Sensorless estimation of pressure head and flow of a continuous flow artificial heart based on input power and rotational speed

The present study has proposed a new method for estimating the pressure head (P(t)[mm Hg]) and flow (Q(t)[L/min]) of a centrifugal pump on the basis of voltage (V(t)[V]), current (I(t)[A]), and rotational speed (N(t)[k(rpm)]) of the DC motor for a pump without any additional sensors. In the proposed estimation method, two auto-regressive exogenous (ARX) models are employed. One ARX model has an output, P(t) or Q(t), and three inputs, VI(t) = V(t)I(t) and N(t) and the steady state gain (K) of the system from VI(t) to N(t). It can be assumed that K may include the information on viscosity of blood. The coefficient parameters of this ARX model are identified in an off-line fashion before implantation of the pump. After implantation, P(t) or Q(t) is estimated by the same ARX model with the already identified parameters. The other ARX model is used to identify Kon the basis of VI(t) and N(t) in an on-line fashion every time the viscosity of blood may change. In the experiment, a mock circulatory system consisting of a centrifugal pump and a reservoir with 37% glycerin or water was employed. The root mean square error between measured Q(t) and its estimate obtained from the proposed method was 1.66L/min. On the other hand, a different method based on a single ARX model with inputs of VI(t) and N(t), but without the additional input of K, yielded the corresponding estimation error of 2.22L/min. This means that the proposed method can reduce its estimation error by about 25% in comparison with a method that cannot cope with the change in blood viscosity.     

Detection of ornithine transcarbamylase deficiency heterozygotes by measuring of urinary uracil

The importance of detecting heterozygosity for X-linked ornithine transcarbamylase deficiency is well known. Although the DNA analysis and the allopurinol loading tests are commonly used for this purpose, both methods require complicated procedures. In order to establish a simple test for detecting female heterozygotes, we examined the uracil and orotic acid in single-voided urine samples from 70 healthy women, and from 12 asymptomatic females with ornithine transcarbamylase deficiency. Based on the results of healthy women, we were able to determine a screening cut-off line of 11.9 micromol/mmol creatinine (mean +/- 1SD in logarithmic form) for uracil. Using this cut-off line, the sensitivity of OCT heterozygotes was 100%. We were also able to establish a second cut-off line of 28.9 micromol/mmol creatinine (mean +/- 3SD in logarithmic form) for diagnosis. Using this second cut-off line, the specificity of OCT heterozygotes was 100%. Our study has shown that the measurement of urinary uracil is a relatively simple and effective method for detecting female heterozygotes.     

High-performance liquid chromatography with peroxyoxalate chemiluminescence detection of bisphenol A migrated from polycarbonate baby bottles using 4-(4,5-diphenyl-1H-imidazol-2-yl)benzoyl chloride as a label

A highly sensitive and selective high-performance liquid chromatographic method with peroxyoxalate chemiluminescence detection for the determination of bisphenol A at sub-ppb levels is described. Bisphenol A was derivatized with 4-(4,5-diphenyl-1H-imidazol-2-yl)benzoyl chloride and the excess unreacted reagent was removed by a simple solid-phase extraction procedure with recoveries of approximately 60%. The separation was carried out isocratically on an ODS column and the derivatized bisphenol A was detected by peroxyoxalate chemiluminescence. A mixture of bis[2-(3,6,9-trioxadecanyloxycarbonyl)-4-nitrophenyl]oxalate (0.6 mM) and hydrogen peroxide (25.0 mM) dissolved in acetonitrile was used as a chemiluminescence reagent solution with a mixture of imidazole-HNO3 buffer (40.0 mM, pH 7.0): acetonitrile (17:83, v/v) as a mobile phase. The linear standard curve was obtained over the range from 0.57 (2.5) to 22.8 (100) ppb (nM) (r=0.996) with a detection limit of 0.38 ppb (2.8 fmol on column) at a signal-to-noise ratio of 3. The method was successfully applied to the determination of bisphenol A in hot water in contact with commercially available baby bottle samples.     

