bluuebunny/crossref_metadata_2025 huggingface dataset:
Lumenal adenosine and AMP rapidly increase glucose transport by intact small intestine
Authors: Kimura Yasuhiro , Turner Jerrold R. , Braasch Dwaine A. , Buddington Randal K.
Published: July 2005

Adenosine modulates the intestinal functions of secretion, motility, and immunity, yet little is known about the regulation of nutrient absorption. Therefore, we measured the carrier-mediated uptake of tracer d-[14C]glucose (2 μM) by everted sleeves of the mouse intestine after a lumenal exposure to adenosine and a disodium salt of AMP. Rates of glucose uptake by intact tissues increased almost twofold after a 7-min exposure to 5 mM adenosine (a physiological dose). The response was slightly more pronounced for AMP and could be induced by forskolin. The response to adenosine was blocked by theophylline and the A2receptor antagonist 3,7-dimethyl-1-proparglyxanthine but not by the A1receptor antagonist 8-phenyltheophylline. Glucose uptake by control and AMP-stimulated tissues was inhibited by phloridzin, implying that sodium-dependent glucose transporter 1 (SGLT1) is the responsive transporter, but the involvement of glucose transporter 2 (GLUT2) cannot be excluded. Of clinical relevance, AMP accelerated the systemic availability of 3- O-methylglucose after an oral administration to mice. Our results indicate that adenosine causes a rapid increase in carrier-mediated glucose uptake that is of clinical relevance and acts via receptors linked to a signaling pathway that involves intracellular cAMP production.
Ethanol feeding enhances age-related deterioration of the rat hepatic mitochondrion
Authors: Cahill Alan , Hershman Stuart , Davies Adrian , Sykora Peter
Published: July 2005

Chronic ethanol feeding damages the hepatic mitochondrion by increasing mitochondrial DNA (mtDNA) oxidation, lowering mtDNA yields and impairing mitochondrial respiration. These effects are also seen during aging. By employing a 21-day chronic feeding regimen, we investigated the effects of ethanol consumption on mtDNA content and mitochondrial respiration in 2-, 12-, and 24-mo-old male rats. Aging resulted in decreased mtDNA content, increased mtDNA damage (as indicated by inhibition of Taq polymerase progression), and a decline in state 3 respiration; effects that were further exacerbated by ethanol feeding. Additionally, ethanol consumption caused an increase in the levels of citrate synthase while not impacting mitochondrial protein content. In conclusion, ethanol and aging combine to cause deterioration in the structural and functional integrity of the hepatic mitochondrion. The additive effects of aging and ethanol feeding may have serious consequences for hepatic energy metabolism in aged animals, and their detrimental combination may serve as one of the molecular mechanisms underlying the progression of alcoholic liver disease.
Transmural gradient of leukocyte-endothelial interaction in the rat gastrointestinal tract
Authors: Perry M. A. , Phillipson M. , Holm L.
Published: July 2005

Gastrointestinal injury usually starts in the superficial mucosa. We investigated whether leukocyte-endothelial interactions were greater in the gastrointestinal mucosa than the submucosa and muscularis in control tissue and after upregulation of adhesion molecules with endotoxin and after chemical insult with nonsteroidal anti-inflammatory drugs. Inactin-anesthetized rats were given either endotoxin, flurbiprofen, or nitric oxide (NO)-flurbiprofen, after which ICAM-1 and P-selectin expression was measured with the dual-label antibody technique. Leukocyte-endothelial interactions in the different gastric layers were assessed after endotoxin using intravital microscopy. Endotoxin caused a two- to threefold increase in ICAM-1 expression in the stomach and duodenum. There was, however, a gradient in expression across the gut wall with the level of expression in the superficial mucosa (per g) being only 10–25% of that in the deeper layers in both control and endotoxin-treated animals. Constituitive expression of P-selectin in control animals was barely detectable. Endotoxin caused a modest increase in mucosal P-selectin but a very significant increase in the deeper layers. Flurbiprofen caused a slight upregulation of ICAM-1 in the gastric mucosa and duodenum, whereas NO-flurbiprofen had no affect on expression. Intravital microscopy revealed no adhesion and virtually no leukocyte rolling in the vessels of the gastric mucosa despite endotoxin treatment. There was, however, some adhesion and significant leukocyte rolling in the submucosa and muscularis. Thus the superficial gastric and duodenal mucosal microcirculations have a much lower density of ICAM-1 and P-selectin and less leukocyte-endothelial interactions than occurs in the deeper layers of the gut wall even during stimulated upregulation with endotoxin.
Functional and molecular analysis of L-type calcium channels in human esophagus and lower esophageal sphincter smooth muscle
Authors: Kovac Jason R. , Preiksaitis Harold G. , Sims Stephen M.
Published: July 2005

Excitation of human esophageal smooth muscle involves the release of Ca2+ from intracellular stores and influx. The lower esophageal sphincter (LES) shows the distinctive property of tonic contraction; however, the mechanisms by which this is maintained are incompletely understood. We examined Ca2+ channels in human esophageal muscle and investigated their contribution to LES tone. Functional effects were examined with tension recordings, currents were recorded with patch-clamp electrophysiology, channel expression was explored by RT-PCR, and intracellular Ca2+ concentration was monitored by fura-2 fluorescence. LES muscle strips developed tone that was abolished by the removal of extracellular Ca2+ and reduced by the application of the L-type Ca2+ channel blocker nifedipine (to 13 ± 6% of control) but was unaffected by the inhibition of sarco(endo)plasmic reticulum Ca2+-ATPase by cyclopiazonic acid (CPA). Carbachol increased tension above basal tone, and this effect was attenuated by treatment with CPA and nifedipine. Voltage-dependent inward currents were studied using patch-clamp techniques and dissociated cells. Similar inward currents were observed in esophageal body (EB) and LES smooth muscle cells. The inward currents in both tissues were blocked by nifedipine, enhanced by Bay K8644, and transiently suppressed by acetylcholine. The molecular form of the Ca2+ channel was explored using RT-PCR, and similar splice variant combinations of the pore-forming α1C-subunit were identified in EB and LES. This is the first characterization of Ca2+ channels in human esophageal smooth muscle, and we establish that L-type Ca2+ channels play a critical role in maintaining LES tone.
Extreme hemodilution with PEG-hemoglobin vs. PEG-albumin
Authors: Cabrales Pedro , Tsai Amy G. , Winslow Robert M. , Intaglietta Marcos
Published: July 2005

