bluuebunny/crossref_metadata_2025 huggingface dataset:
Scale of protection and the various types of sports mouthguard
Authors: Patrick D G , van Noort R , Found M S
Published: April 2005

Objectives:To present a grading system of the protection offered by various types of mouthguard, together with an indication of associated risks, in order to make athletes aware of the consequences of improper or no mouth protection.

Methods:A review of the literature on mouthguards, mouthguard materials, and novel laminates for mouthguards was carried out as it was apparent that information on mouthguards was lacking. Studies on stock (or unfitted) mouthguards, mouth formed (boil and bite) mouthguards, and custom mouthguards are reviewed.

Results:A scale of protection offered by various mouthguards and novel laminates has been produced, where 0 indicates no mouthguard and 10 indicates a custom made mouthguard offering excellent protection.

Conclusions:From work carried out on laminates and the manufacturing processes of mouthguards, it became apparent that information was lacking to enable athletes make informed decisions about the best oral protection for their chosen sport.
A prospective study of injuries and training amongst the England 2003 Rugby World Cup squad
Authors: Brooks J H M , Fuller C W , Kemp S P T , Reddin D B
Published: April 2005

Objectives:To assess the aetiology, incidence, severity, and causes of injuries to England rugby union players during preparation for and participation in the 2003 Rugby World Cup.

Method:A 63 week prospective design was employed to study the training practices and injuries of England rugby players. The team physician reported all training and match injuries and provided details of the location, diagnosis, severity, and mechanism of each injury. The team fitness coach reported details of the number and duration of training sessions and the time dedicated to rugby and conditioning training. Players’ stature, body mass, and skinfolds were measured at the beginning and end of the study period.

Results:The overall incidence of injury was 17 injuries/1000 h of exposure (match: 218 injuries/1000 h; training: 6.1 injuries/1000 h). The major locations of injuries were the lower (60%) and upper (17%) limbs and the most common diagnoses were muscle and tendon (50%) and joint (non-bone) and ligament (41%) injuries. The highest incidences of match injuries occurred whilst being tackled (50 injuries/1000 h) and in a ruck or maul (35 injuries/1000 h), whilst the greatest incidences of training injuries occurred during endurance running (24 injuries/1000 h) and contact activities (20 injuries/1000 h). Players’ average body mass increased and skinfold measurement decreased significantly over the study period.

Conclusions:The incidence of match injuries at international level was found to be higher than previously reported. The tackle, ruck, and maul elements of match play and the endurance running and contact elements of training presented the highest risk of injury for all players.
Acute effects of a single open sea air dive and post-dive posture on cardiac output and pulmonary gas exchange in recreational divers
Authors: Dujic Z , Bakovic D , Marinovic-Terzic I , Eterovic D
Published: April 2005

Objective:To evaluate the cardiopulmonary effects of open sea scuba air diving to 39 m (30 minutes bottom time) with standard decompression. To account for possible gravity dependent effects of venous gas bubbles, the variables were measured in different post-dive body postures and compared with the baseline values before the dive in the same posture.

Methods:Eight male divers conducted two similar dives on successive days. Their posture before and after the dive was either sitting or supine, in random order. The divers were evaluated before and 30, 60, and 90 minutes after the dive. Venous bubbles were detected by precordial Doppler after the dive in four divers in the supine posture and two divers in the sitting posture.

Results:Arterialised oxygen tension had decreased at all times after the dive (−11.3 mm Hg, p  =  0.00006), due to decreased alveolar oxygen tension, irrespective of posture. Apart from an increase in the sitting posture 30 minutes after the dive, pulmonary capacity for carbon monoxide diffusion and cardiac index decreased, mostly 60 minutes after the dive (−9%, p  =  0.0003 and −20%, p  =  0.0002 respectively). The decrease in cardiac index was greater in the supine posture (p  =  0.0004), and the physiological dead space/tidal volume ratio increased more in the sitting position (p  =  0.006).

Conclusions:Field dives are associated with moderate impairments in cardiac output and gas exchange. Some of these impairments appear to depend on the posture of the diver after the dive.
The kick with the kite: an analysis of kite surfing related off shore rescue missions in Cape Town, South Africa
Authors: Exadaktylos A K , Sclabas G M , Blake I , Swemmer K , McCormick G , Erasmus P
Published: April 2005

Background:This study analyses kite surfing related off shore rescue missions in Cape Town, South Africa with the aim of providing more information on the frequency, pattern, and severity of kite surfing related injuries.

Methods:The observation period for this study started on October 1, 2003 and ended on May 1, 2004 and included 30 air rescue missions. Data and information were collected prospectively.

Results:The Air Mercy Service in Cape Town Province responded to 30 requests for help. Twenty five accidents were attributed to inability to detach the kite from the harness. Injuries occurred in five incidents and included fractures of the upper arm, ribs and ankle, and lacerations and contusions to the head and neck. Two patients suffered from hypothermia and one experienced severe exhaustion. All surfers were rescued successfully and there were no fatal accidents.

Discussion:The risk potential of this new sport is unclear. Dangerous situations can occur despite proper training and safety precautions due to unpredictable conditions and difficulties with equipment. Safety should be stressed. Surfers should sailing with a fellow kiter and should wear a life vest. More efforts must be taken to make this booming new water sport safer.
Exercise over-stress and maximal muscle oxidative metabolism: a31P magnetic resonance spectroscopy case report
Authors: Newcomer B R , Sirikul B , Hunter G R , Larson-Meyer E , Bamman M
Published: April 2005

Objective:31P magnetic resonance spectroscopy (MRS) was used to document long lasting losses in muscle oxidative capacity after bouts of intense endurance exercise.

