Damage and the repeated bout effect of arm,leg, and trunk muscles induced by eccentric resistance exercises

This study compared nine resistance eccentric exercises targeting arm, leg, and trunk muscles in one session for changes in maximal voluntary isometric contraction strength (MVC), delayed onset muscle soreness (DOMS), plasma creatine kinase (CK) activity, and myoglobin (Mb) concentration after the first and second bouts. Fifteen sedentary men (20‐25 years) performed 5 sets of 10 eccentric contractions with 80% of MVC load for the elbow flexors (EF), elbow extensors (EE), pectoralis, knee extensors (KE), knee flexors (KF), plantar flexors (PF), latissimus, abdominis, and erector spinae (ES) in a randomized order and repeated the same exercises 2 weeks later. MVC decreased at 1 (16%‐57%) to 4 (13%‐49%) days, DOMS developed (peak: 43‐70 mm), and CK activity (peak: 23 238‐207 304 IU/L) and Mb concentration showed large increases after the first bout. The magnitude of decrease in MVC was greater (P < 0.05) for EF, EE, and PEC than others and for KF than KE, PF, and ES. DOMS was greater (P < 0.05) for EF, EE, and ES than others. Changes in all measures were smaller (P < 0.05) after the second than the first bout, and the magnitude of the repeated bout effect was similar among the muscles. Plasma CK activity and Mb concentration did not increase significantly after the second exercise bout. It was concluded that muscle damage was greater for arm than leg muscles, and muscle proteins in the blood increased to a critical level after unaccustomed whole‐body resistance exercises, but the magnitude of damage was largely attenuated for all muscles similarly after the second bout.     

Expression of macrophage migration inhibitory factor and CD74 in the inner ear and middle ear in lipopolysaccharide-induced otitis media

Conclusion: Significant expression of macrophage migration inhibitory factor and its receptor (CD74) was observed in both the middle ear and inner ear in experimental otitis media in mice. Modulation of macrophage migration inhibitory factor and its signaling pathway might be useful in the management of inner ear inflammation due to otitis media.

Objectives: Inner ear dysfunction secondary to otitis media has been reported. However, the specific mechanisms involved are not clearly understood. The aim of this study is to investigate the expression of macrophage migration inhibitory factor and CD74 in the middle ear and inner ear in lipopolysaccharide-induced otitis media.

Method: BALB/c mice received a transtympanic injection of either lipopolysaccharide or phosphate-buffered saline (PBS). The mice were sacrificed 24?h after injection, and temporal bones were processed for polymerase chain reaction (PCR) analysis, histologic examination, and immunohistochemistry.

Results: PCR examination revealed that the lipopolysaccharide-injected mice showed a significant up-regulation of macrophage migration inhibitory factor in both the middle ear and inner ear as compared with the PBS-injected control mice. The immunohistochemical study showed positive reactions for macrophage migration inhibitory factor and CD74 in infiltrating inflammatory cells, middle ear mucosa, and inner ear in the lipopolysaccharide-injected mice.     

Glycogen synthase kinase 3 activity during development of bone marrow-derived dendritic cells (DCs) essential for the DC function to induce T helper 2 polarization

Dendritic cells (DCs) polarize naive CD4(+) T cells to either T helper 1 (Th1) or Th2 cells. We examined the role of glycogen synthase kinase 3 (GSK3) activity during DC development from murine bone marrow (BM) cells. DCs were generated by culturing lineage-marker-negative BM cells with granulocyte-macrophage colony-stimulating factor in the presence or absence of a specific inhibitor of GSK3 (Gi), SB415286, for 6 days. DCs generated in the presence (GiDC) or absence (control DC) of SB415286 similarly exhibited a conventional DC phenotype (CD11b(+) B220(-) CD8(-)). These DCs were mixed with allogeneic CD4(+) T cells and the ability to polarize Th1 or Th2 cells was evaluated. The GiDCs exhibited markedly impaired function to induce Th2 polarization compared to control DCs. In contrast, the ability of GiDCs to generate Th1 cells was slightly higher than that of control DCs. CD86 expression and CD40-mediated interleukin-6 production were completely diminished in GiDCs, which might be associated with the impaired ability of the GiDCs to induce Th2 differentiation. These results suggest that the GSK3 activity during DC development is essential for the establishment of the DC function to induce Th2, but not Th1, differentiation.     

