Electrical Stimulation-Based Twitch Exercise Suppresses Progression of Immobilization-Induced Muscle Fibrosis via Downregulation of PGC-1?/VEGF Pathway.

This study aimed to determine whether electrical stimulation-based twitch exercise is effective in inhibiting the progression of immobilization-induced muscle fibrosis. 19 Wistar rats were randomly divided into a control group (n=6), an immobilization group (n=6; with immobilization only), and a Belt group (n=7; with immobilization and twitch exercise through the belt electrode device, beginning 2 weeks after immobilization). The bilateral soleus muscles were harvested after the experimental period. The right soleus muscles were used for histological analysis, and the left soleus muscles were used for biochemical and molecular biological analysis. As a result, in the picrosirius red images, the perimysium and endomysium were thicker in both the immobilization and Belt groups compared to the control group. However, the perimysium and endomysium thickening were suppressed in the Belt group. The hydroxyproline content and alpha-SMA, TGF-beta1, and HIF-1alpha mRNA expressions were significantly higher in the immobilization and belt groups than in the control group. These expressions were significantly lower in the Belt group than in the immobilization group. The capillary-to-myofiber ratio and the mRNA expressions of VEGF and PGC-1alpha were significantly lower in the immobilization and belt groups than in the control group, these were significantly higher in the Belt group than in the immobilization group. From these results, Electrical stimulation-based twitch exercise using the belt electrode device may prevent the progression of immobilization-induced muscle fibrosis caused by downregulating PGC-1alpha/VEGF pathway, we surmised that this intervention strategy might be effective against the progression of muscle contracture. Keywords: Immobilization, Skeletal muscle, Fibrosis, Electrical stimulation-based twitch exercise, PGC-1alpha/VEGF pathway.

Skeletal Muscle Electrical Stimulation Prevents Progression of Disuse Muscle Atrophy via Forkhead Box O Dynamics Mediated by Phosphorylated Protein Kinase B and Peroxisome Proliferator-Activated Receptor gamma Coactivator-1alpha.

Although electrical muscle stimulation (EMS) of skeletal muscle effectively prevents muscle atrophy, its effect on the breakdown of muscle component proteins is unknown. In this study, we investigated the biological mechanisms by which EMS-induced muscle contraction inhibits disuse muscle atrophy progression. Experimental animals were divided into a control group and three experimental groups: immobilized (Im; immobilization treatment), low-frequency (LF; immobilization treatment and low-frequency muscle contraction exercise), and high-frequency (HF; immobilization treatment and high-frequency muscle contraction exercise). Following the experimental period, bilateral soleus muscles were collected and analyzed. Atrogin-1 and Muscle RING finger 1 (MuRF-1) mRNA expression levels were significantly higher for the experimental groups than for the control group but were significantly lower for the HF group than for the Im group. Peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha) mRNA and protein expression levels in the HF group were significantly higher than those in the Im group, with no significant differences compared to the Con group. Both the Forkhead box O (FoxO)/phosphorylated FoxO and protein kinase B (AKT)/phosphorylated AKT ratios were significantly lower for the Im group than for the control group and significantly higher for the HF group than for the Im group. These results, the suppression of atrogin-1 and MuRF-1 expression for the HF group may be due to decreased nuclear expression of FoxO by AKT phosphorylation and suppression of FoxO transcriptional activity by PGC-1alpha. Furthermore, the number of muscle contractions might be important for effective EMS.

Heat treatment inhibits skeletal muscle atrophy of glucocorticoid-induced myopathy in rats.

The purpose of this study was to investigate the influence of heat treatment on glucocorticoid (GC)-induced myopathy. Eight-week-old Wistar rats were randomly assigned to the control, Dex, and Dex + Heat groups. Dexamethasone (2 mg/kg) was injected subcutaneously 6 days per week for 2 weeks in the Dex and Dex + Heat group. In the Dex + Heat group, heat treatment was performed by immersing hindlimbs in water at 42 °C for 60 min, once every 3 days for 2 weeks. The extensor digitorum longus muscle was extracted following 2 weeks of experimentation. In the Dex + Heat group, muscle fiber diameter, capillary/muscle fiber ratio, and level of heat shock protein 72 were significantly higher and atrogene expression levels were significantly lower than in the Dex group. Our results suggest that heat treatment inhibits the development of GC-induced myopathy by decreasing atrogene expression and increasing angiogenesis.

