bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Appropriate Recording Force for Non-Invasive Measurement of Arterial Pressure Pulses
Authors: Driscoll M. Darcy , Malcolm J. , Arnold O. , Marchiori Gordon E. , Harker Linda A. , Sherebrin Marvin H. 
Published: August 2015

1. Non-invasive recording techniques of the arterial pressure pulse will distort the arterial wall and may alter pulse wave measurements. We hypothesized that intersubject variability of these measurements would be reduced if recording forces were normalized to reflect individualized arterial occlusion forces.
2. In 10 normal male subjects (age 24 ± 1 years), brachial, radial and finger arterial pressure pulses were recorded simultaneously using volume displacement pulse transducers (Fukuda TY-303) and a finger pressure monitoring system (Finapres, Ohmeda 2300) and were made at 2, 5 and 10–100% (10% increments) of the brachial arterial force associated with marked distortion of finger pulsations. Forces were applied at the brachial site in a randomized order while a constant 1.8 N force was applied at the radial artery site. Pressure pulses were analysed using the discrete fast Fourier transform.
3. Pulse amplitude, contour, wave velocity and relative transmission ratios remained relatively constant until the brachial artery recording force exceeded 59.9 ± 0.3% of the largest recording force used in each subject (7.14 ± 0.75 N). The finger pulse pressures (P &lt; 0.0001), radial pulse amplitudes (P &lt; 0.0001) and contours (harmonics 2–6, P &lt; 0.003), pulse wave velocity (P &lt; 0.021) and relative transmission ratios (harmonics 3–7, P &lt; 0.01) then decreased with higher recording forces.
4. To avoid distortion, non-invasive recordings of arterial pressure pulse amplitude, contour, pressure wave velocity and relative transmission ratios along a peripheral arterial segment should use recording forces of less than 60% of the force associated with marked distortion of finger pulsations.
Determination of Urea Kinetics by Isotope Dilution with [13C]Urea and Gas Chromatography–isotope Ratio Mass Spectrometry (GC–IRMS) Analysis
Authors: Kloppenburg W. D. , Wolthers B. G. , Stellaard F. , Elzinga H. , Tepper T. , De Jong P. E. , Huisman R. M. 
Published: August 2015

1. Stable urea isotopes can be used to study urea kinetics in humans. The use of stable urea isotopes for studying urea kinetic parameters in humans on a large scale is hampered by the high costs of the labelled material. We devised a urea dilution for measurement of the distribution volume, production rate and clearance of urea in healthy subjects and renal failure patients using the inexpensive single labelled [13C]urea isotope with subsequent analysis by headspace chromatography—isotope ratio MS (GC—IRMS) of the [13C]urea enrichment.
2. The method involves measurement of the molar percentage excess of [13C]urea in plasma samples taken over a 4 h period after an intravenous bolus injection of [13C]urea. During the sample processing procedure, the plasma samples together with calibration samples containing a known molar percentage excess of [13C]urea are acidified with phosphoric acid to remove endogenous CO2, and are subsequently incubated with urease to convert the urea present in the plasma samples into CO2. The 13C enrichment of the generated CO2 is analysed by means of GC—IRMS. This method allows measurement of the molar percentage excess of [13C]urea to an accuracy of 0.02%.
3. Reproducibility studies showed that the sample processing procedure [within-run coefficient of variation (CV) &lt;2.8% and between-run CV &lt;8.8%] and the GC—IRMS analysis (within-day CV &lt;1.3% and between-day CV &lt;1.3%) could be repeated with good reproducibility.
4. In clinical urea kinetic studies in a healthy subject and in a renal failure patient without residual renal function, reproducible values of the distribution volume, production rate and clearance of urea were determined using minimal amounts of [13C]urea (25–50 mg).
5. Because only low [13C]urea enrichments are needed in this urea dilution method using GC—IRMS analysis, the costs of urea kinetic studies are reduced considerably, especially in patients with renal failure.
Fermentable Dietary Fibre, Intestinal Microflora and Plasma Hormones in the Rat
Authors: Ghatei M. A. , Ratcliffe B. , Bloom S. R. , Goodlad R. A. 
Published: August 2015

