Estrogen controls branched-chain amino acid catabolism in female rats

A diurnal rhythm occurs in the activity state of branched-chain alpha-keto acid dehydrogenase complex (BCKDC) in female but not male rats. We attempted to determine the role played by ovarian hormones in this difference in enzyme regulation. A series of experiments examined the effects of the 4-d estrous cycle, ovariectomy, and replacement of female sex steroids on the catabolism of BCAAs. A proestrous decrease in the activity state of the complex corresponded to an increase in the plasma 17beta-estradiol level. Withdrawal of gonadal steroids by ovariectomy resulted in an increase in the activity state of BCKDC and a decrease in the activity of the branched-chain alpha-keto acid dehydrogenase kinase (BDK). However, 17beta-estradiol reversed these effects, resulting in an increase in the BDK activity, thereby decreasing the activity of the complex. Progesterone administration was ineffective. The changes in the percentage of active BCKDC caused by 17beta-estradiol withdrawal and replacement resulted from changes in the amount of BDK protein associated with the complex and therefore its activity. Thus, the marked diurnal variation in the activity state of BCKDC exhibited by female rats involves estrogenic control of BDK activity. We hypothesize that the 17beta-estradiol-controlled feeding pattern produces these variations in BCKDC activity. This may function in female rats to conserve essential amino acids for protein synthesis.     

Clinical evaluation of a transdermal therapeutic system of the beta2-agonist tulobuterol in patients with mild or moderate persistent bronchial asthma

Tulobuterol transdermal therapeutic system (TTS) is the world's first commercially available transdermal preparation of tulobuterol, a beta2-stimulant that can maintain effective blood tulobuterol (CAS 41570-61-0) levels for 24 h when applied once daily. In the present study, a total of 24 adult patients with mild persistent (Step 2) or moderate persistent (Step 3) bronchial asthma, consisting of 13 and 11 patients, who were or were not using inhalational steroids, respectively, used tulobuterol TTS (Hokunalin Tape) for one year and underwent measurement of peak expiratory flow (PEF) once daily. Peripheral eosinophil count, serum eosinophil cationic protein (ECP) level and airway responsiveness (Dmin) were evaluated at 6 months and 1 year, respectively, after the start of the study. PEF exhibited significant improvements after 6 months and 1 year in patients treated with or without inhalational steroids, while serum ECP was improved significantly only in the patients on inhalational steroids. Patients not using inhalational steroids exhibited significant exacerbation of Dmin at neither after 6 months nor after 1 year. One-year treatment with tulobuterol TTS did not appear to cause tachyphylaxis. The significant improvements in Dmin observed after 6 months and after 1 year in the patients using inhalational steroids suggested beneficial effects of inhalational steroids in controlling airway inflammation. Tulobuterol TTS is considered quite beneficial in improving quality of life (QOL) in patients with bronchial asthma because its incidence of adverse effects including palpitations and shivering is significantly lower than those of oral preparations because of its remarkable improvement of pulmonary function and symptoms of airway obstruction without increasing airway responsiveness even after repeated use, and because it is simple to use and ensures excellent clinical efficacy.     

Adenosine induces apoptosis in the human gastric cancer cells via an intrinsic pathway relevant to activation of AMP-activated protein kinase

Extracellular adenosine significantly reduced cell viability in a dose (0.1-20mM)- and treatment time (24-72h)-dependent manner in GT3-TKB cells, a human gastric cancer cell line. Nuclei of cells were reactive to Hoechst 33342, a marker of apoptosis, and an anti-single-stranded DNA. Adenosine-induced GT3-TKB cell death was significantly inhibited by dipyridamole, an inhibitor of adenosine transporter, and 5'-amino-5'-deoxyadenosine, an inhibitor of adenosine kinase, but the effect was not affected by theophylline, a broad inhibitor of adenosine receptors, 8-cyclopentyltheophylline, an inhibitor of A(1) adenosine receptors or 3,7-dimethyl-1-propargylxanthine, an inhibitor of A(2a) adenosine receptors. Adenosine had no effect on mitochondrial membrane potentials. The effect of adenosine on GT3-TKB cell death was not inhibited by a pancaspase inhibitor or inhibitors of caspase-1,-3,-4,-8, and -9. 5-Aminoimidazole-4-carboxamide ribonucleoside (AICAR), an activator of AMP-activated protein kinase (AMPK), significantly reduced GT3-TKB cell viability, but the AICAR action was not reinforced in the presence of adenosine. The results of the present study, thus, suggest that extracellular adenosine induces apoptosis in GT3-TKB cells by its uptake into cells and conversion to AMP followed by activation of AMPK, regardless of caspase activation linked to the mitochondria and the endoplasmic reticulum.     