Methods:The subject was a 34 year old highly fit female cyclist (Vo2max =  53.3 ml/kg/min). Over a five month period, she participated in three separate intense bouts of acute unaccustomed exercise.31P MRS measurements were performed seven weeks after the first bout and every two weeks for 14 more weeks. In all cases,31P MRS measurements followed three days after each bout.

Results:The subject showed a decreased ability to generate ATP from oxidative phosphorylation and an increased reliance on anaerobic ATP production during the 70% and 100% maximal voluntary contractions after the exercise bouts. Increased rates of fatigue and increased indicators of exercise difficulty also accompanied these reductions in muscle oxidative capacity. Increased oxidative and anaerobic ATP production were needed to maintain the work level during a submaximal 45% maximal voluntary contraction exercise.

Conclusions:Acute increases in intensity accompanied by a change in exercise mode can influence the ability of muscle to generate ATP. The muscles were less economical and required more ATP to generate force during the submaximal exercises. During the maximal exercises, the muscle’s mitochondria showed a reduced oxidative capacity. However, these reductions in oxidative capacity at the muscle level were not associated with changes in whole body maximal oxygen uptake. Finally, these reductions in muscular oxidative capacity were accompanied by increased rates of anaerobic ATP production, fatigue, and indicators of exercise difficulty.
EXCITATIONS IN CONFINED LIQUID 4He
Authors: ALBERGAMO FRANCESCO
Published: April 2005

The spectacular properties of liquid helium at low temperature are generally accepted as the signature of the bosonic nature of this system. Particularly the superfluid phase is identified with a Bose–Einstein condensed fluid. However, the relationship between the superfluidity and the Bose–Einstein condensation is still largely unknown. Studying a perturbed liquid 4 He system would provide information on the relationship between the two phenomena. Liquid 4 He confined in porous media provides an excellent example of a boson system submitted to disorder and finite-size effects.

Much care should be paid to the sample preparation, particularly the confining condition should be defined quantitatively. To achieve homogeneous confinement conditions, firstly a suitable porous sample should be selected, the experiments should then be conducted at a lower pressure than the saturated vapor pressure of bulk helium.

Several interesting effects have been shown in confined 4 He samples prepared as described above. Particularly we report the observation of the separation of the superfluid-normal fluid transition temperature, T c , from the temperature at which the Bose–Einstein condensation is believed to start, T BEC , the existence of metastable densities for the confined liquid accessible to the bulk system as a short-lived metastable state only and strong clues for a finite lifetime of the elementary excitations at temperatures as low as 0.4 K .
ION SPUTTERING NANOSTRUCTURING CRYSTALLINE MgF2 SURFACE AND ITS ENERGY-DEPENDENT SURFACE ROUGHNESS
Authors: SONG FENGQI , LI ZHENLIN , LI XUEFEI , ZHANG LU , HAN MIN , WANG GUANGHOU
Published: April 2005

The topography of crystalline MgF 2 surfaces eroded by low energy Ar + beam has been investigated by atomic force microscopy (AFM). Applying the optimal experimental parameters, regular nanoripples of 83 nm wavelength have been fabricated on the surface and the ripples direction is parallel to the ion beam. It is also found that both the surface roughness and the ripple direction are of obvious energy dependence, which we attribute to competing balance between kinetic roughening and ion-induced surface diffusion. We also explain why the roughness value of produced ripples reaches maximum at a rather medium energy point, instead of increasing with the ion energy.
Altered hepatic cholesterol metabolism compensates for disruption of phosphatidylcholine transfer protein in mice
Authors: Wu Michele K. , Cohen David E.
Published: April 2005

Phosphatidylcholine transfer protein (PC-TP) is a member of the steroidogenic acute regulatory transfer protein-related domain superfamily and is enriched in liver. To explore a role for PC-TP in hepatic cholesterol metabolism, Pctp−/−and wild-type C57BL/6J mice were fed a standard chow diet or a high-fat, high-cholesterol lithogenic diet. In chow-fed Pctp−/−mice, acyl CoA:cholesterol acyltransferase (Acat) activity was markedly increased, 3-hydroxy-3-methylglutaryl-CoA reductase activity was unchanged, and cholesterol 7α-hydroxylase activity was reduced. Consistent with increased Acat activity, esterified cholesterol concentrations in livers of Pctp−/−mice were increased, whereas unesterified cholesterol concentrations were reduced. Hepatic phospholipid concentrations were also decreased in the absence of PC-TP and consequently, unesterified cholesterol-to-phospholipid ratios in liver remained unchanged. The lithogenic diet downregulated 3-hydroxy-3-methylglutaryl-CoA reductase in wild-type and Pctp−/−mice, whereas Acat was increased only in wild-type mice. In response to the lithogenic diet, a greater reduction in cholesterol 7α-hydroxylase activity in Pctp−/−mice could be attributed to increased size and hydrophobicity of the bile salt pool. Despite higher hepatic phospholipid concentrations, the unesterified cholesterol-to-phospholipid ratio increased. The lack of Acat upregulation suggests that, in the setting of the dietary challenge, the capacity for esterification to defend against hepatic accumulation of unesterified cholesterol was exceeded in the absence of PC-TP expression. We speculate that regulation of cholesterol homeostasis is a physiological function of PC-TP in liver, which can be overcome with a cholesterol-rich lithogenic diet.
Effect of chronic ethanol administration on hepatic eNOS activity and its association with caveolin-1 and calmodulin in female rats
Authors: Wang Xu , Abdel-Rahman Abdel A.
Published: April 2005

