bluuebunny/crossref_metadata_2025_split huggingface dataset:
Learning and memory after neonatal exposure to 3,4‐methylenedioxymethamphetamine (ecstasy) in rats: Interaction with exposure in adulthood
Authors: Cohen Martha A. , Skelton Matthew R. , Schaefer Tori L. , Gudelsky Gary A. , Vorhees Charles V. , Williams Michael T. 
Published: June 2005

AbstractThis study determined whether developmental and adult 3,4‐methylenedioxymethamphetamine (MDMA) exposures in rats have interactive effects on body temperature, learning, other behaviors, and monoamine concentrations in the hippocampus, prefrontal cortex, and striatum. Learning was assessed in the Cincinnati water maze (CWM), Morris water maze (MWM), and novel object recognition (NOR). On acquisition trials in the MWM, significant differences from developmental MDMA exposure were found on latency, cumulative distance, path length, and angle of first bearing to the goal, but the early and adult MDMA exposure group performed no worse than the developmental‐only MDMA group. In the reversal trials, however, an interaction was seen: latency to the goal, cumulative distance, and angle of first bearing were increased in animals treated both developmentally and in adulthood with MDMA compared with those treated only developmentally. Other tests (elevated zero maze, CWM, NOR, and open‐field activity) did not show an interaction, nor did hippocampal concentrations of serotonin or dopamine. However, several behavioral tests showed neonatal MDMA effects, including increased errors in the CWM, reduced time spent with a new object in the NOR test, and reduced locomotor activity in the open‐field. By contrast, adult MDMA decreased the number of entries into open quadrants of the elevated zero maze. Litter effects were controlled by treating litter as the experimental unit and using mixed models repeated measures analyses. Correlational analyses suggested that the MWM reversal interaction involves multiple monoamine changes. The results indicate that developmental MDMA exposure can interact with adult exposure to interfere with some aspects of learning. Synapse 57:148–159, 2005. © 2005 Wiley‐Liss, Inc.
Persistent upregulation of μ‐opioid, but not adenosine, receptors in brains of long‐term withdrawn escalating dose “binge” cocaine‐treated rats
Authors: Bailey Alexis , Gianotti Robert , Ho Ann , Kreek Mary Jeanne 
Published: June 2005

AbstractThere is evidence showing that the opioid and adenosine systems play an important role in cocaine addiction; fewer studies have examined their roles in cocaine withdrawal. To determine whether cocaine and/or chronic withdrawal from cocaine alters the specific components of the opioid and adenosine systems, we carried out quantitative autoradiographic mapping of μ‐opioid, A1 and A2A adenosine receptors in the brains of rats treated with an escalating dose “binge” cocaine administration paradigm and of rats chronically withdrawn from cocaine. Male Fischer rats were injected with saline or cocaine (15 × 3 mg/kg/day for 4 days, 20 × 3 mg/kg/day for 4 days, 25 × 3 mg/kg/day for 4 days and 30 × 3 mg/kg/day for 2 days) at 1‐h intervals for 14 days. Similarly treated rats were withdrawn from that paradigm for 14 days. A significant increase in [3H]DAMGO binding to μ‐receptors was detected in the frontal and cingulate cortex, as well as in the caudate putamen, of long‐term withdrawn rats after an escalating dose “binge” cocaine administration paradigm and in chronic cocaine‐treated rats. No significant cocaine‐induced change was found in A1 or A2A receptor binding in any region analyzed. These results reconfirm that μ‐opioid (MOP) receptors undergo upregulation in response to chronic escalating dose “binge” cocaine administration. This upregulation was shown for the first time to persist at least 14 days into withdrawal after escalating “binge” cocaine. Synapse 57:160–166, 2005. © 2005 Wiley‐Liss, Inc.
Enhanced dopamine uptake in the striatum following repeatedrestraint stress
Authors: Copeland Benjamin J. , Neff Norton H. , Hadjiconstantinou Maria 
Published: June 2005