1. Conventional and germ-free rats were fed a fibre-free elemental diet with or without the addition of fermentable dietary fibres. We have previously reported that fibre was associated with greatly increased epithelial cell proliferation, but only in the conventional group, implying that it is the breakdown of fibre by the colonic microflora that is the main determinant of mucosal proliferation in the hind gut. The relationship of these changes to various plasma hormones implicated in intestinal growth control are described in this paper.
2. The most dramatic finding was that plasma levels of enteroglucagon and peptide YY were greatly increased in the germ-free groups. The response of these rats to fibre differed in that fibre decreased levels of enteroglucagon and peptide YY in the germ-free animals, but increased them in the conventional rats. Gastrin and insulin levels were significantly lowered in the fibre-supplemented groups, but were not affected by the microflora.
3. These results corroborate our previous findings that the effects of fibre and its fermentation are dynamically complex, and demonstrate that, like proliferation, direct effects and indirect fermentation-derived effects on plasma hormones also coexist.
Plasma Immunoreactive Leptin Concentration in End-Stage Renal Disease
Authors: Howard Jane K. , Lord Graham M. , Clutterbuck Elaine J. , Ghatei Mohammad A. , Pusey Charles D. , Bloom Stephen R. 
Published: August 2015

1. Leptin is thought to be an inhibitor of appetite. As the kidney helps clear several polypeptide hormones, plasma leptin may accumulate in end-stage renal disease.
2. Plasma immunoreactive leptin was measured in four groups of subjects: haemodialysis, continuous ambulatory peritoneal dialysis and renal transplant patients and a group of healthy controls. Leptin was also measured before and after a single dialysis session.
3. There was a strong correlation between plasma immunoreactive leptin and body mass index in all groups except female haemodialysis patients. Leptin was higher in females than in males in all groups when controlled for body mass index. Mean plasma leptin [mean (SD)] was significantly higher in all renal groups [haemodialysis, 15.1 (3.6) ng/ml; continuous ambulatory peritoneal dialysis, 25.4 (4.3) ng/ml; transplants, 11.6 (2.6) ng/ml] compared with controls [5.3 (2.3) ng/ml]. There was a significant difference in the regression equations relating leptin and body mass index (dialysis &gt; transplants &gt; controls), even when controlled for gender. Leptin correlated modestly with serum creatinine in non-dialysis subjects. Plasma leptin immunoreactivity was slightly reduced by haemodialysis, but post-dialysis leptin was still significantly higher than that found in controls.
4. Chromatographic characterization of the high level of leptin immunoreactivity found in haemodialysis subjects showed a single elution peak corresponding to that of the highly purified human leptin standard.
5. In conclusion, leptin is higher than expected for body mass index in end-stage renal disease. Hyper-leptinaemia could contribute to the anorexia and poor nutritional status commonly seen in renal failure.
Site of Insulin Resistance after Surgery: The Contribution of Hypocaloric Nutrition and Bed Rest
Authors: Nygren Jonas , Thorell Anders , Efendic Suad , Nair K. Sree , Ljungqvist Olle 
Published: August 2015

1. Insulin resistance after surgery has been shown to be related to several important derangements in protein and fat metabolism. However, mechanisms of impaired glucose tolerance after surgery remain ill-defined.
2. Insulin sensitivity and glucose kinetics (6,62H2-glucose) were studied in seven patients before and after elective surgery (surgery group), by two step-hyperinsulinaemic (0.3 and 0.8 munits kg−1 min−1), normoglycaemic (4.5 mmol/l) clamps. Six healthy subjects were studied, using the same protocol, before and after a similar period of bed rest and hypocaloric nutrition (fast/bed rest group) to delineate the effects of surgery per se.
3. Basal endogenous glucose production and whole-body glucose disposal was higher after surgery (P &lt; 0.001), whereas no change was found after fast/bed rest. During glucose clamps, the glucose infusion rates required to maintain normoglycaemia and whole-body glucose disposal decreased (P &lt; 0.001) after surgery, while endogenous glucose production increased (P &lt; 0.001). In the control subjects, levels of endogenous glucose production remained unchanged after fast/bed rest. In contrast, glucose infusion rates and whole-body glucose disposal during glucose clamps also decreased after fast/bed rest (P &lt; 0.01). However, the relative decrease in both these parameters was greater after surgery compared with after fast/bed rest (P &lt; 0.01).
4. After surgery, energy expenditure and fat oxidation increased (P &lt; 0.001), whereas glucose oxidation decreased (P &lt; 0.05). No significant change was found in glucose utilization postoperatively. After fast/bed rest, no change was found in energy expenditure. However, fat oxidation increased (P &lt; 0.01), whereas glucose oxidation and glucose utilization decreased (P &lt; 0.05).
5. In conclusion, impaired glucose tolerance develops after surgery as a result of decreased insulin-stimulated whole-body glucose disposal as well as increased endogenous glucose release. Despite the increase in endogenous glucose production, the reduction in endogenous glucose production with each elevation of insulin was unaffected by surgery. Perioperative bed rest and/or hypocaloric nutrition contribute to the decrease in insulin-stimulated whole-body glucose disposal in the postoperative state, whereas these factors have no effects on endogenous glucose production.
Timing of Administration of Dexamethasone or the Nitric Oxide Synthase Inhibitor, Nitro-l-Arginine Methyl Ester, is Critical for Effective Treatment of Ischaemia-Reperfusion Injury to Rat Skeletal Muscle
Authors: Zhang Baimeng , Knight Kenneth R. , Dowsing Bruce , Guida Elizabeth , Phan Long H. , Hickey Michael J. , Morrison Wayne A. , Stewart Alastair G. 
Published: August 2015

