change and clinical significance of serum level Apo A1 in MM patients. Methods: In total, 412 multiple myeloma patients were examined. SPSS 22.0 was used for data analysis. Correlation analysis was performed using linear correlation or Spearman rank correlation coefficients. Measurement data were analyzed with the t-test, Mann-Whitney U-test, or oneway analysis of variance (ANOVA) . Used the ROC curve to calculate the cutoff value and compared the OS and PFS between high Apo A1 subgroup and low Apo A1 subgroup with Kaplan-Meier survival analysis. Results: Our study showed that value of Apo A1 in the patient group was lower than that in the control group (0.89 g/L vs 1.24 g/L, P<0.05) . We found that Apo A1 dynamically changed with different MM stages. As it was increased when the disease was in remission, and decreased after disease in progression. According the result of multivariate analysis Apo A1 reduction become the independent risk factors of MM. On the basis of Kaplan-Meier survival analysis between high Apo A1 subgroup and low Apo A1 subgroup, we found higher Apo A1 patienta had longer OS rate and PFS. Conclusions: Apo A1 is a useful biomarker of tumor burden and a prognostic factor of multiple myeloma.

MiRNA-365a-3p promotes the progression of osteoporosis by inhibiting osteogenic differentiation via targeting RUNX2.

OBJECTIVE: The aim of this study was to explore the exact role of miRNA-365a-3p in the progression of osteoporosis, as well as its function in regulating osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs). PATIENTS AND METHODS: The serum level of miRNA-365a-3p in osteoporosis patients and normal controls was determined by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). After transfection of miRNA-365a-3p mimics, miRNA-365a-3p inhibitor or si-RUNX2 in hBMSCs, the relative expression levels of miRNA-365a-3p, osteocalcin (OCN), osteopontin (OPN) and collagen I were determined by qRT-PCR. Western blot was conducted to examine the protein expression of RUNX2 influenced by miRNA-365a-3p. Subsequently, the regulatory effects of miRNA-365a-3p and RUNX2 on osteogenic differentiation and capability of mineralization were evaluated by alkaline phosphatase (ALP) determination and alizarin red staining, respectively. Furthermore, the binding relationship between miRNA-365a-3p and RUNX2 was predicted and verified by miRanda and Dual-Luciferase reporter gene assay, respectively. RESULTS: MiRNA-365a-3p was highly expressed in osteoporosis patients. The expression of miRNA-365a-3p in hBMSCs decreased gradually with the prolongation of osteogenic differentiation. The subsequent results showed that RUNX2 could bind to miRNA-365a-3p, which was negatively regulated by miRNA-365a-3p in hBMSCs. Down-regulation of miRNA-365a-3p significantly decreased the expression levels of OCN, OPN and collagen I. Furthermore, overexpression of miRNA-365a-3p markedly weakened the capability of mineralization of hBMSCs, whereas was further reversed by transfection of si-RUNX2. CONCLUSIONS: MiRNA-365a-3p negatively regulates osteogenic differentiation of hBMSCs by targeting RUNX2, thus promoting the progression of osteoporosis.

MicroRNA-645 is an oncogenic regulator in colon cancer.

Despite advances in early diagnosis and the development of molecularly targeted therapy, curative treatment of colon cancer once it has metastasized is yet to be accomplished. This is closely associated with deregulated CRC cell proliferation and resistance to apoptosis. Here we reveal that upregulation of microRNA-645 (miR-645) through DNA copy number gain is responsible for enhanced proliferation and resistance to apoptosis in colon cancer. MiR-645 was upregulated in most colon cancer tissues related to adjacent normal mucosa. This appeared to be associated with amplification of a section of chromosome 20q13.13, where miR-645 is located. Inhibition of miR-645 reduced proliferation and enhanced sensitivity to apoptosis triggered by the chemotherapeutic drugs 5-fluorouracil and cisplatin in CRC cells, and retarded colon cancer xenograft growth. Conversely, overexpression of miR-645 in normal colon epithelial cells enhanced proliferation and triggered anchorage-independent cell growth. Although SRY-related HMG-box 30 (SOX30) was identified as a miR-645 target, its expression was only partially affected by miR-645, suggesting that miR-645 is a fine-tuning mechanism of SOX30 expression. Moreover, overexpression of SOX30 only moderately inhibited promotion of CRC cell proliferation by miR-645, indicating that miR-645 may have more targets that contribute to its pro-proliferation effect in colon cancer. Together, this study reveals that miR-645 can regulate oncogenesis in colon cancer with SOX30 being one of its targets.