Isovolemic hemodilution to 11% systemic hematocrit was performed in the hamster window chamber model using 6% dextran 70 kDa (Dx 70) and 5% human serum albumin (HSA). Systemic and microvascular effects of these solutions were compared with polyethylene glycol (PEG)-conjugated 5% albumin (MPA) and PEG-conjugated 4.2% Hb (MP4). These studies were performed for the purpose of comparing systemic and microvascular responses of PEG vs. non-PEG plasma expanders and similar oxygen-carrying vs. noncarrying blood replacement fluids. Mean arterial blood pressure was statistically significantly reduced for all groups compared with baseline ( P < 0.05), HSA, MPA, and MP4 higher than Dx 70 ( P < 0.05). MP4 and MPA had a significantly higher cardiac index than HSA and Dx 70, in addition to a positive base excess. Microvascular blood flow and capillary perfusion were significantly higher for the PEG compounds compared with HSA and Dx 70. Intravascular Po2 for MP4 and MPA was higher in arterioles ( P < 0.05) compared with HSA and Dx 70, but there was no difference in either tissue or venular Po2 between groups. Total Hb in the MP4 group was 4.8 ± 0.4 g/dl, whereas the remaining groups had a range of 3.6–3.8 g/dl. The hemodilution results showed that PEG compounds maintained microvascular conditions with lower concentrations than conventional plasma expanders. Furthermore, microvascular oxygen delivery and extraction in the window chamber tissue were significantly higher for the PEG compounds. MP4 was significantly higher than MPA ( P < 0.05) and was not statistically different from baseline, an effect due to the additional oxygen release to the tissue by the Hb MP4.
Active metabolite of GLP-1 mediates myocardial glucose uptake and improves left ventricular performance in conscious dogs with dilated cardiomyopathy
Authors: Nikolaidis Lazaros A. , Elahi Dariush , Shen You-Tang , Shannon Richard P.
Published: July 2005

We have shown previously that the glucagon-like peptide-1 (GLP-1)-(7–36) amide increases myocardial glucose uptake and improves left ventricular (LV) and systemic hemodynamics in both conscious dogs with pacing-induced dilated cardiomyopathy (DCM) and humans with LV systolic dysfunction after acute myocardial infarction. However, GLP-1-(7–36) is rapidly degraded in the plasma to GLP-1-(9–36) by dipeptidyl peptidase IV (DPP IV), raising the issue of which peptide is the active moiety. By way of methodology, we compared the efficacy of a 48-h continuous intravenous infusion of GLP-1-(7–36) (1.5 pmol·kg−1·min−1) to GLP-1-(9–36) (1.5 pmol·kg−1·min−1) in 28 conscious, chronically instrumented dogs with pacing-induced DCM by measuring LV function and transmyocardial substrate uptake under basal and insulin-stimulated conditions using hyperinsulinemic-euglycemic clamps. As a result, dogs with DCM demonstrated myocardial insulin resistance under basal and insulin-stimulated conditions. Both GLP-1-(7–36) and GLP-1-(9–36) significantly reduced ( P < 0.01) LV end-diastolic pressure [GLP-1-(7–36), 28 ± 1 to 15 ± 2 mmHg; GLP-1-(9–36), 29 ± 2 to 16 ± 1 mmHg] and significantly increased ( P < 0.01) the first derivative of LV pressure [GLP-1-(7–36), 1,315 ± 81 to 2,195 ± 102 mmHg/s; GLP-1-(9–36), 1,336 ± 77 to 2,208 ± 68 mmHg] and cardiac output [GLP-1-(7–36), 1.5 ± 0.1 to 1.9 ± 0.1 l/min; GLP-1-(9–36), 2.0 ± 0.1 to 2.4 ± 0.05 l/min], whereas an equivolume infusion of saline had no effect. Both peptides increased myocardial glucose uptake but without a significant increase in plasma insulin. During the GLP-1-(9–36) infusion, negligible active (NH2-terminal) peptide was measured in the plasma. In conclusion, in DCM, GLP-1-(9–36) mimics the effects of GLP-1-(7–36) in stimulating myocardial glucose uptake and improving LV and systemic hemodynamics through insulinomimetic as opposed to insulinotropic effects. These data suggest that GLP-1-(9–36) amide is an active peptide.
NMDA channels control meal size via central vagal afferent terminals
Authors: Gillespie B. R. , Burns G. A. , Ritter R. C.
Published: July 2005