Hyperglycemia inhibits recovery from disuse-induced skeletal muscle atrophy in rats.

The purpose of this study was to evaluate the effects of hyperglycemia on skeletal muscle recovery following disuse-induced muscle atrophy in rats. Wistar rats were grouped as streptozotocin-induced diabetic rats and non-diabetic rats. Both ankle joints of each rat were immobilized to induce atrophy of the gastrocnemius muscles. After two weeks of immobilization and an additional two weeks of recovery, tail blood and gastrocnemius muscles were isolated. Serial cross sections of muscles were stained for myosin ATPase (pH 4.5) and alkaline phosphatase activity. Serum insulin and muscle insulin-like growth factor-1 (IGF-1) levels were also measured. Serum insulin levels were significantly reduced in the diabetic rats compared to the non-diabetic controls. The diameters of type I, IIa, and IIb myofibers and capillary-to-myofiber ratio in the isolated muscle tissue were decreased after immobilization in both treatments. During the recovery period, these parameters were restored in the non-diabetic rats, but not in the diabetic rats. In addition, muscle IGF-1 levels after recovery increased significantly in the non-diabetic rats, but not in the diabetic rats. We conclude that decreased levels of insulin and IGF-1 and impairment of angiogenesis associated with diabetes might be partly responsible for the inhibition of regrowth in diabetic muscle.

Thirty cases of bronchial asthma associated with exposure to pet hamsters.

BACKGROUND: The identification, isolation, and elimination of allergen(s) causing bronchial asthma are the most efficient form of treatment. The pet industry has diversified recently, increasing the risk of exposure of pet owners to many unknown antigens. We clinically studied the characteristics of asthma associated with exposure to pet hamsters. METHODS: The study group comprised 30 adults in whom the onset, recurrence, or exacerbation of asthma was triggered by contact with pet hamsters. Clinical characteristics such as sex, age, period required for symptom onset, species of hamster, treatment and disease course, smoking status, and hamster-specific IgE antibodies in serum were studied. RESULTS: The male: female ratio of the study group was 1:1.3, and mean age was 37.7 years. Patients with no previous history of asthma initially presented with cough, progressing to episodes of asthma. Asthmatic symptoms were associated with hamster contact and ranged in severity from mild to severe. Three patients required hospital admission for treatment. The mean period from the start of hamster exposure to the onset of asthmatic episodes was 15.7 months. Dwarf hamsters were responsible for most cases. The CAP-RAST score for hamster-specific IgE antibodies was 1 to 4 in 22 patients and 0 in 8 patients. Eight patients with a score of 1 or higher for hamster-specific IgE antibodies had a CAP-RAST score of 0 for mite antigen. In these patients, terminating hamster contact resulted in a rapid improvement in symptoms, with no need for further treatment. Twenty-three of the 30 subjects (76.7%) were smokers. CONCLUSION: Exposure to pet hamsters is an important risk factor for the onset, recurrence, or exacerbation of asthma. Smoking may also increase the risk of asthmatic symptoms in patients exposed to hamsters.

[Torsion of the middle lobe after right upper lobectomy of the lung; report of a case and the review of the Japanese literatures].