[Relationship between overweight/obesity and hypertension among adults in China: a prospective study].

OBJECTIVE: To evaluate the influence of overweight/obesity on the incidence of hypertension among adults in China. METHODS: The subjects of this prospective study were 13 739 Chinese adults aged 35-74 years recruited at the baseline surveys of China Multicenter Collaborative Study of Cardiovascular Disease Epidemiology and International Collaborative Study of Cardiovascular Disease in Asian. Baseline surveys were conducted in 1998 and during 2000-2001, respectively, and the follow-up was conducted during 2007-2008. According to the body mass index, the subjects were divided into four groups: underweight group(<18.5 kg/m(2)), normal weight group(18.5-23.9 kg/m(2)), overweight group(24.0-27.9 kg/m(2))and obesity group(≥28.0 kg/m(2)). Age-standardized cumulative incidence of hypertension was calculated for each group, respectively. The relative risks(RRs)and 95% confidence intervals(CIs)for the incidence of hypertension of underweight, overweight and obesity groups were estimated by using generalized linear regression model with normal weight group as reference. RESULTS: During 8.1 years of follow-up, 4 271 hypertension cases were detected(2 012 in men and 2 259 in women). Age-standardized cumulative incidence of hypertension for the underweight, normal weight, overweight and obesity groups were 20.3%, 30.9%, 43.6% and 50.8% in men, respectively; and 22.9%, 30.4%, 41.1% and 50.8% in women, respectively. Compared with the normal weight group, multivariate-adjusted RR(95% CI)for the incidence of hypertension in underweight, overweight and obesity groups were 0.78(0.64-0.95), 1.22(1.13-1.30)and 1.28(1.16-1.42)in men, respectively; and 0.89(0.77-1.03), 1.16(1.09-1.23)and 1.28(1.18-1.38)in women, respectively. The overweight and obese subjects had higher risk for the incidence of hypertension, with the population attributable risk proportion of 7.4% in men and 8.8% in women, respectively. CONCLUSION: Overweight or obese people are at an increased risk of developing hypertension, thus prevention and control of overweight/obesity are needed to reduce hypertension incidence among adults in China.

INPP4B is an oncogenic regulator in human colon cancer.

Inositol polyphosphate 4-phosphatase type II (INPP4B) negatively regulates phosphatidylinositol 3-kinase signaling and is a tumor suppressor in some types of cancers. However, we have found that it is frequently upregulated in human colon cancer cells. Here we show that silencing of INPP4B blocks activation of Akt and serum- and glucocorticoid-regulated kinase 3 (SGK3), inhibits colon cancer cell proliferation and retards colon cancer xenograft growth. Conversely, overexpression of INPP4B increases proliferation and triggers anchorage-independent growth of normal colon epithelial cells. Moreover, we demonstrate that the effect of INPP4B on Akt and SGK3 is associated with inactivation of phosphate and tensin homolog through its protein phosphatase activity and that the increase in INPP4B is due to Ets-1-mediated transcriptional upregulation in colon cancer cells. Collectively, these results suggest that INPP4B may function as an oncogenic driver in colon cancer, with potential implications for targeting INPP4B as a novel approach to treat this disease.

Correlation of increased MALAT1 expression with pathological features and prognosis in cancer patients: a meta-analysis.

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been identified as a potential cancer biomarker, yet the mechanism by which it influences the development of cancer remains unknown. In this study, we aimed to correlate MALAT1 expression with pathological features and prognosis in cancer patients. Several databases were searched using combinations of keywords relating to MALAT1 and cancer. After selection of relevant cohort studies according to strict criteria, a meta-analysis was conducted. Twelve studies were analyzed, involving 958 cancer patients. Elevated MALAT1 expression was associated with poor prognosis and larger tumors [prognosis: hazard ratio = 3.11, 95% confidence interval (CI) = 1.98-4.23, P = 0.000; tumor size: odds ratio (OR) = 0.40, 95%CI = 0.21-0.74, P = 0.003]. However, no connection with histological grade, T-stage, lymph node (LN) metastasis, or distant metastasis was established (all P > 0.05). A correlation between increased expression and poor prognosis was observed in the large and small sample-size subgroups (all P< 0.05), as was a relationship with large tumor size (OR = 0.30, 95%CI = 0.13-0.71, P = 0.006). Expression was correlated with T-stage and distant metastasis in the small sample-size subgroup (all P < 0.05), but no association was detected regarding histological grade, LN metastasis in either subgroup (all P > 0.05). Our findings demonstrate that elevated MALAT1 expression correlates with large tumor size, advanced tumor stage, and poor prognosis, and might therefore be utilized to evaluate clinical pathological features and prognostic out come for cancer patients.

