Invited Review Articles
Smooth Muscle Contraction by Small GTPase Rho
YOJI KAWANO, TAKESHI YOSHIMURA and KOZO KAIBUCHI
pg(s) 1- 8
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Abnormal contraction of vascular smooth muscle contributes to a variety of diseases such as hypertension and vasospasm in coronary and cerebral arteries. An increment in a cytoplasmic Ca2+ concentration is the key event in smooth muscle contraction. However, smooth muscle contraction is modified upon the stimulation by agonists as well as in some pathophysiological situations in Ca2+-independent mechanism. The molecular mechanism underlying this modulation was not elucidated. Recent studies have shown the important role of small GTPase Rho and its effector, Rho-associated kinase (Rho-kinase)/ROK/ROCK in Ca2+-independent regulation of smooth muscle contraction. The Rho/Rho-kinase pathway modulates the phosphorylation level of myosin light chain (MLC) of myosin II, mainly through the inhibition of myosin phosphatase, and contributes to the agonist-induced Ca2+-sensitization in smooth muscle contraction. The Rho/Rho-kinase pathway is involved in the pathogenesis of hypertension, vasospasm and arteriosclerosis, and is a potent target of new therapies for these diseases.
Microglia : Immunoregulatory Cells in the Central Nervous System
AKIO SUZUMURA
pg(s) 9- 20
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Original Papers
Effect of Lactase Preparations in Asymptomatic Individuals with Lactase Deficiency – Gastric Digestion of Lactose and Breath Hydrogen Analysis –
KAI-PING GAO, TAKAHIRO MITSUI, KOTOYO FUJIKI, HIROSHI ISHIGURO and TAKAHARU KONDO
pg(s) 21- 28
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We compared two lactase preparations derived from Aspergillus orizae (AOL) and Penicillinase multicolor (PML) for stability in the stomach and overall enzymatic activity in 10 asymptomatic subjects with lactase deficiency. The subjects were given 10,000 FCC units of either AOL or PML 30 min prior to or simultaneously with 300 ml of milk. Gastric juice was withdrawn through a nasogastric tube immediately after and every 15 min for 60 min, and breath was sampled before and every 15 min for 6 h after the milk ingestion. When lactase was given simultaneously with the milk, gastric juice lactase activity and galactose concentration were significantly higher than the control levels. When lactase preparations were given 30 min prior to the milk, neither lactase activity nor galactose was detected in the gastric juice. The pH of the gastric juice was about 6.0 after the milk ingestion. Breath hydrogen did not increase when milk was ingested simultaneously with enzymes, but did increase if enzymes were given 30 min prior to milk ingestion. There were no significant differences in lactase activity, galactose concentration in gastric juice, or breath hydrogen when AOL and PML were compared. In conclusion, with exogenous lactase, digestion of lactose begins in the stomach when pH is raised to 6.0 by the buffering action of milk. Lactase preparations are effective assessed by breath hydrogen analysis in asymptomatic individuals with lactase deficiency if the enzymes are given simultaneously with milk.
Influence of Choking and Arm Lock Technique in Judo on the Acoustic Reflex Threshold (ART) in Healthy Well-Trained Male and Female Judoka
CHRISTOPH RASCHKA, HORST JOSEF KOCH and RUDIGER RAU
pg(s) 29- 36
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The objective of this controlled parallel group study was to assess the effects of standardized choke holds (test) and arm lock techniques (controls) in on the acoustic hearing threshold. 104 (test group, 32 female subjects and 72 male subjects, mean age = 28.0 years, SD = 7.9 years) and 51 experienced judoka (controls, 21 female subjects, 30 male subjects; mean age = 26.8 years; SD = 13.2 years) participated. Acoustic reflex thresholds (ART [dB]) were measured separately before and after each manoeuvre both for air and bone conduction of the right and left side. The difference Dart of the ART before and after a manoeuvre (Dart = ARTbefore – ARTafter) was calculated. Data were presented descriptively and nonparametric statistics was applied for nonrelated (Kruskal Wallis ANOVA) or related samples (Friedman ANOVA). Wilcoxon tests were used for pre/post comparisons of original ART values.
The effect of choking on Dart was significantly different from the effect of the arm lock technique on Dart independent of the experimental condition. A significant influence of applied frequencies on Dart was ascertained if a choking technique was used. For all frequency ranges applied a highly significant improvement of the ART after choking was found. With regard to bone conduction thresholds increased by an average of 6.1 dB and for air conduction the average increase was 4.9 dB. On the contrary, arm locks induced a slight mean deterioration of the ART for bone conduction of 1.8 dB. The ART for bone conduction also showed a trend towards a reduction after arm locks with a mean decrease of about 1.2 dB. In conclusion, standardized choking manoeuvres reduced the ART corresponding to an improved hearing both with regard to air and bone conduction. Such an effect on hearing ability was not found for arm lock techniques.
Effect of Exercise Testing Protocol on the Relationship between Minute Ventilation and Carbon Dioxide Production
MASANOBU IKOMA, REIZO BABA, SHINSUKE MOCHIDUKI and SUKETSUNE IWAGAKI
pg(s) 37- 42
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Background: The effect of exercise protocol on the slope of the relationship between minute ventilation and carbon dioxide production (deltaVE/deltaVCO2) has not fully been studied. METHODS: Twenty-five healthy volunteers performed two sessions of incremental bicycle exercise, one with a rapidly increasing staged (RIS: 25W every minute) protocol and another with a slowly increasing staged (SIS: 25W every 3 minutes) protocol to calculate the deltaVE/deltaVCO2. Six of the subjects also participated in sessions of steady state exercise (SSE) test various work rates. RESULTS: The deltaVE/deltaVCO2 was significantly lower when the RIS protocol was used than when the SIS protocol was used (23.3 +/- 2.3 vs. 24.9 +/- 1.8, p < 0.001). Data from the subjects who also underwent SSE sessions revealed that the deltaVE/deltaVCO2 from the SSE protocols was greater than that from the RIS protocol and identical with that from the SIS protocol (125.1 +/- 3.7. 20.6 +/- 1.7, and 24.0 +/- 2.7, respectively, p < 0.05), while arterial partial pressure of carbon dioxide during exercise was not different between the protocols (43.0 +/- 3.3. 39.9 +/- 2.1, and 40.8 +/- 2.6, respectively, n.s.). C ONCLUSIONS: Care must be taken in the interpretation of the values of deltaVE/deltaVCC2, as they are influenced by the difference in exercise protocol.