AbstractIn mice administered chronic stress—repeated overnight restraint stress for 7 days—there was a prolonged enhancement of dopamine (DA) uptake into synaptosomes. The mRNA for the DA transporter (DAT) was found to be concomitantly increased in the midbrain, as was the binding of the transporter ligand mazindol to DAT in the nucleus accumbens and caudate‐putamen. Kinetic analysis showed an increase in Vmax for DA, with little change in Km. No changes in tyrosine hydroxylase activity and tissue DA or 3,4‐dihydroxyphenylacetic acid (DOPAC) content were observed. However, homovanillic acid (HVA) was found to be increased in the striatum of the stressed animals. Enhanced DAT activity attributable to chronic stress was still observed in animals treated with the DA D2 receptor antagonist haloperidol or the glucocorticoid receptor antagonist mifepristone. Modulation of DAT activity may be a physiological mechanism for regulating the concentration of DA that reaches receptors, following periods of stress. Synapse 57:167–174, 2005. © 2005 Wiley‐Liss, Inc.
Atrial Response to Ventricular Antitachycardia Pacing Discriminates Mechanism of 1:1 Atrioventricular Tachycardia
Authors: RIDLEY DARYL P. , GULA LORNE J. , KRAHN ANDREW D. , SKANES ALLAN C. , YEE RAYMOND , BROWN MARK L. , OLSON WALTER H. , GILLBERG JEFFREY M. , KLEIN GEORGE J. 
Published: June 2005

Background: Inappropriate shocks from implantable cardioverter defibrillators (ICD) remain a significant clinical problem despite device discrimination algorithms. The atrial response to antitachycardia pacing (ATP) may determine the mechanism of 1:1 A:V tachycardia. Methods: For this study we refer to sinus tachycardia, atrial tachycardia (AT), atrial fibrillation, and flutter as atrial tachycardia (AT), and all other tachycardia as “non‐AT.” Three atrial response patterns during the burst of ATP were determined. The atrial cycle length (ACL) may be unchanged (type 1) indicating AT. The ACL may show variation during ATP (type 2) indicating variable VA block and does not discriminate between an AT and a non‐AT mechanism, in which case a default diagnosis of non‐AT is made. The ACL may accelerate to the ATP cycle length (type 3) indicating entrainment. A VAAV response at the end of ATP was considered diagnostic of AT (type 3A) whereas a VAV or VVA response was considered a non‐AT mechanism (type 3B). This algorithm was applied to ICD tracings from 68 episodes of spontaneous 1:1 A:V tachycardia that had 136 sequences of ATP administered. The rhythm “truth” was determined by consensus of two experienced clinicians. Results: The algorithm correctly identified AT with a sensitivity of 71.9% (95% CI: 67.1–73.6), and specificity of 95% (83.5–99.1). The PPV was 97.2% (90.9–99.5), and NPV 58.5% (51.4–61.0). Kappa was 0.57 (0.43–0.62). If used clinically the algorithm would have aborted 53.3% (8/15) of inappropriate shocks delivered into an AT‐mechanism tachycardia and would not have withheld a shock for any episode of VT. Conclusion: Analysis of atrial response patterns during and after ventricular ATP can successfully discriminate tachycardia mechanism and may reduce inappropriate ICD shocks.
Effects of Cardiac Resynchronization Therapy on Ventricular Repolarization in Patients with Congestive Heart Failure
Authors: BERGER THOMAS , HANSER FRIEDRICH , HINTRINGER FLORIAN , POELZL GERHARD , FISCHER GERALD , MODRE ROBERT , TILG BERNHARD , PACHINGER OTMAR , ROITHINGER FRANZ X 
Published: June 2005

Introduction: Biventricular pacing has been shown to improve the clinical status of patients with congestive heart failure, but little is known about its influence on ventricular repolarization. The aim of our study was to evaluate the effect of biventricular pacing on ECG markers of ventricular repolarization in patients with congestive heart failure. Methods and Results: Twenty‐five patients with congestive heart failure, sinus rhythm (SR), and complete LBBB (6 females; age 61 ± 8 years; NYHA class II–III; echocardiographic ejection fraction 21 ± 5%; QRS ≥ 130 ms) underwent permanent biventricular DDDR pacemaker implantation. A high‐resolution 65‐lead body‐surface ECG recording was performed at baseline and during right‐, left‐, and biventricular pacing, and the total 65‐lead root mean square curve of the QRST complex and the interlead QT dispersion were assessed. The QRS duration was increased during right (RV)‐ and left ventricular (LV) pacing (127 ± 26% and 117 ± 40%; P < 0.05), as compared to SR (100%) and biventricular pacing (93 ± 16%; ns). The QTc interval was increased during RV and LV pacing (112 ± 12% and 114 ± 14%; P < 0.05) as compared to SR (100%) or biventricular pacing (99 ± 12%). There was no effect on JT interval during all pacing modes. The Tpeak‐end interval was increased during right (120 ± 34%; P < 0.01) and LV pacing (113 ± 29%; P < 0.05) but decreased during biventricular pacing (81 ± 19%; P < 0.01). A similar effect was found for the Tpeak‐end integral and the Tpeak amplitude. QT dispersion was increased during right ventricular (129 ± 16 ms; P < 0.05) and decreased during biventricular pacing (90 ± 12 ms; P < 0.01), as compared to SR (114 ± 22 ms). Conclusions: Using a high‐resolution surface ECG, biventricular pacing resulted in a significant reduction of ECG markers of ventricular dispersion of repolarization.
Superior Vena Cava Flutter: Electrophysiology and Ablation
Authors: MERINO JOSE L. , PEINADO RAFAEL , ABELLO MAURICIO , GNOATTO MARIANA , VASSEROT MAR G. , SOBRINO JOSE A. 
Published: June 2005

