bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plasma Arachidonic Acid-Rich Phospholipids in Crohn's Disease: Response to Treatment
Authors: Pereira Stephen P. , Cassell Theresa B. , Engelman Jeffrey L , Sladen Gordon E. , Murphy Gerard M. , Dowling R. Hermon 
Published: August 2015

1. Increased concentrations of plasma polyunsaturated fatty acids have been implicated in the pathogenesis of Crohn's disease. However, it is not known whether there are corresponding changes in circulating phospholipids - the major source of fatty acids in the plasma.
2. Fasting plasma samples were obtained from 17 control subjects and 13 patients with active Crohn's disease [Simple Index of Crohn's Disease Activity (SICDA) &gt;6] before, and 2 and 8 weeks after, treatment with either a peptide diet or oral prednisolone.
3. Before treatment, the Crohn's disease patients had mildly active disease (SICDA 9.9 ± 0.8, erythrocyte sedimentation rate 26.4 ± 6.5 mm/h, serum C-reactive protein 2.8 ± 0.4 mg/l). The proportions of the polyunsaturated phosphatidylcholine species, 16:0–20:4 (10.0 ± 0.7%) and 16:0–22:6 (7.1 ± 0.8%), were both significantly higher than those in healthy controls (7.6 ± 0.5%, P &lt; 0.01 and 5.3 ± 0.5%, P &lt; 0.05 respectively).
4. After 2 weeks treatment, the SICDA in the Crohn's disease patients decreased to 3.2 ± 0.6 (P &lt; 0.0001 compared with the pretreatment value), and there were corresponding falls in the erythrocyte sedimentation rate (to 12.6 ± 2.7 mm/h, P &lt; 0.05) and C-reactive protein concentration (to 1.7 ± 0.3 mg/l, P &lt; 0.05)—these improvements being maintained at 8 weeks. There was also a fall to normal values in 16:0–20:4 (to 7.7 ± 0.6%, P &lt; 0.01 compared with the pretreatment value) and in 16:0–22:6 (to 5.7 ± 0.5%, P not significant), by week 8.
5. The proportions of polyunsaturated phosphatidylcholine molecular species were increased in the plasma of patients with active Crohn's disease, but fell to normal levels during disease remission. These observations are consistent with the theory that, in active Crohn's disease, the mucosal phospholipids containing polyunsaturated fatty acids are increased, contribute to eicosanoid synthesis and ‘spill’ into the plasma.
Recovery of 13CO2 and 14CO2 in Human Bicarbonate Studies: A Critical Review with Original Data
Authors: Leijssen D. P. C. , Elia M. 
Published: August 2015

1. In order to establish biological and/or methodological explanations for the wide variability in recovery (50–100%) of labelled CO2 after administration of [13C]bicarbonate or [14C]bicarbonate, 34 human bicarbonate studies involving 480 subjects were analysed, and potential methodological issues were investigated in the laboratory.
2. Overall, continuous infusion studies reported a higher recovery than bolus studies (84 ± 11% versus 69 ± 12%; P &lt; 0.001). No significant differences in recovery were found between 14C and 13C studies, children and adults, obese and lean subjects, or rest and exercise (steady state). Higher recoveries were found during feeding than during fasting (84 ± 8% versus 74 ± 7%; P &lt; 0.001). Different methods used to analyse the results (0–10%) and different study protocols, which include differences in the duration of infusions and background drift in 13C enrichment (0–10%), contribute to the variability.
3. The laboratory studies suggest multiple sources of potential error, including loss of CO2 from the scintillation fluid (up to &gt;30%, but only in 14C studies in which the scintillation fluid is not alkalized), diffusion of CO2 through syringes and tubing (0 to &gt; 10%), non-linearity of CO2 analysers (up to 8%), inaccuracies in the measurement of bicarbonate concentrations (13C studies) or the strength of CO2-trapping agents (14C studies; 0–8%).
4. It is concluded that much of the variability in the recovery of labelled bicarbonate is likely to be attributable to methodological differences, and that attention to these will ensure better interpretation of metabolic studies that involve oxidation of carbon-labelled substrates.
Subcutaneous Abdominal Adipose Tissue Blood Flow: Variation within and between Subjects and Relationship to Obesity
Authors: Summers Lucinda K. M. , Samra Jaswinder S. , Humphreys Sandy M. , Morris Richard J. , Frayn Keith N. 
Published: August 2015

