bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of Lymphocyte Proliferation by Uterine Serpin: Interleukin‐2 mRNA Production, CD25 Expression and Responsiveness to Interleukin‐2
Authors: Peltier Morgan R. , Liu Wen‐Jun , Hansen Peter J.
Published: August 2010

Abstract. During pregnancy, the endometrium of the ewe secretes large amounts of a progesterone‐induced protein of the serpin superfamily of serine proteinase inhibitors called ovine uterine serpin (OvUS). This protein inhibits lymphocyte proliferation in response to concanavalin A (ConA), phytohemagglutinin (PHA), or mixed lymphocyte reaction. The purpose of these experiments was to characterize the mechanism by which OvUS inhibits lymphocyte proliferation. Ovine US caused dose‐dependent inhibition of lymphocyte proliferation induced by phorbol myristol acetate (PMA), an activator of protein kinase C. The PHA‐induced increase in CD25 expression was inhibited in peripheral blood mononuclear leukocytes (PBML) by OvUS. However, no effect of OvUS on Con A‐induced expression of CD25 was observed. Further analysis using two‐color flow cytometry revealed that OvUS inhibited ConA‐induced expression of CD25 in γδ‐TCR− cells but not γδ‐TCR+ cells. Stimulation of PBML for 14 hr with ConA resulted in an increase in steady state amounts of interleukin‐2 (IL‐2) mRNA that was not inhibited by OvUS. Ovine US was also inhibitory to lymphocyte proliferation induced by human IL‐2. Results suggest that OvUS acts to inhibit lymphocyte proliferation by blocking the upregulation of the IL‐2 receptor and inhibiting IL‐2–mediated events. Lack of an effect of OvUS on ConA‐stimulated CD25 expression in γδ‐TCR+ cells may reflect a different mechanism of activation of these cells or insensitivity to inhibition by OvUS.
Omega‐3 Fatty Acids Enhance Ligament Fibroblast Collagen Formation in Association with Changes in Interleukin‐6 Production
Authors: Hankenson Kurt D. , Watkins Bruce A. , Schoenlein Ingrid A. , Allen Kenneth G. D. , Turek John J.
Published: August 2010

Abstract. Altering dietary ratios of n‐3 and n‐6 polyunsaturated fatty acids (PUFA) represents an effective nonpharmaceutical means to improve systemic inflammatory conditions. An effect of PUFA on cartilage and bone formation has been demonstrated, and the purpose of this study was to determine the potential of PUFA modulation to improve ligament healing. The effects of n‐3 and n‐6 PUFA on the in vitro healing response of medial collateral ligament (MCL) fibroblasts were investigated by studying the cellular coverage of an in vitro wound and the production of collagen, PGE2, IL‐1, IL‐6, and TNF. Cells were exposed to a bovine serum albumin (BSA) control or either eicosapentaenoic acid (EPA, 20:5n‐3) or arachidonic acid (AA, 20:4n‐6) in the form of soaps loaded onto BSA for 4 days and wounded on Day 5. AA and EPA improved the healing of an in vitro wound over 72 hr. EPA increased collagen synthesis and the overall percentage of collagen produced, but AA reduced collagen production and total protein. PGE2 production was increased in the AA‐treated group and decreased in the EPA‐treated group, but was not affected by wounding. IL‐1 was not produced at the time point evaluated, but TNF and IL‐6 were both produced, and their levels varied relative to the PUFA or wounding treatment. There was a significant linear correlation (r2 = 0.57, P = 0.0045) between IL‐6 level and collagen production. These results demonstrate that n‐3 PUFA (represented by EPA in this study) positively affect the healing characteristics of MCL cells and therefore may represent a possible noninvasive treatment to improve ligament healing. Additionally, these results show that MCL fibroblasts produce PGE2, IL‐6, and TNF and that IL‐6 production is related to MCL collagen synthesis.
Perinatal Ontogeny of Brain Growth in the Domestic Pig
Authors: Pond W. G. , Boleman S. L. , Fiorotto M. L. , Ho H. , Knabe D. A. , Mersmann H. J. , Savell J. W. , Su D. R.
Published: August 2010

Abstract. The perinatal development of the brain is highlighted by a growth spurt whose timing varies among species. The growth of the porcine cerebrum was investigated from the third trimester of gestation (70 days postconception) through the first 3.5 weeks of postnatal life (140 days postconception). The shape of the growth curves for cerebrum weight, total protein mass, total cell number (estimated by DNA content), and myelination (estimated by cholesterol accretion) were described. The growth velocity of cerebrum weight had two peaks, one at 90 days and the other at 130 days postconception, whereas that of total protein was greatest from 90 to 130 days postconception, and that of total DNA was greatest between 90 and 110 days and again at 130 days postconception. The growth velocity for total cholesterol continued to increase during the entire period, suggesting that myelination continued after the growth spurts for cells (protein and DNA). The growth velocity patterns observed in these contemporary pigs suggest that this species may be an appropriate model for human brain development, not only in the perinatal pattern of increase in mass of the cerebrum, as established previously, but also with regard to the patterns of cellular development and myelination.
Tumor Necrosis Factor‐α–Induced Insulin Resistance in Adipocytes
Authors: Qi Chen , Pekala Phillip H.
Published: August 2010

