Age-related differences in management of heart disease: a study of cardiac medication use in an older cohort. Pacemaker Selection in the Elderly (PASE) Investigators

Bone mass, bone metabolic markers, and calcium regulation hormones were measured in members of an Antarctic wintering team who stayed at the Japanese Antarctic station, Syowa (latitude: south 69 degrees 00', longitude: east 39 degrees 35') for 1 year. Subjects included 31 healthy Japanese males, aged 24-51 years (mean age 34.5 years) at the beginning of this study, ingesting 488 IU/day of vitamin D and 550.9 mg/day of calcium per person. The long-term coefficient of variation (CV) of the equipment used in the assessments of bone mass was 0.67% in single X-ray absorptiometry (SXA), 0.17% in the speed of sound (SOS) by quantitative ultrasound method (QUS), and 0.63% in broadband ultrasound attenuation (BUA) by QUS. The seasonal changes in the calcaneal bone mineral density (BMD) by SXA were not significant, whereas the SOS measured by QUS decreased during the measurement period (0.55%, p < 0.001), and BUA increased (1.9%, p < 0.01). Bone-specific alkaline phosphatase and osteocalcin levels increased significantly during summer (p < 0.001) and urinary calcium level decreased significantly during winter (p < 0.05). Urinary pyridinoline and deoxypyridinoline levels decreased significantly at the end of winter (p < 0.001). Serum 1,25(OH)2D3 level did not change significantly, whereas serum 25(OH)D3 level decreased significantly during winter (p < 0.001). Serum parathyroid hormone (PTH) level significantly increased at the end of winter (p < 0.01), although both PTH level and 25(OH)D3 level remained within the normal range. We concluded that the 25(OH)D3 level in subjects who stayed in Antarctica for 1 year decreased significantly with the reduction in duration of sunshine, but there were no clear changes in bone mass.     

Dietary amino acids as new and novel agents to enhance allograft survival

Little is known about the long-term effects of fluoride-releasing materials on carious dentine in vivo. The aim was to investigate the 2-year influence of a resin-modified glass ionomer cement (RM-GIC) and amalgam on the bacteriological counts of carious dentine that remained under class I restorations. To enable a split-mouth design, 33 molar pairs in 33 patients (mean age 15.1 years, SD 1.4) were selected, based on clinically and radiographically diagnosed occlusal dentine caries. The enamel of the carious molars was removed, and the carious dentine was sampled under aseptic conditions just beneath the dentinoenamel junction. The molars were alternately restored with RM-GIC or amalgam without further removal of carious dentine. The samples were processed for microbiological determination of total viable counts (TVC), mutans streptococci (MS), and lactobacilli (LB). The molar pairs of 25 patients were reevaluated after 2 years using the same clinical techniques and were permanently restored after complete caries removal. Both materials showed a substantial decrease in numbers of TVC and LB of the carious dentine after the 2-year period. Compared to amalgam, the decrease in the numbers of LB was significantly more pronounced for RM-GIC. No microorganisms were detected in only 11 molars (6 RM-GIC and 5 amalgam) after the 2-year period. Based on this study, we suggest that complete removal of carious dentine is still the best conservative treatment, irrespective of the restorative material used.     

ESR and HPLC-EC analysis of the interaction of hydroxyl radical with DMSO: rapid reduction and quantification of POBN and PBN nitroxides

The low stability of hydroxyl radical (OH.)-derived nitroxides is a limiting factor for direct spin-trapping of OH. in biological systems. The latter experimental difficulty is partly solved with the introduction of dimethyl sulfoxide (DMSO) into the studied systems. Hydroxyl radical oxidizes DMSO to methyl radical, which forms relatively stable nitroxides. The results of the present work provide evidence that in alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN) and alpha-phenyl-N-tert-butylnitrone (PBN) spin-trapping experiments aimed to detect methyl radical in biological systems, the nitroxides formed can be reduced to their ESR-"silent" hydroxylamine derivatives. The nitroxides and their hydroxylamine derivatives were successfully analyzed by HPLC with electrochemical (EC) and UV detection. The lowest limits of UV and EC detection of POBN/CH3 hydroxylamine was evaluated to be in the micro- and nanomolar range, respectively. In parallel ESR and HPLC-EC analysis of the metabolism of menadione by either HepG2 cells or isolated rat hepatocytes in the presence of DMSO, the HPLC-EC method has proven to be more sensitive in detecting the production of methyl radical. The use of the HPLC-EC detection of POBN/CH3 and PBN/CH3 is expected to be advantageous in detection of hydroxyl radical in biological systems in the presence of DMSO.     

Hormonal factors in the development of differences in strength between boys and girls during adolescence: a longitudinal study

The mitochondrial transition pore (MTP) is implicated as a mediator of cell injury and death in many situations. The MTP opens in response to stimuli including reactive oxygen species and inhibition of the electron transport chain. Sporadic Parkinson's disease (PD) is characterized by oxidative stress and specifically involves a defect in complex I of the electron transport chain. To explore the possible involvement of the MTP in PD models, we tested the effects of the complex I inhibitor and apoptosis-inducing toxin N-methyl-4-phenylpyridinium (MPP+) on cyclosporin A (CsA)-sensitive mitochondrial swelling and release of cytochrome c. In the presence of Ca2+ and Pi, MPP+ induced a permeability transition in both liver and brain mitochondria. MPP+ also caused release of cytochrome c from liver mitochondria. Rotenone, a classic non-competitive complex I inhibitor, completely inhibited MPP(+)-induced swelling and release of cytochrome c. The MPP(+)-induced permeability transition was synergistic with nitric oxide and the adenine nucleotide translocator inhibitor atractyloside, and additive with phenyl arsine oxide cross-linking of dithiol residues. MPP(+)-induced pore opening and cytochrome c release were blocked by CsA, the Ca2+ uniporter inhibitor ruthenium red, the hydrophobic disulfide reagent N-ethylmaleimide, butacaine, and the free radical scavenging enzymes catalase and superoxide dismutase. MPP+ neurotoxicity may derive from not only its inhibition of complex I and consequent ATP depletion, but also from its ability to open the MTP and to release mitochondrial factors including Ca2+ and cytochrome c known to be involved in apoptosis.     

Comparison of fixation disparity curve variables measured with the Sheedy Disparometer and the Wesson Fixation Disparity Card

BACKGROUND: Previous studies suggest differences in the fixation disparity curves obtained with the Sheedy Disparometer and the Wesson Fixation Disparity Card, the two most commonly used methods for measuring fixation disparity. In one study the investigators proposed that the differences do not exist for subgroups divided by phoria. The purpose of this paper is to try to clarify this issue by use of two large sets of data. METHODS: Dissociated phorias were measured by the von Graefe method. Fixation disparity curves were plotted using the Disparometer and the Wesson card. RESULTS: Type I fixation disparity curves were most common with the Wesson card. Type II curves were found more often with the Disparometer than with the Wesson card. The x-intercepts were shifted in the base-in (BI) direction with the Wesson card compared to the Disparometer. The y-intercepts were shifted in the exo direction with the Wesson card compared to the Disparometer. The differences were statistically significant regardless of whether the dissociated phoria was exo or eso. The slope of the fixation disparity curve was steeper with the Wesson card than with the Disparometer. The difference was statistically significant for exophores but not for esophores. The differences between results obtained with the two instruments are not consistent from one subject to another as shown by high standard deviations of the differences. CONCLUSIONS: The fixation disparity curves measured with these two instruments are different. Fixation disparity parameters obtained from one of these instruments cannot be used with normative findings from the other.