Stress-induced impairment of inhibitory avoidance learning in female neuromedin B receptor-deficient mice

Neuromedin B (NMB) is a mammalian bombesin (BN)-like peptide that exerts its function via the neuromedin B receptor (NMB-R). The NMB/NMB-R system is involved in stress response, and therefore we examined behavioral properties in female mice lacking NMB-R using a restraint-induced stress paradigm. Thirty minutes of restraint in a wire mesh cage constituted a sufficient stress stimulus for mice as evidenced by elevated blood glucose concentrations in stressed wild-type and NMB-R-deficient mice. Using a one-trial passive avoidance test, stressed NMB-R-deficient mice exhibited a marked reduction in memory performance. NMB-R-deficient mice exhibited elevated spontaneous activity in a novel environment compared to non-stressed mutant mice after 30-min stress, and a similar difference was also observed between stressed/non-stressed wild-type mice. An elevated plus maze test showed that the stress stimulus had no effect on anxiety in either wild-type or NMB-R-deficient mice. Furthermore, pain response of wild-type and NMB-R-deficient mice induced by electric foot shock was not affected under either stressed or non-stressed conditions. These results indicate that impaired memory performance in stressed NMB-R-deficient mice is not a consequence of changes in spontaneous activity, anxiety, or pain response, and suggest that the NMB/NMB-R pathway may play a role in regulating the stress response via the neural system that controls learning and memory.     

Natural occurrence of myofiber cytoplasmic enlargement accompanied by decrease in myonuclear number

It has been shown that changes in the nuclear number in myofibers are synchronized with myofiber size. Therefore, under some conditions, the myonuclear number is thought to be a determinant factor of myofiber size. However, we have clearly shown that denervation-induced fiber atrophy occurs without any decrease in myonuclear number, indicating that the myonuclear number is not always an important determinant factor of myofiber size. However, this was an event found under experimental conditions. In the present study, we examined the morphological features of single myofibers under normal conditions throughout the lifespan of normal mice. We discovered that the C/N ratio (cell volume/nucleus) greatly increases during the growth period and clearly decreases during the aging period. From 5 weeks to 6 months old, the myofibers undergo fiber hypertrophy accompanied by a decrease in myonuclear number. In muscle at 18 months, we found no correlation between myonuclear number and fiber cross-sectional area. These results suggest that, even under normal physiological conditions, the myonuclear number is not always a determinant factor of the myofiber size.     

Chemoprevention of heterocyclic amine-induced mammary carcinogenesis in rats

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is one of the most prevalent carcinogenic heterocyclic amines in the environment, targeting the colon, prostate, pancreas, and mammary gland in rodents. Chemopreventive effects of synthetic and naturally occurring compounds on PhIP-induced rat mammary carcinogenesis were investigated in a series of experiments. In a PhIP feeding model, groups of 20-21 female F344 rats each, were treated with 0.02% PhIP alone or PhIP plus 0.5% 1-O-hexyl-2,3,5-trimethylhydroquinone (HTHQ), 1% green tea catechins, 1% alpha-tocopherol, 0.1% ellagic acid, or 1% chlorophyllin, each in the diet, or 0.1% caffeine in drinking water for 52 weeks. To assess the mechanism of HTHQ and caffeine inhibition of PhIP-induced carcinogenesis, effects of these compound on the in vitro metabolic activation of PhIP were examined in the presence of S9 mix. In the next series of experiments, the PhIP intragastric dose model was applied to allow separate investigation of the effects of chemicals during the initiation and postinitiation periods. In these experiments, female Sprague-Dawley rats were given eight intragastric doses of 100 mg/kg body weight during the first 4-8 weeks for initiation. Either during initiation or after initiation, or only after initiation, animals were treated with either corn or perilla oil at doses of 5 and 20%, conjugated fatty acid derived from safflower oil (CFA-S) or perilla oil (CFA-P) at a dose of 1%, arctiin at doses of 0.02 and 0.2% in the diet, or sodium nitrite (NaNO(2)) at a dose of 0.2% in drinking water. In the PhIP feeding model, administration of PhIP alone for 52 weeks induced adenocarcinomas in 40% of rats, but the incidence was remarkably reduced to 5% by the simultaneous treatment with 0.5% HTHQ, a strong lipophilic phenolic antioxidant, or to 10% by 0.1% caffeine. Administration of 1% chlorophyllin exerted similar, albeit weaker, effects. alpha-Tocopherol at a dose of 0.5% only reduced the multiplicity of carcinomas, and 1% green tea catechins only the mean size of mammary tumors. In a metabolic activation study of PhIP, HTHQ and caffeine clearly inhibited the formation of metabolites. In the PhIP gastric dose model, among the naturally occurring compounds examined, a plant lignan arctiin, perilla oil, which contains a large amount of n-6 alpha-linolenic acid, and CFA-S or CFA-P inhibited mammary tumor development, particularly in the postinitiation period, although a clear dose response was not observed. Treatment with 0.2% NaNO(2) in the initiation period was found to lower the volume of mammary tumors. The present results indicate that a number of compounds may be candidate chemopreventive agents against PhIP-induced mammary carcinogenesis, acting through different mechanisms and depending on the stage of carcinogenesis.     