1. We assessed the variation in subcutaneous abdominal adipose tissue blood flow within and between subjects and investigated whether it is correlated with body mass index.
2. We measured body mass index and subcutaneous abdominal adipose tissue blood flow in 38 fasting subjects on the same day and on different days and, in a subgroup of 16 subjects, after a mixed meal.
3. In 190 measurements in the fasted state, subcutaneous abdominal adipose tissue blood flow was significantly more variable between subjects than could be accounted for by the within-subject variation alone. Subcutaneous abdominal adipose tissue blood flow was also significantly more variable between days within subjects than could be accounted for by within-day variation alone. Fasting and post-prandial subcutaneous abdominal adipose tissue blood flow were negatively correlated with body mass index, as was the post-prandial rise in subcutaneous abdominal adipose tissue blood flow. Multiple regression analysis showed that fasting blood flow was not dependent on insulin concentration after allowing for body mass index. There was no correlation between post-prandial subcutaneous abdominal adipose tissue blood flow and insulin concentration.
4. Insulin does not appear to have a direct vasodilatory effect in subcutaneous adipose tissue. Obese subjects have lower fasting and post-prandial subcutaneous abdominal adipose tissue blood flow. This may be because of a blunted response to sympathetic stimulation, or it may be another aspect of the insulin-resistant state.
Small Artery Structural Alterations of Patients with Microvascular Angina (Syndrome X)
Authors: Bund S. J. , Tweddel A. , Hutton I. , Heagerty A. M. 
Published: August 2015

1. There is increasing evidence that a substantial number of patients who suffer from angina have normal epicardial arteries (Syndrome X), and it has been suggested that these individuals have a generalized disorder of small vessels not confined to the intramyocardial vasculature.
2. Small arteries were therefore obtained from biopsies of skin and subcutaneous fat from nine normotensive patients with Syndrome X and nine matched control subjects. Vessels were dissected and mounted as ring preparations in a myograph for morphological and functional assessment.
3. Morphological measurements revealed a significant increase in media thickness/lumen diameter ratio in arteries from patients with Syndrome X. Contractile responses to U46619 were similar in arteries from patients and control subjects. Endothelium-dependent relaxation induced with acetylcholine and bradykinin was greater in arteries from patients although differences were not statistically significant. Endothelium-independent relaxation induced by forskolin and sodium nitroprusside was not different.
4. In conclusion, these data demonstrate that subcutaneous small arteries from patients with Syndrome X are characterized by increased media thickness/lumen diameter ratios, although contractile responses were normal. Additionally, endothelium-dependent relaxation was not impaired in arteries from these patients. Thus, no significant functional abnormalities were associated with the observed structural differences.
Assessment of Postural Differences in Regional Pulmonary Perfusion in Man by Single-Photon Emission Computerized Tomography
Authors: Ross David J. , Wu Pearl , Mohsenifar Zab 
Published: August 2015

1. With the advent of single-photon emission computerized tomography, controversy has arisen with regard to the significance of gravitational influences on regional pulmonary perfusion (Q̊r) in the supine versus prone postures. We investigated the dorsal—ventral distributions of Q̊r in prone (n = 5) and supine (n = 5) normal subjects, as assessed by single-photon emission computerized tomography after intravenous injection of technetium-99m-labelled macroaggregated albumin at end-tidal expiration. Reconstructed serial (one pixel thickness) coronal sections were traced on a computer screen, to yield the encompassed radioactive counts and number of pixels per each image. Coronal section data (expressed as mean radioactive counts/pixel) were expressed in a ‘profile’ and normalized to the maximum coronal section of each lung (%maximum).
2. Coefficients of variation and linear regression slopes for the prone versus supine profiles for left and right lungs were not statistically different (unpaired Student's t-test). The coronal section with maximum Q̊r was identified in the more dependent lung regions and, hence, affected by gravity.
3. We conclude that, in contrast to previous canine models, which have suggested postural differences in dorsal-ventral perfusion gradients, in normal man gravity primarily determines the non-dependent to dependent distribution of Q̊r. We speculate that interspecies differences in physiology may be teleological and related to the different perfusion demands of the quadruped compared with upright man.
Plasma RRR-α-tocopherol Concentrations Are Lower in Smokers Than in Non-Smokers after Ingestion of a Similar Oral Load of this Antioxidant Vitamin
Authors: Munro Lisa H. , Burton Graham , Kelly Frank J. 
Published: August 2015