Introduction: Reentry within a major thoracic vein has been suggested as a cause of atrial arrhythmias. However, little is known about these potential reentrant circuits. Methods and Results: Atypical atrial flutter was induced and mapped in 67 out of 225 atrial flutter ablation procedures. Reentry around the superior vena cava (SVC) was suspected in three patients. The suspected SVC flutter was induced and terminated by pacing in all patients. Fusion was demonstrated during flutter entrainment by subeustachian isthmus pacing in all of them. The postpacing interval following entrainment by pacing from different sites of the right atrium (RA) or coronary sinus was longer than the flutter cycle length. Macroreentry within the SVC was demonstrated both by sequential activation and a postpacing interval matching the flutter cycle length when pacing from different sites around the SVC in all patients. Atrial–venous–atrial electrogram sequence was demonstrated following flutter entrainment by atrial pacing. Flutter was terminated by an electrical stimulus delivered to the SVC, which was not propagated to the trabeculated RA, in one patient, and linear radiofrequency application from the distal SVC to the posterior wall of the RA, or to the superoseptal portion of the crista terminalis, in the other two. Conclusion: Macroreentry within the SVC is a distinctive mechanism responsible for rapid atrial activation, which is different from other reported flutter mechanisms, such as upper loop reentry. SVC longitudinal radiofrequency application can eliminate the arrhythmia without the need for complete electrical disconnection of the vein.
Ventricular Tachycardia Duration and Form Are Associated with Electrical Discontinuities Bounding the Core of the Reentrant Circuit
Authors: CIACCIO EDWARD J. 
Published: June 2005

Background: Successful prediction of reentrant ventricular tachycardia duration and form from sinus‐rhythm electrogram signals in canine hearts is relevant to clinical studies, to potentially improve catheter ablation treatment during EP study. Methods/Results: Following LAD ligation of canine hearts, activation maps were constructed from 312 border zone sites 4–5 days postinfarction. When reentrant ventricular tachycardia was inducible via programmed stimulation, the core of the circuit was defined on the maps as the enclosed area formed by the adjoining lines of slowest conduction and block bounding the protected region of the reentrant circuit. The number, location, and width of points of entrance or exit of the activation wavefront about the core were determined. Core perimeter location was then marked on the sinus‐rhythm activation map, and the difference in activation time at opposite recording sites along the core perimeter was measured. Mean sinus‐rhythm activation was highly discontinuous along the core perimeter in 10 transient reentry experiments (30.1 ± 4.4 ms), moderately discontinuous in 13 sustained experiments (16.7 ± 1.8 ms), and only slightly discontinuous in 5 noninducible experiments (9.7 ± 1.7 ms). For transient versus sustained experiments, the entrance/exit points were narrower (mean: 6.5 ± 1.0 mm vs 9.5 ± 1.8 mm) with larger sinus‐rhythm discontinuity across them (mean: 23.8 ± 6.0 ms vs 11.8 ± 2.1 ms). As core size increased, so did the number of entrance/exits present during reentry (P < 0.001). With increasing core size, four‐loop (quatrefoil) reentry was frequently observed. Conclusions: Whether reentrant ventricular tachycardia will be inducible in the canine infarct border zone, and its duration and form, is associated with the characteristics of electrical discontinuities present about the core perimeter.
Iron metabolism in copper-deficient rats
Authors: Marston H. R. , Allen Shirley H. , Swaby S. L. 
Published: June 2005