1. The effects of the nitric oxide synthase (NOS) inhibitors, NG-nitro-l-arginine-methyl ester (l-NAME), nitroiminoethyl-l-ornithine and S-methylisothiourea on skeletal muscle survival following 2 h of tourniquet ischaemia and 24 h of reperfusion were compared with those of the antiinflammatory steroid, dexamethasone.
2. Administration of each of the NOS inhibitors or dexamethasone 30 min before reperfusion reduced the degree of skeletal muscle necrosis 24 h after reperfusion.
3. The influence of timing of drug administration was investigated. l-NAME administered 30 min before reperfusion, at 3 h after reperfusion, but not thereafter, significantly improved muscle survival compared with saline-treated controls. Dexamethasone administered 30 min before, or at 3 or 8 h after reperfusion, but not at 16 h, significantly improved muscle survival, but neither agent had protective effects when administered before ischaemia.
4. After 8 h of reperfusion of ischaemic skeletal muscle, cell-free homogenates contained Ca2+-independent (inducible) NOS activity which was reduced in dexamethasone-treated (2.5 mg/kg) rats. Furthermore, inducible NOS mRNA levels, as detected by reverse transcriptase-PCR, were increased after 8 h of reperfusion in saline, but not in dexamethasone-treated rats.
5. These data suggest a significant deleterious effect of endogenous NO which may be restricted to the first 3 h of the reperfusion phase of ischaemia-reperfusion injury, and raise the possibility of effective treatment of incipient reperfusion injury, even after several hours of reperfusion.
Enrichment in Urinary Ammonia and Urea with Hourly Oral Doses of [15N]glycine: Evidence for a Step Function and a Circadian Rhythm in Protein Turnover
Authors: Jackson A. A. , Soares M. J. , Grove G. , Waterlow J. C. 
Published: August 2015

1. The present study sought to determine the possible existence of a pool of proteins which turn over with life-time kinetics. The pattern of enrichment of ammonia and urea in hourly samples of urine was determined in normal adults to whom oral doses of [15N]glycine were given hourly for 36 h. The subjects received hourly meals throughout, and in six the study commenced at 06.00 hours, in five at 12.00 hours and in two at 18.00 h.
2. A plateau level of enrichment was achieved in urinary ammonia within 4–6 h. Regardless of the time at which the study started this plateau was held until about midnight, at which time there was an increase in enrichment, with a second higher plateau 5–6 h later. The second plateau was held to the end of the study. For urinary urea the rate of rise in enrichment was slower and smoother, because of the slow turnover of the urea pool.
3. Protein synthesis, derived from the first ammonia plateau, 179 mg h−1 kg−1, was significantly higher than that derived from the second plateau, 118 mg h−1 kg−1. Using the plateau in urea towards the end of the 36 h, the estimate of protein synthesis was 153 mg h−1 kg−1.
4. The results are considered to provide evidence of a pool of proteins for which degradation takes place in harmony with a circadian rhythm.
Activation of Two Inward Chloride Transport Systems in Rat Femoral Arterial Smooth Muscle in Deoxycorticosterone Acetate/Salt Hypertension
Authors: Harper Alexander A. , Davis Julian P. L. , Chipperfield Alan R. 
Published: August 2015