Conserved RARE localization in amphioxus Hox clusters and implications for Hox code evolution in the vertebrate neural crest.

The Hox code in the neural crest cells plays an important role in the development of the complex craniofacial structures that are characteristic of vertebrates. Previously, 3' AmphiHox1 flanking region has been shown to drive gene expression in neural tubes and neural crest cells in a retinoic acid (RA)-dependent manner. In the present study, we found that the DR5-type RA response elements located at the 3' AmphiHox1 flanking region of Branchiostoma floridae are necessary and sufficient to express reporter genes in both the neural tube and neural crest cells of chick embryos, specifically at the post-otic level. The DR5 at the 3' flanking region of chick Hoxb1 is also capable of driving the same expression in chick embryos. We found that AmphiHox3 possesses a DR5-type RARE in its 5' flanking region, and this drives an expression pattern similar to the RARE element found in the 3' flanking region of AmphiHox1. Therefore, the location of these DR5-type RAREs is conserved in amphioxus and vertebrate Hox clusters. Our findings demonstrate that conserved RAREs mediate RA-dependent regulation of Hox genes in amphioxus and vertebrates, and in vertebrates this drives expression of Hox genes in both neural crest and neural tube. This suggests that Hox expression in vertebrate neural crest cells has evolved via the co-option of a pre-existing regulatory pathway that primitively regulated neural tube (and possibly epidermal) Hox expression.     

Denervation causes changes in electrophysiological properties in rat phrenic motoneurons

Thirty-nine male adult rats were divided into a control group and a denervation group that had been subjected to phrenicotomy 4 weeks earlier. Electrophysiological membrane properties (input resistance and rheobase) of phrenic motoneurons were measured from intracellular recordings made with glass microelectrodes. Under anesthetized and artificially ventilated conditions, the recorded motoneurons were divided into recruited (spike discharge) and non-recruited (depolarization only) types. There was a significant inverse relationship between the rheobase and input resistance in the control rats, but not in the denervated rats. In the control rats, the mean value of rheobase in the non-recruited motoneurons was significantly higher than that in the recruited motoneurons. In denervated rats, however, the mean value of rheobase in the recruited motoneurons was identical to that in the non-recruited motoneurons. The results indicated that phrenicotomy induced a de-differentiation of electrophysiological properties of the phrenic motoneurons, and that these changes might be restricted to the motoneurons innervating fast-twitch, low fatigue resistance muscle fibers.     

Modifying effects of 1'-acetoxychavicol acetate (ACA) and the novel synthetic retinoids Re-80, Am-580 and Am-55P in a two-stage carcinogenesis model in female rats

Effects of dietary administration of 1'-acetoxychavicol acetate (ACA) and the novel synthetic retinoids 4-[1-hydroxy-3-oxo-3-(5,6,7,8-tetrahydro-3-hydroxy-5,5,8,8-tetramethyl-2-naphthalenyl)-1-propenyl]benzoic acid (Re-80); 4-[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)carboxamido]benzoic acid (Am-580); and 6-[(3,5-di-tert-butylphenyl) carbamoyl]nicotinic acid (Am-55P) were examined using a two-stage rat carcinogenesis model. A total of 190 female SD rats was treated sequentially with 1,2-dimethylhydrazine (DMH, s.c.); 7,12-dimethylbenz(a)anthracene (DMBA, i.g.); and 2,2'-dihydroxy-di-n-propylnitrosamine (DHPN, in the drinking water) during the first three weeks (DDD-initiation), and an additional 60 rats received the vehicle alone (non-initiation). One week after the completion of the initiation period, they were divided into nine groups and administrated Re-80 (at dose levels of 1.0 or 0.4 ppm), Am-580 (20 or 4 ppm), Am-55P (20 ppm), ACA (100 ppm), all-trans-retinoic acid (10 or 2 ppm) or no supplement in the diet for 33 weeks, until survivors were euthanatized at week 37 weeks. After DDD-initiation, all-trans-retinoic acid at the high dose delayed the development of mammary tumors. The multiplicity of colon tumors in the group fed Am-55P and the incidences of nephroblastomas with ACA or Am-580 were decreased as compared with the control values, but the other chemicals had no modifying effects on tumor development in any organs. Thus, among ACA and the novel synthetic retinoids tested, only Am-55P showed a weak inhibitory effect on a neoplasm of general interest under the present experimental conditions.