Abstract. Recent studies examining the link between insulin resistance and the development of obesity and noninsulin‐dependent diabetes mellitus are consistent with the involvement of tumor necrosis factor–α (TNF‐α) as a central mediator. In insulin resistant obese mouse models, neutralization of TNF‐α in circulation has been demonstrated to restore insulin‐mediated glucose uptake. Adipose tissue has been shown to be a site for synthesis of TNF‐α, with the degree of adiposity directly correlated with the level of synthesis. Studies conducted on obese human patients have demonstrated a correlation between levels of TNF‐α, the extent of obesity, as well as the level of hyperinsulinemia observed. Mechanistic studies in cell culture have suggested that TNF‐α functions to render cells insulin resistant through regulation of the synthesis of the insulin responsive glucose transporter as well as through interference with insulin signaling. This review will address these issues and additionally introduce the reader to the molecular aspects of TNF‐α, its receptors as well as TNF‐α–initiated signaling cascades, that are necessary to understand the function of this cytokine in the regulation of adipose tissue metabolism.
Pluripotent Hemopoietic Stem Cells in Mice and Humans
Authors: Ikehara Susumu
Published: August 2010

Abstract. Although it has been reported previously that pluripotent hemopoietic stem cells (P‐HSCs) express c‐kit, the receptor for stem cell factor (steel factor), we and other groups have recently shown that P‐HSCs do not express c‐kit. In this review, we provide evidence that c‐kit 2 years) and the capacity to form colony‐forming units in spleen (CFU‐S) on Day 16, although c‐kitlow HSCs or c‐kit+ HSCs have LTRA less than 1.5 years and the capacity to form CFU‐S on Day 14 or on Day 10, respectively. In addition, we have found that there is a major histocompatibility complex (MHC) restriction between P‐HSCs and stromal cells; normal P‐HSCs can proliferate and differentiate efficiently in collaboration with MHC class I‐compatible (but not MHC class I‐incompatible) stromal cells. In humans, we also show that c‐kit<low P‐HSCs can differentiate into c‐kitlow cells, then c‐kit+ cells in vitro.
Regional Fat Deposition in the Legs Is Useful as a Presumptive Marker of Antiatherogenesity in Japanese
Authors: Tatsukawa Mari , Kurokawa Mamoru , Tamari Yuichi , Yoshimatsu Hironobu , Sakata Toshiie
Published: August 2010

Abstract. To examine the pathological role of regional fat deposition in development of metabolic and cardiovascular disorders, regional fat distribution was evaluated using metabolites and hormones as measures of obesity‐related disorders. The subjects enrolled were 100 sex‐matched inpatients, who were admitted, regardless of their body mass index values, for further examination of unusual results from periodic medical screening tests, and for examination of obesity‐induced complications and treatment of obesity. Body fat distribution was analyzed using dual energy X‐ray absorptiometry (DEXA). Analysis of parameters regarding fat distribution showed that gender was one of the determinants affecting correlation between fat distribution and metabolites of fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), total cholesterol (TC), or triglyceride (TG). However, regardless of gender, both leg trunk fat (L/Tr) and arm trunk fat (A/Tr) ratios negatively correlated with a total body fat (% total fat) ratio, whereas the intercept value of female regression line in L/Tr was greater than that in males, but not in A/Tr. Percentage total fat, L/Tr, and A/Tr in males correlated significantly with FPG, TC, TG, low‐density lipoprotein (LDL), very low density lipoprotein (VLDL), atherogenic index (A.I.), and apoB/A1 only low density lipoprotein (LDL) was significantly correlated solely to L/Tr and A/Tr. These results indicate that regional fat distribution in males may not be a major determinant for development of metabolic disorders in obese patients. Unlike male regional fat distribution, female L/Tr correlated significantly not only with TC, TG, and LDL, but also with FPG and HbA1c, although both of the latter 2 glucose‐related parameters in males showed no correlation with any parameters of fat deposition. The remaining female parameters of fasting plasma insulin, VLDL, A.I., and ApoB/A1 correlated with each of the three parameters of fat deposition, as similarly shown in males. The powerful and negative correlation was thus evident, particularly in females, between leg fat deposition and parameters of glucose and lipid metabolites. The resulting information provides a novel insight that regional fat deposition at the legs is useful as a marker for metabolic and cardiovascular disorders associated with obesity.
Carotenoid Supplementation Reduces Erythema in Human Skin After Simulated Solar Radiation Exposure
Authors: Lee Jeongmin , Jiang Shuguang , Levine Norman , Watson Ronald R.
Published: August 2010

Abstract. Excessive exposure to solar radiation, especially ultraviolet A (UVA: 320–400 nm) and ultraviolet B (UVB: 290–320 nm) radiation, may induce UV‐carcinogenesis and erythema in the skin. Although the protective effects of carotenoids against skin lesions are still unclear, β‐carotene has been proposed as an oral sun protectant. The purpose of this study was to determine the magnitude of the protective effects of oral α‐ and β‐carotene supplementation for 24 weeks on UVA‐ and UVB‐induced erythema in humans. While being exposed to UVA and UVB radiation, 22 subjects (11 men and 11 women) were supplemented with natural carotenoids for 24 weeks. Each day for the first 8 weeks, subjects were given 30 mg of natural carotenoids containing 29.4 mg of β‐carotene, 0.36 mg of α‐carotene, and traces of other carotenoids in vegetable oil. The natural carotenoid dose was progressively raised by 30‐mg increments, at every 8 weeks, from 30 mg to 90 mg. Small areas (1 cm2) of the skin were exposed to increasing doses of UV light (16–42 mJ/cm2) to determine the minimal erythema dose (MED). MED was defined as a uniform pink color with well‐defined borders. MED readings were obtained by visual inspection 24 hr postirradiation. Blood samples taken during supplementation were used to determine α‐ and β‐carotene serum levels and for a lipid peroxidation analysis. During natural carotenoid supplementation, the MED of solar simulator radiation increased significantly (P < 0.05). After 24 weeks of supplementation, serum β‐carotene levels were increased from 0.22 μg/ml (95% CI; 0.16–0.27) to 1.72 μg/ml (95% CI;1.61–1.83). Similarly, α‐carotene serum levels increased from 0.07 μg/ml (95% CI;0.048–0.092) to 0.36 μg/ml (95% CI; 0.32–0.40). Serum lipid peroxidation was significantly (P < 0.05) inhibited in a dose‐dependent manner during natural carotenoid supplementation. The present data suggest that supplementation with natural carotenoids may partially protect human skin from UVA‐ and UVB‐induced erythema, although the magnitude of the protective effect is modest.
A Model that Reproduces Syndromes Associated with Human Multiple Myeloma in Nonirradiated SCID Mice
Authors: Barton Beverly E. , Cullison Jennifer , Jackson James , Murphy Thomas
Published: August 2010