We report a case of torsion of the residual right middle lobe of the lung, following right upper lobectomy for lung cancer. A 71-year-old man who had medical treatment for emphysema was admitted with a lung tumor on chest computed tomography. The tumor was diagnosed as pulmonary adenocarcinoma by transbronchial biopsy. Right upper lobectomy with mediastinal lymph node dissection, and partial resection of the right lower lobe were performed. On the following day, chest X-ray showed an opacification in the right upper lung field, which gradually increased. Bronchoscopic examination revealed a stenotic middle lobe bronchus. Torsion of the middle lobe was suspected, and rethoracotomy was performed on the second postoperative day. The middle lobe was torsed 90-degree counterclockwise around its bronchovascular pedicle. A middle lobectomy was performed secondary to severe congestion. The patient was discharged in good condition on the 11th postoperative day. In reviewing the literatures including this case, 13 of 16 torsions occurred after right upper lobectomy of the lung. Thirteen patients had rethoracotomy, 10 of them underwent resection of the rotated lung. Simple detorsion was carried out in 3 patients, and 1 of them developed cerebral infarction. Lung torsion was reported to be potentially life-threatening. Therefore, fixation of a remaining lobe should be performed. Exploratory thoracotomy should be performed without delay, if lung torsion is suspected.

Influences of a dietary fatty acid composition on the emergence of glutathione S-transferase-P (GST-P) positive foci in the liver of carcinogen-treated rats.

The rats treated with a single i.p. injection of diethylnitrosoamine (DEN) and percial hepatectomy were fed for 11 weeks with a high fat diet mixed with 10% lard, eicosapentaenoic-acid-rich oil (EPA-oil) or arachidonic-acid-rich oil (AA-oil) and the emergence of glutathione S-transferase placental form (GST-P) in the liver was evaluated. There were no significant differences in the serum aminotransferase activities. The molar ratio of n-6 and n-3 fatty acid in the liver phospholipids was significantly low in the EPA-oil group compared with the other groups. In the EPA-oil group, the area percent and the unit area of GST-P positive foci were significantly smaller than the other groups. In the AA-oil group, no significant differences were recognized in the quantitative values for GST-P positive foci compared with the control and lard groups. In conclusion, a hepatic neoplasmic lesion induced by DEN was suppressed with EPA-rich fish oil, and arachidonic-acid-rich oil showed no effect of suppression or acceleration.

Effect of arachidonic acid-rich oil on lipids and arachidonate metabolites in ethanol- treated rats.

The effects of dietary arachidonic acid-rich oil (AAoil) on lipids and arachidonate metabolites in the liver and plasma were evaluated in ethanol-treated rats. Rats were fed a purified diet containing 10% weight of lard or AAoil for 14 days. Ethanol was administered by gavage at a single daily dose of 3 g/kg body weight. Comparing with the lard group, a decrease was observed in liver fatty vacuoles in the AAoil group. Plasma 6-keto-prostaglandin (PG) F1 alpha and thromboxane (TX) B(2)levels and the 6-keto-PGF1 alpha/TXB(2)ratio increased significantly in the AAoil group. Liver 6-keto-PGF1 alpha also increased but not leukotriene B(4)in the AAoil group. In the phospholipid fraction of liver tissue, plasma and red blood cells, arachidonic acid (20:4n-6) and docosatetraenoic acid (22:4n-6) increased and oleic acid (18:1n-9) and linoleic acid (18:2n-6) decreased significantly in the AAoil group compared with the lard group. These observations suggest that AAoil supplementation reduces liver injury of ethanol-treated rats, although longer observation will be necessary for confirmation.

Cloning of cDNA encoding a soybean allergen, Gly m Bd 28K.

A cDNA clone encoding a soybean allergen, Gly m Bd 28K, has been isolated. The clone has a 1567-bp cDNA insert with a 1419-bp open reading frame and a 148-bp 3'-untranslated region, followed by a polyadenylation tail. The open reading frame was shown to encode a polypeptide composed of 473 amino acids. The chemically determined amino acid sequences of the peptides obtained from the allergen, including its N-terminal peptide, were shown to be contained in the N-terminal region of the amino acid sequence deduced from the cDNA, showing that the first half of the cDNA encodes the allergen with a preceding segment of 21 amino acids. The peptide fragment including the allergen was expressed as a fusion protein with glutathione S-transferase in Escherichia coli and immunoblotted with the sera of soybean-sensitive patients and the monoclonal antibody against the allergen. Furthermore, homology analyses demonstrate that the polypeptide for the cDNA exhibits high homology with the MP27/MP32 proteins in pumpkin seeds and the carrot globulin-like protein. This finding suggests that the polypeptide may consist of a 21-amino acid segment as a part of the signal peptide and the proprotein, which may be converted to two mature proteins, Gly m Bd 28K and a 23-kDa protein, during the development of soybean cotyledons.