The N-methyl-d-aspartate (NMDA) ion channel blocker MK-801 administered systemically or as a nanoliter injection into the nucleus of the solitary tract (NTS), increases meal size. Furthermore, we have observed that ablation of the NTS abolishes increased meal size following systemic injection of dizocilpine (MK-801) and that MK-801-induced increases in intake are attenuated in rats pretreated with capsaicin to destroy small, unmyelinated, primary afferent neurons. These findings led us to hypothesize that NMDA receptors on central vagal afferent terminals or on higher-order NTS neurons innervated by these vagal afferents might mediate increased food intake. To evaluate this hypothesis, we examined 15% sucrose intake after 50-nl MK-801 injections ipsilateral or contralateral to unilateral nodose ganglion removal (ganglionectomy). On the side contralateral to ganglionectomy, vagal afferent terminals would be intact and functional, whereas ipsilateral to ganglionectomy vagal afferent terminals would be absent. Three additional control preparations also were included: 1) sham ganglionectomy and 2) subnodose vagotomy either contralateral or ipsilateral to NTS cannula placement. We found that rats with subnodose vagotomies increased their sucrose intake after injections of MK-801 compared with saline, regardless of whether injections were made contralateral (12.6 ± 0.2 vs. 9.6 ± 0.3 ml) or ipsilateral (14.2 ± 0.6 vs. 9.7 ± 0.4 ml) to vagotomy. Rats with NTS cannula placements contralateral to nodose ganglionectomy also increased their intake after MK-801 (12.2 ± 0.9 and 9.2 ± 1.1 ml for MK-801 and saline, respectively). However, rats with placements ipsilateral to ganglionectomy did not respond to MK-801 (8.0 ± 0.5 ml) compared with saline (8.3 ± 0.4 ml). We conclude that central vagal afferent terminals are necessary for increased food intake in response to NMDA ion channel blockade. The function of central vagal afferent processes or the activity of higher-order NTS neurons driven by vagal afferents may be modulated by NMDA receptors to control meal size.
Functional coupling of adenine nucleotide translocase and mitochondrial creatine kinase is enhanced after exercise training in lung transplant skeletal muscle
Authors: Guerrero Karen , Wuyam Bernard , Mezin Paulette , Vivodtzev Isabelle , Vendelin Marko , Borel Jean-Christian , Hacini Rachid , Chavanon Olivier , Imbeaud Sandrine , Saks Valdur , Pison Christophe
Published: July 2005

Mechanisms responsible for limitation of exercise capacity in lung transplant recipients (LR) and benefits gained by exercise training were studied. Mitochondrial respiration parameters, energy transfer, and cell structure were assessed in vastus lateralis biopsies using the permeabilized fiber technique with histochemical and morphometric measurements. Twelve male controls (C) and 12 LR performed exercise training over 12 wk. Before exercise training, there were strong correlations between exercise capacity (maximal O2 consumption and endurance time at 70% maximal power output) and cellular events, as assessed by percentage of type I fibers and apparent Km for exogenous ADP. Anticalcineurins were not involved in LR exercise limitation, since there were no differences in maximal mitochondrial rate of respiration before exercise training and no abnormalities in respiratory chain complexes compared with C. Training resulted in a significant increase in physiological parameters both at the cellular (apparent Km for exogenous ADP and stimulating effect of creatine) and integrated (maximal O2 consumption, power output at ventilatory threshold, maximal power output, and endurance time at 70% maximal power output) levels in LR and C. After the training period, improvements in maximal O2 consumption and in maximal mitochondrial rate of respiration were noted, as well as changes in endurance time and percentage of type I fibers. Because there were no changes in diameters and fiber types, baseline alteration of apparent Km for exogenous ADP and its improvement after training might be related to changes within the intracellular energetic units. After the training period, intracellular energetic units exhibited a higher control of mitochondrial respiration by creatine linked to a more efficient functional coupling adenine nucleotide translocase-mitochondrial creatine kinase, resulting in better exercise performances in C and LR.
Phospholipid profile of developing heart of rats exposed to low-protein diet in pregnancy
Authors: Tappia Paramjit S. , Nijjar Mohinder S. , Mahay Aric , Aroutiounova Nina , Dhalla Naranjan S.
Published: July 2005

Although the myocardial phospholipid and fatty acid content have profound effects on the heart function, very little information is available on the effects of restricted maternal protein intake during pregnancy on the phospholipid profile and fatty acid content of the developing heart. The present study was therefore undertaken to examine the effect of pregnant dams fed diets containing either 180 (normal) or 90 (low) g/kg casein diet for 2 wk before mating and throughout pregnancy on myocardial phospholipid and fatty acid content of male offspring. Whereas no changes in phosphatidylcholine and phosphatidylethanolamine were detected, increases in lysophosphatidylcholine, phosphatidylserine, and sphingomyelin were seen in the hearts of offspring in the low-protein (LP) group. Analysis of cardiac fatty acids revealed that although the saturated fatty acid (myristate, palmitate, and stearate) levels were significantly reduced, the unsaturated fatty acid (linoleate, arachidonate, and decosahexanoate) levels were significantly increased in the developing heart in the LP group. Furthermore, assessment of nuclear transcription factors involved in regulation of cardiac metabolism revealed a decrease in myocyte enhancer factor-2C mRNA levels in the LP group, whereas an increase in the mRNA amount of peroxisome proliferator-activated receptor-α was observed in this group. These results demonstrate that maternal LP diet can induce changes in the phospholipid profile and fatty acid content of the developing heart, which may have implications for metabolism of the neonatal heart.
Supramaximal exercise mobilizes hematopoietic progenitors and reticulocytes in athletes
Authors: Morici Giuseppe , Zangla Daniele , Santoro Alessandra , Pelosi Elvira , Petrucci Eleonora , Gioia Maria , Bonanno Anna , Profita Mirella , Bellia Vincenzo , Testa Ugo , Bonsignore Maria R.
Published: July 2005