Abstract. A human myeloma line was used to create a model of human multiple myeloma in vivo that would reproduce the pathophysiology of the disease, including the cachexia associated with cancer. Unirradiated severe combined immunodeficient (SCID) mice were used as surrogate hosts for in vivo experiments that allowed the effects of autocrine (human) verus paracrine (murine) cytokines on the development of myeloma to be studied. Serum levels of human paraprotein increased over time and with the number of cells transplanted. Transplanted mice developed major syndromes, cachexia and paralysis (due to invasion of bones by myeloma cells), associated with multiple myeloma. Analyses of serum samples obtained from transplanted mice revealed that when the mice were terminal, total serum protein decreased on average by 20%, whereas serum triglycerides decreased on average by 50%. These data indicate the mice were cachectic, which was confirmed by necropsy. The mice had low but measurable levels of both human and murine interleukin (IL)‐6, soluble IL‐6 receptor, and murine IL‐10 in their sera. The presence of these cytokines and the IL‐6 receptor in sera are also characteristics of human myeloma in patients. Since human cells do not respond to murine IL‐6, it was possible to demonstrate clearly the importance of autocrine IL‐6 in establishing myeloma in situ. By reproducing both the hallmarks of a cancer as well as the accompanying paraneoplastic syndromes, this model should be useful in designing more effective therapies for both the primary cancer as well as the accompanying secondary diseases.
Ileal Lipid Infusion Stimulates Jejunal Synthesis of Apolipoprotein A‐IV Without Affecting mRNA Levels
Authors: Kalogeris Theodore J. , Painter Richard G. , Holden V. Roger
Published: August 2010

Abstract. We examined the effect of ileal infusions of lipid emulsion on mRNA levels and biosynthesis of apolipoprotein A‐IV (apo A‐IV) in jejunal Thiry‐Vella fistulas in rats. The rats were surgically prepared with jejunal Thiry‐Vella fistulas; after recovery they were deprived of food, equipped with ileal infusion cannulas, then given 8 hr ileal infusions of fatty acid/monoglyceride emulsions. Mucosal synthesis and transcript levels of apo A‐IV in the Thiry‐Vella loop were then measured. Lipid infusion produced a two‐fold stimulation in incorporation of 3H‐leucine into apo A‐IV‐specific protein, but had no significant effect on apo A‐IV mRNA levels. These results support the hypothesis that a lipid‐elicited, distal gut‐derived, systemic signal stimulates the production of apo A‐IV by a post‐transcriptional mechanism.
Microfilament Network Is Needed for the Endocytosis of Water Channels and Not for Apical Membrane Insertion Upon Vasopressin Action
Authors: Dibas Adnan , Mia Abdul , Yorio Thomas
Published: August 2010

Abstract. In the current study, a novel role for the microfilaments in vasopressin‐induced water transport in toad urinary bladders, a popular model for the mammalian collecting duct, was established. Vasopressin‐induced water transport was not affected by cytochalasin D (CD, 20 μM) or latrunculin B (Lat B, 0.5–2 μM), microfilament‐disrupting reagents, suggesting that the initial trafficking of vesicles containing water channels and insertion of membranes into the apical membrane are microfilament‐independent. After the removal of vasopressin, bladders treated with CD or Lat B continued to transport water at least 2–3‐fold greater than those that received the vehicle. Furthermore, the enhanced water transport was inhibited by HgCl2 (1 mM), a potent inhibitor of water channel–mediated water flow, suggesting that the enhanced water flow was through water channels. In addition, Lat B and CD inhibited vasopressin‐induced endocytosis of horseradish peroxidase (HRP), a fluid endocytotic marker. These results suggested that although microfilaments are not needed for the initial trafficking of water channels to the apical side, the microfilament network is essential for the retrieval of water channels following their insertion into apical membranes.
Vitamin D and Autoimmunity: Is Vitamin D Status an Environmental Factor Affecting Autoimmune Disease Prevalence?
Authors: Cantorna Margheritia T.
Published: August 2010

Abstract.The environment in which the encounter of antigen with the immune system occurs determines whether tolerance, infectious immunity, or autoimmunity results. Geographical areas with low supplies of vitamin D (for example Scandinavia) correlate with regions with high incidences of multiple sclerosis, arthritis, and diabetes. The active form of vitamin D has been shown to suppress the development of autoimmunity in experimental animal models. Furthermore, vitamin D deficiency increases the severity of at least experimental autoimmune encephalomyelitis (mouse multiple sclerosis). Targets for vitamin D in the immune system have been identified, and the mechanisms of vitamin D‐mediated immunoregulation are beginning to be understood. This review discusses the possibility that vitamin D status is an environmental factor, which by shaping the immune system affects the prevalence rate for autoimmune diseases such as multiple sclerosis, arthritis, and juvenile diabetes.
Serum Leptin, Lipids, Free Fatty Acids, and Fat Pads in Long‐Term Dehydroepiandrosterone‐Treated Zucker Rats
Authors: Richards Robert J. , Porter Johnny R. , Svec Frank
Published: August 2010

