Magnetic resonance imaging findings related to sacroiliac joint pain in high-performance athletes.

BACKGROUND: Sacroiliac joint (SIJ) dysfunction in athletes affects competitiveness. However, the pathology and imaging features have not been clarified. OBJECTIVE: To clarify the association between SIJ pain and MRI findings in high-performance athletes. METHODS: Fifty-two Japanese high-performance athletes with or without SIJ pain were recruited. MRI short tau inversion recovery (STIR) semi-coronal and semi-axial images of their SIJs were taken. The relationships between high-signal changes in MRI-STIR and SIJ pain and pain duration were investigated. Six athletes with continuous SIJ pain were prospectively followed. RESULTS: The proportion of athletes with high-signal changes in the SIJ was significantly higher among athletes with SIJ pain for one month or more (76.9%, 10/13) than among athletes with SIJ pain for less than one month (18.2%, 2/11) and among athletes without SIJ pain (28.6%, 8/28). High-signal changes on painful SIJs were most often present in the sacrum. In three of the six athletes who were prospectively followed, the high-signal area and intensity on MRI both diminished as their symptoms improved. CONCLUSIONS: High-signal changes of the SIJ on MRI-STIR images in high-performance athletes may reflect their SIJ pain.

Preexercise High-Fat Meal Following Carbohydrate Loading Attenuates Glycogen Utilization During Endurance Exercise in Male Recreational Runners.

ABSTRACT: Iwayama, K, Tanabe, Y, Yajima, K, Tanji, F, Onishi, T, and Takahashi, H. Preexercise high-fat meal following carbohydrate loading attenuates glycogen utilization during endurance exercise in male recreational runners. J Strength Cond Res 37(3): 661-668, 2023-This study aimed to investigate whether one preexercise high-fat meal can increase glycogen conservation during endurance exercise, as compared with one preexercise high-carbohydrate meal. Ten young male recreational runners (22.0 ± 0.6 years; 171.3 ± 0.9 cm; 58.3 ± 1.9 kg; maximal oxygen uptake [V̇ o2 max], 62.0 ± 1.6 ml·kg -1 ·min -1 ) completed 2 exercise trials after high-carbohydrate loading: eating a high-carbohydrate (CHO; 7% protein, 13% fat, 80% carbohydrate) meal or eating a high-fat (FAT; 7% protein, 42% fat, 52% carbohydrate) meal 3.5 hours before exercise. The order of the 2 trials was randomized, and the interval between trials was at least 1 week. The experimental exercise consisted of running on a treadmill for 60 minutes at 95% of each subject's lactate threshold. Muscle and liver glycogen content were assessed using noninvasive carbon magnetic resonance spectroscopy before the experimental meal as well as before and after exercise; respiratory gases were measured continuously during exercise. The respiratory exchange ratio during exercise was statistically lower in the FAT trial than in the CHO trial ( p < 0.01). In addition, muscle ( p < 0.05) and liver ( p < 0.05) glycogen utilization during exercise was less in the FAT trial than in the CHO trial. Therefore, one high-fat meal following carbohydrate loading reduced muscle and liver glycogen use during the 60-minute exercise. These results suggest that this dietary approach may be applied as a strategy to optimize energy utilization during endurance exercise.

Diurnal variation in the glycogen content of the human liver using 13 C MRS.

Glycogen in tissues functions not only as carbohydrate reserves, but also as molecular sensors capable of activating signaling pathways in response to physical activity. While glycogen in the skeletal muscles is mainly a local energy substrate, glycogen in the liver serves as a glucose reserve to maintain normal blood glucose levels in the body, even during the sleep state. The aim of this study is to compare the diurnal variation of glycogen in the muscle and liver of human subjects under normal conditions. The glycogen content was measured in the muscle and liver of 10 young, healthy, male volunteers using 13 C MRS, a non-invasive technique. The subjects remained sedentary, and glycogen concentration was measured six times daily. Experimental meals were provided to achieve individual energy balance, estimated according to the energy requirement guideline for patients from Japan. The largest variation in muscle glycogen compared with 1 h after supper (20:00 on Day 1) was 3.1 ± 8.2 mmol/L (16:00 on Day 2). In the liver, however, the glycogen content decreased by 80.6 ± 40.4 mmol/L through the overnight fasting period (07:00 on Day 2). This study demonstrated that the glycogen content in the liver was significantly lower in the morning, while the glycogen content in the calf muscles underwent minimal diurnal variation. The overnight fast is a characteristic daily condition, in which liver glycogen content is low, whereas muscle glycogen content is relatively unaffected.