Although chronic and excessive alcohol consumption is associated with liver disease, the mechanism of alcoholic liver injury is still not clear. Whether reduced hepatic production of nitric oxide, which is evident in models of liver injury, is associated with alcohol-induced liver injury has not been investigated. We measured nitric oxide synthase (NOS) activity in the liver of pair-fed rats receiving liquid diet with or without alcohol [3% (vol/vol)] for 12 wk. Compared with control rats, hepatic NOS activity was significantly reduced in alcohol-treated rats along with the evidence of liver injury. Interestingly, there was no difference in the hepatic expression of endothelial NOS (eNOS) between ethanol-fed and pair-fed rats. We then tested the hypothesis that an imbalance between the binding of eNOS with inhibitory and stimulatory proteins may underlie the reduced activity of eNOS because eNOS catalytic activity is regulated partly through dynamic interactions with the inhibitory protein caveolin-1 and the stimulatory protein calmodulin. We found that hepatic caveolin-1 was markedly increased in alcohol-treated rats compared with control rats, whereas calmodulin remained unaltered. The binding of caveolin-1 and calmodulin with eNOS was increased and decreased, respectively, in alcohol-treated rats. Our results suggest that chronic alcohol intake attenuates hepatic eNOS activity by increasing the expression of the inhibitory protein caveolin-1 and enhancing its binding with eNOS.
Interaction between left ventricular wall motion and intraventricular flow propagation in acute and chronic ischemia
Authors: Edvardsen Thor , Rodevand Olaf , Endresen Knut , Ihlen Halfdan
Published: April 2005

Myocardial ischemia has been associated with left ventricular (LV) postsystolic shortening. The combination of tissue Doppler imaging and high frame-rate acquisition of two-dimensional color flow makes it possible to study the interaction between LV wall motion and intraventricular flow propagation. The aim of this study was to examine in a clinical model the impact that acute myocardial ischemia and prior myocardial infarct might have on LV flow patterns and to explain the underlying mechanisms from the tissue Doppler data. LV flow propagation and tissue velocities during early diastole were studied in 18 healthy individuals, 17 patients with prior anterior myocardial infarct, and 16 patients before and during percutaneous coronary intervention (PCI) of the left anterior descending artery. Normal individuals had intraventricular flow propagation toward the apex during isovolumic relaxation. During this early diastolic time phase, myocardial velocities measured at mid- and apical septal segment were directed away from the apex. Before PCI, patients without myocardial infarction had similar findings as in normal individuals. In contrast, each patient with either prior myocardial infarction or PCI-induced acute ischemia had flow propagation opposite to normal individuals, and tissue velocities reversed toward the apex during early diastole. Reversal of early diastolic LV flow propagation in acute and chronic anterior myocardial ischemia reflects postsystolic shortening in the dyskinetic apical and septal myocardial segments.
Cardiovascular dysfunction caused by cecal ligation and puncture is attenuated in CD8 knockout mice treated with anti-asialoGM1
Authors: Tao Weike , Enoh Victor T. , Lin Cheng Y. , Johnston William E. , Li Peng , Sherwood Edward R.
Published: April 2005

The present study was designed to assess hemodynamics and myocardial function at 18 h after injury caused by cecal ligation and puncture (CLP) in CD8-knockout mice treated with anti-asialoGM1 (CD8KO/αAsGM1 mice). Arterial pressure was measured by carotid artery cannulation, and left ventricular pressure-volume measurements were obtained by use of a 1.4-Fr conductance catheter. Blood acid-base balance and indexes of hepatic, renal, and pulmonary injury were also measured. CD8KO/αAsGM1 mice exhibited higher mean arterial pressure and increased systemic vascular resistance compared with wild-type mice. Cardiac output was significantly decreased in wild-type, but not CD8KO/αAsGM1, mice compared with sham controls. Myocardial function was better preserved in CD8KO/αAsGM1 mice as indicated by less impairment of left ventricular pressure development over time, time varying maximum elastance, end-systolic pressure-volume relationship, and preload recruitable stroke work. The impairment in myocardial function was associated with induction of proinflammatory cytokine mRNAs in the hearts of wild-type mice. The hemodynamic derangements in wild-type mice were coupled with significant metabolic acidosis and elevated serum creatinine levels. Overall, this study shows that cardiovascular collapse and shock characterized by hypotension, myocardial depression, low systemic vascular resistance, and metabolic acidosis occurs after CLP in wild-type mice but is attenuated in CD8KO/αAsGM1 mice. These observations likely explain, in part, the previously observed survival advantage of CD8KO/αAsGM1 mice following CLP.
Sugar and fat conditioned flavor preferences in C57BL/6J and 129 mice: oral and postoral interactions
Authors: Sclafani Anthony , Glendinning John I.
Published: April 2005

C57BL/6J (B6) mice consume more sugar and fat solutions than do 129 mice in 24-h preference tests. Previous studies have attributed this observation to strain differences in taste responsiveness to these nutrients. We tested the hypothesis that differences in postingestive responsiveness contribute to the strain differences. In experiment 1, B6 and 129 mice were trained to associate consumption of a flavored solution (CS+) with intragastric (IG) infusions of 16% sucrose and a different flavored solution (CS−) with IG water infusions (22 h/day). They were then retrained with new flavors paired with IG infusions of 5.6% soybean oil and water. Although both strains developed preferences for the nutrient-paired CS+ solutions, the B6 mice displayed significantly stronger preferences. The B6 mice consumed more CS+ during training, which may have contributed to their enhanced preference. In a second experiment, training intakes were equated by giving B6 and 129 mice “isosweet” CS solutions prepared with different amounts of sucrose and saccharin. The B6 and 129 mice consumed more of the sugar- or fat-paired CS+ than the water-paired CS− during training. The two strains also displayed equally strong preferences for the CS+ over CS− in choice tests, indicating that they had similar postingestive responsiveness to the sucrose and soybean oil. We propose that B6 mice consume more sugar and fat than 129 mice because their stronger orosensory response stimulates greater intake, which leads to greater stimulation of postingestive nutrient detectors and further enhancement of consumption.
Negative feedback regulation of nerve-mediated contractions by KCachannels in mouse urinary bladder smooth muscle
Authors: Herrera Gerald M. , Etherton Bud , Nausch Bernhard , Nelson Mark T.
Published: April 2005