Abstract. The obese Zucker rat has a genetically flawed leptin system and is a model of hyperphagia, obesity, hyperlipidemia, and markedly elevated leptin levels. Dehydroepiandrosterone (DHEA) administration reduces hyperphagia, hyperlipidemia, and obesity in Zucker rats. Since serum leptin levels are associated with body fat, we wondered what the effects of fat pad weight reduction from DHEA administration would have on leptin levels. This experiment investigated the effects of DHEA on intra‐abdominal fat pads, serum lipids, and peripheral leptin in male lean and obese Zucker rats that were administered DHEA in their food from 4 weeks of age to 20 weeks. Lean and obese rats received plain chow or chow containing DHEA. Additional chow‐fed groups of lean and obese weight‐matched controls and obese pair‐fed rats helped to control for the reduced body weight, food intake, and fat pad weights seen with DHEA administration. DHEA administration to lean Zucker rats reduced body weight and fat pad weights, but leptin levels showed a lower trend. Among obese rats, both DHEA treatment and pair‐feeding reduced body weight and fat pad weights, but only DHEA lowered leptin levels. The weight‐matched controls had reductions in fat pad weights similar to the DHEA‐treated group, but with increased leptin levels. Thus, DHEA may exert a small, independent effect on leptin levels in this animal model, but the reduction is less than what would be expected.
Nitroprusside Attenuates Myocardial Stunning Through Reduced Contractile Delay and Time
Authors: Leone Richard J. , Scholz Peter M. , Weiss Harvey R.
Published: August 2010

Abstract. We hypothesized that myocardial stunning would be reversed through increased cyclic GMP caused by nitroprusside, and that this would be accomplished through a decreased proportion of regional work during diastole. Hearts were instrumented to measure left ventricular pressure, and regional myocardial mechanics were recorded using a miniature force transducer and ultrasonic dimension crystals in eight open‐chest anesthetized dogs. Following baseline (CON), the left anterior descending coronary artery (LAD) was occluded for 15 min, followed by a 30‐min recovery (STUN). Then intracoronary LAD infusion of sodium nitroprusside (NP) (4 μg/kg/min) was begun. The time delay (msec) to regional shortening increased significantly from 18 ± 13 to 73 ± 13 following stunning, but was reduced to 49 ± 18 by NP. Total regional work (g*mm/min) at baseline (1368 ± 401 CON) was unchanged with stunning (1320 ± 333 STUN), but reduced (961 ± 240) following NP. Time to peak force development (msec) increased significantly with stunning from 284 ± 13 (CON) to 333 ± 11 (STUN), but was reduced to 269 ± 12 following NP. The percentage work during systole was reduced from 96%± 2% (CON) to 77%± 7% (STUN), but returned to 98%± 1% with NP. Regional O2 consumption was unaffected by either treatment. Cyclic GMP was unchanged by stunning (2.9 ± 0.3–2.9 ± 0.4 pmol/g) but increased significantly with NP (4.6 ± 0.6). These data indicated that regional myocardial stunning could be attenuated by nitroprusside, which increased cyclic GMP, decreased contractile delay, increased the proportion of work done during systole, and reduced time of shortening.
Alterations in Hypertrophic Gene Expression by Dietary Copper Restriction in Mouse Heart
Authors: Kang Y. James , Wu Huiyun , Saari Jack T.
Published: August 2010

Abstract.Dietary copper (Cu) restriction causes a hypertrophic cardiomyopathy similar to that induced by work overload in rodent models. However, a possible change in the program of hypertrophic gene expression has not been studied in the Cu‐deficient heart. This study was undertaken to fill that gap. Dams of mouse pups were fed a Cu‐deficient diet (0.35 mg/kg diet) or a Cu‐adequate control diet (6.10 mg/kg) on the fourth day after birth, and weanling mice continued on the dams′ diet until they were sacrificed. After 5 weeks of feeding, Cu concentrations were dramatically decreased in the heart and the liver of the mice fed the Cu‐deficient diet. Corresponding to these changes, serum ceruloplasmin concentrations and hepatic Cu,Zn‐superoxide dismutase activities were significantly (P< 0.05) depressed. The size of the Cu‐deficient hearts was greatly enlarged as estimated from the absolute heart weight and the ratio of heart weight to body weight. The abundances of mRNAs for atrial natriuretic factor, β‐myosin heavy chain, and α‐skeletal actin in left ventricles were all significantly increased in the Cu‐ deficient hearts. Furthermore, Cu deficiency activated the expression of the c‐myconcogene in the left ventricle. This study thus demonstrated that a molecular program of alterations in embryonic genes, similar to that shown in the work‐overloaded heart, was activated in the hypertrophied heart induced by Cu deficiency.
The Effect of a Special Herbal Tea on Obesity and Anovulation in Androgen‐Sterilized Rats
Authors: Sun Fei , Yu Jin
Published: August 2010

