Teikyo Heisei University

In patients with diminished muscle mass, serum creatinine (SCr) levels may be misleadingly low, potentially leading to overestimations of kidney function and unexpectedly high blood levels of vancomycin. This study aimed to identify factors contributing to this discrepancy and develop a flowchart for stratifying the risk of excessive vancomycin exposure, measured as an upward deviation in the area under the concentration–time curve (AUC) in patients with low SCr levels.

We analyzed data from patients who received vancomycin and had an SCr value <0.6 mg/dL. The discrepancy between the AUC24–48 h initial dosing and AUC24–48 h TDM was calculated; a ratio (AUC24–48 h TDM/AUC24–48 h initial dosing) higher than 1.2 defined an upward deviation in the AUC. A decision tree model was constructed using classification and regression tree algorithms.

Among the 95 patients (median age [interquartile range], 69 [58, 80] years; 68% female), the upward AUC deviation was 40% (38/95). Three factors (creatinine clearance: 115 ml/min, age: 69 years, and blood urea nitrogen/SCr: 17) were selected for the decision flowchart and included in four subgroups.

We developed a flowchart to identify patients with low SCr levels whose AUC at therapeutic drug monitoring deviated upward by >20% from the predicted AUC.

The reproducibility of immobilization is critical in small animal radiotherapy, especially for the head region. We developed a reusable immobilization method using a thermoplastic mask molded with cylinders that can be universally applied, eliminating the need for individual patient-specific masks. We aimed to compare the effectiveness of this method with two conventional techniques, namely immobilization using a cylinder and patient-specific thermoplastic mask immobilization. Five beagle dogs underwent repeated CT scans for each method, and the positional errors of the anatomical landmarks were measured. In addition to the maxilla, we examined the mandible and lymph nodes in the head and neck region, which have rarely been considered in previous studies. The results demonstrated that the accuracy of the new universal immobilization method was comparable with that of the conventional methods, with no significant differences in the positioning of the bony landmarks. Universal immobilization outperformed cylindrical immobilization for the lymph nodes. However, large errors were observed in the positions of the lymph nodes across all tested head immobilization methods. The universal method required the shortest setup time, emphasizing its efficiency. It also eliminated the need for patient-specific individual masks, making it simple and sustainable. Despite certain limitations, such as the exclusive use of beagle dogs and the single-day anesthesia protocol, the study concluded that the cylindrical thermoplastic mask is a promising method that offers precision and efficiency. This study represents a model investigation rather than a validated clinical approach. Further proof-of-principle investigations are required to validate the clinical utility of this approach.

Resistance training reduces arterial compliance. Although cardiac pulsatile energy is distributed between arterial compliance and arterial wall viscosity, arterial wall viscosity in resistance-trained men remains unclear. Therefore, this study aimed to examine whether resistance-trained men exhibit increased arterial wall viscosity. This cross-sectional study included 28 young men (18-25 years), with 12 resistance-trained men and 16 non-trained sedentary controls. We measured arterial wall viscosity, arterial compliance, carotid and brachial blood pressures, peak oxygen uptake, and left ventricular mass and functions. Resistance-trained men had higher arterial wall viscosity (3064 ± 1208 vs. 1993 ± 831 mmHg·s/mm: p = 0.010) and lower compliance (0.093 ± 0.029 vs. 0.153 ± 0.054 mm²/mmHg: p = 0.003) than controls, with an elevated beta-stiffness index (7.90 ± 2.80 vs. 5.86 ± 1.26 AU: p = 0.015). Intima-media thickness and brachial systolic and diastolic blood pressures, peak oxygen uptake, and stroke volume did not differ between groups, although there were significantly higher carotid systolic blood pressure and pulse pressure in resistance-trained men compared to controls. Resistance-trained men showed concentric left ventricular hypertrophy. The present study indicated that central arterial wall viscosity is higher and arterial compliance is lower in resistance-trained men.