When the urinary bladder is full, activation of parasympathetic nerves causes release of neurotransmitters that induce forceful contraction of the detrusor muscle, leading to urine voiding. The roles of ion channels that regulate contractility of urinary bladder smooth muscle (UBSM) in response to activation of parasympathetic nerves are not well known. The present study was designed to characterize the role of large (BK)- and small-conductance (SK) Ca2+-activated K+(KCa) channels in regulating UBSM contractility in response to physiological levels of nerve stimulation in UBSM strips from mice. Nerve-evoked contractions were induced by electric field stimulation (0.5–50 Hz) in isolated strips of UBSM. BK and SK channel inhibition substantially increased the amplitude of nerve-evoked contractions up to 2.45 ± 0.12- and 2.99 ± 0.25-fold, respectively. When both SK and BK channels were inhibited, the combined response was additive. Inhibition of L-type voltage-dependent Ca2+channels (VDCCs) in UBSM inhibited nerve-evoked contractions by 92.3 ± 2.0%. These results suggest that SK and BK channels are part of two distinct negative feedback pathways that limit UBSM contractility in response to nerve stimulation by modulating the activity of VDCCs. Dysfunctional regulation of UBSM contractility by alterations in BK/SK channel expression or function may underlie pathologies such as overactive bladder.
Voluntary exercise protects against acute doxorubicin cardiotoxicity in the isolated perfused rat heart
Authors: Chicco Adam J. , Schneider Carole M. , Hayward Reid
Published: April 2005

The clinical use of doxorubicin (DOX) is limited by a dose-dependent cardiotoxicity. The purpose of this study was to determine whether voluntary exercise training would confer protection against DOX cardiotoxicity in the isolated perfused rat heart. Female Sprague-Dawley rats were randomly assigned to standard holding cages or cages with running wheels for 8 wk. Twenty-four hours after the sedentary (SED) or voluntary exercise (VEX) running period, rats were anesthetized with pentobarbital sodium, and hearts were isolated and perfused with oxygenated Krebs-Henseleit (KH) buffer at a constant flow of 15 ml/min. After a 20-min stabilization period, hearts were paced at 300 beats per minute and perfused with KH buffer containing 10 μM DOX for 60 min. A set of control hearts from SED and VEX rats were perfused under identical conditions without DOX for the same period. DOX perfusion led to significant decreases in left ventricular developed pressure, +dP/d t, and −dP/d t, and significant increases in LV lipid peroxidation in sedentary rats compared with non-DOX controls ( P < 0.05). Prior voluntary exercise training attenuated these DOX-induced effects and was associated with a significant increase (78%, P < 0.05) in heat shock protein (HSP72), but not mitochondrial isoform of SOD (MnSOD) or CuZnSOD protein expression in the hearts of wheel-run animals. These data indicate that chronic physical activity may provide resistance against the cardiac dysfunction and oxidative damage associated with DOX exposure and provide novel evidence of HSP72 induction in the heart after voluntary exercise.
Airway smooth muscle tone modulates mechanically induced cytoskeletal stiffening and remodeling
Authors: Deng Linhong , Fairbank Nigel J. , Cole Darren J. , Fredberg Jeffrey J. , Maksym Geoffrey N.
Published: April 2005

The application of mechanical stresses to the airway smooth muscle (ASM) cell causes time-dependent cytoskeletal stiffening and remodeling (Deng L, Fairbank NJ, Fabry B, Smith PG, and Maksym GN. Am J Physiol Cell Physiol 287: C440–C448, 2004). We investigated here the extent to which these behaviors are modulated by the state of cell activation (tone). Localized mechanical stress was applied to the ASM cell in culture via oscillating beads (4.5 μm) that were tightly bound to the actin cytoskeleton (CSK). Tone was reduced from baseline level using a panel of relaxant agonists (10−3 M dibutyryl cAMP, 10−4 M forskolin, or 10−6 M formoterol). To assess functional changes, we measured cell stiffness (G′) using optical magnetic twisting cytometry, and to assess structural changes of the CSK we measured actin accumulation in the neighborhood of the bead. Applied mechanical stress caused a twofold increase in G′ at 120 min. After cessation of applied stress, G′ diminished only 24 ± 6% (mean ± SE) at 1 h, leaving substantial residual effects that were largely irreversible. However, applied stress-induced stiffening could be prevented by ablation of tone. Ablation of tone also inhibited the amount of actin accumulation induced by applied mechanical stress ( P < 0.05). Thus the greater the contractile tone, the greater was applied stress-induced CSK stiffening and remodeling. As regards pathobiology of asthma, this suggests a maladaptive positive feedback in which tone potentiates ASM remodeling and stiffening that further increases stress and possibly leads to worsening airway function.
Muscle-tendon interaction and elastic energy usage in human walking
Authors: Ishikawa Masaki , Komi Paavo V. , Grey Michael J. , Lepola Vesa , Bruggemann Gert-Peter
Published: April 2005

