Cleavage of Alzheimer's amyloid precursor protein (APP) by secretases occurs after O-glycosylation of APP in the protein secretory pathway. Identification of intracellular compartments in which APP cleavage occurs without using toxic agents that interfere with protein metabolism

beta-Amyloid peptide (Abeta) is a principal component of parenchymal amyloid deposits in Alzheimer's disease. Abeta is derived from amyloid precursor protein (APP) by proteolytic cleavage. APP is subject to N- and O-glycosylation and potential tyrosine sulfation, following protein synthesis, and is then thought to be cleaved in an intracellular secretory pathway after or during these post-translational modifications. Studies utilizing agents that affect a series of steps in the protein secretory pathway have identified the possible intracellular sites of APP cleavage and Abeta generation within the protein secretory pathway. In the present study, using cells with normal protein metabolism, but expressing mutant APP with defective O-glycosylation, we demonstrated that the majority of APP cleavage by alpha-, beta-, and gamma-secretases occurs after O-glycosylation. Cells expressing the mutant APP noticeably decreased the generation of the intracellular APP carboxyl-terminal fragment (alphaAPPCOOH), a product of alpha-secretase, and both Abeta40 and Abeta42 in medium, a product of beta- and gamma-secretases. Furthermore, we found that the cells accumulate the mutant APP in intracellular reticular compartments such as the endoplasmic reticulum. Agents that could ambiguously affect the function of specific intracellular organelles and that may be toxic were not used. The present results indicate that APP is cleaved by alpha-, beta-, and gamma-secretases in step(s) during the transport of APP through Golgi complex, where O-glycosylation occurs, or in compartments subsequent to trans-Golgi of the APP secretory pathway.     

New sensorless control for brushless DC motors using disturbanceobservers and adaptive velocity estimations

A brushless DC motor has been represented by a nonlinear equation. Therefore, it has been difficult to apply linear control theory to brushless DC motor systems. In this paper, to apply the linear control theory to brushless DC motor systems, the authors propose considering the nonlinear term of the equation as a disturbance and to realize a sensorless control of the brushless DC motor using both the disturbance observer and the adaptive velocity estimation. With proper pole locations of the disturbance observer, stability of the position estimation is guaranteed, and stability of the adaptive velocity estimation is also guaranteed by Popov's hyperstability theory. The experimental results show that the proposed method is very useful     

Potential role of streptozotocin in enhancing ossification of the posterior longitudinal ligament of the cervical spine in the hereditary spinal hyperostotic mouse (twy/twy)

The differential diagnosis of ascites often leads to confusion and an inability to exclude its multitude of causes in many patients. In this review, we outline the clinical features and laboratory investigations that usually elucidate the cause of ascites for the clinician in a simple and logical manner. Roughly 80-85% of cases of ascites are related to underlying chronic liver disease, but cardiac failure, tuberculosis, malignancy-related ascites and other less common causes should always be considered. Careful evaluation of the patient, including a clinical history, physical examination and diagnostic paracentesis should routinely be performed to determine the cause of ascites. Fluid should be sent for cell count and albumin along with simultaneous determination of serum albumin to determine the serum: ascites albumin gradient. This gradient allows classification of the cause of ascites into portal hypertension-related and nonrelated with a diagnostic accuracy of > or = 97%. The causes of ascites are individually discussed in relationship to their clinical features and to the laboratory investigations that are relevant in each situation.     

5-formylcytidine (f5C) found at the wobble position of the anticodon of squid mitochondrial tRNA(Met)CAU

In squid (Loligo breekeri) mitochondria, AUA codons are translated as methionine instead of the universal isoleucine. Here, we present the nucleotide sequence of squid mitochondrial tRNA(Met)CAU. This tRNA(Met)CAU has 5-formylcytidine (f5C) at the wobble position of the anticodon, though it is partially modified. This result indicates the common feature with bovine and nematoda mitochondrial systems in that f5C at the wobble position of the anticodon is very likely involved in translation of AUA codons as methionine in squid mitochondria.     

Development of a large sonochemical reactor at a high frequency

The large sonochemical reactor was developed by using 12 PZT transducers. The frequency was 500 kHz and the total effective electric power applied to transducers was 620 W. The sample and volume were aqueous solution of potassium iodide and 112 dm³, respectively. The ultrasonic power dissipated into solutions was measured by a calorimetric method.

