A study was designed to examine the effects of exercise intensity on renal clearance parameters. Five healthy male subjects underwent exercise tests on an bicycle ergometer at 4 different work loads for 15 min. The indicators of exercise intensity employed were the percentage of maximal oxygen uptake (%VO₂max), heart rate (HR) and blood lactate level (La) . As parameters of renal clearance, para-aminohippurate clearance (CPAH), thiosulfate clearance (C_thio) and creatinine clearance (C_cr) were measured by the continuous infusion technique during the exercise.
1) The renal clearance parameters during exercise decreased linearly as the exercise intensity increased. The percentage of maximal oxygen uptake at the onset of the decreases in %C_PAH, %C_chiu and %C_cr were 36, 45 and 47%VO₂max, respectively.
2) Among the indicators of exercise intensity, the decrease in La showed the closest correlation with renal clearance during the exercise.
3) The renal plasma flow, which was measured as C_PAH, began to decrease linearly at a significantly lower exercise intensity than the glomerular filtration rate, which was measured as both C_thio and C_cr.
The above results suggest that renal clearance parameters begin to decrease at the threshold as exercise intensity increases.

Methods: We investigated patients who underwent surgical intervention for LL-OVC (L3, L4, and/or L5) with symptomatic foraminal and/or central stenosis from eight spine centers. Only patients with a minimum follow-up duration of 1 year were included. We developed new criteria to grade vertebral collapse severity (grade 1, 0%–25%; grade 2, 25%–50%; grade 3, 50%–75%; and grade 4, 75%–100%). The clinical features and outcomes were compared based on the collapse grade and surgical procedures performed (i.e., decompression alone, posterior lateral fusion [PLF], lateral interbody fusion [LIF], posterior/transforaminal interbody fusion [PLIF/TLIF], or vertebral column resection [VCR]). Results: In this study, 59 patients (average age, 77.4 years) were included. The average follow-up period was 24.6 months. The clinical outcome score (Japanese Orthopaedic Association score) was more favorable in the LIF and PLIF/TLIF groups than in the decompression alone, PLF, and VCR groups. The use of VCR was associated with a high rate of revision surgery (57.1%). No significant difference in clinical outcomes was observed between the collapse grades; however, grade 4 collapse was associated with a high rate of revision surgery (40.0%). Conclusions When treating LL-OVC, appropriate instrumented reconstruction with rigid intervertebral stability is necessary. According to our newly developed criteria, LIF may be a surgical option for any collapse grade. The use of VCR for grade 4 collapse is associated with a high rate of revision.

Objective: The authors retrospectively investigated prognostic factors for severe isolated head trauma in patients evacuated by a physician-staffed helicopter emergency medical service (HEMS) or ground ambulance using data from the Japan Trauma Data Bank (JTDB).Patients and Methods: This study was a retrospective analysis of data housed in the JTDB database. The study period was from January 2004 to May 2019. Subjects were divided into two groups according to the method of transportation: helicopter (i.e., HEMS), which included patients transported by a physician-staffed helicopter; and ambulance, which included patients transported by ground ambulance.Results: A total of 41,358 patients were enrolled in the study, including 2,029 in the helicopter group and 39,329 in the ambulance group. The ratio of males, median head Abbreviated Injury Scale and Injury Severity Scale (ISS) scores were significantly greater in the helicopter group than in the ambulance group, while the average age, median Glasgow Coma Scale, average Revised Trauma Score (RTS), and survival rate were significantly lower in the helicopter group than in the ambulance group. Of the variables that demonstrated statistical significance in the univariate analysis and classification of transportation and included in the multivariate analysis, the following were identified as significant predictors of survival outcomes: younger age, lower ISS, female sex, and greater RTS. HEMS was not a significant predictor of survival.Conclusion: The present study revealed no effect of HEMS transport on the outcomes of patients who experienced severe isolated head trauma compared with ground ambulance transportation. Further prospective studies, including an analysis of the operation time or distance traveled by the HEMS and the functional outcome(s) of patients with severe head injury transported by HEMS, are warranted.