Effect of docosahexaenoic acid on hippocampal neurons in high-glucose condition: involvement of PI3K/AKT/nuclear factor-κB-mediated inflammatory pathways.

Accumulating evidence suggested that hyperglycemia played a critical role in hippocampus dysfunction in patients with diabetes mellitus. However, the multifactorial pathogenesis of hyperglycemia-induced impairments of hippocampal neurons has not been fully elucidated. Docosahexaenoic acid (DHA) has been shown to enhance learning and memory and affect neural function in various experimental conditions. The present study investigated the effects of DHA on the lipid peroxidation, the level of inflammatory cytokines and neuron apoptosis in the hippocampal neurons in high-glucose condition. High-glucose administration increased the level of tumor necrosis factor α (TNF-α) and IL-6, induced oxidative stress and apoptosis of hippocampal neurons in vitro. DHA treatment reduced oxidative stress and TNF-α expression, protected the hippocampal neurons by increasing AKT phosphorylation and decreasing caspase-3 and caspase-9 expression. These results suggested that high-glucose exposure induced injury of hippocampal neurons in vitro, and the principle mechanisms involved in the neuroprotective effect of DHA were its antioxidant and anti-apoptotic potential. DHA may thus be of use in preventing or treating neuron-degeneration resulting from hyperglycemia.

Fish oil improves learning impairments of diabetic rats by blocking PI3K/AKT/nuclear factor-κB-mediated inflammatory pathways.

Previous research has demonstrated that diabetes induces learning and memory deficits. However, the mechanism of memory impairment induced by diabetes is poorly understood. Dietary fatty acids, especially polyunsaturated fatty acids, have been shown to enhance learning and memory and prevent memory deficits in various experimental conditions. The present study investigated the effects of fish oil supplementation on the lipid peroxidation, inflammation and neuron apoptosis in the hippocampus of streptozotocin (STZ)-induced diabetes rats. The effects of diabetes and fish oil treatment on the spatial learning and memory were also evaluated using the Morris Water Maze. STZ-induced diabetes impaired spatial learning and memory of rats, which was associated with the inflammation, oxidative stress and apoptosis of hippocampal neurons. Fish oil administration ameliorated cognitive deficit, reduced oxidative stress and tumor necrosis factor α (TNF-α), protected the hippocampal neurons by increasing Protein Kinase B (AKT) phosphorylation and decreasing caspase-9 expression. These results suggested that the principle mechanisms involved in the antidiabetic and neuroprotective effect of fish oil were its antioxidant, anti-inflammatory and anti-apoptosis potential, supporting a potential role for fish oil as an adjuvant therapy for the prevention and treatment of diabetic complications.

MicroRNA-497 targets insulin-like growth factor 1 receptor and has a tumour suppressive role in human colorectal cancer.

Past studies have shown that amplified insulin-like growth factor 1 (IGF1)/IGF1 receptor (IGF1-R) signalling has an important role in colorectal cancer (CRC) development, progression and resistance to treatment. In this report, we demonstrate that downregulation of microRNA-497 (miR-497) as a result of DNA copy number reduction is involved in upregulation of IGF1-R in CRC cells. MiR-497 and miR-195 of the miR-15/16/195/424/497 family that share the same 3' untranslated region (3'UTR) binding seed sequence and are predicted to target IGF1-R were concurrently downregulated in the majority of CRC tissues relative to paired adjacent normal mucosa. However, only overexpression of miR-497 led to suppression of the IGF1-R 3'UTR activity and downregulation of the endogenous IGF1-R protein in CRC cells. This was associated with inhibition of cell survival, proliferation and invasion, and increased sensitivity to apoptosis induced by various stimuli including the chemotherapeutic drugs cisplatin and 5-fluorouracil, and the death ligand tumour necrosis factor-related apoptosis-inducing ligand. The biological effect of miR-497 on CRC cells was largely mediated by inhibition of phosphatidylinositol 3-kinase/Akt signalling, as overexpression of an active form of Akt reversed its impact on cell survival and proliferation, recapitulating the effect of overexpression of IGF1-R. Downregulation of miR-497 and miR-195 appeared to associate with copy number loss of a segment of chromosome 17p13.1, where these miRs are located at proximity. Similarly to miR-195, the members of the same miR family, miR-424 that was upregulated, and miR-15a, miR-15b and miR-16 that were unaltered in expression in CRC tissues compared with paired adjacent normal mucosa, did not appear to have a role in regulating the expression of IGF1-R. Taken together, these results identify downregulation of miR-497 as an important mechanism of upregulation of IGF1-R in CRC cells that contributes to malignancy of CRC.

