Haemodynamic changes in human masseter and temporalis muscles induced by different levels of isometric contraction.

This study evaluated the influence of low contraction forces on intramuscular haemodynamics in human masseter and temporalis using near-infrared tissue spectroscopy. This method allowed the intramuscular haemoglobin (Hb) to be assessed dynamically before, during and after a 5, 15, 25 and 100% maximum voluntary contraction (MVC). Twenty volunteers, 10 males and 10 females, without pain or dysfunction in the masticatory system were included in this study. Data were recorded for 30 s before, 30 s during and 5 min after the four sustained contraction tasks. The results showed that all four levels of voluntary contraction produced a clear haemodynamic response (during and after contraction) in both muscles. For analytical purposes, the maximum Hb achieved after 100% MVC was set equal to 1.00. In the masseter the mean peak Hb during the 5, 15, 25 and 100% MVC was 0.49, 0.92, 1.30 and 1.73 while after the contractions it was 0.50, 0.65, 0.78 and 1.00, respectively. In the temporalis the peak Hb during the contractions was 0.23, 0.36, 0.48 and 0.66 and after the contractions 0.32, 0.45, 0.56 and 1.00, respectively. Repeated-measures analysis of variance revealed a significant main effect for the different contraction levels both in the masseter (during contraction, p = 0.001; after contraction, p<0.001) and the temporalis (during contraction, p = 0.002; after contraction, p<0.001). These data suggest that low levels of contraction induce a clear haemodynamic response, even at 5% effort. When compared, the masseter and anterior temporalis showed clearly different patterns for the Hb signal during the contraction (p<0.001) as well as after it (p = 0.007). Specifically, the Hb during the contractions in the masseter appeared more stable than in the temporalis, which showed a strong return to baseline. Obviously the contracting masseter had a stronger and more sustained venous occlusion than the contracting temporalis. It is speculated that variation in architecture between the two muscles contributes to these differences in blood flow.     

A case of intrapulmonary schwannoma that should be distinguished from lung cancer

A 32-year-old woman was referred to our division because of abnormal shadow on a chest X-ray film taken at an annual health survey. Chest X-ray films and chest CT scanning revealed a smooth-surface mass at the left hilus. A bronchoscopic examination revealed severe extraluminal compression in the left basal bronchus but no visible tumors. Surgical treatment was performed on the suspicion of lung cancer. Since the intraoperative frozen section examination revealed a benign tumor, the tumor mass was resected. Based on intraoperative and pathological findings, benign intrapulmonary schwannoma associated with the left basal bronchus was diagnosed. Only 15 cases of intrapulmonary schwannoma have been reported in Japan.     

High frequency oscillatory ventilation attenuates the activation of alveolar macrophages and neutrophils in lung injury

BACKGROUND: Recent investigations have shown that leukocyte activation is involved in the pathogenesis of ventilator-associated lung injury. This study was designed to investigate whether the inflammatory responses and deterioration of oxygenation in ventilator-associated lung injury are attenuated by high-frequency oscillatory ventilation (HFO). We analyzed the effects of HFO compared with conventional mechanical ventilation (CMV) on the activation of pulmonary macrophages and neutrophils in 10 female rabbits. RESULTS: After surfactant depletion, the rabbits were ventilated by CMV or HFO at the same mean airway pressure. Surfactant-depletion followed by 4 h mechanical ventilation hindered pulmonary oxygenation in both groups. Impairment of oxygenation was less severe in the HFO group than in the CMV group. In the HFO group the infiltration of granulocytes into alveolar spaces occurred more readily than in the CMV group. Compared with CMV, HFO resulted in greater attenuation of beta2-integrin expression, not only on granulocytes, but also on macrophages. CONCLUSIONS: In the surfactant-depleted lung, the activation of leukocytes was attenuated by HFO. Reduced inflammatory response correlated with decreased impairment of oxygenation. HFO may reduce lung injury via the attenuation of pulmonary inflammation.     

An Overview of Regular Dialysis Treatment in Japan (As of 31 December 2010)

A nationwide statistical survey of 4226 dialysis facilities was conducted at the end of 2010, and 4166 facilities (98.6%) responded. The number of new patients introduced into dialysis was 37 512 in 2010. This number has decreased for two consecutive years since it peaked in 2008. The number of patients who died in 2010 was 28 882, which has been increasing every year. The number of patients undergoing dialysis at the end of 2010 was 298 252, which is an increase of 7591 (2.6%) compared with that at the end of 2009. The number of dialysis patients per million at the end of 2010 was 2329.1. The crude death rate of dialysis patients in 2010 was 9.8%, and has been gradually increasing. The mean age of the new patients introduced into dialysis was 67.8 years and the mean age of the entire dialysis patient population was 66.2 years. Regarding the primary disease of the new patients introduced into dialysis, the percentage of patients with diabetic nephropathy was 43.6%, which is a slight decrease from that in the previous year (44.5%). Patients with diabetic nephropathy as the primary disease accounted for 35.9% of the entire dialysis patient population, which approaches the percentage of patients with chronic glomerulonephritis as the primary disease (36.2%). The percentage of patients who had undergone carpal tunnel release surgery (CTx) was 4.3%, which is a slight decrease from that at the end of 1999 (5.5%). The decrease in the percentage of patients who had undergone CTx was significant among the patients with dialysis durations of 20–24 years (1999, 48.0%; 2010, 23.2%). A total weekly Kt/V attributable to peritoneal dialysis and their residual functional kidney was 1.7 or higher for 59.4% of patients who underwent peritoneal dialysis.     