Marathon runners show increased circulating CD34+ cell counts and postexercise release of interleukin-6 (IL-6), granulocyte-colony stimulating factor (G-CSF) and flt3-ligand (Bonsignore MR, Morici G, Santoro A, Pegano M, Cascio L, Bonnano A, Abate P, Mirabella F, Profita M, Insalaco G, Gioia M, Vignola AM, Majolino I, Testa U, and Hogg JC. J Appl Physiol 93: 1691–1697, 2002). In the present study we hypothesized that supramaximal (“all-out”) exercise may acutely affect circulating progenitors and reticulocytes and investigated possible mechanisms involved. Progenitor release was measured by flow cytometry ( n = 20) and clonogenic assays ( n = 6) in 20 young competitive rowers (13 M, 7 F, age ± SD: 17.1 ± 2.1 yr, peak O2consumption: 56.5 ± 11.4 ml·min−1·kg−1) at rest and shortly after 1,000 m “all-out.” Release of reticulocytes, cortisol, muscle enzymes, neutrophil elastase, and several cytokines/growth factors was measured. Supramaximal exercise doubled circulating CD34+ cells (rest: 7.6 ± 3.0, all-out: 16.3 ± 9.1 cells/μl, P < 0.001), and increased immature reticulocyte fractions; AC133+ cells doubled, suggesting release of angiogenetic precursors. Erythrocyte burst forming units and colony forming units for granulocytes-monocytes and all blood series increased postexercise by 3.4-, 5.5-, and 4.8-fold, respectively ( P < 0.01 for all). All-out rowing acutely increased plasma cortisol, neutrophil elastase, flt3-ligand, hepatocyte growth factor, VEGF, and transforming growth factor-β1, and decreased erythropoietin; K-ligand, stromal-derived factor-1, IL-6, and G-CSF were unchanged. Therefore, all-out exercise is a physiological stimulus for progenitor release in athletes. Release of reticulocytes and proangiogenetic cells and mediators suggests tissue hypoxia as possibly involved in progenitor mobilization.
Gas exchange during exercise in habitually active asthmatic subjects
Authors: Haverkamp H. C. , Dempsey J. A. , Miller J. D. , Romer L. M. , Pegelow D. F. , Rodman J. R. , Eldridge M. W.
Published: July 2005

We determined the relations among gas exchange, breathing mechanics, and airway inflammation during moderate- to maximum-intensity exercise in asthmatic subjects. Twenty-one habitually active (48.2 ± 7.0 ml·kg−1·min−1 maximal O2 uptake) mildly to moderately asthmatic subjects (94 ± 13% predicted forced expiratory volume in 1.0 s) performed treadmill exercise to exhaustion (11.2 ± 0.15 min) at ∼90% of maximal O2 uptake. Arterial O2 saturation decreased to ≤94% during the exercise in 8 of 21 subjects, in large part as a result of a decrease in arterial Po2 (PaO2): from 93.0 ± 7.7 to 79.7 ± 4.0 Torr. A widened alveolar-to-arterial Po2 difference and the magnitude of the ventilatory response contributed approximately equally to the decrease in PaO2 during exercise. Airflow limitation and airway inflammation at baseline did not correlate with exercise gas exchange, but an exercise-induced increase in sputum histamine levels correlated with exercise PaO2 (negatively) and alveolar-to-arterial Po2 difference (positively). Mean pulmonary resistance was high during exercise (3.4 ± 1.2 cmH2O·l−1·s) and did not increase throughout exercise. Expiratory flow limitation occurred in 19 of 21 subjects, averaging 43 ± 35% of tidal volume near end exercise, and end-expiratory lung volume rose progressively to 0.25 ± 0.47 liter greater than resting end-expiratory lung volume at exhaustion. These mechanical constraints to ventilation contributed to a heterogeneous and frequently insufficient ventilatory response; arterial Pco2 was 30–47 Torr at end exercise. Thus pulmonary gas exchange is impaired during high-intensity exercise in a significant number of habitually active asthmatic subjects because of high airway resistance and, possibly, a deleterious effect of exercise-induced airway inflammation on gas exchange efficiency.
Long-range diffusion of hyperpolarized 3He in explanted normal and emphysematous human lungs via magnetization tagging
Authors: Woods Jason C. , Yablonskiy Dmitriy A. , Choong Cliff K. , Chino Kimiaki , Pierce John A. , Hogg James C. , Bentley John , Cooper Joel D. , Conradi Mark S. , Macklem Peter T.
Published: July 2005

Long-range diffusivity of hyperpolarized 3He gas was measured from the decay rate of sinusoidally modulated longitudinal nuclear magnetization in three normal donor and nine severely emphysematous explanted human lungs. This (long-range) diffusivity, which we call Dsec, is measured over seconds and centimeters and is ∼10 times smaller in healthy lungs (0.022 cm2/s) than the more traditionally measured Dmsec, which is measured over milliseconds and submillimeters. The increased restriction of Dsec reflects the complex, tortuous paths required to navigate long distances through the maze of branching peripheral airways. In emphysematous lungs, Dsec is substantially increased, with some regions showing nearly the unrestricted value of the self-diffusion coefficient (0.88 cm2/s for dilute 3He in air, a 40-fold increase). This suggests the presence of large collateral pathways opened by alveolar destruction that bypass the airways proper. This destruction was confirmed by comparison with histology in seven lungs and by removal of trapped gas via holes in the pleural surface in five lungs.
Cyclopiazonic acid activates a Ca2+-permeable, nonselective cation conductance in porcine and bovine tracheal smooth muscle
Authors: Helli Peter B. , Pertens Evi , Janssen Luke J.
Published: July 2005

Capacitative Ca2+ entry has been examined in several tissues and, in some, appears to be mediated by nonselective cation channels collectively referred to as “store-operated” cation channels; however, relatively little is known about the electrophysiological properties of these channels in airway smooth muscle. Consequently we examined the electrophysiological characteristics and changes in intracellular Ca2+ concentration associated with a cyclopiazonic acid (CPA)-evoked current in porcine and bovine airway smooth muscle using patch-clamp and Ca2+-fluorescence techniques. In bovine tracheal myocytes, CPA induced an elevation of intracellular Ca2+ that was dependent on extracellular Ca2+ and was insensitive to nifedipine (an l-type voltage-gated Ca2+ channel inhibitor). Using patch-clamp techniques and conditions that block both K+ and Cl− currents, we found that CPA rapidly activated a membrane conductance ( ICPA) in porcine and bovine tracheal myocytes that exhibits a linear current-voltage relationship with a reversal potential around 0 mV. Replacement of extracellular Na+ resulted in a marked reduction of ICPA at physiological membrane potentials (i.e., −60 mV) that was accompanied by a shift in the reversal potential for ICPA toward more negative membrane potentials. In addition, ICPA was markedly inhibited by 10 μM Gd3+ and La3+ but was largely insensitive to 1 μM nifedipine. We conclude that CPA induces capacitative Ca2+ entry in porcine and bovine tracheal smooth muscle via a Gd3+- and La3+-sensitive, nonselective cation conductance.
Mechanical Signals, IGF-I Gene Splicing, and Muscle Adaptation
Authors: Goldspink Geoffrey
Published: July 2005