The present study was designed to explore how the interaction between the fascicles and tendinous tissues is involved in storage and utilization of elastic energy during human walking. Eight male subjects walked with a natural cadence (1.4 ± 0.1 m/s) on a 10-m-long force plate system. In vivo techniques were employed to record the Achilles tendon force and to scan real-time fascicle lengths for two muscles (medial gastrocnemius and soleus). The results showed that tendinous tissues of both medial gastrocnemius and soleus muscles lengthened slowly throughout the single-stance phase and then recoiled rapidly close to the end of the ground contact. However, the fascicle length changes demonstrated different patterns and amplitudes between two muscles. The medial gastrocnemius fascicles were stretched during the early single-stance phase and then remained isometrically during the late-stance phase. In contrast, the soleus fascicles were lengthened until the end of the single-stance phase. These findings suggest that the elastic recoil takes place not as a spring-like bouncing but as a catapult action in natural human walking. The interaction between the muscle fascicles and tendinous tissues plays an important role in the process of release of elastic energy, although the leg muscles, which are commonly accepted as synergists, do not have similar mechanical behavior of fascicles in this catapult action.
Advancing age alters rapid and spontaneous refilling of caffeine-sensitive calcium stores in sympathetic superior cervical ganglion cells
Authors: Vanterpool Conwin K. , Pearce William J. , Buchholz John N.
Published: April 2005

Intracellular calcium concentration ([Ca2+]i) release from smooth endoplasmic reticulum (SER) stores plays an important role in cell signaling. These stores are rapidly refilled via influx through voltage-gated calcium channels or spontaneously via store-operated calcium channels and subsequent pumping by SER Ca2+-ATPases. We measured [Ca2+]itransients in isolated fura 2-loaded superior cervical ganglion cells from 6-, 12-, 20-, and 24-mo-old Fischer 344 rats. For rapid refilling, [Ca2+]itransients were elicited by a 1) 5-s exposure to K+, 2) caffeine to release Ca2+from SER stores, 3) K+to refill SER Ca2+stores, and 4) caffeine. The percent difference between the peak and rate of rise of the first and second caffeine-evoked [Ca2+]itransient significantly declined over the age range of 12–24 mo. To estimate spontaneous refilling, cells were depolarized for 5 s with 68 mM K+(control), followed by a 10-s exposure to 10 mM caffeine “conditioning stimulus” to deplete [Ca2+]istores. Caffeine was then rapidly applied for 5 s at defined intervals from 60 to 300 s. Integrated caffeine-evoked [Ca2+]itransients were measured and plotted as a percentage of the K+response vs. time. The derivative of the refilling time curves significantly declined over the age range from 12–24 mo. Overall, these data suggest that the ability of superior cervical ganglion cells to sustain release of [Ca2+]ifollowing rapid or spontaneous refilling declines with advancing age. Compromised ability to sustain calcium signaling may possibly alter the overall function of adrenergic neurons innervating the cerebrovasculature.
Rifaximin, a Poorly Absorbed Antibiotic: Pharmacology and Clinical Potential
Authors: Scarpignato Carmelo , Pelosini Iva
Published: April 2005

Rifaximin (4-deoxy-4′-methylpyrido[1′,2′-1,2]imidazo- [5,4-c]-rifamycin SV) is a synthetic antibiotic designed to modify the parent compound, rifamycin, in order to achieve low gastrointestinal (GI) absorption while retaining good antibacterial activity. Both experimental and clinical pharmacology clearly show that this compound is a nonsystemic antibiotic with a broad spectrum of antibacterial action covering Gram-positive and Gram-negative organisms, both aerobes and anaerobes. Being virtually nonabsorbed, its bioavailability within the GI tract is rather high with intraluminal and fecal drug concentrations that largely exceed the minimal inhibitory concentration values observed in vitro against a wide range of pathogenic organisms. The GI tract represents, therefore, the primary therapeutic target and GI infections the main indication. The appreciation of the pathogenic role of gut bacteria in several organic and functional GI diseases has increasingly broadened its clinical use, which is now extended to hepatic encephalopathy, small intestine bacterial overgrowth, inflammatory bowel disease and colonic diverticular disease. Potential indications include the irritable bowel syndrome and chronic constipation, Clostridium difficile infection and bowel preparation before colorectal surgery. Because of its antibacterial activity against the microorganism and the lack of strains with primary resistance, some preliminary studies have explored the rifaximin potential for Helicobacter pylori eradication. Oral administration of this drug, by getting rid of enteric bacteria, could also be employed to achieve selective bowel decontamination in acute pancreatitis, liver cirrhosis (thus preventing spontaneous bacterial peritonitis) and nonsteroidal anti-inflammatory drug (NSAID) use (lessening in that way NSAID enteropathy). This antibiotic has, therefore, little value outside the enteric area and this will minimize both antimicrobial resistance and systemic adverse events. Indeed, the drug proved to be safe in all patient populations, including young children. Although rifaximin has stood the test of time, it still attracts the attention of both basic scientists and clinicians. As a matter of fact, with the advancement of the knowledge on microbial-gut interactions in health and disease novel indications and new drug regimens are being explored. Besides widening the clinical use, the research on rifaximin is also focused on the synthesis of new derivatives and on the development of original formulations designed to expand the spectrum of its clinical use.
Rifaximin: In vitro and in vivo Antibacterial Activity – A Review
Authors: Jiang Z.D. , DuPont H.L.
Published: April 2005

