Estimation of the Lymph Flow Through Thoracic Duct in Human Subjects Using the Urine Osmolarity: Applicable for Evaluating the Effectiveness of Manual Lymph Drainage.

Currently, there are many methods to evaluate the effectiveness of manual lymph drainage in the treatment of lymphedema, that is, limb volume measurement, bio-electrical impedance measurement, computer tomography, and ultrasound imaging. However, it is difficult for these methods to accurately address the lymph flow generated by manual lymph drainage. Therefore, we aimed at developing a concise and accurate method to measure the lymph flow through the thoracic duct in human subjects, which is applicable for evaluating the effectiveness of manual lymph drainage. In the present mini-review, we demonstrate the developed method in detail and its scientific evidence for the effectiveness obtained with animal and human clinical experiments. In rat in vivo experiments, intragastric administration of distilled water significantly increased mesenteric flow, which was transported via the cisterna chyli and then the thoracic duct. The manual massage on the cisterna chyli in the anesthetized rabbit significantly accelerated the lymph flow through the thoracic duct, resulting in marked hemodilution. Abdominal respiration in the supine position in human subjects produced similar hemodilution, with a marked decrease in the concentration of vasopressin in the blood. On this basis, we developed a new method to accurately measure the lymph flow through the thoracic duct by using changes in the concentration of vasopressin in the blood. In addition, with changes in urine osmolarity depending on the concentration of vasopressin in the blood, we developed a more concise and noninvasive method for evaluating the lymph flow through the thoracic duct in human subjects. These methods may be applicable for evaluating the effectiveness for the manual lymph drainage in the patients with lymphedema.

Lymph Drainage from the Chylocyst-Induced Hemodilution in an In Vivo Rabbit Study.

To confirm our previous study that abdominal respiration has induced hemodilution in human subjects, we performed in-vivo experiments involving anesthetized rabbits. Fifteen 6- to 7-month-old male Japanese white rabbits were used in the animal experiments. Anesthesia was maintained with 2.5%-3.0% isoflurane under N2O + 100% O2 inhalation. Ventilation was maintained at 40 mL/breath for 20 breaths/min. Physiological saline solution was administered at rated 18 mL/h during the experiments. First, we attempted to evaluate lymph flow through the thoracic duct using Sonazoid-based contrast-enhanced ultrasound (CEUS)-guided method and then investigated the effects of manual lymph drainage of the chylocyst on the numbers of red blood cells (RBC), hematocrit (Ht) levels, and the blood concentrations of total protein (TP) and hemoglobin (Hb). In this study, we established surgical methods for identifying the left venous angle and chylocyst using Evans blue dye in anesthetized rabbits. We also confirmed that a Sonazoid-based CEUS-guided method was the most useful technique for producing real-time images of lymph flow through the thoracic duct in anesthetized rabbits. In addition, in present experiments involving anesthetized rabbits, we confirmed that manually massaging the chylocyst produced significant hemodilution. Thus, the procedure produced significant reductions of TP, RBC, Hb, and Ht level in the rabbits.

Effects of exercise intensity, posture, pressure on the back and ambient temperature on palmar sweating responses due to handgrip exercises in humans.

We have, by using newly developed ratemeters, attempted to examine the effects of exercise intensity, posture, pressure on the skin of the back, and ambient hyperthermic conditions (approximately 30 degrees C) on the 5-s handgrip exercise-mediated responses of active palmar sweating in humans. Thirty-five right-handed male (n=5) and female (n=30) volunteer students (20.2+/-1.3 years old) participated in the present study. Oral explanation of only the isometric handgrip exercise (IHG) caused a rapid and oscillatory response (pre-operational) of active palmar sweating in almost all subjects (10 of 14 subjects). Performing the IHG for 5-s caused a significant increase in active sweating rate (operation-mediated response) in both ipsi- and contra-lateral palmar surfaces of the thumbs of all subjects. The operation-mediated responses of active palmar sweating to the IHG were reproducible, resulting in no habituation. The increase of operation-mediated responses to the IHG was dependent upon exercise intensity (100-25% maximal voluntary contractions). The IHG-mediated ipsi- and contra-lateral responses of active palmar sweating were significantly decreased by changing the body posture from a seated to a supine position or by pressing the skin of the back. Ambient hyperthermic conditions (approximately 30 degrees C) for 60 min also resulted in a significant decrease in the back-pressure-dependent reduction of the operation-mediated responses of active palmar sweating to the IHG. In conclusion, in order to optimize the precision and reproducibility of clinical tests involving palmar sweating responses, it is important that subjects maintain a constant handgrip force and posture and that ambient temperature be kept under normothermic conditions.