1. Using deuterium-labelled α-tocopherol (vitamin E), the plasma kinetics of α-tocopherol derived from supplemental RRR-α-tocopherol and RRR-α-tocopheryl acetate were determined in asymptomatic individuals who smoke and, for comparison, in a group of healthy non-smokers.
2. Venous blood samples were withdrawn 6, 12 and 27 h after the oral administration of a gelatin capsule containing an equimolar mixture of RRR-α-tocopherol and RRR-α-tocopheryl acetate. Plasma concentrations of endogenous and administered forms of α-tocopherol were determined by a combination of HPLC and GC-MS.
3. Both the free phenol and the acetate ester concentrations of α-tocopherol were lower in smokers than in non-smokers: 0.99 versus 1.60 (P &lt; 0.05) and 0.66 versus 1.49 (P &lt; 0.05) μmol/mmol cholesterol for RRR-α-tocopherol and RRR-α-tocopheryl acetate respectively. The highest concentation of α-tocopherol derived from administered RRR-α-tocopherol and its acetate ester were observed in plasma at 12 h (compared with 6-h and 27-h measurements) in most subjects.
4. Although the two forms of α-tocopherol were administered in equal doses, plasma from smokers contained significantly higher concentrations of RRR-α-tocopherol derived from the free phenol form than from the acetate form (0.99 versus 0.66 μmol/mmol cholesterol, P &lt; 0.05, 12 h). Non-smokers did not exhibit preferential uptake of either form of vitamin E.
5. These results suggest that individuals who smoke have either a reduced ability to absorb α-tocopherol, particularly when it is presented as the acetate ester, or increased clearance of newly absorbed α-tocopherol compared with non-smokers.
Dietary Fish Oil Reduces Survival and Impairs Bacterial Clearance in C3H/Hen Mice Challenged with Listeria Monocytogenes
Authors: Fritsche K. L. , Shahbazian L. M. , Feng C. , Berg J. N. 
Published: August 2015

1. To investigate the effect of dietary fat source on host resistance to intracellular pathogens, weanling female C3H/Hen mice were fed one of three experimental diets containing, 20% by weight, lard, soybean oil or 17% menhaden fish oil plus 3% corn oil. After 4 weeks, survival of mice (n = 12/treatment group) injected intraperitoneally with 2 × 106 colony forming units of live Listeria monocytogenes was determined. In a second study, bacterial clearance from the liver and spleen at 2, 4 and 7 days post-challenge was determined (n = 8/treatment group).
2. We found that the survival of mice fed the diets with soybean oil or menhaden fish oil was significantly lower than those fed lard (P &lt; 0.05). Survival rates were 58% (7/12), 33% (4/12) and 100% (12/12), respectively, for mice fed soybean oil, menhaden fish oil and lard. In the second study, mice fed menhaden fish oil had approximately 1 login greater bacteria in their spleens at day 4 than mice fed lard or soybean oil (P &lt; 0.001). There were no significant treatment differences in the number of bacteria recovered from liver samples.
3. In summary, dietary fat source significantly affects murine resistance to Listeria, with diets rich in n-3 polyunsaturated fatty acids, such as from fish oil, having the most detrimental effect.
Isometric Contraction of Arm Flexor Muscles as a Method of Evaluating Cardiac Vagal Tone in Man
Authors: Al-Ani M. , Robins K. , Al-Khalidi A. H. , Vaile J. , Townend J. , Coote J. H. 
Published: August 2015

1. We have previously shown that brief voluntary isometric contractions of upper arm flexor muscles performed for one respiratory cycle elicit a significant decrease in the R—R interval. The present study was designed to determine if similar changes are produced by non-voluntary electrically evoked contractions and, if so, to establish the consistency and repeatability of the associated changes in the R—R interval.
2. The heart rate (R—R interval) response to voluntary or non-voluntary brief isometric contraction equivalent to 40% of the maximum voluntary contraction was studied in 10 healthy young male subjects during controlled ventilation at supine rest.
3. The absolute values of R—R intervals occurring in any one of 10 arbitrary phases of a respiratory cycle were measured and plotted by a computer.
4. Both voluntary and non-voluntary contractions elicited similar changes in heart rate and R—R interval, which were greater during expiration than during inspiration.
5. This confirms our previous finding that the magnitude of the R—R interval changes, with brief isometric contraction, is positively related to the degree of cardiac vagal tone.
6. Analysis of the variability between repeated tests initiated in either inspiration or expiration revealed that there was significantly less variability with the electrically induced contraction.
7. It was concluded that electrically induced contractions of 40% maximal voluntary contraction are a viable alternative to voluntary contractions and provide a more controllable means of measuring cardiac vagal withdrawal.
An Analysis of Arterial Disease Mortality and BUPA Health Screening Data in Men, in Relation to Outdoor Temperature
Authors: Donaldson G. C. , Robinson D. , Allaway S. L. 
Published: August 2015