[Desmoid tumor of the chest wall infiltrating into the brachial plexus: report of a resected case].

We report a case of a desmoid tumor which developed in the apex of the chest wall. A 18-year-old woman was admitted with left shoulder pain. Chest X-ray showed a mass shadow in the left upper lung field. Chest MRI demonstrated the mass infiltrated into the left brachial plexus. A desmoid tumor was suspected on percutaneous needle biopsy. Resection of the tumor was performed. The mass was 13 x 9 x 5 cm in size and diagnosed pathologically as desmoid tumor. Adjunctive postoperative radiation therapy of 60 Gy was done. Postoperative course was uneventful except motor disturbances of the left fingers. At 15 months postoperatively, there was no evidence of recurrence.

Effects of short duration stretching on disuse muscle atrophy in immobilized rat soleus muscles.

The purpose of this study was to determine whether short duration stretching is ameliorating for disuse muscle atrophy in immobilized rat soleus muscles. Eighteen male Wistar rats (age, 8 weeks; weight, 311.0 ± 35.6 g) were divided randomly into control (n=3) and experimental (n=15) groups. Bilateral ankles of each rat in the experimental group were fixed in full planter flexion with a plaster cast. After the experimental groups rats were immobilized for 4 weeks, animals were divided into three groups: immobilization alone (group I, n=3), stretch training for 30 min/day for 1 or 3 weeks after remobilization (group S, n=6), and spontaneous recovery (non stretch training) for 1 or 3 weeks after remobilization (group NS, n=6). At the end of the experimental periods, the soleus muscle was extracted from hindlimb, and the frozen sections were stained with myofibrillar adenosine triphosphatase. After 1 week of remobilization, the means of the muscle fiber diameters for type I fibers in group S had increased significantly compared with group NS, but those for type II fibers in group S did not significantly differ from that for group NS. After 3 weeks of remobilization, the means of the muscle fiber diameters for types I and II fibers in group S had increased significantly compared with group NS. No difference in the fiber type distribution were observed between the experimental group. Our findings suggest that short duration stretching induces recovery from disuse muscle atrophy after joint fixation.

Decreased food intake and body weight in pancreatic polypeptide-overexpressing mice.

BACKGROUND & AIMS: Pancreatic polypeptide (PP) is a 36-amino acid hormone produced by F cells within the pancreatic islets and the exocrine pancreas. The definitive function of PP in mammalian physiology remains to be determined. This study examined the effects of chronic overexpression of PP through the development of PP transgenic mice. METHODS: PP transgenic mice were created by using mouse PP complementary DNA under the control of the cytomegalovirus immediate early enhancer-chicken beta-actin hybrid promoter (pCAGGS expression vector). RESULTS: A unique line of transgenic mice was created that overexpresses PP in the pancreatic islets with low levels of expression in other tissues including the brain. Plasma PP concentrations were more than 20 times higher than those of control littermates. However, PP overproduction led to postnatal lethality in half of the pups because of markedly decreased milk intake. The remaining PP transgenic mice gained less weight with specifically reduced food intake and fat mass compared with controls, a result that was more evident in male than in female mice. The transgenic mice exhibited a reduced rate of gastric emptying of a solid meal but had normal oxygen consumption and fasting leptin levels. Immunoneutralization with anti-PP antiserum reversed the phenotypic changes of transgenic animals. CONCLUSIONS: PP could be involved in feeding and body weight regulation partly through regulation of gastric emptying.

Low plasma levels of docosahexaenoic acid in patients with liver cirrhosis and its correction with a polyunsaturated fatty acid-enriched soft oil capsule.

