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Aim Short-term exercise training may induce metabolic and performance adaptations before any changes in mitochondrial enzyme potential. However, there has not been a study that has directly assessed changes in mitochondrial oxidative capacity or metabolic control as a consequence of such training in vivo. Therefore, we used 31P-magnetic resonance spectroscopy (31P-MRS) to examine the effect of short-term plantar flexion exercise training on phosphocreatine (PCr) recovery kinetics and the control of respiration rate. Method To this aim, we investigated 12 healthy men, experienced with this exercise modality (TRA), and 7 time-control subjects (TC). Results After 5 days of training, maximum work rate during incremental plantar flexion exercise was significantly improved (P

SUMMARYSurveillance is an important component of influenza control. This report describes the establishment and first results of the Korean Influenza Surveillance Scheme (KISS), an integrated clinical and laboratory surveillance network involving 622 public health centres (PHCs) and private clinics. Sentinel physicians reported cases of influenza-like illness (ILI) weekly and forwarded specimens for virus isolation and characterization. Influenza activity during the opening 2000–2001 season was milder and delayed compared with previous years. The ILI consultation rate corresponded well with the number of influenza virus isolates, both peaking in week 10 of 2001. Influenza A(H3N2) was the dominant isolate. The peak ILI consultation rate was higher in private clinics than in PHCs (5·04 vs 1·79 cases/1000 visits). An evaluation questionnaire generated potential enhancements to the scheme. KISS appears to represent the pattern of influenza activity accurately and will have a valuable role in monitoring and preventing epidemics in Korea.

Magnetic Resonance Imaging (MRI) was used to measure granular-flow in a partially filled, steadily rotating, long, horizontal cylinder. This non-invasive technique can yield statistically averaged two-dimensional concentrations and velocity profiles anywhere in the flow of suitable granular materials. First, rigid body motion of a cylinder fill with granular material was studied to confirm the validity of this method. Then, the density variation of the flowing layer where particles collide and dilate, and the depth of the flowing layer and the flow velocity profile were obtained as a function of the cylinder rotation rate.

Problems associated with techniques currently used to measure the T1 of flowing blood are evaluated and a method to improve the consistency and repeatability of measurements is presented. Similar to some currently used techniques, the pulse sequence employs a nonselective adiabatic inversion pulse followed by a series of ECG-gated gradient echo EPI (echo planar imaging) images to obtain images where the blood (fluid) signal exhibits a T1-dependent inversion recovery signal from which the spin lattice relaxation constant (T1) of the flowing fluid can be measured. The new method combines curve fitting with a measure of the curve null point to acquire more accurate and consistent T1 values. Simulation and experimental results show that this combined fitting-nulling method is more stable and consistent in measuring the T1 of flowing fluid. The feasibility of temperature measurement of a flowing fluid based on the temperature dependence of the T1 of water protons is shown in this paper. ECG gating is used to reduce the effects of cyclic intensity changes for measurement of T1 in pulsatile flowing blood.

The purpose of this study was to assess the role of inflamed synovial volume (ISV) in defining a state of remission in rheumatoid arthritis (RA) with contrast-enhanced, fat-suppression, three-dimensional (3D) gradient-recalled acquisition in the steady state with radiofrequency spoiling (SPGR) magnetic resonance (MR) imaging. Sixteen patients with RA (5 remission and 11 non-remission patients) were enrolled in this study. Contrast-enhanced, fat-suppression, 3D-SPGR MR imaging was performed before (n = 12) and after (n = 16) a mean 17 months of disease-modifying antirheumatic drugs (DMARDs). ISV was calculated by using a segmentation method. Statistical analysis of changes in ISVs and residual ISVs between the remission and the non-remission groups was performed. Intra- and inter-observer reproducibility was tested. Residual ISVs and relative changes in ISVs were 3.23 +/- 1.84 cm(3) and 51.4% (range 47.6-55.2%) in the remission group and 6.26 +/- 2. 03 cm(3)and 31.4% (range -73.5-53.5%) in the non-remission group. Both values were significantly different between the two groups (P0.05 and 0.05, respectively). Volume measurement showed high reproducibility: Intra- and inter-observer mean percentage errors were 5.04, 7.06, and 5.09%, respectively. Residual ISVs and relative changes in ISVs measured by MR imaging may provide objective and quantitative parameters in defining a state of remission in RA after therapy; however, the clinical utility of these measurements remains to be verified. J. Magn. Reson. Imaging 1999;10:202-208.

The object of this study was to correlate the laminae of articular cartilage on magnetic resonance (MR) imaging with histologic layers. T1- and fast spin-echo T2-weighted images of articular cartilage with artificial landmarks were obtained under high gradient echo strength (25 mT/m) conditions and a voxel size of 78 x 156 x 2000 microm. Images were also obtained with a) changed frequency-encoding directions; b) changed readout gradient strength; and c) a varied number of phase-encoding steps. T2 mapping was performed with angular variations. Artificial landmarks allowed accurate comparison between the laminae on MR images and the histologic zones. No alterations of the laminae were noted by changing the frequency gradient direction. Altering readout gradient strengths did not show a difference in the thickness of the laminae, and increasing the phase-encoding steps resulted in a more distinct laminated appearance, ruling out chemical shift, susceptibility, and truncation artifacts. The T2 mapping profile showed an anisotropic angular dependency from the magic angle effect. In conclusion, the laminated appearance of articular cartilage on spin-echo and fast spin-echo MR images correlated with the histologic zones rather than MR artifacts.

NMR imaging was used to study the flow of pairs of density stratified, immiscible fluids in a horizontal, rotating cylinder. Mixtures of oil and water, oil and ethyl alcohol, and air and water were studied in the regime of slow rotation in which stratification was maintained. Two types of NMR experiments were performed. A NMR tagging method was used to visualize the flow fields, and a phase method was used to measure detailed, quantitative two‐dimensional velocities far from the ends of the cylinder. The difference of the spin‐lattice relaxation times of the liquids was exploited to discriminate between the fluids. Both NMR experiments showed that the flows were composed of boundary layers rotating with the cylinder, interfacial currents, and slowly counter‐rotating internal regions.