1. Intracellular [Cl−] ([Cl−]i) was measured with ion-selective microelectrodes in rat femoral arterial smooth muscle in normotensive controls and after the induction of deoxycorticosterone acetate/salt hypertension.
2. Linear regression of [Cl−]i and time after the induction of hypertension showed good correlation (r = 0.96) for 5–6 weeks, as [Cl−]i increased from 30 ± 1 mmol/l (mean ± SD, n = 16), to 49 ± 2 mmol/l (n = 9, P &lt; 0.0001).
3. Arterial systolic blood pressure also increased linearly (r = 0.97) for 5–6 weeks as hypertension developed from 122 ± 1 mmHg (n = 20) to 187 ± 7 mmHg (n = 14): there was consequently a linear relationship between [Cl−]i and arterial systolic blood pressure (r = 0.96).
4. The increase in [Cl−]i was partly because Na+−K+−Cl− co-transport activity, estimated from the fall in [Cl−]i caused by bumetanide, was greater in hypertension (18 mmol/l) than in normotension (10 mmol/l). This finding, and the depolarization of the membrane potential in hypertension (−56 ± 3 mV compared with −64 ± 4 mV in normotension; P &lt; 0.0001), confirms previous studies.
5. The increase in [Cl−]i was also partly due to greater activity of an Na+- and HCO3−-independent, acetazolamide-sensitive inward Cl− transport system; thus acetazolamide reduced [Cl−]i by 7 mmol/l in normotension and by 16 mmol/l in hypertension.
6. In Cl−-free media, the membrane potential in normotension (−59 ± 5 mV) was not significantly different from that in hypertension (−60 ± 4 mV).
7. The role of [Cl−]i in the depolarization of the membrane potential in hypertension is discussed.
Maternal Carbenoxolone Treatment Lowers Birthweight and Induces Hypertension in the Offspring of Rats Fed a Protein-Replete Diet
Authors: Langley-Evans Simon C. 
Published: August 2015

1. In the rat low birthweight and raised systolic blood pressure are the consequence of fetal exposure to maternal low protein diets. Nutritional down-regulation of the placental isoform of 11β-hydroxysteroid dehydrogenase, which may increase exposure of the fetus to maternal glucocorticoids, has been suggested to underlie effects of low protein diets on fetal growth and blood pressure.
2. Pregnant rats were fed control (18% casein) or low protein (9% casein) diets throughout gestation. Animals fed the control diet were injected with carbenoxolone, an inhibitor of 11β-hydroxysteroid dehydrogenase. Injections were administered either throughout pregnancy (days 0–22), or targeted to specific periods in early (days 0–7), mid- (days 8–14) or late (days 15–22) gestation.
3. Exposure to a low protein diet reduced birthweight and at 4 weeks of age systolic blood pressure was significantly elevated in the rats exposed to low protein. These hypertensive animals had small kidneys in proportion to body weight.
4. Fetal exposure to carbenoxolone at any period in gestation resulted in lower weight at birth. In rats exposed to the inhibitor over days 8–14, 15–22 or 0–22 systolic blood pressure at 4 weeks was significantly higher than in control animals. The greatest elevation of pressure was associated with carbenoxolone treatment in late (days 15–22) gestation. Animals with carbenoxolone-induced hypertension did not exhibit evidence of retarded renal growth.
5. Increased fetal exposure to maternal glucocorticoids impairs fetal growth and programmes elevated blood pressure in later life.
Absorption of all-trans and 9-Cis β-Carotene in Human Ileostomy Volunteers
Authors: Faulks Richard M. , Hart David J. , Wilson Peter D. G. , Scott K. John , Southon Susan 
Published: August 2015

1. Mass balance studies were carried out in fasted ileostomy subjects (n = 5) given an oral physiological dose (10 mg) of β-carotene [all-trans: 9-cis, 84:16 (w/w)] dispersed in vegetable oil. Blood and ileal effluent samples were collected and analysed for β-carotene.
2. Results showed that 90% (range 97.0–74.3%) of the total β-carotene was absorbed without measurable perturbation of plasma total β-carotene concentration, or change in the all-trans: 9-cis β-carotene ratio. Peak loss of β-carotene in ileal effluent occurred at 4.9 h (range 2.9–8.4 h) postingestion, and no further loss was detected after 5.4–12.4 h, depending upon the individual. Comparison of the ratio of all trans-β-carotene to 9 cis-β-carotene in the test meal and effluent indicated that isomerization did not occur during passage through the gastrointestinal tract and that both isomers were similarly absorbed. However, the all-trans: 9-cis β-carotene ratio of the plasma did not change. Reasoned assumptions allowed the construction of a mathematical model of plasma β-carotene disposal.
3. It is concluded that physiological doses of isolated all-trans and 9-cis β-carotene are well absorbed without necessarily causing detectable excursions in plasma β-carotene concentrations, or altering the ratio of all-trans to 9-cis β-carotene. Isomerization of β-carotene does not occur during passage through the gastrointestinal tract. Absorbed β-carotene is rapidly cleared from the plasma to an unobservable pool at a rate similar to that of chylomicron triacylglycerol.
Matrix Metalloproteinases: Implication in Vascular Matrix Remodelling during Atherogenesis
Authors: Ye Shu , Humphries Steve , Henney Adriano 
Published: August 2015