Plasma levels of docosahexaenoic acid (DHA, C22:6 omega 3) were found to be decreased in 11 patients with alcoholic and non-alcoholic liver cirrhosis depending on the severity of liver damage. In this reduction, we found impaired metabolism of omega-3 long-chain polyunsaturated fatty acids in the cirrhotic liver and poor dietary intake of DHA to involved in the reduction of DHA plasma levels. The deficiency of this fatty acid, which is concentrated in the nervous tissues, may be related to the impaired neural function observed in hepatic encephalopathy of these patients. Oral DHA supplementation was supplied in the form of a polyunsaturated fatty acid-enriched soft oil capsule (omega 3/omega 6 ratio = 0.91, and P/S ratio = 1.87). Twelve capsules per day (containing 408 mg DHA, which corresponds to one-fourth of the DHA content in a normal daily diet) improved the DHA contents in the plasma phospholipid fractions of 5 alcoholic patients with low DHA levels.

Analysis of the fatty acid components in a perchloric acid-soluble protein.

We had previously found that a perchloric acid-soluble protein (PSP1) occurs in rat liver, and that this novel protein inhibits protein synthesis in a rabbit reticulocyte lysate system (T. Oka, H. Tsuji, C. Noda, K. Sakai, Y.-H. Hong, I. Suzuki, S. Muñoz, Y. Natori, J. Biol. Chem. 270 (1995) 30060-30067). In the present study, we analyzed lipid components bound to PSP1. Native PSP1 was purified from rat liver using Sephadex G-75, DE-52 cellulose and IgGPSP-affinity chromatography, and the lipid components were extracted. The components obtained from the purified PSP1 were shown to be free fatty acids by thin-layer chromatography. By GC-MS, six major fatty acids were identified as 14:0, 16:0, 18:0, 18:1, 18:2 and 20:4. 1 mol of PSP1 contained 1.26 mol of total fatty acid components. The fatty acid-binding assay of PSP1 showed that the Bmax was 1.25 mol fatty acid/mol PSP1 and the Kd value for palmitic acid was 6.03 microM. The concentration of PSP1 mRNA in rat liver increased 2.3-fold by the administration of peroxisome proliferator, bezafibrate. These findings show that PSP1 is a fatty acid-binding protein-like protein, which is involved in the intracellular metabolism of fatty acid and is quite different from the known fatty acid-binding proteins.

Abnormal serum lysophospholipids in multiple myeloma patients.

Lysophosphatidylcholine (LPC) and lysophosphatidic acid (LPA) mediate various kinds of biological activities and play an important role in cellular signal transduction. We analyzed serum phospholipids obtained from 16 multiple myeloma (MM) patients and observed that serum LPA level was significantly higher in MM patients (5.3 +/- 0.5 nmol/mL) than in normal controls (1.7 +/- 0.3 nmol/mL). LPC level was also higher than that in normal controls, and it correlated significantly with the concentration of LPA (r = 0.678, P < 0.01). In MM patients, palmitic acid/linoleic acid ratios in phosphatidylcholine and LPC were higher than those in normal controls. In the 12-mon follow-up study of two patients with the immune globulin G type, we recognized that the increase of LPC, LPA, and arachidonic acid/linoleic acid ratio in phosphatidylinositol corresponded with a decline in the serum albumin level and choline esterase activity.

Effects of corticotropin-releasing factor on feeding and pancreatic polypeptide response in the dog.

We have previously reported that corticotropin-releasing factor (CRF) is a potent stimulator of adrenocorticotropic hormone and cortisol secretion in the dog. Therefore, in the present study, we investigated the extrahypophysiotropic actions of CRF in this species. When CRF was injected into the third cerebral ventricle, it failed to inhibit food intake significantly at doses of 1.19, 3.57, and 11.9 nmol. This is in sharp contrast with the results in rodents. At the 3.57 and 11.9 nmol doses, CRF markedly stimulated the secretion of pancreatic polypeptide (PP), a hormone under vagal control, and at the highest dose CRF increased plasma glucose levels. These results suggest species differences in the feeding response to CRF and activation of the parasympathetic nervous system in the dog.

