Intracellular Ca-Mediated Mechanisms for the Pacemaker Depolarization of the Mouse and Guinea Pig Sinus Node Tissue.

Intracellular Ca-mediated mechanisms for pacemaker depolarization were studied in sinus node tissue preparations from mice and guinea pigs. Microelectrode recordings revealed that the sinus node of the mouse, which had a higher beating rate, had a steeper slope of the pacemaker depolarization than that of the guinea pig. BAPTA and ryanodine, agents that interfere with intracellular Ca, significantly decreased the slope of the pacemaker depolarization in both species.

Assessment of between-instrument variations in a HPLC method for serum lipoproteins and its traceability to reference methods for total cholesterol and HDL-cholesterol.

Background: The main purpose of this study was to evaluate the between-instrument variation of the HPLC method for the measurement of total cholesterol (TC), HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C), VLDL-cholesterol (VLDL-C), chylomicron cholesterol (CM-C), LDL size, and HDL size. Furthermore, the accuracy of the HPLC was assessed for the determination of TC and HDL-C, compared with CDC reference methods.

Methods: We used four HPLC instruments with different column-load numbers from 250 to 5000.

The possible role of remnant-like particles as a risk factor for sudden cardiac death.

Postmortem plasma lipid and lipoprotein levels were analyzed in two groups of Japanese subjects who died suddenly and unexpectedly due to cardiac (n = 93) or non-cardiac (n = 26) causes. No individuals in either group had a significant medical or cardiac history. In this study, we measured plasma total cholesterol, triglycerides, VLDL-cholesterol, LDL-cholesterol, HDL-cholesterol, and especially triglyceride-rich lipoprotein remnants.

Genetic divergence and evolutionary relationships of the old and new world emberizidae.

Genetic differentiation and evolutionary relationships were surveyed on 12 species of the Old and seven species of the New World Emberizidae by allozyme electrophoresis of 20 loci. Genetic variability of the Emberizidae is similar to those of the other Passeriformes. The degree of genetic differentiation in the family were large among species of the genus Emberiza of the Old World, and also among genera of the New World Emberizidae.