1. Laboratory studies have shown that cold exposure causes an increase in blood pressure, cholesterol and erythrocyte count. However, whether the mild cold exposures received during everyday life are sufficient to cause such changes is unclear.
2. To test this, outdoor temperatures in central London between 1986 and 1992 were related to both haematological and blood pressure data on 50–69-year-old men attending BUPA health screening examinations in London, and to mortality in South-East England. Since any association with temperature may be an artifact due to common, temperature-independent, annual rhythms in the parameters, these data were also analysed after removal of these circannual components by digital filtering.
3. It was found that short-term falls in temperature produced significant increases in Hb, erythrocyte count, packed cell volume, mean corpuscular Hb concentration, serum albumin, systolic and diastolic blood pressure, and significant decreases in mean corpuscular volume and erythrocyte sedimentation rate. Mean corpuscular Hb, leucocyte count, platelet count and serum cholesterol concentrations were unchanged. Time-series analysis showed that these changes occurred almost immediately in response to a fall in temperature, but persisted for longer intervals of up to 1–2 days.
4. Mortalities from ischaemic heart disease and cerebrovascular disease were also significantly increased by short-term falls in temperature.
5. These findings indicate that in the general population the cold exposures of normal life are sufficient to induce significant and prolonged haemoconcentration and hypertension, which may explain why deaths from arterial disease are more prevalent in the winter.
Comparison between Reproducibility and Sensitivity of Muscle Sympathetic Nerve Traffic and Plasma Noradrenaline in Man
Authors: Grassi Guido , Bolla Giambattista , Seravalle Gino , Turri Carlo , Lanfranchi Antonio , Mancia Giuseppe 
Published: August 2015

1. Although plasma noradrenaline and muscle sympathetic nerve traffic have been shown to be suitable markers of sympathetic activity in man, no study has systematically compared the reproducibility and sensitivity of these two indices of adrenergic tone.
2. Reproducibility data were collected in 10 subjects, in whom plasma noradrenaline was assessed by HPLC on blood samples withdrawn from an antecubital vein and efferent postganglionic muscle sympathetic nerve activity was measured by microneurography from a peroneal nerve, together with arterial blood pressure (Finapres technique). Measurements were obtained in a first session (session 1), 60 min later (session 2) and after 14 days (session 3). While muscle sympathetic nerve activity values recorded in the three different experimental sessions were closely and significantly correlated with each other (r always &gt;0.90, P &lt; 0.001), noradrenaline showed a less significant correlation between sessions 1 and 2 (r = 0.71, P &lt; 0.05) or no correlation between sessions 1 and 3 (r = 0.45, P not significant).
3. Sensitivity data were collected by evaluating muscle sympathetic nerve activity and noradrenaline values in three different age groups (young, middle-age and old subjects, n = 18), in three groups with different blood pressures (normotensive, mild and severe hypertensive subjects, n = 30) and in a group of eight subjects before and after a physical training programme, i.e. conditions known to increase or reduce sympathetic cardiovascular drive. Muscle sympathetic nerve activity was significantly increased by aging and hypertension, and reduced by physical training. The noradrenaline changes were much less marked and consistent.
4. These data suggest that muscle sympathetic nerve activity has a greater short- and medium-term reproducibility than noradrenaline. In several conditions known to modify sympathetic cardiovascular drive muscle sympathetic nerve activity also appears to change more clearly than noradrenaline.
Effect of High-Dose Chemotherapy on Intestinal Permeability in Humans
Authors: Keefe D. M. K. , Cummins A. G. , Dale B. M. , Kotasek D. , Robb T. A. , Sage R. E. 
Published: August 2015

