1.Electromyogram patterns during ankle joint movements at various angular velocities in the triceps surae muscles.
HIROYUKI TAMAKI ; KOJI KITADA ; HIROSHI KURATA
Japanese Journal of Physical Fitness and Sports Medicine 1993;42(3):292-300
Surface electromyograms (EMGs) were recorded from the triceps surae muscles in order to examine muscle activities during concentric and eccentric ankle joint movements at various angular velocities under constant load (5 and 10%MVC) . The results were summarized as follows ;
1) At slow angular velocity (6 deg/s) of ankle joint movement, EMG amplitude tended to increase at a larger ankle joint angle in the gastrocnemius muscle, and at a smaller angle in the soleus muscle.
2) Following an increase in angular velocities (6→30→60 deg/s), peak values of integrated EMGs were significantly increased (7-15%) in the medial gastrocnemius muscle. However, these peak values were significantly decreased in the soleus muscle (22-49%) . These results suggest selective recruitment of motor units depending on angular velocity.
3) Ankle joint angle at the peak integrated EMGs was significantly increased following an increase in angular velocity (6→30→60 deg/s) in the soleus muscle. This suggests that the angle at the recruitment of motor units may be dependent on angular velocity in the soleus muscle.
2.Changes in activity in triceps surae muscles during prolonged isometric contractions.
HIROYUKI TAMAKI ; KOJI KITADA ; HIROSHI KURATA
Japanese Journal of Physical Fitness and Sports Medicine 1995;44(4):457-464
In order to examine muscle activities, surface electromyo-grams (EMGs) were recorded from the triceps surae muscles (lateral gastrocnemius: LG, medial gastrocnemius: MG, soleus: SOL) during prolonged isometric contractions at 20°of ankle joint angle under constant load (10% MVC) . The results were summarized as follows;
1) EMG recordings were obtained which showed complementary activity in each muscle in the time course. Changes in activity was found between whole muscles in the synergist of triceps surae muscles.
2) Muscle activity most frequently took the form of MG+SOL, followed by MG acting alone and SOL acting alone. Ta/Ts value (the ratio of total activity period and total silent period on EMG activity) showed 4.0 in MG and SOL. In contrast, it showed 0.3 in the LG.
3) In the latter half of all exercise times, frequent changes in activity were shown, and Ta/Ts value increased in the gastrocnemius muscle and decreased in the soleus muscle. These results indicate that frequent changes in activity in the latter half were caused by the reduc tion in Ts in the gastrocnemius muscle, and the reduction in Ta in the soleus muscle.
4) Mean integrated EMGs increased significantly in the middle and latter phases in each burst activity, but those in the latter phase did not increase compared to those in the middle phase. These results suggest that the rotation of activity between muscles may have occured before the remarkable increase of EMG activity with fatigue.
3.Time course of twitch potentiation after tetanic nerve and direct stimulations in the thumb adduction in man.
KOJI KITADA ; HIROYUKI TAMAKI ; HIROSHI KURATA
Japanese Journal of Physical Fitness and Sports Medicine 1996;45(1):227-236
Effects of various tetanic stimulation frequencies (50 Hz, 100 Hz and 200 Hz) on the time course of twitch potentiation were examined in the adduction of human pollicis. Isometric twitch tension curve and surface electromyogram were recorded immediately after (1 sec) the 10 sec-tetanus and at intervals of lOsec (up to 300sec) . The stimulating methods were by nerve and direct stimulations in order to examine the role of nerve on the post-tetanic potentiation. The results were summarized as follows :
1) The greatest potentiation was observed immediately after the tetanus. The potentiation decreased rapidly in the period of 60 sec after the tetanus. Then, the potentiation continued to decrease at the low frequency (50 Hz) ; however, it tended to level off at the high frequencies (100 Hz and 200 Hz) .
2) The time course of twitch potentiation by the nerve stimulation was larger than that by the direct stimulation. This result suggests that nerve has a factor which enhances potentiation. The duration of the potentiation varied according to the stimulation frequencies by the nerve stimulation. It seems that this phenomenon was strongly influenced by the nerve.
3) The degree of increase in twitch tension tended to depend greatly on the peak rate of force development. This result suggests that the increase in twitch tension was closely related to the intensity of the active state.
4) Time course of time to peak tension relatively corresponded to the half relaxation time. It seems possible for the duration of the active state to be related to calcium uptake at the sarcoplasmic reticulum.
5) The coupling efficiency by the direct stimulation tended to be smaller than that by the nerve stimulation after 10 sec. This result suggests that the stimulating nerve possesses a factor which prolongs the period of potentiation.
4.Preoperative lymphocyte-to-C-reactive protein ratio predicts hepatocellular carcinoma recurrence after surgery
Masashi UTSUMI ; Masaru INAGAKI ; Koji KITADA ; Naoyuki TOKUNAGA ; Midori KONDO ; Yuya SAKURAI ; Kosuke YUNOKI ; Ryosuke HAMANO ; Hideaki MIYASOU ; Yousuke TSUNEMITSU ; Shinya OTSUKA
Annals of Surgical Treatment and Research 2022;103(2):72-80
Purpose:
This study was performed to determine the prognostic value of lymphocyte-to-CRP ratio after curative resection for hepatocellular carcinoma.
Methods:
Between July 2010 and October 2021, 173 consecutive patients (144 male, 29 female) who underwent surgical resection for pathologically confirmed hepatocellular carcinoma were included in this retrospective study. Cox regression analysis was used to evaluate the relationship between clinicopathological characteristics and recurrence-free survival (RFS) and overall survival (OS). A P-value of <0.05 was considered statistically significant.
Results:
The patients (mean age, 71 years) were stratified into high (≥9,500, n = 108) and low (<9,500, n = 65) lymphocyteto-CRP ratio groups. The low lymphocyte-to-CRP ratio group had significantly worse RFS and OS. Low lymphocyte-toCRP ratio (hazard ratio [HR], 1.865; 95% confidence interval [CI], 1.176–2.960; P = 0.008), multiple tumors (HR, 3.333; 95% CI, 2.042–5.343; P < 0.001), and microvascular invasion (HR, 1.934; 95% CI, 1.178–3.184; P = 0.009) were independently associated with RFS, whereas low albumin-to-globulin ratio (HR, 2.270; 95% CI, 1.074–4.868; P = 0.032), α-FP of ≥25 ng/mL (HR, 2.187; 95% CI, 1.115–4.259; P = 0.023), and poor tumor differentiation (HR, 2.781; 95% CI, 1.041–6.692; P = 0.042) were independently associated with OS. Lymphocyte-to-CRP ratio had a higher area under the curve (0.635) than other inflammation-based markers (0.51–0.63).
Conclusion
Lymphocyte-to-CRP ratio is superior to other inflammation-based markers as a predictor of RFS in patients with surgically resected hepatocellular carcinoma.