1. The effects of ingestion of diets deficient in both copper and iron on storage of these elements and on the red cell indices have been studied in rats.2. Injection of Cu into rats whose stores of Cu had been virtually exhausted resulted in a temporary increase in the concentration of plasma Fe and depletion of the Fe stored in the liver. Storage of Fe in the spleen seemed to be affected somewhat differently from that in the liver.3. Fe injected into Cu-deficient rats was transported to storage sites but, although the plasma Fe concentration was presumably transiently increased thereby, there was no lasting effect.4. The hypotheses that Cu mediates in the release of Fe from ferritin and that of Osaki, Johnson & Frieden (1966) that caeruloplasmin promotes the rate of Fe-saturation of apotransferrin are discussed.
A theoretical consideration of the effect of preventing rumen fermentation on the efficiency of utilization of dietary energy and protein in lambs
Authors: Black J. L. 
Published: June 2005

1. The effect of preventing rumen fermentation of feed on the utilization of energy and protein by growing lambs has been studied by theoretical means.2. Initially, the differences in feed utilization resulting from microbial fermentation compared with digestion by host enzymes were estimated. It was assumed that a diet containing 85% of unspecified carbohydrate and 15% casein was placed directly into the rumen (ruminant lamb) or abomasum (non-ruminant lamb) of animals weighing 20 kg, and that in both instances the diet was completely digested. In the non-ruminant lamb from 39 to 45% more net energy was available for maintenance, and from 22 to 61% more net energywas available for production, than in the ruminant lamb. The smaller differences applied to concentrate diets and the larger differences to highly fibrous diets. When dietary protein was completely degraded by microbes approximately 50% less protein was absorbed from the small intestine in the ruminant lamb than in the non-ruminant lamb. It is suggested that this may significantly reduce tissue synthesis and growth in early-weaned lambs weighing less than 30 kg, but it may not limit growth in heavier animals.3. Because part of the food of ruminants generally escapes fermentation and is digested by enzymes in the small intestine, and because part of the food of non-ruminants is fermented in the hind-gut, the estimates were adjusted accordingly. In this situation the utilization of digested energy in the non-ruminant lamb was from 30 to 45 % more efficient for maintenance and from 10 to 60 % more efficient for production than in the ruminant lamb. Some dietary proteins are so resistant to microbial degradation that a lower efficiency of utilization in the ruminant lamb when these proteins are given could only result from a limit in availability of energy.4. Since ruminants digest crude fibre more efficiently than non-ruminants, it was calculated that the level of dietary crude fibre must exceed at least 22%, and in some instances 35%, of the dry matter before the ruminant digestive system results in a better utilization of dietary energy in lambs. Thus, many common feeding-stuffs would be more efficiently used by lambs if they by-passed the rumen. The possible limitations to the adoption of this procedure are discussed.5. The present techniques available for reducing the degradation of food within the rumen are outlined. It is suggested that an improvement in food utilization in ruminants could be achieved by feeding fats or formaldehyde-treated fat-casein complexes in solid diets, or alternatively, by feeding liquid diets which activate the reticular groove.
The influence of sex and age on the deposition of L-xyloascorbic acid in tissues of guinea-pigs
Authors: Hughes R. E. , Jones P. R. 
Published: June 2005

1. Young male and female guinea-pigs of similar age and male guinea-pigs of various ages were given daily oral supplements of vitamin C (L-xyloascorbic acid) (AA) on a body-weight basis for periods of 10–15 d and the resulting concentration of AA in several organs was determined.2. There was no difference between the sexes in the concentrations of AA in the adrenal glands and spleen. The concentration of AA in the spleen, adrenal glands and eye lens was significantly lower in older animals, and in brain it was significantly higher than the corresponding values for the young guinea-pigs.3. The tissue deposition after oral administration of AA for 10 d was compared with that resulting from intramuscular injection of the same quantity of AA over 10 d in males aged 60 d, males aged 500 d and females aged 500 d. In the 60-d-old guinea-pigs intramuscular injection raised the concentration of AA in the spleen and adrenal glands 35% and 50% respectively above that resulting from oral dosing. In the older guinea-pigs (500 d) the corresponding values were 108% and 127% respectively. It is concluded that reduced gastrointestinal absorption is, at least in part, responsible for the low AA concentrations in certain organs from older guinea-pigs. In the 500-d-old guinea-pigs there was no significant difference between the AA levels in the spleen, adrenals and brain of the two sexes, but AA level in the lens of females was significantly lower than that in males, irrespective of the mode of administration of the AA.
Iodine metabolism in children and women with endemic goitre in Ceylon
Authors: Deo M. G. , Subramanian T. A. V. 
Published: June 2005