Dietary ω-3 polyunsaturated fatty acids improves learning performance of diabetic rats by regulating the neuron excitability.

Previous research has demonstrated that diabetes induced learning and memory deficits. However, the mechanism of memory impairment induced by diabetes is poorly understood. Dietary fatty acids, especially polyunsaturated fatty acids (PUFA), have been shown to enhance learning and memory and prevent memory deficits in various experimental conditions. Sprague-Dawley rats were used in the present study to investigate the effect of fish oil supplementation on spatial learning and memory of streptozotocin (STZ)-induced diabetic rats with the Morris Water Maze. The excitability of CA1 pyramidal neurons and the related ionic currents was also examined. Diabetes impaired spatial learning and memory of rats. Diabetes decreased the sodium currents and increased the potassium currents, and further led to the reduction of excitability of CA1 pyramidal neurons, effects which may contribute to the behavioral deficits. Fish oil dietary supplementation decreased the transient currents and Kv4.2 expression in the hippocampus and partially improved learning performance of diabetic rats. The results of the present study suggested that sodium and potassium currents contributed to the inhibitory effect of diabetes on neuron excitability, further influencing learning and memory processing. Dietary fish oil may modulate the membrane excitability and is a possible strategy for preventing the impairments of diabetes on hippocampal function.

Sleep deprivation impairs spatial learning and modifies the hippocampal theta rhythm in rats.

Previous work from our laboratory suggests that paradoxical sleep deprivation (PSD) decreases persistent sodium currents and hyperpolarization-activated cation currents in CA1 pyramidal neurons, and this leads to decreases in neuron excitability. Here, we further investigate the mechanisms of rhythmic theta-range activity in the hippocampus by examining the resonance characteristics of hippocampal pyramidal neurons. Sleep deprivation (SD) interfered with the rhythmic activity of theta band in the hippocampus, which may be involved in the deficit of the spatial learning ability of rats. Additionally, SD changes the voltage dependence of resonance. The effect of SD on the ion currents may contribute to the alternation of the theta resonance of neurons and further influence the physiological function. These results suggest that changes in neuron resonance lead to changes in the generation of rhythmic theta activity, and may contribute to behavioral deficits associated with theta activity during learning and memory tasks. We suggest the resonant properties of hippocampal neurons are potential targets for preventing deleterious effects of sleep deprivation.

Determination of low-level mercury based on a renewable-drops sensing technique.

The design and characteristics of a novel drop-based fluorescence-detection technique for the determination of mercury(II) are described. The method, using a flow injection technique, is based on the renewable-drops of 3,3',5,5'-tetramethylbenzidine(TMB), which are formed at the bottom tip of a silica capillary tube connected to the end of the flow system. An excitation beam from a high-pressure Hg lamp directly illuminates the drops, the fluorescence emission is conducted to a photodiode (PD) to convert the photocurrent into a voltage signal (mV). Optimum analytical conditions for Hg(II) assays have been established. In NaAc/HAc buffer at pH 3.09 this assay has a wide linear range for Hg(II) from 8.0 x 10(-8) to 2.0 x 10(-5) mol/L with a detection limit of 2.0 x 10(-8) mol/L. The use of renewable drops allowing a fresh reaction surface for each sample is of particular value to solving the problems of irreversible reactions. Besides its high sensitivity, the method permits a simple, fast, and inexpensive measurement with only micro-quantities of reagent consumption. The technique described provides a simple and sensitive way to fabricate sensors of feasible prospects and commercial advantages.

Pressor and bradycardic effects of centrally administered relaxin in conscious rats.

The current study tested the hypothesis that centrally administered relaxin elevates arterial pressure in conscious rats and that this hypertensive effect is mediated, at least in part, by central or peripheral vasopressin. Injection of human relaxin (0.068 or 0.34 microgram in 200 nL artificial cerebrospinal fluid) into the right lateral ventricle of conscious, unrestrained Sprague-Dawley rats caused significant dose-related increases in arterial pressure and decreases in heart rat. The pressor and bradycardic responses to intracerebroventricular injections of relaxin were significantly blunted by pretreatment with either intracerebroventricular or intravenous injection of a vasopressin receptor (V1) antagonist, suggesting that the cardiovascular effects of central relaxin are mediated, at least in part, by V1 receptors in the brain and perhaps also by vasopressin released into the peripheral circulation. Neither intracerebroventricular injection of the vehicle alone nor intravenous injection of relaxin (0.34 microgram) altered arterial pressure or heart rate. In contrast to the above, intravenous injections of relaxin (40 micrograms/kg) elicited pressor and tachycardic responses that were not blunted by pretreatment with either intracerebroventricular or intravenous injection of the V1 receptor antagonist. Together, these data suggest that in the central nervous system relaxin contributes to the regulation of cardiovascular function and that the mechanisms for the cardiovascular effects of central and peripheral relaxin are distinct.