In vitro inhibitory activity of rifaximin is directed against Gram-positive and Gram-negative, aerobic and anaerobic bacteria. It is effective in the treatment of gastrointestinal infections when given orally because of the high concentration of the drug remaining in the gut lumen. Laboratory investigations have been carried out to assess the in vitro activity of rifaximin on different bacterial strains isolated from both human and domestic animals. The objective of this project is to review the in vitro and in vivo activity of rifaximin against bacterial infection with Gram-negative rods, Gram-positive rods and Gram-positive cocci and their resistance to rifaximin. The available data suggest that rifaximin is active in vitro and in vivo in the treatment of bacterial infection of adults and children.
Management of Inflammatory Bowel Disease: Does Rifaximin Offer Any Promise?
Authors: Gionchetti Paolo , Rizzello Fernando , Morselli Claudia , Romagnoli Rossella , Campieri Massimo
Published: April 2005

An increasing number of both clinical and laboratory-derived observations support the importance of luminal components in driving the inflammatory response in ulcerative colitis and Crohn’s disease. Although its role is unclear, antibiotic therapy is commonly used in clinical practice for the treatment of moderately to severely active ulcerative colitis. Metronidazole and/or ciprofloxacin are currently employed in active Crohn’s disease, particularly in patients with colonic involvement and with perianal disease. Rifaximin, a rifamycin-derived antibiotic, is characterized by a wide range of antibacterial activity and a very low systemic absorption. Some preliminary data show its efficacy in severe active ulcerative colitis, pouchitis and prevention of postoperative recurrence in Crohn’s disease.
Mechanical and Antibacterial Bowel Preparation in Colon and Rectal Surgery
Authors: Nichols Ronald Lee , Choe Ella U. , Weldon Christopher B.
Published: April 2005

Colorectal surgery performed prior to 1970 was fraught with postoperative infectious complications which occurred in more than 30–50% of all operations. Diversion of the fecal stream appeared mandatory when operating on an urgent or emergent basis, thereby requiring the performance of multiple, staged operations instead of a single surgery encompassing resection and primary anastomosis as is performed commonly today. Multiple studies conducted in the early 1970s determined that anaerobic colonic microflora were causative agents in postoperative infections in colon and rectal surgery, and these studies initiated the development of effective oral preoperative antibiotic prophylaxis in combination with preoperative mechanical bowel preparation. This dual-tier regimen significantly reduced the incidence of postoperative infectious complications, thus allowing most uncomplicated colon and rectal surgeries to be performed in a single stage without the need for the diversion of the fecal stream and multiple operations. Therefore, a preoperative mechanical and antibacterial bowel regimen serves as the cornerstone of modern elective colorectal surgery, and these regimens now comprise three therapeutic directives. The first step is preoperative mechanical cleansing of the bowel, which is then followed by preoperative oral antibiotic prophylaxis. Finally, perioperative parenteral antibiotics directed against aerobic and anaerobic colonic microflora are utilized.
Thermographische Untersuchung zur Wärmeausbreitung nach aufgesetztem Schreckschuss
Authors: Just T. , Pau H.W. , Wild W.
Published: April 2005

Fragestellung: Ziel der thermographischen Untersuchung war es, die Wärmeeinbringung, -ausbreitung und -verteilung im Gewebe nach aufgesetztem Schreckschuss mittels Infrarotthermographie darzustellen. Dabei sollte geklärt werden, welche Gewebeschädigung durch die thermischen Effekte hervorgerufen wird. Material und Methoden: Als Untersuchungsmaterial dienten 7 nicht eingefrorene Schweinehälse mit Kopf. Die Untersuchungen erfolgten mit dem Thermovisionssystem AGEMA 470. Insgesamt 4 handelsübliche Schreckschusspistolen verschiedener Fabrikate kamen zur Anwendung. Als Munition wurden 9-mm-Knallkartuschen von 3 verschiedenen Herstellern verwendet. Die Treibmittel waren entweder Nitrozellulose oder Schwarzpulver. Es wurden 2 verschiedene Versuchsanordnungen gewählt (kaudale Schnittfläche im Halsniveau und Hals-«Scheiben»). Zur Markierung anatomischer Landmarken wurden Stahldrähte in die Präparate eingebracht. Von den Videoaufzeichnungen, die eine räumliche und zeitliche Auswertung zulassen, konnten später Einzelbilder herausgesucht und ausgewertet werden. Ergebnisse und Schlussfolgerungen: Die Temperaturen an der Hautoberfläche nach aufgesetztem Schreckschuss überschreiten 100°C und sind bei Verwendung von nitrozellulosehaltigen Kartuschen höher als nach Verwendung von schwarzpulverhaltigen Kartuschen. Im Gewebe werden Temperaturerhöhungen bis 30 K beobachtet. Die Einwirkzeit beträgt wenige Millisekunden. Nach Verwendung von Nitrozellulose als Treibmittel werden auch in den tiefer liegenden Gewebsschichten grössere Temperaturmaxima registriert als mit schwarzpulverhaltigen Kartuschen. Der Verschmutzungsgrad der Wundhöhle ist bei Einsatz von Schwarzpulver ausgeprägter als bei Nitrozellulose. Neben der operativen Wundrevision stehen bei der Behandlung Funktionserhaltung der verletzten Strukturen und Infektionsprävention im Vordergrund.
Das Plattenepithelkarzinom der Zunge beim jungen Patienten
Authors: Hagemann M. , Zbären P.
Published: April 2005