Combining physiological and molecular biology methods made it possible to identify and characterize a local muscle growth/repair factor (MGF). Following resistance exercise, MGF “kick starts” muscle hypertrophy and is important in local tissue repair. Loss of muscle mass in old age and certain diseases is associated with an impaired ability to express MGF.
Skeletal Muscle Glucose Uptake During Exercise: How is it Regulated?
Authors: Rose Adam J. , Richter Erik A.
Published: July 2005

The increase in skeletal muscle glucose uptake during exercise results from a coordinated increase in rates of glucose delivery (higher capillary perfusion), surface membrane glucose transport, and intracellular substrate flux through glycolysis. The mechanism behind the movement of GLUT4 to surface membranes and the subsequent increase in transport by muscle contractions is largely unresolved, but it is likely to occur through intracellular signaling involving Ca2+-calmodulin-dependent protein kinase, 5′-AMP-activated protein kinase, and possibly protein kinase C.
Biogenic Amine Neurotransmitter Transporters: Just When You Thought You Knew Them
Authors: Blakely Randy D. , DeFelice Louis J. , Galli Aurelio
Published: July 2005

Plasma membrane transporters have long been known to support the reuptake of biogenic amine neurotransmitters following release in the central and peripheral nervous systems. Using high-resolution imaging, patch-clamp and amperometric approaches, as well as molecular manipulations of transporter-regulatory pathways, surprising new details have been uncovered as to how transporters work and are influenced by signaling pathways and psychostimulants.
Myosins: Tails (and Heads) of Functional Diversity
Authors: Krendel Mira , Mooseker Mark S.
Published: July 2005

The myosin family of actin filament-based molecular motors consists of at least 20 structurally and functionally distinct classes. The human genome contains nearly 40 myosin genes, encoding 12 of these classes. Myosins have been implicated in a variety of intracellular functions, including cell migration and adhesion; intracellular transport and localization of organelles and macromolecules; signal transduction; and tumor suppression. In this review, recent insights into the remarkable diversity in the mechanochemical and functional properties associated with this family of molecular motors are discussed.
Turning Signals On and Off: GLUT4 Traffic in the Insulin-Signaling Highway
Authors: Thong Farah S. L. , Dugani Chandrasagar B. , Klip Amira
Published: July 2005

Insulin stimulation of glucose uptake into skeletal muscle and adipose tissues is achieved by accelerating glucose transporter GLUT4 exocytosis from intracellular compartments to the plasma membrane and minimally reducing its endocytosis. The round trip of GLUT4 is intricately regulated by diverse signaling molecules impinging on specific compartments. Here we highlight the key molecular signals that are turned on and off by insulin to accomplish this task.
Long-Term Results of Lamivudine Monotherapy in Korean Patients with HBeAg-Positive Chronic Hepatitis B: Response and Relapse Rates, and Factors Related to Durability of HBeAg Seroconversion
Authors: Yoon Seung Kew , Jang Jeong Won , Kim Chang Wook , Bae Si Hyun , Choi Jong Young , Choi Sang Wook , Lee Young Sok , Lee Chang Don , Chung Kyu Won , Sun Hee Sik , Kim Boo Sung
Published: July 2005

Objective: The aim of this study was to evaluate retrospectively the long-term effects of lamivudine in 461 Korean patients with chronic hepatitis B who were treated for more than 12 months. Methods: The annual rates of virological response and breakthrough were examined and the predictive factors for post-treatment relapse in 114 patients who achieved hepatitis B e antigen (HBeAg) loss or seroconversion after lamivudine therapy were also analyzed. Results: During follow-up, the rates of HBeAg seroconversion after 1, 2, 3, 4 and 5 years of treatment were 22.9, 33.2, 47.6, 54.2 and 58.8%, respectively, while those for virological breakthrough at 1, 2, 3 and 4 years were 8.2, 41.7, 55.7 and 64.8%, respectively. Ninety-five patients (20.6%) had HBeAg seroconversion and 19 (4.1%) showed HBeAg loss alone with disappearance of hepatitis B virus DNA in serum. Seroconversion was higher with prolonged treatment in patients who had elevated serum alanine aminotransferase. The cumulative relapse rates in the seroconversion group were 52.0 and 55.7% 1 and 2 years after treatment, respectively. Age and the duration of additional treatment were significant predictive factors for post-treatment relapse. Patients aged ≤40 who had additional treatment for >12 months after seroconversion had the lowest relapse rate (p < 0.001). Conclusions: These results suggest that additional treatment for over 12 months after HBeAg seroconversion in younger patients may produce a better long-term outcome.
Mycosis fungoides in European Russia: No Antibodies to Human T Cell Leukemia Virus Type I Structural Proteins, but Virus-Like Sequences in Blood and Saliva
Authors: Morozov Vladimir A. , Syrtsev Alexander V. , Ellerbrok Heinz , Nikolaeva Elena V. , Bavykin Andrei S. , Pauli Georg
Published: July 2005