Electromagnetic imaging for complex cylindrical objects.

Electronic imaging of complex cylindrical objects with arbitrary cross sections was investigated, assuming an incident wave upon both penetrable inhomogeneous dielectric cylinders and perfectly conducting cylinders with known shape, and external measurements of the scanned field. By properly processing the scattered held measurements, the dielectric permittivity distribution of the scanned object can be reconstructed. A theoretical formulation was based on proper arrangement of the incident field directions resulting in a set of integral equations derived and solved by the moment method and the unrelated illumination method. Numerical results demonstrate the capability of the imaging algorithm. Good reconstruction results were obtained even in the presence of additive random noise. In addition, noise effects on the reconstruction results were investigated.

Sodium-proton (Na+/H+) exchange inhibition increases blood pressure in spontaneously hypertensive rat.

The current study was designed to determine the role of sodium-proton (Na+/H+) exchange in blood pressure regulation in sodium chloride (NaCl)-sensitive and NaCl-resistant spontaneously hypertensive rats and control Wistar-Kyoto rats (WKY) using 5-(N,N-hexamethylene)amiloride (HMA), a potent and selective inhibitor of Na+/H+ exchange. The response of mean arterial pressure to intravenous infusion of HMA was examined in conscious, unrestrained male rats maintained on normal (1%) or high (8%) NaCl diets for 3 weeks beginning at age 7 weeks. The HMA significantly increased mean arterial pressure in NaCl-sensitive spontaneously hypertensive rats and NaCl-resistant spontaneously hypertensive rats that were fed 1% NaCl, but not in WKY rats that were fed 1% NaCl; the 8% NaCl diet enhanced this pressor response in all 3 strains. The pressor response was accompanied by significant increases in plasma norepinephrine levels in NaCl-sensitive spontaneously hypertensive rats on both diets, but not in NaCl-resistant spontaneously hypertensive rats or WKY rats on either diet. There were no differences in steady-state levels (30-60 nM) of plasma HMA between diet groups in any strain. Therefore, administration of HMA in a dose at which it is highly selective for the Na+/H+ exchanger (Ki = 160 nM) caused a systemic pressor response in spontaneously hypertensive rats that was enhanced by dietary NaCl supplementation. With these data, it is suggested that inhibition of Na+/H+ exchange in vivo has a pressor effect greater in spontaneously hypertensive rats than in WKY rats and is further enhanced by NaCl supplementation.

Role of anterior hypothalamic angiotensin II in the pathogenesis of salt sensitive hypertension in the spontaneously hypertensive rat.

Selective alterations in noradrenergic mechanisms in the anterior hypothalamic area (AHA) of NaCl-sensitive spontaneously hypertensive rats (SHR-S) have been demonstrated during dietary NaCl supplementation. To test the hypothesis that endogenous angiotensin II (Ang II) in the AHA also plays a role in blood pressure regulation and in NaCl sensitive hypertension in the SHR-S, Type 1 Ang II (AT1) receptors in the AHA were blocked by local microinjection of losartan, a selective nonpeptide AT1 receptor antagonist, and the effects of the intervention on blood pressure were observed. Microinjection of losartan into the AHA of conscious rats caused a significant dose-related decrease in mean arterial pressure in SHR-S but not in Wistar-Kyoto (WKY) rats. To test the hypothesis that the depressor response to AHA AT1 receptor blockade is enhanced by high (8%) NaCl feeding in SHR-S, losartan was microinjected into the AHA of conscious SHR-S and WKY rats that had been fed 1% or 8% NaCl diets for 3 weeks. The magnitude and duration of the depressor response to losartan were significantly greater in the 8% NaCl fed SHR-S than in the 1% NaCl fed rats. These findings, along with the observation that Ang II receptor numbers are increased in neurons isolated from brain of SHR compared with WKY rats, suggest that endogenous Ang II acting on AT1 receptors in the AHA participates in the tonic control of blood pressure in SHR-S but not in normotensive WKY rats. In addition, it is involved in the pathogenesis of NaCl sensitive hypertension in the SHR-S.