Positive chronotropic and negative inotropic effects induced by potassium chloride in the isolated canine atrium

The effects of potassium chloride on inotropic and chronotropic activity were investigated in five isolated canine atrium preparations which were suspended in a bath and perfused with arterial blood from the carotid artery of the heparinized support dog. Potassium chloride administered into the cannulated sinus node artery in a dose range of 100 mug-1 mg produced a dose-related negative inotropic and a positive chronotropic effect. These effects were not influenced by treatment with either atropine or propranolol. From these results, it is concluded that potassium had a direct negative effect on atrial contractility and a direct positive effect on atrial rate.     

Quantitative detection system for maize sample containing combined-trait genetically modified maize

Various countries have established regulations that stipulate the labeling of agricultural commodities, feed, and food products that contain or are made from genetically modified (GM) material or that contain adventitious GM material in amounts that exceed certain threshold levels. While regulations in some countries refer to GM material on a weight per weight (w/w) percentage, the currently applied detection methods do not directly measure the w/w percentage of the GM material. Depending on the particular method and the sample matrix it is applied to, the conversion of analytical results to a w/w percentage is challenging or not possible. The first rapid PCR system for GM maize detection on a single kernel basis has been developed. The equipment for the grinding of individual kernels and a silica membrane-based 96-well DNA extraction kit were both significantly revised and optimized for this particular purpose, respectively. We developed a multiplex real-time PCR method for the rapid quantification of GM DNA sequences in the obtained DNA solutions. In addition, a multiplex qualitative PCR detection method allows for the simultaneous detection of different GM maize traits in each kernel and thereby for identification of individual kernels that contain a combination of two or more GM traits. Especially for grain samples that potentially contain combined-trait GM maize kernels, the proposed methods can deliver informative results in a rapid, precise, and reliable manner.     

Microstructures and bond strengths of plasma-sprayed hydroxyapatite coatings on porous titanium substrates

Hydroxyapatite (HA) coating was carried out by plasma spraying on bulk Ti substrates and porous Ti substrates having a Young’s modulus similar to that of human bone. The microstructures and bond strengths of HA coatings were investigated in this study. The HA coatings with thickness of 200–250 μ m were free from cracks at interfaces between the coating and Ti substrates. XRD analysis revealed that the HA powder used for plasma spraying had a highly crystallized apatite structure, while the HA coating contained several phases other than HA. The bond strength between the HA coating and the Ti substrates evaluated by standard bonding test (ASTM C633-01) were strongly affected by the failure behavior of the HA coating. A mechanism to explain the failure is discussed in terms of surface roughness of the plasma-sprayed HA coatings on the bulk and porous Ti substrates.     

Coagulation-fibrinolysis system in poststroke patients receiving antiplatelet medication

BACKGROUND AND PURPOSE: We studied the activities of the coagulation-fibrinolysis system in the chronic stage of poststroke patients and the effect of antiplatelet medication on the system. METHODS: We determined fibrinogen, antithrombin III, thrombin-antithrombin III complex, tissue plasminogen activator antigen, plasminogen activator inhibitor-1, plasmin-alpha 2 plasmin inhibitor complex, and D-dimer in plasma from 153 poststroke patients in the chronic phase (ie, 33 patients not receiving antiplatelet medication, 78 patients receiving 200 mg/d ticlopidine, and 42 patients receiving 40 mg/d aspirin), and compared the results in control subjects and among the treatment groups. RESULTS: The concentrations of fibrinogen, thrombin-antithrombin III complex, antithrombin III, plasmin-alpha 2 plasmin inhibitor complex, and tissue plasminogen activator were slightly but significantly increased in all treatment groups compared with control subjects (P < .01) but did not differ among the treatment groups. The plasminogen activator inhibitor-1 levels were significantly elevated in patients not receiving antiplatelet medication compared with control subjects (P < .01), whereas they were in the normal range and significantly lower in patients receiving ticlopidine or aspirin than in patients not receiving antiplatelet medication (P < .01). The plasminogen activator inhibitor-1 levels were significantly lower in patients whose platelet aggregation was inhibited by antiplatelet medication than in patients with uninhibited platelet aggregability (P < .05). CONCLUSIONS: These findings suggest that coagulation-fibrinolysis markers are mildly increased in poststroke patients in the chronic phase and that antiplatelet medication is effective in reducing the elevated plasminogen activator inhibitor-1 levels.     