Objective: Mycosis fungoides (MF) is the most frequent form of cutaneous T cell lymphoma (CTCL). Human T cell leukemia virus type 1 (HTLV-1) involvement in MF progression is a matter of debate. The goal of the investigation was to search for HTLV-1 markers in a group of MF patients from a nonendemic area to HTLV-1. Materials and Methods: Fifty MF patients and 60 healthy donors from Moscow and the Moscow region were examined for HTLV-1 markers by Western blot, PCR, nested PCR, PCR/Southern hybridization, TaqMan real-time PCR and sequencing. Results: Plasma samples from MF patients were repeatedly negative for antibodies to HTLV-1 structural proteins. HTLV-1 tax-related sequences (corresponding to the second exon) were found in blood from 20 of 50 MF patients and in 3 of 5 saliva specimens. Three of 8 sequenced tax-like amplimers were identical and 5 of 8 contained 1–2 substitutions. tax transcripts and antibodies to p40tax were detected in some ‘PCR-tax’-positive MF patients. Defective HTLV-1 genomes were demonstrated in 2 of 50 MF patients. Phylogenetic analysis of the defective genome 5′-LTR sequence revealed a relationship with HTLV-1a sequences from the transcontinental subgroup of HTLV-1. Conclusions: HTLV-1 tax-like sequences were revealed in blood and for the first time in saliva from MF patients living in an HTLV-1 nonendemic region. Expression of tax-like sequences was confirmed by both reverse transcription PCR and Western blot.
Polymerase Domain B Mutation Is Associated with Hepatitis Relapse during Long-Term Lamivudine Therapy for Chronic Hepatitis B
Authors: Nakanishi Hiroyuki , Kurosaki Masayuki , Asahina Yasuhiro , Onuki Yuko , Ueda Ken , Nishimura Yuki , Tsuchiya Kaoru , Kitamura Takatoshi , Uchihara Masakatsu , Miyake Shozo , Enomoto Nobuyuki , Izumi Namiki
Published: July 2005

Breakthrough hepatitis remains the major issue in long-term lamivudine therapy for chronic hepatitis B. However, the emergence of drug-resistant hepatitis B virus (HBV) is not always accompanied by a relapse of hepatitis. To elucidate factors predictive of breakthrough hepatitis, 53 patients with genotype C of HBV on long-term lamivudine therapy were analyzed. HBV reappeared during therapy in 19 patients with a cumulative incidence of 15% at 1 year, 34% at 2 years, and 60% at 3 years. Within this group, breakthrough hepatitis developed in 12 patients (63%). A polymerase gene domain B mutation (rt180M) emerged in 13 patients, and domain C mutations (rt204I, rt204V) were found in 19 patients. The rt180M mutation was associated with breakthrough hepatitis (p < 0.05) with a positive predictive value of 85% and a negative predictive value of 83%. Patients with the rt180M mutation had higher HBV-DNA levels during viral breakthrough compared to patients with rt180wt (p < 0.05). The mutational pattern of rt204 was not associated with breakthrough hepatitis. In conclusion, genotypic assays for the rt180M mutation after viral breakthrough may be useful in predicting the risk of breakthrough hepatitis and in deciding when to initiate alternative or additive nucleoside analogue therapy.
Nucleic Acid Sequence Analysis of Basal Core Promoter/Precore/Core Region of Hepatitis B Virus Isolated from Chronic Carriers of the Virus from Kolkata, Eastern India: Low Frequency of Mutation in the Precore Region
Authors: Banerjee Arup , Banerjee Soma , Chowdhury Abhijit , Santra Amal , Chowdhury Sujit , Roychowdhury Susanta , Panda Chinmoy Kumar , Bhattacharya Sujit Kumar , Chakravarty Runu
Published: July 2005

Objective: The aim of the present study was to characterize the predominant hepatitis B virus (HBV) strains and their molecular variants present in the HBV isolates of the different genotypes found among the chronic carriers of the virus in our community. Methods: Precore/core and core promoter regions of HBV DNA were amplified by polymerase chain reaction and then subjected to direct sequencing. Of the 64 hepatitis B surface antigen (HBsAg)-positive chronic HBV carriers investigated, 44 were HBeAg negative and 20 were HBeAg positive. Results: In addition to genotype D, which was the predominant genotype, 12 genotype C (18.7%) and 6 genotype A (9.4%) were also detected. Presence of T at nt 1858 has often been related to the development of precore stop mutation at nt 1896, while that of C has been related to the development of 1762–1764 double mutation. In our study group, 39 of the 44 HBeAg-negative samples have T1858. The precore stop codon mutation was found in only 8 (18%) of the HBeAg-negative samples. More than half of the HBeAg-negative samples had wild-type sequence in the precore region. The core promoter region could be sequenced from 40 samples, and 1762–1764 double mutation was detected in 13 (32.5%) of them. No significant changes could be detected in the core amino acid sequence of these isolates. Conclusion: The pattern of core promoter and precore mutation of HBV isolates in the present study is atypical and not in accordance with reports from other parts of the world, where genotype D and genotype C with T at codon 1858 are common.
Usefulness of the Serum KL-6 Assay in Patients with Hepatitis C Virus
Authors: Arase Yasuji , Ikeda Kenji , Suzuki Fumitaka , Suzuki Yoshiyuki , Saitoh Satoshi , Kobayashi Masahiro , Akuta Norio , Someya Takashi , Hosaka Tetsuya , Sezaki Hitomi , Kobayashi Mariko , Kumada Hiromitsu
Published: July 2005

Objective: The aim of this study is to evaluate the serum level of KL-6 in hepatitis C virus (HCV)-positive patients with chronic liver disease. Methods and Results: Subjects consisted of 502 HCV-positive patients. The serum samples of these patients stored at –80°C were measured by enzyme-linked immunosorbent assay for KL-6 at the same time. The cutoff point of the serum KL-6 level was defined as 500 U/ml. The serum KL-6 level of the 502 patients ranged between 71 and 2,295 (median, 223) U/ml. Thirty-two of the 502 (6.4%) patients showed an elevated KL-6 level of >500 U/ml. Three of the 32 (9.4%) patients with elevated KL-6 level >500 U/ml had idiopathic pulmonary fibrosis. Multivariate analysis showed that patients achieved elevated KL-6 when: (1) they had hepatocellular carcinoma (HCC; p = 0.0007), and (2) age was >60 years (p = 0.0085). The HCC rate was 37.5% (12/32) in the patients with elevated KL-6 and 8.3% (39/470) in the patients with normal KL-6 group. The median (range) age was 70 (56–77) years in the patients with elevated KL-6 group and 60 (12–92) years in the patients with normal KL-6. Conclusion: The patients with HCC aged >60 years had significantly elevated serum levels of KL-6.
Dose-Dense Sequential Adriamycin-Paclitaxel-Cyclophosphamide Chemotherapy Is Well Tolerated and Safe in High-Risk Early Breast Cancer
Authors: Kahan Zsuzsanna , Uhercsak Gabriella , Hajnal-Papp Rozalia , Boda Krisztina , Thurzo Laszlo
Published: July 2005