Effects of adenoviral-mediated hepatocyte growth factor on liver regeneration after massive hepatectomy in rats

Resection is the only curative treatment for liver metastasis of colorectal cancers. Despite the supreme regenerative potential of the liver, major hepatectomy sometimes leads to liver failure, and the limitation of resectable liver volumes makes advanced tumors inoperable. This study was attempted to promote liver regeneration using hepatocyte growth factor (HGF) gene transfection by venous-administered adenovirus and to improve the survival of rats after massive hepatectomy. The adenovirus that encodes HGF was administered to rats before 85%-hepatectomy. The administration of HGF gene improved the survival of rats after massive hepatectomy, while the administration of control adenovirus deteriorated their survival. Gene transfection of HGF showed up-regulation of serum HGF, stimulation of hepatocellular proliferation and rapid liver regeneration. Moreover, HGF administration reduced apoptosis of hepatocytes. The administration of HGF gene prevented liver dysfunction after major hepatectomy and may be a new assist for surgery.     

Multiple gastrointestinal stromal tumors in neurofibromatosis type 1 treated with laparoscopic surgery

Gastrointestinal stromal tumors (GISTs) have been reported to occasionally occur in patients with neurofibromatosis type 1 (NF-1), and many cases have had multiple lesions predominantly involving the small intestine. We report herein a case of multiple GISTs associated with NF-1 from whom laparoscopic surgery was beneficial. In a 79-year-old female admitted with anemia and melena, the abdominal computed tomography revealed a tumor arising from the small intestine. Laparoscopic surgery was performed, and another small tumor was revealed during laparoscopic observation. Extracorporeal partial and wedge resection of the small intestine were undertaken. Both lesions were diagnosed as typical GISTs of low risk. Laparoscopic surgery would be useful for examination and a minimally invasive approach to tumors of the small intestine, especially on cases with the possibility of multiple tumors.     

Melatonin attenuates radiation-induced learning deficit and brain oxidative stress in mice

Oxidative stress has been implicated in cognitive impairment in both experimental animals and humans. This implication has led to the notion that antioxidant defence mechanisms in the brain are not sufficient to prevent oxidative damage, and that dietary intake of a variety of antioxidants might be beneficial for preserving brain function. The present study, therefore, aimed to investigate the protective effect of melatonin against radiation-induced impairment in the learning ability of mice. Twenty days oral administration of melatonin (0.1 mg/kg b.w.), followed by an acute exposure to T-radiation (6 Gy), inhibited the radiation-induced decline in learning ability. Biochemical estimation of brain protein carbonyls, malondialdehide (MDA) and reduced glutathione (GSH) in these mice indicated that radiation-induced augmentation of protein oxidation and lipid peroxidation had been significantly ameliorated in melatonin treated, irradiated mice. Radiation-induced deficit of glutathione was also normalized by melatonin administration, as there was no statistical difference from normal at P < 0.001. Results indicate the antioxidative as well as neuroprotective properties ofmelatonin against the radiation. These findings support results showing melatonin as a free radical scavenger.     

Preheparin lipoprotein lipase mass and apolipoproteinC-III ratio helps identify postprandial triglyceride metabolic marker

Serum lipid profiles have usually been evaluated using blood specimen in fasting state. However, postprandial hypertriglyceridemia is important risk factor for atherosclerosis. In the present study, we determined several parameters of triglyceride (TG) metabolism in healthy volunteers. Serum concentrations of TG in fasting state correlated negative the ratio of preheparin serum lipoprotein lipase mass (pLPL) and apoC-III (pLPL/apoC-III) in both fasting (r = -0.771, p < 0.0001) and postprandial (r = -0.640, p < 0.0001) state. To exclude the effect of high density lipoprotein (HDL) in serum, we purified the fraction of TG rich lipoprotein (TRL) using ultracentrifugation method 3 healthy volunteers with postprandial state. The pLPL/apoC-III was reduced constantly during postprandial state in all volunteers. These findings suggest that pLPL/apoC-III may be a useful marker for evaluation of TG metabolism using postprandial blood specimens.