1. Iodine metabolism was studied using labelled sodium iodide in subjects with endemic goitre which is prevalent in the south-west part of Ceylon, where the iodine content of the drinking water was shown to be low. The study was confined mostly to children of school age.2. The patients showed raised thyroidal uptake of 181I and 48 h serum protein-bound radio-active iodine, lowered plasma inorganic iodide and urinary iodide.3. These findings suggest that the goitre which is endemic in Ceylon is due to environmental iodine deficiency rather than to a goitrogen.
Cranial transillumination in early and severe malnutrition
Authors: Jaime Rozovski N. , Fernando Novoa S. , Jorge Abarzúa F. , Fernando Mönckeberg B. 
Published: June 2005

1. By means of a cranial transillumination method used in conjunction with lumbar and bregmatic punctures, an increase in the space which contains the cerebro-spinal fluid in the cranial region is suggested in children with severe marasmic malnutrition.2. The results appear to indicate that this is due to a diminished brain size, creating a space in the interior of the cranium which secondarily fills with cerebro-spinal fluid.
Artificial rearing of pigs
Authors: Braude R. , Newport M. J. , Porter J. W. G. 
Published: June 2005

1. Baby pigs were removed from the sow 36–48 h after birth and reared on a diet of reconstituted whole-milk powder until 28 d of age. The whole milk was either mildly or severely heated before spray-drying; the severe heating completely denatured the whey proteins.2. When the two milks were given at a high level of intake, either at hourly intervals or twice daily, severe scouring and some deaths occurred, the incidence being higher among pigs receiving the severely heated milk. The severe heat treatment also reduced the nutritive value of the milk powder as measured by the performance of the pigs during the 1st week of life. However, no difference in the nutritive value of the two milks was apparent for the surviving pigs over the whole experimental period.3. There were no deaths when the two milks were given at a moderate level of intake and at hourly intervals. The effect of heat treatment on performance was similar to that at the high level of intake.4. The apparent digestibility of the nitrogen in the diet was similar for both milks. However, balance trials could not be carried out when scouring occurred, when differences between the milks were most likely to be apparent. The N retention was similar with both milks at 7 d of age, although retention was higher when the severely heated milk was given to pigs between 14 and 21 d of age.5. The digestion of the two milks was studied in 28-d-old pigs. The ability of the severely heated milk to clot in the stomach was greatly reduced compared with that of the mildly heated milk, but the performance of the pigs was unaffected. No other differences in the digestion of the milks were found. The ability of the diet to clot in the stomach appeared to be unimportant at this age.6. It is possible that a reduction in the clotting ability of the severely heated milk was responsible for the decreased efficiency of digestion during the 1st week of life.
Measurement of the bacterial nitrogen entering the duodenum of the ruminant using diaminopimelic acid as a marker
Authors: Hutton K. , Bailey F. J. , Annison E. F. 
Published: June 2005

1. A technique for the separation and colorimetric estimation of 2, 4-diaminopimelic acid (DAP) using automated ion-exchange chromatography coupled with an acid ninhydrin detection system is described.2. Only traces of DAP were found in rumen protozoa and no DAP was detected in rumen fluid prepared by ultracentrifugation or dialysis.3. The concentration of DAP in rumen bacteria from sheep on a constant feeding regimen, and the ratio of nitrogen to DAP for these bacteria were found to be constant over a 3-month period.4. The method has proved suitable for the estimation of bacterial N in the duodenal digesta of ruminants.5. The contribution of bacterial N to the total N leaving the abomasum of a lactating cow fitted with a permanent re-entrant cannula in the duodenum was found to be 50%.
Protein-calorie deficiency in rats
Authors: Stewart R. J. C. , Sheppard Hilda G. 
Published: June 2005

1. Rats born of well-fed mothers and maintained from weaning on diets having protein values of NDpCal% = 10 or 5 were mated at 3 months of age with well-fed males.2. The litters produced by the malnourished mothers weighed significantly less (P > 0.01) than those from the well-fed group.3. The average number of individuals per litter was lower in the malnourished than in the well-fed group, but the difference was not statistically significant ( P < 0.0 5 ).4. The congenitally malnourished litters weighed less than the well-fed even when litters of equal number were compared.5. The differences in litter weights were not related to the length of gestation, which was similar in both groups.6. There was a high neonatal death rate (63%) among the congenitally malnourished animals and the survivors grew very slowly so that at 5 weeks of age they weighed only half as much as the well-fed controls.