The energy conversion efficiency from electricity to ultrasound was 70%. When the liquid height was from 400 to 435 mm, the production rate has a maximum value. The production rate increased with increasing ultrasonic power. In the case of high ultrasonic power, the production rate for transducers located at the side wall was higher than that at the bottom wall. The sonochemical efficiency for a large sonochemical reactor operated at 500 kHz was close in value to those for laboratory scale reactors at 500 kHz.     

In situ monitoring of microfracture during plasma spray coating by laser AE technique

Atmosphere plasma spray coating materials include many pores and lamellar boundaries formed by flattened particles during spraying process although high reliability are required in ceramic coatings for turbines. These boundaries become an origin of the microcracks and following crack growth. As it is known that spraying parameters strongly affect the microstructure and strength of coating, it is expected to establish in situ monitoring technique for coating process. However, there is a limit to apply the existing non-destructive evaluation techniques to real-time monitoring at elevated temperature. We have investigated a non-contact measuring system to detect acoustic emission (AE) signals due to microfractures using a laser interferometer, and applied this technique for understanding microfracture process of ceramic coating at elevated temperature. In this paper, we evaluated the effect of several spraying parameters on the initiation and growth process of microcrack by detecting AE signals during coating process using a non-contact laser AE technique.     

Centrifugal Modeling of Seismic Behavior of Large-Diameter Pipe in Liquefiable Soil

This study focused on the behavior of a large-diameter burial pipe with special reference to its stability against flotation subject to soil liquefaction. Centrifugal modeling technique was used where the results are presented for a total of eight shaking table tests conducted on the burial pipe in a laminar box under 30g gravitational field. The ground was prepared with Nevada sand at a relative density of 38% and shaken with a sinusoidal wave at an amplitude of 0.5g. The use of a viscous fluid in a saturated soil deposit satisfied the time scaling relationships of both dynamic and dissipation phenomena. The centrifugal modeling technique simulated flotation of pipeline as the soil liquefied. A technique that used gravels and geosynthetic material was used to mitigate flotation. The response of the soil deposit, in terms of acceleration and excess pore pressure, was investigated. The uplifting of the pipe, earth pressure response and ground surface deformation were also presented. Based on the test results, a design procedure was proposed for the burial pipe in resisting flotation due to soil liquefaction. The deadweight and stiffness of the gravel unit, which was confined by geosynthetic, were important items in design.     

Effects of surfactants on glucosyltransferase production and in vitro sucrose-dependent colonization by Streptococcus mutans

OBJECTIVE: To study the distribution of myocardial structural elements in a univentricular experimental model (Halobatrachus didactylus) and the changes induced by acute exposure to a sublethal concentrations of cadmium. DESIGN: 15 specimens of H. didactylus (marine teleost) were divided in three groups: CTRL: the control group, the fish were injected with a saline solution; 24 H: 1 mg/kg of cadmium chloride was injected and fish were sacrificed after 1 day post injection; 7 D: fish where subjected to the same cadmium concentration and sacrificed after 7 days post injection. INTERVENTIONS: Histological sections (5 microns) of ventricle were coloured by PicroSirius method and used to determine the fraction area occupied by the several myocardium structural elements, using specific software Optimas Bioscan 5.2. MEASUREMENTS AND RESULTS: The different structural elements of H. didactylus myocardium displayed in different ways and its distribution along the ventricular wall remained unchanged on exposure to cadmium. The structural elements of H. didactylus myocardium showed a characteristic pattern: collagen type I revealed a heterogeneous distribution, with fractional area values greater in epicardial and endocardial layers; collagen type III, has a homogeneous distribution with the myocardial wall thickness with lesser fractional area values than collagen I; cardiac muscle tissue showed a tendency to occupy a greater fractional area in the epicardial-endocardial region. Cadmium toxicity resulted in an increase in the fractional area occupied by muscle tissue to the detriment of the area occupied by the intertrabecular spaces (lacunae), with no alterations in the other structural components. CONCLUSIONS: On our H. didactylus fish model, cadmium may have induced a myocardial edema which resulted in an increase in the fractional area occupied by muscle tissue, with no alterations in other structural components of the myocardium or in the relative ventricular mass.