bluuebunny/crossref_metadata_2025 huggingface dataset:
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 > 50% of control) in preserving muscle function.
Dietary Fish Oil Suppresses Human Colon Tumour Growth in Athymic Mice
Authors: Calder P. C. , Davis J. , Yaqoob P. , Thies H. Pala F. , Newsholme E. A.
Published: August 2015

1. Human colon tumour growth, initiated by subcutaneous inoculation of HT29 cells, was measured in athymic mice fed ad libitum on high-fat (210 g/kg) diets rich in coconut oil (CO), olive oil (OO), safflower oil (SO) or fish oil (FO); a low fat (LF; 25 g/kg) diet was used as the control. In one experiment the mice were fed the experimental diets for 3 weeks before HT29 cell inoculation and were killed 2 weeks post-inoculation. In a second experiment the mice were maintained on the LF diet until 4 days post-HT29 cell inoculation; they were then fed the experimental diets for 17 days.

2. Compared with mice fed the LF diet, tumour size was increased in mice fed the CO, OO or SO diets for 3 weeks before HT29 cell inoculation; FO feeding did not significantly increase tumour size.

3. Feeding mice the CO or OO diets from 4 days post-inoculation increased tumour growth rate and tumour size compared with feeding the LF, SO or FO diets; tumour growth rate and size did not differ among mice fed the latter diets.

4. The fatty acid composition of the tumours was markedly influenced by the fatty acid composition of the diet.

5. We conclude that human colon tumour growth is influenced by the type of fat consumed in the diet. Human colon tumour growth in this model is promoted by feeding high fat diets rich in medium chain saturated fatty acids (CO) or monounsaturated fatty acids (OO). A high fat diet, rich in long chain n — 3 polyunsaturated fatty acids (FO), does not promote colon tumour growth. The effect of a high fat diet rich in n — 6 polyunsaturated fatty acids (SO) depends upon the time at which it is fed: if fed before tumour cell inoculation such a diet promotes tumour growth, whereas if fed once tumour growth is initiated it does not. This suggests that n — 6 polyunsaturated fatty acids promote the initiation of colon tumour growth, but do not exert growth-promoting effects on colon tumours once they are established.
Cerebral Blood Flow Velocity during and after Sustained Isometric Skeletal Muscle Contractions in Man
Authors: Imms F. J. , Russo F. , Iyawe V. I. , Segal M. B.
Published: August 2015

1. Twenty-seven young subjects used their right hand to perform sustained, isometric contractions at 40% of maximum for 2 min while lying supine.

2. During the last 30 s of exercise, mean arterial blood pressure increased by 38 ± 4 mmHg (mean ± S.E.M.) and heart rate by 27 ± 2 beats/min.

3. Nineteen of the subjects respired eucapnically during exercise, increasing ventilation by 4.1 ± 0.5 litres/min. Eight subjects hyperventilated (7.1–19.6 litres/min) and decreased end-tidal Pco2 by 8.2 to 15.1 mmHg during the last minute of exercise.

4. In the eucapnic subjects mean flow velocity in the right (i.e. contralateral to the activated cortex) middle cerebral artery increased by 11.4 ± 1.0 cm/s, a change of 17%, during the contraction. This represents an increase in volume flow to the territory of this vessel, but an increase in global flow to the brain cannot be inferred.

5. In the eight subjects who hyperventilated during exercise, there was no rise of flow velocity in the middle cerebral artery, and in some subjects there was a fall during the first 2 min of recovery. These findings suggest that if subjects hyperventilate during handgrip exercise there could be a fall in volume flow to many regions of the brain during and after the exercise.
Inappropriately High Plasma Leptin Levels in Obese Haemodialysis Patients Can be Reduced by High Flux Haemodialysis and Haemodiafiltration
Authors: Wiesholzer Martin , Harm Ferdinand , Hauser Anna-Christine , Pribasnig Andreas , Balcke Peter
Published: August 2015

1. Blood leptin levels are increased in obese subjects and seem to play a major role in the hypothalamic regulation of appetite and energy expenditure.

2. We measured plasma leptin levels in a cohort of 46 patients on maintenance haemodialysis treatment and 26 control subjects.

3. Higher body mass indices were associated with higher plasma leptin levels in both groups.

4. The increase was more pronounced in the dialysis group than in the control group (P = 0.001), leading to inappropriately high plasma levels.

5. Haemodialysis with low flux cellulosic dialysers did not result in a decrease in plasma levels, while dialysis with high flux dialysers and haemodiafiltration led to a substantial reduction of the initial value to 76.95 ± 14.89% (P = 0.013) and 62.90 ± 24.94% (P = 0.001) respectively.