Abstract. A special herbal tea has been used to treat clomiphene‐resistant anovulatory disease and obesity effectively, especially in polycystic ovary syndrome (PCOS) cases with hyperinsulinemia. The effect of the herbal tea on obesity and anovulation was investigated in androgen‐sterilized rats (ASR). The ASR model was established by subcutaneous injection of 1.25 mg testosterone propionate to Sprague‐Dawley female rats at the age of 9 days. Rats were sacrificed around 112 days of age. ASR manifested with PCO, anovulation, high food intake, elevated body weight, and obesity. Immunocytochemistry demonstrated that estrogen receptors (ER) were predominantly distributed in the cytoplasm of neuropeptide Y (NPY)‐containing neurons in the preoptic area (POA), and the coexpression was also found in the nuclei and fibers of NPY‐synthesizing neurons in the arcuate nucleus (ARC). Compared with that in normal control rats, NPY expression was increased, the numbers of ER in hypothalamic ARC‐median eminence (ME) decreased, gonadotropin‐releasing hormone (GnRH) levels in ME was decreased, serum estrogen (E2) and leptin were elevated, and follicular stimulating hormone (FSH) and luteinizing hormone (LH) levels were reduced significantly in ASR. Significantly negative correlations between NPY and ER or GnRH, and between leptin and FSH or LH were observed. A positive correlation existed between serum leptin and body weight. These metabolic‐endocrine changes in ASR were normalized after feeding the herbal tea. Both obesity and hypogonadotropin were expressed in ASR. The abnormal ovarian hormone milieu (elevated E2 levels) may have enhanced NPY expression and resulted in less GnRH and gonadotropin secretion. The herbal tea reduced body weight and induced ovulation in ASR.
β‐Adrenergic Agonist Hyperplastic Effect Is Associated with Increased Fibronectin Gene Expression and Not Mitogen‐Activated Protein Kinase Modulation in C2C12 Cells
Authors: Izevbigie Ernest B. , Bergen Werner G.
Published: August 2010

Abstract. β‐Adrenergic agonists (β‐AA) enhance protein accretion in skeletal muscles. This stimulation is characterized by increased protein synthesis, increased expression of myofibrillar protein genes and a depression in protein degradation in animals, and increased proliferation and DNA synthesis in muscle cells in vitro. The mechanism or signal path in muscle whereby β‐AA would elicit these physiological effects upon binding to the G protein–coupled β‐adrenergic receptor (β‐AR) is unclear. C2C12 myoblasts were used to determine β‐AR ligand binding characteristics, cyclic AMP synthesis in response to isoproterenol (ISO) stimulation, and effects of ISO on DNA synthesis, mitogen activated protein kinase (MAPK), and fibronectin (FN) gene expression. Results showed that C2C12 cells possess β‐AR which are specific, saturable, and of high affinity (Kd = 0.2 nM). Forskolin and ISO stimulated cAMP production by ≈ 20‐fold (P < 0.001) and 17‐fold (P < 0.001), respectively. ISO and the cAMP analog, 8‐bromo‐cAMP (8‐BC) stimulated DNA synthesis in proliferating cells by 150% (P < 0.05) and 200% (P < 0.01), respectively, without modulating MAPK activity, whereas addition of fetal bovine serum to culture resulted in a 500% increase (P < 0.01) in DNA synthesis and MAPK activation. DNA synthesis in C2C12 cells treated with ISO, 8‐BC, or FBS was abolished in the presence of 25 μM PD098059, an MAPK‐kinase inhibitor, suggesting that an MAPK‐dependent pathway is likely involved in C2C12 proliferation. During cAMP elevating agent stimulation, basal MAPK activity may be sufficient, in the presence of other putative signaling molecules, to support proliferation in these cells. ISO or 8‐BC treatment increased FN mRNA by three‐ and seven‐fold, respectively, in growing C2C12 cells implying a connection between increased DNA synthesis and FN gene expression.
Response of Rat Exocrine Pancreas to High‐Fat and High‐Carbohydrate Diets
Authors: Chowdhury Parimal , Nishikawa Masahiro , Blevins George W. , Rayford Phillip L.
Published: August 2010

Abstract. Intake of diets with high fat content is a risk factor for acute pancreatitis and pancreatic cancer. The underlying mechanisms leading to the development of these diseases due to high fat intake are currently unknown. The current study was designed in rats to determine the physiologic and pathological consequences of a high‐fat diet that contained excess amounts of cottonseed oil or a high‐carbohydrate diet that contained high amounts of sucrose on the exocrine pancreas. Rats were maintained on the diets for 4 weeks, and a cannula was inserted into the right jugular vein and one into the pancreatic duct for collection of pancreatic juice. Volume of the pancreatic juice and concentrations of amylase, lipase, and trypsinogen in the pancreatic juice were measured before and after infusions of CCK‐8. Results showed that basal and CCK‐stimulated pancreatic outputs of volume, amylase and lipase but not trypsinogen, were significantly elevated in intact rats given a high‐fat diet when compared with rats given a high‐carbohydrate diet. Forty‐eight hours later, rats were sacrificed, and parts of the pancreas were removed for isolation of pancreatic acinar cells and for histopathologic studies. Pancreatic acini isolated from rats on a high‐fat diet showed significantly lower basal and CCK‐stimulated amylase release when compared with those on a high‐carbohydrate diet. Histology of the pancreas of rats on a high‐carbohydrate diet appeared normal; however, the pancreas of rats on high‐fat diet showed significant alterations in exocrine pancreas. These results showed abnormalities in the exocrine pancreas of rats on a high‐fat diet, that were not found in rats on a high‐carbohydrate diet; further, they support the contention that a high‐fat diet has a deleterious effect on the pancreas.
Dietary Phytoestrogens Have Anti‐Inflammatory Activity in a Guinea Pig Model of Asthma
Authors: Regal Jean F. , Fraser Daniel G. , Weeks Charles E. , Greenberg Norman A.
Published: August 2010