Fragestellung: In der Literatur wird häufig über eine Zunahme der Zungenkarzinome bei jungen Patienten berichtet. Zudem wird vermutet, dass diese Karzinome bei jungen Patienten schneller wachsen und häufiger rezidivieren. Patienten und Methoden: Wir haben die Daten von 141 Patienten mit Zungenkarzinomen retrospektiv analysiert. Die Patienten wurden nach Alter in zwei Gruppen eingeteilt und diese bezüglich Tumorstadium, Rezidivrate und Überleben miteinander verglichen. Ergebnisse: Hierbei fanden sich bei den «jungen Patienten» initial kleinere Primärtumore bei gleicher Häufigkeit von N-Klassifizierungen. Die Lokalrezidivrate war in beiden Gruppen gleich gross und die Regionalrezidivrate bei den «jungen Patienten» deutlich höher. Die tumorspezifischen 3- und 5-Jahres-Überlebensraten waren in beiden Gruppen gleich gross. Schlussfolgerung: Das Zungenkarzinom scheint bei jungen Patienten eine aggressivere Erkrankung mit einer hohen regionären Rezidivrate zu sein.
Baseline Oxysterols and Other Markers of Oxidative Stress, Inflammation and Malnutrition in the Vitamin E and Intima Media Thickness Progression in End-Stage Renal Disease (VIPER) Cohort
Authors: Boaz Mona , Iuliano Luigi , Himmelfarb Jonathan , Matas Zipora , Micheletta Fausta , McMonagle Ellen , Friedman Victoria , Natoli Silvia , Gvirtz Gabriella , Biro Alexander , Smetana Shmuel , Sabo Gideon , Gafter Uzi , Weinstein Talia
Published: April 2005

Background and Objectives: Oxysterols are markers of oxidative stress, levels of which have not yet been reported in hemodialysis (HD) patients. This study was designed to compare levels of the oxysterols 7-ketocholesterol (7KC) and 7β-hydroxycholesterol (7βOH) between a cohort of HD patients and healthy controls. Methods: This nested cross-sectional study reflects baseline (pre-intervention) values for markers of oxidative stress, inflammation and nutrition status in the 160-member vitamin E and carotid intima media thickness progression in end-stage renal disease (VIPER) cohort (age 64.1 ± 8.8, 33.5% female). Age- and sex-matched healthy volunteers served as controls. Plasma oxysterols 7KC and 7βOH were determined by isotope dilution gas chromatography/mass spectrometry. Results: Despite higher plasma α-tocopherol levels in HD patients than controls (36.0 ± 9.3 vs. 31.8 ± 8.4 µmol/l, p = 0.007), 7KC levels (9.8 ± 6.9 vs. 5.9 ± 2.8 nmol/mmol cholesterol, p < 0.0001) and 7βOH levels (8.7 ± 4.3 vs. 2.7 ± 1.6 nmol/mmol cholesterol, p < 0.0001) were higher in HD patients. The oxysterol 7βOH was significantly, inversely associated with prealbumin (r = –0.18, p = 0.03), though neither oxysterol was significantly associated with any other marker of oxidative stress, inflammation or nutrition status and did not discriminate for CVD in HD patients. Conclusions: Elevated levels of the oxysterols 7KC and 7βOH indicate that HD patients are in a state of oxidative stress compared to healthy controls. However, oxysterols 7KC and 7βOH did not appear to contribute additional information about oxidative stress among HD patients.
The Place of the Posterior Surgical Approach for Lesions of the Rectum
Authors: Terkivatan T. , den Hoed P.T. , Lange J.F.M. , Koot V.C.M. , van Goch J.J. , Veen H.F.
Published: April 2005

Background: Although there are many advantages of a posterior approach to rectal disease, these procedures are not widely accepted because many surgeons fear the postoperative complications. Methods: The medical records were reviewed of 57 patients who underwent a posterior approach to the rectum between January 1980 and December 2002. Results: Twenty-eight men and 29 women with a mean age of 70.5 (range 47–83) years underwent either a posterior transsacral (n = 52) or a transsphincteric (n = 5) procedure. Indications for surgery were benign lesions (n = 33), e.g. villous adenoma, rectal prolapse and endometriosis as well as invasive adenocarcinoma (n = 24). All patients with an invasive adenocarcinoma were classified as ASA grade III or IV. Postoperative morbidity occurred in 12 patients (21%), consisting of temporary incontinence, anastomotic leakage, wound infection, and hemorrhage. There was no mortality. During a mean follow-up of 29 (range 2–86) months, 3 patients with a villous adenoma and 2 patients who were treated for a malignant lesion had a locally recurrent lesion. Conclusion: We believe that a posterior approach to the rectum should be considered for various benign and selected malignant diseases, especially in case of elderly patients or patients with a compromised general condition, and has to be a part of the surgeon’s armamentarium.
c-Myc Antisense Oligonucleotides Preserve Smooth Muscle Differentiation and Reduce Negative Remodelling following Rat Carotid Arteriotomy
Authors: Forte Amalia , Galderisi Umberto , De Feo Marisa , Gomez Maria F. , Esposito Salvatore , Santè Pasquale , Renzulli Attilio , Agozzino Lucio , Hellstrand Per , Berrino Liberato , Cipollaro Marilena , Cotrufo Maurizio , Rossi Francesco , Cascino Antonino
Published: April 2005