1. Mucositis is a common side-effect of chemotherapy which is difficult to assess except by invasive means such as upper gastrointestinal endoscopy. Differential absorption of mono- and di-saccharides, such as rhamnose and lactulose, is a non-invasive measure of intestinal damage.
2. The purpose of the study was to assess the duration and severity of intestinal damage in patients undergoing high-dose chemotherapy and autologous blood stem-cell transplantation for malignant disease.
3. Thirty-five patients were studied before treatment and at 7, 28, 60 and 90 days after treatment.
4. The median lactulose/rhamnose ratios before treatment and at 7 and 90 days post-treatment were 0.09, 0.62 and 0.06 respectively. Altered permeability was due to both increased lactulose permeation and decreased rhamnose absorption. These abnormalities suggest a defect in tight-junction integrity as well as a decrease in surface area of small bowel.
5. We conclude that chemotherapy given for malignant disease is associated with a transient abnormality in intestinal sugar permeability, which peaks at 7 days after treatment and is composed of both mono- and di-saccharide absorption abnormalities.
Effects of Ordinary Meals on Plasma Concentrations of 3,4-Dihydroxyphenylalanine, Dopamine Sulphate and 3,4-Dihydroxyphenylacetic Acid
Authors: Eldrup Ebbe , Møller Svend Erik , Andreasen JAN , Christensen Niels Juel 
Published: August 2015

1. Plasma concentrations of 3,4-dihydroxyphenylalanine (DOPA), dopamine sulphate (DA-S), and 3,4-dihydroxyphenylacetic acid (DOPAC) in humans have been claimed to be indexes of sympathetic nervous activity, but the source and significance of plasma DOPA, DOPAC and DA-S have not been completely elucidated.
2. The effects of ordinary meals on plasma concentrations of total dopamine, mainly DA-S, DOPAC and DOPA were studied in seven healthy subjects. Venous blood was collected every hour for 25 h, while subjects were either fasting or received three meals at 9.00 hours, 13.00 hours and 18.00 hours. Catecholamines and metabolites were determined by reverse-phase HPLC with electrochemical detection. Neutral amino acids were measured by ionexchange chromatography with photometric detection.
3. The food contained relatively little DOPA as compared with phenylalanine, tyrosine, isoleucine and tryptophan. The content of DA and DA-S varied considerably, with the greatest amount in the evening meal of open sandwiches.
4. Plasma DOPA decreased significantly after the meals at 13.00 hours and 18.00 hours, whereas concentrations of the other amino acids increased as expected.
5. Plasma DA-S increased significantly after meals and especially after the evening meal. Increments in DA-S above basal values after a meal were closely related to the content of DOPA+DA+DA-S in the meal. Plasma DOPAC increased significantly after the evening meal.
6. The decrease in plasma DOPA observed after a meal was probably due to uptake of DOPA by muscle tissue. Changes in plasma DA-S and DOPAC during this 25-h study reflected to a large extent the content of DOPA, DA and DA-S in the meals.
Maternal Serum Vascular Endothelial Growth Factor during Early Pregnancy
Authors: Evans Phylip , Wheeler Timothy , Anthony Frederick , Osmond Clive 
Published: August 2015

1. The objectives of the study were: (i) to investigate the serum concentrations of vascular endothelial growth factor (VEGF) in pregnant and non-pregnant women; and (ii) to study the relationship between the levels of maternal serum VEGF and the serum concentrations of human chorionic gonadotrophin (hCG) and progesterone during the first trimester.
2. Total immunoreactive VEGF was measured by competitive RIA using recombinant human VEGF165 and a polyclonal antiserum. Serum VEGF was measured in 60 non-pregnant women of child-bearing age. These data were compared with serum VEGF measured in 363 women between 41 and 91 days of gestation.
3. The median serum VEGF concentration was 1.10 μg/l (interquartile range 0.91–1.30) in the nonpregnant women and 2.13 μg/l (interquartile range 1.62–2.77) in the pregnant women. Serum levels of VEGF were significantly higher among the pregnant cohort (P &lt; 0.0001). Serum VEGF concentration was positively correlated with gestational age, increasing until ten completed weeks of pregnancy. Serum VEGF was negatively correlated with maternal height and weight, and positively correlated with serum hCG and serum progesterone (P ≤ 0.0001 in all cases). Serum VEGF was lower in the pregnant women who smoked (P = 0.06).
4. Our data show a positive and highly significant correlation between maternal serum levels of VEGF and hormones reflecting placental function (hCG, progesterone). We speculate that VEGF production is increased by progesterone and hCG, and that VEGF has a positive influence on trophoblast development. VEGF may also be involved in the initiation of the maternal cardiovascular adaptation to pregnancy.