6. Our data suggest that high flux dialysis membranes can decrease plasma leptin levels and that inappropriately high plasma leptin levels may play a role in the nutrition of haemodialysis patients.
Acute Hypertension Impairs Endothelium-Dependent Vasodilatation
Authors: Millgård Jonas , Lind Lars
Published: August 2015

1. Previous investigations have demonstrated an impaired endothelium-dependent vasodilatation (EDV) in patients with hypertension. The present study aimed to investigate if an acute rise in blood pressure to hypertensive levels impairs EDV in otherwise normotensive subjects.

2. Twenty-seven young, healthy, normotensive subjects were studied. Eight of these underwent evaluation of EDV and endothelium-independent vasodilatation (EIDV) by means of forearm blood flow measurements during local intra-arterial infusions of methacholine (2 and 4 μg/min) and sodium nitroprusside (5 and 10 μg/min), before and after 1 h of sustained hypertension, induced by noradrenaline given intravenously. Identical measurements were made in 11 subjects before and during concomitant local intra-arterial infusion of noradrenaline without change in blood pressure and eight subjects were studied during saline infusions.

3. One hour of sustained hypertension (diastolic blood pressure > 95 mmHg) significantly attenuated both forearm blood flow (17.4 ± 6.8 versus 27.4 ± 6.8 ml · min−1 · 100 ml−1 tissue at baseline, P < 0.05) and forearm vascular resistance decrease (3.2 ± 0.87 versus 7.4 ± 2.5 units at baseline, P < 0.05) during methacholine infusion. These attenuations were significantly more pronounced for methacholine than for sodium nitroprusside (P < 0.05). In contrast, local intra-arterial noradrenaline infusions impaired vasodilatation induced by methacholine and sodium nitroprusside to a similar extent. Saline infusions did not change either EDV or EIDV.

4. Thus, an acute rise in blood pressure to hypertensive levels induced by noradrenaline impaired EDV more than EIDV in otherwise normotensive subjects, while no such selective effect of local noradrenaline was seen, suggesting that a high blood pressure impairs endothelial vasodilator function.
Suppression of Post-Glucose Hyperinsulinaemia Does Not Affect Blood Pressure in Either Normotensive or Hypertensive Subjects
Authors: Savage Mark W. , Mohamed-Ali Vidya , Williams Gareth
Published: August 2015

1. Hyperinsulinaemia and insulin resistance are thought to be intimately involved in the development of hypertension, but controversy remains as to whether hyperinsulinaemia is a consequence or a cause of hypertension per se, and whether it plays a role in the short-term regulation of blood pressure.

2. We studied six hypertensive patients [blood pressure 161(9)/101(2) mmHg] and seven normotensive control subjects [blood pressure 122(6)/76(4) mmHg], (P < 0.005) using two oral glucose tolerance tests of 3 h duration. In one of these tests the endogenous insulin response was inhibited with subcutaneous octreotide.

3. After placebo, hypertensive patients had slightly but significantly higher blood glucose levels than controls (P < 0.0001), but comparable insulin concentrations (P > 0.5). Plasma noradrenaline levels were consistently lower in the hypertensive group (P < 0.001). Blood pressure did not change in either group during the 3 h after glucose ingestion.

4. Octreotide completely abolished the immediate insulin response to glucose in all subjects (both P < 0.0001) and caused a delayed and significantly increased glycaemic response in born groups (P < 0.0001). There were no significant differences in plasma glucose responses between groups; however, after octreotide, the hypertensive subjects had a greater insulin suppression than the controls (P < 0.02). Octreotide suppressed noradrenaline levels in the normotensive group (P < 0.001); they were also suppressed in the hypertensive group, but just failed to reach significance (P = 0.056). Throughout the study the hypertensive group's noradrenaline levels remained generally lower than those in the control group (P < 0.0001).

5. In this study there were no differences between hypertensive and normotensive subjects in fasting or post-glucose insulin levels, nor any significant change in blood pressure in either group when post-glucose hyperinsulinaemia was suppressed. This argues against insulin playing a direct role in the short-term regulation of blood pressure.
Heart rate control of blood pressure variability in children: a study in subjects with fixed ventricular pacemaker rhythm
Authors: CONSTANT Isabelle , VILLAIN Elizabeth , LAUDE Dominique , GIRARD Arlette , MURAT Isabelle , ELGHOZI Jean-Luc
Published: August 2015

1.To investigate the influence of heart rate variability on blood pressure variability, short-term variability in heart rate and blood pressure was studied in 10 children with fixed ventricular pacemaker rhythm (80 beats/min). Ten healthy children, in sinus rhythm, served as a reference population.