Improvement of Alveolar Hemorrhaging in an Elderly and Renally Impaired Patient with Relapsing Anti-neutrophil Cytoplasmic Autoantibody-associated Vasculitis by Single Infusion of Rituximab.

Rituximab (RTX) has become a therapeutic option for inducing remission of anti-neutrophil cytoplasmic autoantibody-associated vasculitis (AAV). However, the optimum dosage of RTX to induce remission of AAV and reduce adverse events, such as infection, remains unclear. We herein report an elderly and renally impaired patient with alveolar hemorrhaging due to refractory AAV who was successfully treated with single infusion of RTX. Single infusion of RTX may be a therapeutic option in refractory AAV patients who are vulnerable to infections.

Ice slurry ingestion reduces human brain temperature measured using non-invasive magnetic resonance spectroscopy.

We previously reported that ice slurry ingestion reduced forehead skin temperature, thereby potentially reducing brain temperature (Tbrain). Therefore, in the current study, we investigated the effect of ice slurry ingestion on Tbrain using proton magnetic resonance spectroscopy, which is a robust, non-invasive method. Eight male participants ingested 7.5 g/kg of either a thermoneutral drink (37 °C; CON) or ice slurry (-1 °C; ICE) for about 5 min following a 15-min baseline period. Then, participants remained at rest for 30 min. As physiological indices, Tbrain, rectal temperature (Tre), mean skin temperature, nude body mass, and urine specific gravity were measured. Subjective thermal sensation (TS) and thermal comfort (TC) were measured before and after the experiment. Tbrain and Tre significantly reduced after ingestion of ICE compared with after ingestion of CON, and there was a significant correlation between Tbrain and Tre. The other physiological indices were not significantly different between beverage conditions. TS and TC were significantly lower with ICE than with CON (p < 0.05). These results indicate that ice slurry ingestion can cool the brain, as well as the body's core.

Neutron spectral fluence measurements using a Bonner sphere spectrometer in the development of the iBNCT accelerator-based neutron source.

The neutron spectral fluence of an accelerator-based neutron source facility for boron neutron capture therapy (BNCT) based on a proton linac and a beryllium target was evaluated by the unfolding method using a Bonner sphere spectrometer (BSS). A 3He-proportional-counter-based BSS was used with weak beam during the development of the facility. The measured epithermal neutron spectra were consistent with calculations. The epithermal neutron intensity at the beam port was estimated and the results gave a numerical target for the enhancement of the proton beam intensity and will be used as reference data for measurements performed after the completion of the facility.

Establishment and characterization of BHD-F59RSVT, an immortalized cell line derived from a renal cell carcinoma in a patient with Birt-Hogg-Dubé syndrome.

Hereditary renal cell carcinomas (RCCs) are life-threatening disorders not only for the patients but also for their relatives. Birt-Hogg-Dubé syndrome (BHD) is an autosomal dominant disorder caused by germline mutations in the folliculin gene (FLCN). The protein product, FLCN, functions as a tumor suppressor, and the affected patients have high risks of developing multiple RCCs. The carcinogenic mechanisms stemming from FLCN dysfunction have been investigated using rodent models and human RCC tissues. However, very limited information has been available about in vitro signaling of human renal cells with genetically mutant FLCN. Herein, we established a new cell line, BHD-F59RSVT, from a BHD patient's chromophobe RCC by transfecting SV40 large T antigen. We investigated FLCN mutations, chromosome profiles, and cytopathologic characteristics of the cell line. BHD-F59RSVT reflected the patient's FLCN germline mutation, a 3-nt deletion in exon 13 (c.1528_1530delGAG). Neither somatic mutation nor loss of heterozygosity of FLCN was detectable. Chromosome 17p11.2 of the FLCN proximal region demonstrated a trimodal pattern. Genome-wide chromosomal analysis revealed a loss of chromosome 16 and mosaic segmental gains in chromosome 7. BHD-F59RSVT cells were positive when immunostained for cytokeratin 7, supporting their origin from distal convoluted tubules. Western blotting analysis demonstrated severely suppressed FLCN expression at the protein level. The collective findings indicate that the established cell line will be suitable for functional analysis of the typical phenotype of BHD-associated RCC with suppressed FLCN expression.