Asymptomatic Becker muscular dystrophy: expression of dystrophin and dystrophin-related protein

We report a patient with systemic lupus erythematosus (SLE), who had developed metabolic alkalosis during plasmapheresis. The metabolic alkalosis could be promptly corrected by reducing the amount of citrate load. The development of metabolic alkalosis can be explained by the citrate load during plasmapheresis. Careful monitoring of acid base status is mandatory in patients with limited renal function and the reduction of citrate load may be advisable in plasmapheresis.     

Clinical diagnostic indicators of renal and bone damage in rats intramuscularly injected with depleted uranium

The toxic effects and changes in biochemical markers related to kidney and bone in depleted uranium (DU)-injected rats were examined in order to clarify the relation between clinical biochemical markers and the degree of damage in these organs. Male Wistar rats received a single injection in the femoral muscles of 0.2, 1.0 or 2.0 mg kg(-1) of DU which was dissolved in nitric acid solution adjusted to pH 3.2, for comparison with the group injected with nitric acid solution, and the control group. Urine and faeces were collected periodically over a 24 h period. Thereafter, the rats were killed at 28 d after DU injection. The body weights of the DU-injected groups decreased dose-dependently for the first 3-7 d, and then began to increase. The DU concentrations in the urine and faeces decreased rapidly within 3-7 d after DU injection. Urinary N-acetyl-beta-D-glucosaminidase (NAG)/creatinine peaked at the third day after DU injection, with a high correlation to the injected DU doses. There were high correlations among the injected DU doses, DU concentrations in the kidney and urinary NAG/creatinine values that were obtained at 28 d, respectively. The blood urea nitrogen (BUN) and creatinine in the serum also showed a high correlation with the DU-injected doses. The results indicated that urinary NAG/creatinine, BUN and creatinine in serum were useful indicators to diagnose the renal damage by DU, as well as to estimate the DU intake and concentration in the kidney when the intake is >2 mg kg(-1) DU. The total bone mineral density of the proximal metaphysis of the tibia decreased in the 2 mg kg(-1) DU group. In addition, alterations of the trabecular bone structure by inhibiting bone formation and promoting bone resorption were observed by bone histomorphometery. The bone biochemical markers osteocalcin, tartrate-resistance acid phosphatase, pyridinoline and rat-parathyroid hormone increased in all the DU injected groups, indicating that these markers were useful as sensitive indicators for diagnosing bone damage, even if the DU dose injected is low.     

Anti-aging effects of caloric restriction: Involvement of neuroendocrine adaptation by peripheral signaling

Many hormonal signals from peripheral tissues contribute to the regulation of energy homeostasis and food intake. These regulators including leptin, insulin, and ghrelin, modulate the orexigenic and anorexigenic neuropeptide expression in hypothalamic nuclei. The anti-aging effects of caloric restriction have been explained from an evolutional viewpoint of the adaptive response of the neuroendocrine and metabolic response systems to maximize survival during periods of food shortage. In organisms, excess energy is stored in adipose tissues as a triglyceride preparation for such survival situations. Adipose tissue has recently been recognized as an endocrine organ, and leptin, as secreted by adipocyte, seems to be an especially important factor for the adaptive response to fasting and neuroendocrine alterations under caloric restriction. In this review, we discuss the potential involvement of neuroendocrine modulators in longevity and the anti-aging effects of caloric restriction.