Abstract.Phytoestrogens are a normal constituent of soy protein and have been shown to have anti‐inflammatory activity in variousin vitroandin vivomodels. The present study was designed to determine if a diet enriched in the phytoestrogen isoflavones, genistin and daidzin, would alter the antigen‐induced cellular infiltration, particularly eosinophilia, characteristic of a guinea pig model of asthma. Throughout the duration of the study, guinea pigs were maintained on a control diet (standard guinea pig chow) or the same diet enriched in isoflavones. The animals were placed on the diet 2 weeks prior to active sensitization with ovalbumin (OA). Three weeks after sensitization, animals were challenged with OA aerosol. The cellular infiltration into the lung and protein and red blood cells (RBC) in the bronchoalveolar lavage fluid (BAL) were determined 17 hr later. In animals maintained on the control diet, OA aerosol challenge resulted in the expected increase in eosinophils in both the BAL and the lung tissue, an increase in neutrophils in the BAL, and an increase in protein and the number of RBC in the BAL. In contrast, in animals maintained on the isoflavone diet, the OA‐induced eosinophilia in the lung tissue was significantly attenuated. In addition, OA challenge caused a greater increase in BAL protein in animals maintained on the isoflavone diet compared with animals on the control diet. Our results indicated that a diet enriched in isoflavones results in reduced antigen‐induced eosinophilia in the lung in the guinea pig model of asthma. However, this beneficial anti‐inflammatory effect of dietary phytoestrogens is accompanied by a potentially detrimental increase in antigen‐induced leakage of protein into the airspace.
Clonal Heterogeneity in Telomerase Activity and Telomere Length in Tumor‐Derived Cell Lines
Authors: Savre‐Train Isabelle , Gollahon Lauren S. , Holt Shawn E.
Published: August 2010

Abstract. The ribonucleoprotein, telomerase, is responsible for the maintenance of telomere length in most immortal and cancer cells. Telomerase appears to be a marker of human malignancy with at least 85% of human cancers expressing its activity. In the present study, we examined a series of tumor‐derived and in vitro immortalized cell lines for telomerase activity levels, telomere lengths, and expression levels of the RNA and catalytic components of telomerase. We found significant variability in both telomere lengths and telomerase activity in clones from tumor cells. In addition, the levels of telomerase components or telomerase activity were not predictive of telomere length. Data from clonally derived cells suggest that critically shortened telomeres in these tumor‐derived cell lines may signal activation of telomerase activity through an increase in the expression of the catalytic subunit of telomerase. Although clones with low telomerase shorten their telomeres over time, their subclones all have high levels of telomerase activity with no telomere shortening. In addition, analysis of early clones for telomerase activity indicates substantial variability, which suggests that activity levels fluctuate in individual cells. Our data imply that cell populations exhibit a cyclic expression of telomerase activity, which may be partially regulated by telomere shortening.
Feedback and Hormonal Regulation of Hepatic 3‐Hydroxy‐3‐Methylglutaryl Coenzyme A Reductase: The Concept of Cholesterol Buffering Capacity
Authors: Ness Gene C. , Chambers Christopher M.
Published: August 2010

Abstract. Regulation of the expression of hepatic 3‐hydroxy‐3‐methylglutaryl coenzyme A (HMG‐CoA) reductase by the major end product of the biosynthetic pathway, cholesterol, and by various hormones is critical to maintaining constant serum and tissue cholesterol levels in the face of an ever‐changing external environment. The ability to downregulate this enzyme provides a means to buffer the body against the serum cholesterol–raising action of dietary cholesterol. The higher the basal expression of hepatic HMG‐CoA reductase, the greater the “cholesterol buffering capacity” and the greater the resistance to dietary cholesterol. This review focuses on the mechanisms of feedback and hormonal regulation of HMG‐CoA reductase in intact animals rather than in cultured cells and presents the evidence that leads to the proposal that regulation of hepatic HMG‐CoA reductase acts as a cholesterol buffer. Recent studies with animals have shown that feedback regulation of hepatic HMG‐CoA reductase occurs at the level of translation in addition to transcription. The translational efficiency of HMG‐CoA reductase mRNA is diminished through the action of dietary cholesterol. Oxylanosterols appear to be involved in this translational regulation. Feedback regulation by dietary cholesterol does not appear to involve changes in the state of phosphorylation of hepatic HMG‐CoA reductase or in the rate of degradation of this enzyme. Several hormones act to alter the expression of hepatic HMG‐CoA reductase in animals. These include insulin, glucagon, glucocorticoids, thyroid hormone and estrogen. Insulin stimulates HMG‐CoA reductase activity likely by increasing the rate of transcription, whereas glucagon acts by opposing this effect. Hepatic HMG‐CoA reductase activity undergoes a significant diurnal variation due to changes in the level of immunoreactive protein primarily mediated by changes in insulin and glucagon levels. Thyroid hormone increases hepatic HMG‐CoA reductase levels by acting to increase both transcription and stability of the mRNA. Glucocorticoids act to decrease hepatic HMG‐CoA reductase expression by destabilizing reductase mRNA. Estrogen acts to increase hepatic HMG‐CoA reductase activity primarily by stabilizing the mRNA. Deficiencies in those hormones that act to increase hepatic HMG‐CoA reductase gene expression lead to elevations in serum cholesterol levels. High basal expression of hepatic HMG‐CoA reductase, whether due to genetic or hormonal factors, appears to result in greater cholesterol buffering capacity and thus increased resistance to dietary cholesterol.
Reproductive Malformation of the Male Offspring Following Maternal Exposure to Estrogenic Chemicals
Authors: Gupta Chhanda
Published: August 2010