1. The matrix metalloproteinases are a family of at least 16 zinc-dependent endopeptidases possessing catalytic activity against extracellular matrix components. Some members of this family have been implicated in vascular matrix remodelling in the pathogenesis of atherosclerosis.
2. A common, naturally occurring variant has been identified in the promoter of the stromelysin gene with one allele having a run of five adenosines (5A) and the other having six adenosines (6A). Functional analyses have shown that the 6A allele has a lower promoter activity than the 5A allele, which is probably attributable to preferential binding of a putative transcriptional repressor protein.
3. In patients with coronary artery disease, the 6A allele has been found to be associated with progression of atherosclerosis assessed by sequential quantitative angiography.
4. In conclusion, the matrix metalloproteinases may be over-expressed in certain locations in atherosclerotic plaques, which might contribute to local destruction of connective tissue and thus plaque rupture. In the majority of lesional areas, however, matrix synthesis is likely to outstrip matrix degradation, because matrix accumulation is a major feature of most atheromas. This imbalance favouring matrix deposition is likely to be exacerbated in individuals with the 6A6A genotype in whom stromelysin expression is lower due to the weaker stromelysin promoter.
Carotenoids, Retinol and Tocopherols in Patients with Insulin-Dependent Diabetes Mellitus and Their Immediate Relatives
Authors: Granado F. , Olmedilla B. , Gil-Martinez E. , Blanco I. , Millan I. , Rojas-Hidalgo E. 
Published: August 2015

1. Patients with insulin-dependent diabetes mellitus are classified among the groups at risk for low vitamin status, and recent studies suggest that some degree of supplementation with antioxidants may be beneficial in helping to prevent certain long-term complications of diabetes mellitus. Our objective was to compare the status of the fat-soluble vitamins and antioxidant-related compounds in patients with well-defined insulin-dependent diabetes mellitus with that of their first-degree relatives, controlling seasonal and analytical variability as factors influencing the interpretation of the data.
2. Fifty-four patients with insulin-dependent diabetes mellitus, 214 non-diabetic, first-degree relatives (controls) and 236 unrelated controls were analysed for retinol, tocopherols (α and γ) and main carotenoids in serum (β-carotene, α-carotene, β-cryptoxanthin, lutein, zeaxanthin and lycopene) by means of a validated HPLC method.
3. Insulin-dependent diabetes mellitus was associated with lower retinol levels and higher levels of β-carotene, α-carotene and β-cryptoxanthin than sex-matched, first-degree relatives. α-Tocopherol, the α-tocopherol/cholesterol ratio, γ-tocopherol, lutein, zeaxanthin and lycopene showed no differences. Retinol and β-carotene were the variables most closely associated with diabetes.
4. Patients with insulin-dependent diabetes mellitus showed lower serum retinol status together with higher concentrations of provitamin-A carotenoids. Serum fat-soluble antioxidant levels were greater than or equal to those in controls. According to the serum status observed, individuals with diabetes do not require supplementation with α-tocopherol or carotenoids, although the need for retinol supplementation in patients with marginal serum levels should be evaluated.
Function of Rat Skeletal Muscles after Storage at 10°C in Various Preservation Solutions
Authors: van der Heijden E. P. A. , Kroese A. B. A. , Werker P. M. N. , Grabietz P. D. , De Jong M. B. , Bär P. R. , Kon M. 
Published: August 2015

1. The purpose of this study was to assess the potential of various preservation solutions, originally designed for solid organs, to protect muscle function during cold storage.
2. The soleus (SOL) and the cutaneous trunci (CT) muscle from the rat were isolated and stored for 2, 4 or 8 h at 10°C. The solutions used, listed in order from an intracellular to an extracellular-like composition, were: University of Wisconsin (UW), Euro-Collins (EC), HTK-Bretschneider (HTK), reversed St. Thomas' Hospital (ST2) and Krebs-Henseleit (KH). After cold storage, the muscles were tested by direct electrical stimulation to obtain the maximum twitch tension (Pt) and the maximum tetanus tension (P0). Subsequently, the muscles were prepared for morphological analysis.
3. In general, storage at 10°C caused a gradual decrease of Pt and P0 with time. After 8 h of storage in the extracellular-like solutions KH and ST2, the P0 was about 50% (SOL) and 35% (CT) of control. Eight hours of storage in intracellular-like solutions resulted in a P0 of 50% of control for HTK, in a P0 of 40% (SOL) and 67% (CT) for UW, but in a P0 of 5% (SOL) and 26% (CT) for EC. These findings corresponded well with the morphological observations.
4. It is concluded that the effects of 10°C storage on skeletal muscle function are not predominantly determined by the intra- or extracellular-like composition of the solutions used. Both UW and HTK were most effective (P0 &gt; 50% of control) in preserving muscle function.