As one approach to exploring whether the mitochondrial DNA 5178 adenine/cytosine (mt5178 A/C) polymorphism is associated with atherosclerosis, we genotyped 461 healthy Japanese individuals and studied the relationship of mt5178 A/C genotypes to serum lipid levels. Blood specimens were obtained after at least a 12-h fasting period from the subjects. The mt5178 A/C was genotyped by the polymerase chain reaction/restriction fragment length polymorphism method. The relative frequency of mt5178 A was 41.6% (192/461) and of mt5178 C was 58.4% (269/461). After adjustments for age and body mass index, the high-density lipoprotein cholesterol concentration in males carrying mt5178 A was significantly higher than that in males carrying mt5178 C ( P=0.026). The tryglyceride (TG) concentration in females carrying mt5178 A was significantly lower than that in females carrying mt5178 C ( P=0.012). This difference in the TG level between the two genotypes was more evident in postmenopausal females than in premenopausal females. Mt5178 A seems to have an antiatherogenic effect. This is the first genetic epidemiological report on the association of mt5178 A/C polymorphism with serum lipid levels in the Japanese population.

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ABSTRACT. The normal concentrations of salivary secretory IgA (sIgA) were examined, and the response of sIgA to acute stress was evaluated in dogs. Ten clinically healthy beagle dogs familiarized with the method of saliva sampling were used. During the non-stress period, saliva samples were collected between 0800 hr and 1700 hr at 1-hr intervals for 7 consecutive days and analyzed for sIgA concentration. After a 1-day control period, a noise stressor was presented for 15 min between 0845 hr and 0900 hr on 2 consecutive days. Saliva was collected at pre-stress, immediately after, 30 min after and 60 min after the stress. The average sIgA concentration over the 2-day period was compared with the control value. Environmental stimuli were restricted. During the non-stress period, significant variations were observed during the diurnal pattern, in which sIgA increased in the morning and then decreased; and the day-to-day variations were significant except at 0800 hr and 0900 hr. During the stress experiments, the sIgA concentration decreased significantly, immediately after and 30 min after the noise stress, and then increased to the same level as the control value by 60 min after the stress. When estimating the effectiveness of salivary sIgA as a marker of stress in dogs, the appropriate time for saliva sampling appears to be in the morning. Salivary sIgA was deemed potentially useful as a marker of stress in dogs.

Noncovalent weak interactions play important roles in biological systems. In particular, such interactions in the second coordination shell of metal ions in proteins may modulate the structure and reactivity of the metal ion site in functionally significant ways. Recently, pi-pi interactions between metal ion coordinated histidine imidazoles and aromatic amino acids have been recognized as potentially important contributors to the properties of metal ion sites. In this paper we demonstrate that in pseudoazurin (a blue copper protein) the pi-pi interaction between a coordinated histidine imidazole ring and the side chains of aromatic amino acids in the second coordination sphere, significantly influences the properties of the blue copper site. Electronic absorption and electron paramagnetic resonance spectra indicate that the blue copper electronic structure is perturbed, as is the redox potential, by the introduction of a second coordination shell pi-pi interaction. We suggest that the pi-pi interaction with the metal ion coordinated histidine imidazole ring modulates the electron delocalization in the active site, and that such interactions may be functionally important in refining the reactivity of blue copper sites.

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