Significance of chymase inhibition for prevention of adhesion formation

To clarify the role of chymase in adhesion formation, we investigated whether a chymase inhibitor could prevent adhesion formation after surgery in hamsters. Hamsters received a lesion produced by uterus scraping. A specific chymase inhibitor, 2-[4-(5-fluoro-3-methylbenzo[b]thiophen-2-yl)sulfonamido-3-methanesulfonylphenyl]oxazole-4-carboxylicacid (TY-51184), or placebo was injected into the abdomen before closing and scores for adhesion formation were assessed at 1, 4, and 12 weeks. A single peritoneal administration of TY-51184 significantly decreased the adhesion scores even at 12 weeks (placebo, 2.80+/-0.20; chymase inhibitor, 1.60+/-0.31). Thus, chymase inhibitors may be a novel strategy to prevent adhesion formation.     

A new system using NMR technology for measurement of body composition in experimental animals

Measurement of body composition (fat mass) is an important item in pathophysiological and pharmacological studies using small animals (mice) in the fields of obesity and diabetes. The existing methods are, however, difficult, time consuming, and require a shielding facility. Now a novel system using nuclear magnetic resonance (NMR) technique was developed for measurement of body composition in small animals (mice) that provides noninvasive and rapid measurement without anesthetics; we introduced and evaluated this system and tried another application of this system. First, we validated this system using canola oil, soft tissues (adipose and skeletal muscle), and various kinds of rodent chows. Accuracy, precision, and reproducibility of this system were demonstrated to be equal to those in standard chemical methods. A strong positive correlation (y=x) between the results of NMR and chemical methods was found. Secondly, we evaluated accuracy and assay range of the NMR method using live mice that were fasted overnight or fed high fat diet (HFD). In fasted mice, a small but quantitative decrease of fat mass (5.1% from 9.1%) was detected. Total decrease of fat and lean mass (5.0 g) in fasted mice was equivalent to the decrease of body weight (5.0 g). In mice fed the HFD, increase of fat mass with relative decrease of lean mass were qualitatively detected in a time-dependent manner. We would like to emphasize that operation of the system was actually easy and measurements were accomplished in a short time (1 minute). Thirdly, we tried to use the NMR system for determination of hepatic fat contents using mice fasted or treated with a PPARgamma agonist; our results showed a quantitative increase in fat by fasting or in decrease in fat by the drug treatment. The changes of fat contents determined by the NMR method were well correlated with the changes in triglyceride and total cholesterol values obtained by the biochemical assays. In conclusion, body composition data acquired by the new NMR system are equivalent in accuracy and precision to classical chemical methods. The NMR analysis is simple, fast, and does not require anesthesia for acquisition of data, which are remarkable advantages compared to the existing methods. This system is expected to contribute to drug discovery and appropriate evaluation in the fields of obesity and diabetes.     

Long-lasting contractile action and the inhibitory action of cupric ions on ileal longitudinal muscle