Objective: The feasibility of dose-dense sequential adjuvant chemotherapy with Adriamycin, paclitaxel and cyclophosphamide was evaluated. Methods: Fifty-five high-risk breast cancer patients were enrolled. The following chemotherapy schedule was used: 4 × Adriamycin → 4 × paclitaxel → 4 × cyclophosphamide, q 2 weeks (Adriamycin, 60 mg/m2; paclitaxel, 200 mg/m2 over 3 h, and cyclophosphamide, 800 mg/m2). Results: The dose intensity was 95.0, 99.8 and 97.4% of that planned for treatment with Adriamycin, paclitaxel and cyclophosphamide, respectively. During treatment with Adriamycin, paclitaxel and cyclophosphamide, 20, 12.7 and 25.5% of the patients, respectively, did not need filgrastim to maintain the dose density. The average number of filgrastim doses per cycle, when necessary, was 3.6. Neutropenia of grade 3–4 was found in 67.3, 13.5 and 10.0% of the patients after treatment with Adriamycin, paclitaxel and cyclophosphamide, respectively. A single case of febrile neutropenia was observed. Anemia occurred in 96.4% of the patients, and was significantly more frequent (p = 0.031) and more severe (p = 0.002) during paclitaxel treatment than in the other chemotherapy cycles. Conclusions: Dose-dense sequential chemotherapy with Adriamycin, paclitaxel and cyclophosphamide is well tolerated and safe. Individual treatment with granulocyte colony-stimulating factor is needed to maintain the dose density in most patients, but some tolerate this regimen without it, probably due to differences in drug clearances.
Leptin Is Associated with an Increased Female Colorectal Cancer Risk: A Nested Case-Control Study in Japan
Authors: Tamakoshi Koji , Toyoshima Hideaki , Wakai Kenji , Kojima Masayo , Suzuki Koji , Watanabe Yoshiyuki , Hayakawa Norihiko , Yatsuya Hiroshi , Kondo Takaaki , Tokudome Shinkan , Hashimoto Shuji , Suzuki Sadao , Kawado Miyuki , Ozasa Kotaro , Ito Yoshinori , Tamakoshi Akiko
Published: July 2005

Objective: To elucidate whether leptin is involved in the etiology of female colorectal cancer. Methods: A case-control study nested in the Japan Collaborative Cohort Study. We compared serum leptin levels in 58 cases of female colorectal cancer with those in 145 controls matched for study area and age. Data were analyzed using a conditional logistic regression model with adjustments for known risk factors for the development of colorectal cancer. Quintile cutoff points were determined on the distribution of leptin levels in cases and controls combined. Results: Serum geometric mean levels of leptin were 6.88 ng/ml in cases and 6.00 ng/ml in controls. The odds ratios of female colorectal cancer risk were 1.40 (95% confidence interval, CI: 0.41–4.78) for the category of the second and third quintiles combined, and 4.84 (CI: 1.29–18.1) for the category of the fourth and fifth quintiles combined relative to the first quintile after adjustment for body mass index (BMI), life-style factors, reproductive factors, and hormonal variables including insulin-like growth factor and its binding protein. Conclusion: Our results suggest that leptin most likely increases the risk of female colorectal cancer substantially independent of BMI.
Phase II Trial of Primary Radiation Therapy and Concurrent Chemotherapy for Patients with Locally Advanced Pancreatic Cancer
Authors: Magnino A. , Gatti M. , Massucco P. , Sperti E. , Faggiuolo R. , Regge D. , Capussotti L. , Gabriele P. , Aglietta M.
Published: July 2005

Objectives: Primary chemoradiotherapy for locally advanced pancreatic cancer (LAPC) may improve local control, curative resection rate and long-term survival. We performed a phase II study to evaluate toxicity and activity of primary radiation therapy and concurrent chemotherapy with gemcitabine (GEM) twice weekly in patients (pts) with LAPC. Methods: From 6/1999 to 6/2003, 23 LAPC pts received GEM 100 mg/m2 twice weekly in the first 15 pts and 50 mg/m2 in the last 8 pts, concurrently with radiotherapy (1.8 Gy/day for a total dose of 45 Gy). Results: The treatment was completed in 19/23 pts. Toxicities: G3–4 hematological toxicity occurred in 35 and 4% respectively; G3 nausea and vomiting and gastrointestinal toxicity in 30%. Clinical benefit was found in 10/18 pts (55%). Overall response: partial response rate 4/18 (22%); stable disease 13/18 (72%); progressive disease 1/18 (6%). Six pts underwent pancreaticoduodenectomy with extended lymphadenectomy (5/6 pts pT3, 1/6 pts microscopic cancer foci, 1/6 N+, 5/6 negative retroperitoneal margin). Median survival: 14 months for the entire group, 12 months for unresected pts, 20 months for resected pts. Conclusions: The treatment with GEM twice weekly at 50 mg/m2 associated with radiotherapy (45 Gy) is feasible and permits to obtain clinical benefit in a good percentage of pts. Objective response, median survival, and local and systemic control are similar to other studies and need further improvement.
Uterine Prolapse in Pregnancy
Authors: Guariglia Lorenzo , Carducci Brigida , Botta Angela , Ferrazzani Sergio , Caruso Alessandro
Published: July 2005