Objectives: The vascular biology of restenosis is complex and not fully understood, thus explaining the lack of effective therapy for its prevention in clinical settings. The role of c-Myc in arteriotomy-induced stenosis, smooth muscle cell (SMC) differentiation and apoptosis was investigated in rat carotids applying full phosphorothioate antisense (AS) oligonucleotides (ODNs). Methods: Carotid arteries from WKY rats were submitted to arteriotomy and to local application of ODNs through pluronic gel. Apoptosis (deoxynucleotidyl transferase-mediated dUTP nick end-labelling), SMC differentiation (SM22 immunofluorescence) and vessel morphology and morphometry (image analysis) were determined 2, 5 and 30 days after injury, respectively. Results: AS ODNs induced a 60% decrease of target c-Myc mRNA 4 h after surgery in comparison to control sense (S) and scrambled ODN-treated carotids (p < 0.05). A significant 37 and 50% decrease in SM22 protein in the media of S ODN-treated and untreated carotids was detected when compared to uninjured contralateral arteries (p < 0.05). This reduction in SM22 expression was prevented in AS ODN-treated carotids. Stenosis was mainly due to adventitial constrictive remodelling. Lumen area in AS ODN-treated carotids was 35% greater than in control arteries 30 days after surgery (p < 0.05). TUNEL assay revealed increased apoptosis in AS ODN-treated carotids (p < 0.05). Conclusions: c-Myc AS ODNs reduce arteriotomy-induced negative remodelling. This is accompanied by maintained SMC differentiation and greater apoptosis. The combination of reduced c-Myc-induced proliferation and increased apoptosis may thus underlie the less severe remodelling upon treatment with c-Myc mRNA AS ODN.
Prognostic Factors of Perforated Sigmoid Diverticulitis in the Elderly
Authors: Mäkelä Jyrki Tapani , Kiviniemi Heikki , Laitinen Seppo
Published: April 2005

Background: The Finnish population is aging fast and the prevalence of perforated sigmoid diverticulitis is simultaneously increasing in northern Finland. The fact that an increasing number of elderly patients, with their age-specific problems, are subjected to emergency surgery for acute diverticulitis underlines the importance of risk stratification.Methods: One hundred and seventy-two patients admitted to Oulu University Hospital because of diverticular perforation from 1983 to 2002 were identified from the computer database. The clinical variables were evaluated as prognostic indicators of postoperative complications, mortality and time of hospitalization. Results: The resection rate was 91%; 64 primary anastomoses, 93 Hartmann’s procedures and two covering colostomies were performed. The overall complication rate was 33%. In patients under 70 years, a stepwise logistic regression analysis showed that the Mannheim Peritonitis Index (MPI) score and American Society of Anesthesiologists (ASA) score were independent prognostic factors. None of factors predicted morbidity in patients over 70 years. Overall mortality rate was 8%, without any significant difference between the procedures. Of the clinical variables, MPI score, ASA score, Hinchey classes and malnutrition correlated with mortality. All patients who died presented with ASA scores of III–IV, and 12 out of 14 patients had an MPI score of II. In a stepwise logistic regression analysis, only the MPI score seemed to be an independent predictor of mortality. Conclusions: Mortality is related to age but age alone is not an independent predictor of mortality. The MPI score is useful in predicting the risk of death in patients with perforated diverticulitis.
Paraganglioma of the Larynx
Authors: da Mosto Maria Cristina , Boscolo-Rizzo Paolo , Marchiori Carlo , Boccato Paolo
Published: April 2005

The laryngeal paraganglioma (LP) is a rare neuroendocrine neoplasm which arises from paraganglionic tissue normally present in the larynx. Immunohistochemistry is essential in the differential diagnosis of the various neuroendocrine neoplasms. The study presents a case of LP arising in an otherwise healthy 30-year-old black woman. Direct laryngoscopy revealed a large mass obstructing the airway almost completely. The patient underwent a total laryngectomy. Histopathological examination showed a population of epithelioid cells arranged in round nests and balls surrounded by a delicate stroma (‘Zellballen’ pattern). The histological and immunohistochemical patterns were coherent with LP. At 24 months after excision, she shows no evidence of disease.
Knockdown of Hepatic ABCA1 by RNA Interference Decreases Plasma HDL Cholesterol Levels and Influences Postprandial Lipemia in Mice
Authors: Ragozin Sergei , Niemeier Andreas , Laatsch Alexander , Loeffler Britta , Merkel Martin , Beisiegel Ulrike , Heeren Joerg
Published: April 2005

Objective—

To investigate the impact of hepatic ABCA1 on systemic lipoprotein metabolism in vivo by an adenovirus-mediated RNA interference approach.

Methods and Results—

Efficiency of plasmid-based small interference RNA (siRNA)-induced knockdown of cotransfected murine ATP binding cassette transporter A1 (mABCA1) in HEK-293 cells was judged by RT-polymerase chain reaction, immunofluorescence, and Western blot analysis. The most effective plasmid was used to generate a recombinant adenovirus as a tool to selectively downregulate ABCA1 expression in mouse liver (C57BL/6). In comparison to controls, Western blot analysis from liver membrane proteins of Ad-anti-ABCA1 infected mice resulted in an ≈50% reduction of endogenous ABCA1 and a clear upregulation of apolipoprotein E. Fast protein liquid chromatography analysis of plasma revealed that hepatic ABCA1 protein reduction was associated with an ≈40% decrease of HDL cholesterol and a reduction of HDL-associated apolipoprotein A-I and E. In the fasted state, other lipoprotein classes were not affected. To analyze the influence of ABCA1 downregulation on postprandial lipemia, infected mice were given a gastric load of radiolabeled trioleate in olive oil. In Ad-anti-ABCA1 infected mice, the postprandial increase of chylomicrons and chylomicron-associated apolipoproteins B and E was significantly reduced as compared with controls.

Conclusion—

Hepatic ABCA1 contributes to HDL plasma levels and influences postprandial lipemia.