Cupric ions (Cu(2+)), at concentrations above 0.03 mM, induced a progressive increase in the tonic contraction of guinea-pig ileal longitudinal muscle. Maximal contraction of 0.1 mM Cu(2+) attained a level above that of the 60-mM K(+)-induced tonic response, within 20 min of application. The tension induced by Cu(2+) persisted for more than several hours. Tetrodotoxin (3 x 10(-6) M) had no effect on the contraction induced by 0.1 mM Cu(2+). After incubation in a Ca(2+)-free medium, the ileal response to 0.1 mM Cu(2+) was lost. Nifedipine, a L-type Ca(2+) channel blocker, dose-dependently inhibited contractions induced by Cu(2+). As the duration of the first application of 0.1 mM Cu(2+) increased above 30 min, after washing with normal medium, the contractile response to a second application of 0.1 mM Cu(2+) decreased gradually. After 150 min of the first application of 0.1 mM Cu(2+), a second application of Cu(2+) could not evoke any contraction. After the application of 0.1 mM Cu(2+) for 150 min, when muscles were washed with a medium containing 1 mM EDTA, the response to 0.1 mM Cu(2+) returned to a greater extent in the normal Ca(2+) medium. In conclusion, Cu(2+) (0.1 mM) induced a maximal ileal tension above that of the K-induced tonic response within 20 min. The ileal contraction to Cu(2+) persisted for more than several hours and depended on extracellular Ca(2+) concentrations. It is possible that a part of Cu(2+), bound to a EDTA-inaccessible site, also has a tension inhibitory effect.     

Pegylated recombinant human megakaryocyte growth and development factor suppresses the development of megakaryoblastic leukemia in mice

We examined the effects of pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) on the development of L-8057, a murine megakaryoblastic leukemia that expresses the thrombopoietin receptor c-Mpl, in mice. PEG-rHuMGDF administration prolonged survival of L-8057 leukemic mice, in which L-8057 cell growth in the spleen was decreased. L-8057 cells harvested from PEG-rHuMGDF-treated leukemic mice had decreased ability to generate leukemic colonies in vitro as well as to induce leukemia in vivo. PEG-rHuMGDF administration also resulted in prolonged survival of mice transplanted with a c-Mpl-expressing erythroleukemia, but had no effect on survival of mice transplanted with a myeloblastic leukemia that does not possess c-Mpl. Thus, PEG-rHuMGDF suppresses the development of c-Mpl-expressing leukemia in vivo in mice.     

The effectiveness of planned esophagectomy after neoadjuvant chemoradiotherapy for advanced esophageal carcinomas

BACKGROUND: The best treatment option for patients with locally advanced esophageal carcinoma has not yet been determined, especially because the benefits of esophagectomy after neoadjuvant chemoradiotherapy are still controversial. We report the results of a retrospective cohort comparison of definitive chemoradiotherapy without surgery (CRT) versus neoadjuvant chemoradiotherapy followed by planned surgery (CRTS) in patients with advanced esophageal squamous cell carcinoma (SCC). MATERIALS AND METHODS: Between January 1991 and December 2002, 67 patients were enrolled in this study. Fifty of the 67 patients were considered to have inoperable tumors due to distant organ metastasis, distant lymph node metastasis, severe organ dysfunction or rejection of surgery by the patient and received CRT, while the remaining 17 patients were treated with CRTS. The clinical responses of the primary tumors were evaluated. RESULTS: In the 50 CRT patients, the one- and 2-year survival rates were 33.8% and 20.2%, respectively, and the median survival time (MST) was 13.5 months. In the 17 CRTS patients, the response rate (CR + PR) was 76.5%, and the pathological complete response (pCR) rate was 29.4%. Their one- and 2-year survival rates were 61.6% and 35.9%, respectively, and the MST was 24.4 months. The survival rates of the CRT patients were lower than those of the CRTS patients (p = 0.1288). When the 12 patients with distant organ metastases were removed from the CRT group, the one- and 2-year survival rates of the remaining 38 patients were 36.5% and 24.1%, respectively, and the MST was 14.7 months. The survival rates of these 38 CRT patients without distant organ metastases were similar to those of the 12 CRTS patients in the pathological partial response (pPR) group (p = 0.6279). CONCLUSION: This retrospective cohort comparison of CRT versus CRTS demonstrated that there may not be any survival benefit from the addition of surgery in the pPR group for advanced esophageal carcinomas. For patients with a poor response to neoadjuvant chemoradiotherapy, we suggest that the addition of chemoradiotherapy, instead of planned esophagectomy, may show a similar survival rate to definitive CRT. Thus, a large series of a randomized control study will be required to confirm the benefit of surgery after chemoradiotherapy.