Central cholinergic regulation of pancreatic polypeptide secretion in conscious dogs.

The secretion of pancreatic polypeptide (PP) is regulated by fluctuations in blood glucose concentrations and food intake, in which vagal-cholinergic mechanisms play an important role, especially for the cephalic phase of PP secretion. In this study, we examined whether central cholinergic mechanisms are also important for PP secretion by relaying information in the brain to the vagus nerve and the muscarinic cholinergic receptors in the pancreas. Atropine sulfate (20-200 micrograms) was administered into the lateral cerebral ventricle and its effects on the basal secretion of PP as well as the secretions stimulated by insulin-induced hypoglycemia (Actrapid MC, 0.25 U/kg) and a mixed meal (243 kcal) were studied in seven dogs. Intralateral cerebroventricular (ILV) atropine (100 and 200 micrograms) abolished the fluctuations in basal PP secretion without appearing in the plasma. Pretreatment with 20, 100, and 200 micrograms ILV atropine significantly decreased the PP response to insulin-induced hypoglycemia, with the integrated PP response to 58, 32, and 26% of that of controls respectively. Atropine (100 micrograms ILV) significantly reduced the postprandial PP secretion in both the cephalic and the gastrointestinal phases, whereas increased insulin and glucose levels were unaffected. Centrally administered atropine was able to suppress the basal secretion of PP as well as the secretions stimulated by hypoglycemia and food intake. These findings suggest that (1) the spontaneous release of PP is governed by an oscillating, central cholinergic tone, and (2) the stimulating PP secretion is, at least in part, regulated by the central cholinergic system.

Elevated levels and altered fatty acid composition of plasma lysophosphatidylcholine(lysoPC) in ovarian cancer patients.

Lysophosphatidylcholine (lysoPC), a product of phosphatidylcholine (PC) hydrolysis via phospholipase A activity, has been proposed to activate cells from a number of lineages. Here, we demonstrate that lysoPC levels are significantly elevated (by 43% overall, relative to normal controls) in the plasma of ovarian cancer patients. This does not appear to be common to all cancers as 5 out of 6 leukemia patients tested had markedly lower (less than one-half of normal) plasma lysoPC. In the plasma of ovarian cancer patients, the percentages of palmitoyl- and stearoyl-lysoPC species were significantly higher, whereas oleoyl and particularly linoleoyl-lysoPC were significantly lower than in control subjects. The molar ratios of lysoPC/PC and palmitoyl-lysoPC/linoleoyl-lysoPC were also significantly elevated in the plasma of ovarian cancer patients compared with those of control subjects. Furthermore, the calculated value of plasma (lysoPC/ PC) x (palmitoyl-lysoPC/linoleoyl-lysoPC) was markedly higher in patients compared with controls.

[Studies of liver macrophage function in the intraabdominal infection after partial hepatectomy in the rat model].

The activities of superoxide (O2-), tumor necrosis factor (TNF) and interleukin-1 (IL-1) of rat liver macrophage (M phi) were studied in the condition of intraabdominal infection (E group), hepatectomy (H group) and intraabdominal infection following hepatectomy (HE group). In the early stage of E and HE groups, O2- production was significantly increased after infection. In the H and HE groups, O2- production was significantly increased at 48 hours after hepatectomy, probably due to liver regeneration. In every group, the changes of TNF activity showed the similar pattern to those of O2- production. In H and E groups, the elevation of IL-1 activities was significantly increased. However in HE group, the IL-1 level remained low during 72 hours. When the M phi 48 hours following hepatectomy was stimulated by lipopolysaccharide (LPS), activities of TNF and IL-1 were correlated and reversely correlated with the LPS level, respectively. In the excessive stimulation by infection following hepatectomy, IL-1 activity is significantly suppressed with production of O2- and TNF by M phi maintained.