Changes of heart rate and QT interval at high altitude in alpinists: analysis by Holter ambulatory electrocardiogram

The purpose of this study is to record continuously electrocardiograms of alpinists during different activities practiced in mountaineering, compare heart rate and QT interval at high altitude with those at sea level, and compare alpinists with nonalpinists. Analysis was attempted on 14 alpinists (9 male, 5 female, ages 26-45) to determine changes in heart rate and QT interval using continuous ambulatory electrocardiograms recorded at sea level and high altitude. Between 1983 and 1984, 9 of 14 alpinists (6 male, 3 female) were subjected to the study at high altitude, that is, at Mt. Kangchenjunga (Himalaya), Mt. Satopanth (Himalaya), and Mt. Jitudake (Butan), 4400 to 7800 m (mean 5710 m). The following were noted: Heart rate at high altitude was significantly higher both in daytime and nighttime. The circadian rhythm of the heart rate disappeared at extremely high altitude in several alpinists. A high correlation was noted between measured QT interval (QTm) and RR interval (r = 0.81, p = 0.005). Nighttime QTm at high altitude was prolonged in comparison with that of daytime so far as the RR interval remained the same. At high altitude, the nighttime corrected QT interval (QTc) was also significantly prolonged in spite of shortened RR interval. The mechanism of QTc prolongation is not clear. Many factors may impact on the QT interval during mountaineering.     

Overview of Regular Dialysis Treatment in Japan as of 31 December 2006

A statistical survey of dialysis patients for the year 2006 was carried out for 4051 medical facilities across Japan, and responses were received from 3985 (98.37%) facilities. There were 264 473 dialysis patients (including 9003 peritoneal dialysis patients) in Japan at the end of 2006, which showed an increase of 6708 (2.6%) from the end of 2005. The number of patients per million population was 2069.9. The crude mortality rate during 2006 was 9.2%. The mean age of the patients who began dialysis (in 2006) was 66.4 years, and the mean age of the entire dialysis population was 64.4 years. The primary renal diseases of the patients who began dialysis were diabetic nephropathy (42.9%), chronic glomerulonephritis (25.6%), and nephrosclerosis (9.4%). Of the 3488 facilities that participated in the survey on the dialysate water quality, 2873 facilities (82.4%) measured the endotoxin concentration in the dialysate; and 1197 facilities (37.1%) out of 3228 measured the bacterial count in the dialysate. The mean hemoglobin concentration in the dialysis population at the end of 2006 was 10.23 ± 1.33 g/dL, which was equal to that at the end of 2005 (10.23 ± 1.37 g/dL). The mean concentration of serum creatinine in 15 853 patients who started dialysis during 2006 was 8.37 ± 3.58 mg/dL. The estimated glomerular filtration rate, which was calculated with formula modified for the Japanese population from the Modification of Diet in Renal Disease (MDRD) Study equation, was 5.46 ± 6.60 mL/min/1.73 m².     

A Beta-adrenoceptor Agonist Evokes a Nitric Oxide-cGMP Relaxation Mechanism Modulated by Adenylyl Cyclase in Rat Aorta: Halotane Does not Inhibit this Mechanism

Background: The objective of this study was to characterize the effects of halothane on the agonist-induced nitric oxide-cyclic GMP (NO-cGMP) mechanisms by comparing the intracellular signal transduction mediating isoproterenol- and acetylcholine-induced nitric oxide formation.

Methods: Isoproterenol-induced relaxations of rat aortic rings with and without endothelia were examined in the absence and presence of halothane. Studies were also done in the presence of inhibitors of nitric oxide-synthase, adenylyl cyclase, calmodulin, protein kinase A, and intracellular Calcium2+ release mechanism. The relaxations under some of these conditions were compared with those induced by acetylcholine. Cyclic nucleotide contents of the rings were also measured.

Results: Isoproterenol relaxed aortic rings via the endothelium-dependent nitric oxide-cyclic GMP mechanism. Inhibition of adenylyl cyclase or of protein kinase A attenuated the isoproterenol-induced relaxations significantly but did not affect those induced by acetylcholine. Inhibition of intracellular Calcium2+ release abolished the acetylcholine-induced relaxations but did not affect those induced by isoproterenol. Calmodulin inhibition attenuated both agonist-induced relaxations significantly. Unlike acetylcholine-induced relaxation, that induced by isoproterenol was not affected by halothane. Isoproterenol increased both the cyclic adenosine monophosphate and cGMP contents of rings significantly when endothelia were intact. Inhibition of nitric oxide synthase attenuated the isoproterenol-induced cGMP content increases significantly but did not affect the cyclic adenosine monophosphate content increases. Halothane (2%) did not affect isoproterenol-induced increases in nucleotide content.