Abstract. Recently, significant concerns have been placed on the widespread use of chemicals with persistent estrogenic activity for their long‐term effects on human health. In this communication, we investigated whether fetal exposure to some of these chemicals at doses consumed by people, has any long‐term effect on the reproductive functions of the male offspring. Thus, time‐pregnant CD‐1 mice were fed diethylstilbestrol (DES), bisphenol A (BPA), and aroclor (aroclor 1016) at an average concentration of 100 ng/kg/day, 50 μg/kg/day, and 50 μg/kg/day, respectively, during Days 16–18 of gestation. A high dose of DES (200 μg/kg/day) was also tested to compare the results of the current study with those of others using the high dose only. The offspring were examined at Day 3, Day 21, and Day 60 following birth. We demonstrated that BPA, aroclor, and the lower dose of DES enhanced anogenital distance, increased prostate size, and decreased epididymal weight. No effect was found on the testicular weight or size. The chemicals also permanently increased androgen receptor (AR) binding activity of the prostate at this dosage. This is the first demonstration that environmental chemicals program AR function permanently at the dosage consumed by the general population. The higher dosage of DES, on the other hand, produced an opposite effect, decreasing prostate weight, prostate AR binding, and anogenital distance, thus confirming the previous reports. To investigate whether the above mentioned effects of the chemicals represent direct or indirect effects, we also tested the effect of the chemicals on prostate development in vitro. Thus fetal urogenital sinus (UGS), isolated at the 17th day of gestation was cultured with the chemicals in the presence and absence of testosterone (10 ng/ml) for 6 days, and prostate growth was monitored by determining the size and branching of the specimen following histology. Results showed that these chemicals induced prostate growth in the presence and absence of testosterone. They also increased androgen‐binding activity. Thus, the results of the in vivo studies were reproduced in the in vitro experiments, suggesting a direct effect of these chemicals on the development of fetal reproductive organs. This is the first demonstration that estrogenic chemicals induce reproductive malformation by direct interference with the fetal reproductive organs and not by interfering with the maternal or fetal endocrine system. The chemicals are able to induce malformation even in the absence of fetal testosterone; however, they are more effective in the presence of testosterone.
Glucocorticoids Maintain the Extracellular Matrix of Differentiated Mammary Tissue During Explant and Whole Organ Culture
Authors: Casey Theresa M. , Boecker Almuth , Chiu Jen‐Fu , Plaut Karen
Published: August 2010

Abstract. Mouse mammary whole organ culture (WOC) and explant culture of lactating tissue were used to investigate the mechanism by which glucocorticoids maintain secretory epithelium following lobuloalveolar development. The relative number of mammary epithelial cells expressing glucocorticoid receptors did not change with the loss of secretory epithelium during involution as demonstrated with competitive binding assays and immunohistochemistry for the glucocorticoid receptor. Furthermore, glucocorticoids did not inhibit AP‐1 binding activity. However, Northern analysis demonstrated that genes associated with the breakdown of the extracellular matrix were not expressed in tissues cultured with glucocorticoids, in contrast to their upregulation during involution of mammary tissue cultured with insulin alone. Tissue inhibitor of metalloproteinase‐1 (TIMP‐1) mRNA expression was lowest in tissue cultured in the presence of glucocorticoids and increased 2.3‐, 3.4‐, and 9‐fold when tissues were involuted in the presence of insulin (Ins) alone, Ins and hydrocortisone (Hyd) with 0.005 mg/ml, or 0.01 mg/ml collagenase IV, respectively. These data indicate that glucocorticoids maintain mammary differentiation in part by inhibiting the turnover of basement membrane.
The Similarity of FSH‐Releasing Factor to Lamprey Gonadotropin‐Releasing Hormone III (l‐GnRH‐III)
Authors: Yu W. H. , Karanth S. , Sower S. A. , Parlow A. F. , McCann S. M.
Published: August 2010

Abstract. To validate further the existence of a specific hypothalamic follicle stimulating hormone releasing factor (FSHRF), stalk‐median eminence (SME) fragments from sheep and whole hypothalami from male rats were purified by gel filtration on Sephadex G‐25, and the gonadotropin‐releasing activity on hemipituitaries of rats incubated in vitro was determined by bioassay and compared with the radioimmunoassayable luteinizing hormone releasing hormone (LHRH) and lamprey gonadotropin releasing hormone (l‐GnRH) activities in the fractions. The FSH‐releasing fractions eluted in the same sequence of tubes from the Sephadex column found earlier by in vivo bioassay and were clearly separated from the immunoassayable and bioassayable LHRH. The radioimmunoassay (RIA) for l‐GnRH recognized equally l‐GnRH‐I and ‐III but had negligible cross‐reactivity with LHRH. Fractionation of rat hypothalamic extract by gel filtration on Sephadex G‐25 revealed three peaks of l‐GnRH determined by RIA, all of which eluted prior to the peak of LHRH. Only the second peak had FSH‐releasing but not LH‐releasing activity. To determine if this FSH‐releasing activity was caused by the presence of l‐GnRH in the fraction, the pituitaries were incubated with normal rabbit serum or the l‐GnRH antiserum (1:1000), and the effect on the FSH‐ and LH‐releasing activity of the FSH‐releasing fraction and the LH‐releasing activity of LHRH was determined. The antiserum had no effect on basal release of either FSH or LH but eliminated the FSH‐releasing activity of the active fraction without altering the LH‐releasing activity of LHRH. Since l‐GnRH‐I has little activity to release FSH or LH, and its activity is nonselective, whereas previous experiments have shown that l‐GnRH‐III highly selectively releases FSH with a potency equal to that of LHRH to release LH, the results support the hypothesis that the FSH‐releasing activity observed in these experiments was caused by l‐GnRH‐III or a closely related peptide.
Morphine Tolerance in Mice Changes Response of Heroin from μ to δ Opioid Receptors
Authors: Rady Jodie J. , Holmes Blythe B. , Portoghese Philip S. , Fujimoto James M.
Published: August 2010