We present a case of a patient developing uterine prolapse during pregnancy. The cervix reached the introitus at 10 weeks gestation and subsequentely protruted progressively as the pregnancy advanced. The patient was conservatively treated with bed rest and the main maternal and fetal risks are avoided. At 4 months postpartum follow-up there was no evidence of uterine prolapse.
Retinal Perfusion Response to a Slow Multifocal M-Sequence Flicker Stimulation
Authors: Palmowski-Wolfe Anja M. , Vilser Walthard , Laack Ulrich , Müller Dieter , Ruprecht Klaus W.
Published: July 2005

Purpose: To assess, if a slow multifocal stimulus (mfS) can provoke a perfusion response that can be measured with the Retinal Vessel Analyzer (RVATM). Methods: Seventeen eyes were examined. Pupils were dilated. A 120-second baseline recording was obtained with the RVA. The subject then turned to view an mfS for 56 s. The mfS consisted of 103 hexagons flickering according to an m-sequence with a stimulus base interval of 53.3 ms (Lmax = 100 cd/m2, Lmin < 1 cd/m2). Immediately thereafter, the subject turned to the RVA, where measurements were resumed as soon as the same retinal vessel was targeted and continued for 104 s. Stimulation and recording was repeated twice. The diameter of a retinal vein and artery was measured for a length of at least 1 mm. The maximum vessel response was obtained by linear interpolation of the measured response within the 20 s following mfS. Results: On average, veins dilated by 6.8% and arteries by 7% following mfS (p > 0.005). Such a dilatation could be observed in 9 veins and 7 arteries. Three venous and 2 arterial measurements did not show a dilatation following mfS. However, 13 of 34 measurements could not be analyzed due to signal problems or because the time from the end of mfS and the uptake of measurement exceeded 20 s. Conclusion: This slow multifocal ERG stimulus results in a dilatation of arteries and veins that can be measured with the RVA. Coupling an mfS to the RVA has the potential to topographically map changes in retinal perfusion in relation to the respective retinal area stimulated. When implementing the mfS into the RVA setup in order not to lose time due to the refixation in the RVA following mfS, one is required to take the transient nature of this perfusion change into consideration.
Peroxisome Proliferator-Activated Receptor γ Ligands Stimulate Endothelial Nitric Oxide Production Through Distinct Peroxisome Proliferator-Activated Receptor γ–Dependent Mechanisms
Authors: Polikandriotis John A. , Mazzella Louis J. , Rupnow Heidi L. , Hart C. Michael
Published: July 2005

Objective—

We recently reported that the peroxisome proliferator-activated receptor γ (PPARγ) ligands 15-deoxy-Δ
12,14
-prostaglandin J
2
(15d-PGJ
2
) and ciglitazone increased cultured endothelial cell nitric oxide (NO) release without increasing the expression of endothelial nitric oxide synthase (eNOS). The current study was designed to characterize further the molecular mechanisms underlying PPARγ-ligand–stimulated increases in endothelial cell NO production.

Methods and Results—

Treating human umbilical vein endothelial cells (HUVEC) with PPARγ ligands (10 μmol/L 15d-PGJ
2
, ciglitazone, or rosiglitazone) for 24 hours increased NOS activity and NO release. In selected studies, HUVEC were treated with PPARγ ligands and with the PPARγ antagonist GW9662 (2 μmol/L), which fully inhibited stimulation of a luciferase reporter gene, or with small interfering RNA to PPARγ, which reduced HUVEC PPARγ expression. Treatment with either small interfering RNA to PPARγ or GW9662 inhibited 15d-PGJ
2
-, ciglitazone-, and rosiglitazone-induced increases in endothelial cell NO release. Rosiglitazone and 15d-PGJ
2
, but not ciglitazone, increased heat shock protein 90-eNOS interaction and eNOS ser
1177
phosphorylation. The heat shock protein 90 inhibitor geldanamycin attenuated 15d-PGJ
2
- and rosiglitazone-stimulated NOS activity and NO production.

Conclusions—

These findings further clarify mechanisms involved in PPARγ-stimulated endothelial cell NO release and emphasize that individual ligands exert their effects through distinct PPARγ-dependent mechanisms.
Pentraxin 3 Inhibits Fibroblast Growth Factor 2–Dependent Activation of Smooth Muscle Cells In Vitro and Neointima Formation In Vivo
Authors: Camozzi Maura , Zacchigna Serena , Rusnati Marco , Coltrini Daniela , Ramirez-Correa Genaro , Bottazzi Barbara , Mantovani Alberto , Giacca Mauro , Presta Marco
Published: July 2005

Objective—The fibroblast growth factor (FGF)/FGF receptor system plays an important role in smooth muscle cell (SMC) activation. Long-pentraxin 3 (PTX3) is a soluble pattern recognition receptor with non-redundant functions in inflammation and innate immunity. PTX3 is produced by different cell types of the vessel wall, including SMCs. PTX3 binds FGF2 and inhibits its angiogenic activity on endothelial cells. We investigated the capacity of PTX3 to affect FGF2-dependent SMC activation in vitro and in vivo.

Methods and Results—When added to human coronary artery SMCs, human PTX3 inhibits cell proliferation driven by endogenous FGF2 and the mitogenic and chemotactic activity exerted by exogenous recombinant FGF2. Accordingly, PTX3 prevents125I-FGF2 interaction with FGF receptors on the same cells. Also, PTX3 overexpression after recombinant adeno-associated virus-PTX3gene transfer inhibits human coronary artery SMC proliferation and survival promoted by FGF2 in vitro. Consistently, a single local endovascular injection of recombinant adeno-associated virus-PTX3gene inhibits intimal thickening after balloon injury in rat carotid arteries.

Conclusions—PTX3 is a potent inhibitor of the autocrine and paracrine stimulation exerted by FGF2 on SMCs. Local PTX3 upregulation may modulate SMC activation after arterial injury.