Abstract.Heroin produced antinociception in the tail flick test through μ receptors in the brain of ICR and CD‐1 mice, a response inhibited by 3‐O‐methylnaltrexone. Tolerance to morphine was produced by subcutaneous morphine pellet implantation. By the third day, the heroin response was produced through δ opioid receptors. The response was inhibited by simultaneous intracerebroventricular (i.c.v.) administration of naltrindole, a δ opioid receptor antagonist. More specifically, δ1rather than δ2receptors were involved because 7‐benzylidenenaltrexone, a δ1receptor antagonist, inhibited but naltriben, a δ2antagonist, did not. Also, antinociception produced by i.c.v. heroin was inhibited by intrathecal administration of bicuculline and picrotoxin consistent with the concept that δ1receptors in the brain mediated the antinociceptive response through descending neuronal pathways to the spinal cord to activate GABAAand GABABreceptors rather than spinal α2‐adrenergic and serotonergic receptors activated originally by the μ agonist action in naive mice. The μ response of 6‐monoacetylmorphine, a metabolite of heroin, was changed by morphine pellet implantation to a δ2response (inhibited by naltriben but not 7‐benzylidenenaltrexone). The agonist action of morphine in these morphine‐tolerant mice remained μ. Thus, the opioid receptor selectivity of heroin and 6‐monoacetylmorphine in the brain is changed by production of tolerance to morphine. Such a change explains how morphine tolerant mice are not cross‐tolerant to heroin.
Mitochondrial Cytochrome c Release and Caspase‐3‐Like Protease Activation During Indomethacin‐Induced Apoptosis in Rat Gastric Mucosal Cells
Authors: Fujii Yasuyoshi , Matsura Tatsuya , Kai Masachika , Matsui Hirofumi , Kawasaki Hironaka , Yamada Kazuo
Published: August 2010

Abstract. Indomethacin (IND), a nonsteroidal anti‐inflammatory drug, has been known to cause gastric mucosal injury as a side effect. Using a rat gastric mucosal cell line, RGM1, we determined whether apoptosis is involved in IND‐mediated gastropathy, and whether caspase activation and mitochondrial cytochrome c release play an important role in producing apoptosis of IND‐treated RGM1 cells in the presence of serum. IND caused caspase‐3‐like protease activation followed by apoptosis in a dose‐ and time‐dependent manner. Caspase‐1‐like protease activity did not change during IND‐induced apoptosis. IND also increased mitochondrial cytochrome c release in a time‐dependent fashion. Mitochondrial cytochrome c efflux occurred just before or at the same time as caspase‐3‐like protease activation, and preceded the increase in apoptotic cell numbers. Z‐VAD‐FMK, a caspase inhibitor, inhibited both the increase in caspase‐3‐like protease activity and apoptosis in IND‐treated RGM1 cells but did not affect caspase‐1‐like protease activity or mitochondrial cytochrome c release. These observations suggest that the apoptosis of gastric mucosal cells could be involved in IND‐induced gastropathy, that cytochrome c is released from mitochondria into the cytosol during the early phase of IND‐mediated apoptosis, and that subsequent activation of caspase‐3‐like protease, but not caspase‐1‐like protease, is required for the execution of apoptosis.
Skeletal Muscle as a Myocardial Substitute
Authors: Astra Louis I. , Stephenson Larry W.
Published: August 2010

Abstract. Skeletal muscle has long been used in the field of cardiac surgery. Its use has progressed from providing myocardial reinforcement to assisting the heart by actively pumping blood. Early experiments revealed that skeletal muscle assistance could augment pressures and blood flow; however, the results were short‐lived due to muscle fatigue. It was later shown that skeletal muscle can be conditioned electrically to be fatigue resistant and therefore may be useful for performing cardiac‐type work. Once the details were formed of how to stimulate and manipulate the muscle to assist the heart, several configurations were devised. Cardiomyoplasty and aortomyoplasty refer to wrapping skeletal muscle around the heart or aorta, respectively. These techniques have been applied in humans; however, the effectiveness is controversial. Although most patients improve clinically, the hemodynamic parameters have not shown consistent improvements, and survival data are unknown. Skeletal muscle ventricles offer a promising alternative to both cardiomyoplasty and aortomyoplasty. These are completely separate pumping chambers constructed from skeletal muscle and connected to the circulation in a variety of configurations. Although these have not been tried in humans, the animal data appear quite convincing. The skeletal muscle ventricles have shown the greatest improvements on hemodynamic parameters with great stability over time.
Branched‐Chain Amino Acid–Enriched Diet: Effects on Insulin Secretion and Cellular Immune Aggression
Authors: Karabatas L. M. , De Bruno L. Fabiano , Pastorale C. , Lombardo Y. B. , Basabe J. C.
Published: August 2010

Abstract. Several reports have demonstrated that high‐protein diets may have beneficial effects on experimental models of diabetes and have raised the possibility that branched‐chain amino acids could play a role in these protective effects. We investigated the effect of a normoproteic, branched‐chain amino acid–enriched diet (experimental diet) on insulin secretion from C57BL/6N mice transferred with splenocytes from diabetic syngeneic donors. Mice previously fed with the experimental or control diet received three intraperitoneal injections, every other day, of 5 × 107 viable mononuclear splenocytes obtained from control or diabetic donors. Results showed that mice fed with the experimental diet and transferred with “diabetic” splenocytes presented: i) normoglycemia, and (ii) significantly higher levels in both phases of glucose‐induced insulin secretion and normal values of arginine‐glucose–induced insulin secretion. To evaluate the in vitro cellular immune aggression, dispersed mouse islet cells were co‐cultured with splenocytes from syngeneic diabetic mice. First, dispersed islet cells from mice on the experimental or control diet were co‐cultured with splenocytes from control or diabetic mice on a commercial diet. In the presence of “diabetic” splenocytes, dispersed islet cells from mice on the experimental diet presented a significantly lower in vitro cellular immune aggression. On the other hand, “diabetic” splenocytes from mice fed with the experimental diet produced a significantly reduced cellular immune aggression on dispersed islet cells. Our results showed that feeding branched‐chain amino acids increased the capacity of β cells to withstand a functional assault and diminished the extent of in vitro cellular immune aggression.