2.Arterial blood pressure and heart rate were measured continuously using a finger arterial device and an ECG respectively. Power spectra for heart rate and blood pressure (systolic and diastolic) were calculated in both supine and orthostatic positions. In addition, acute changes in blood pressure and heart rate during active standing were studied.

3.Healthy children exhibited considerable heart rate variability, which was slightly more pronounced in the supine position, while children with a fixed ventricular rate had no heart rate variability in either position.

4.Despite the differences in heart rate variability, mean systolic blood pressure and its variability profiles were poorly affected by the suppression of heart rate variability. The lack of autonomic control on the sinus node was associated with a reduction in magnitude of the changes in systolic blood pressure variability induced by orthostatic posture.

5.The suppression of heart rate fluctuations induced a noticeable decrease in diastolic blood pressure fluctuations, which was most conspicuous in the children with fixed cardiac rhythm when in the supine position. This may be explained by the lack of diastolic blood pressure fluctuations, physiologically due to heart rate fluctuations through the run-off effect: the longer the cardiac cycle, the greater the diastolic pressure decay. These results may challenge the classical theory of baroreflex-mediated diastolic blood pressure control described in adult patients.

6.During active standing, the early drop in systolic blood pressure was greater in subjects with fixed ventricular rhythm. A rise in heart rate of 36 beats/min was observed in the healthy subjects in response to active standing.

7.We conclude that in normal children, heart rate fluctuations increase the blood pressure variability rather than buffering it. However, during acute orthostatic stress, the abrupt baroreflex-mediated heart rate rise may partly compensate for the reduction in blood pressure.
Characteristics of small bowel motility in patients with irritable bowel syndrome and normal humans: an Oriental study
Authors: LU Ching-Liang , CHEN Chih-Yen , CHANG Full-Young , LEE Shou-Dong
Published: August 2015

1.Small bowel dysmotility may be one of the clinical manifestations in Occidental patients with irritable bowel syndrome. Here we studied the characteristics of small bowel motility in Oriental patients with irritable bowel syndrome and identified the factors responsible for disturbed small bowel motility.

2.We enrolled 90 patients with irritable bowel syndrome and 45 ;healthy controls to the study. The patients with irritable bowel syndrome were further divided according to their predominant bowel habits. Of those, 45 were constipation-predominant and 45 were diarrhoea-predominant. Small bowel transit was measured by the non-invasive hydrogen breath test in the fasting state.

3.The transit times obtained in constipation-predominant and diarrhoea-predominant patients with irritable bowel syndrome and in controls were 108.4±34.3, 67.4±19.6 and 85.3±37.3 ;min respectively (P< 0.05). Delayed transit characterized constipation-predominant patients with irritable bowel syndrome, whereas accelerated transit was observed in diarrhoea-predominant patients with irritable bowel syndrome. The ages of constipation-predominant and diarrhoea-predominant patients with irritable bowel syndrome and of controls displayed a significant positive correlation with their small bowel transit times (r = 0.34, 0.31 and 0.39 respectively; P< 0.05) and body mass indexes also demonstrated a positive correlation (r = 0.31, 0.41 and 0.30 respectively; P< 0.05). Other demographic characteristics did not influence the small bowel transit times.

4.Accelerated or delayed small intestinal transit is exhibited in Oriental patients with irritable bowel syndrome showing either diarrhoea-predominant or constipation-predominant symptoms. Age and body mass index must be taken into consideration to study patients with suspected small intestinal dysmotility.
Nitric oxide synthase activity is increased in relation to the severity of liver dysfunction
Authors: GALLEY Helen F. , COOMANSINGH David , WEBSTER Nigel R. , BRUNT Peter W.
Published: August 2015

1.Nitric oxide is a potent vasodilator which plays a major role in the control of blood pressure. The hyperdynamic circulation of cirrhosis has been linked to nitric oxide.

2.We measured neutrophil nitric oxide synthase activity in relation to the level of hepatic dysfunction in patients with liver disease of varying aetiology and severity.

3.Neutrophils were isolated from 21 patients (7 Child-Pugh score A, 6 grade B and 8 grade C) aged 28–76 (median 49) years. Nitric oxide synthase activity was measured using the conversion of oxyhaemoglobin to methaemoglobin by nitric oxide and expressed in terms of cell protein. Blood pressure and biochemical indices were recorded. Data were assessed using Kruskal–Wallis one-way analysis of variance, Mann–Whitney U-test or Pearson correlation as appropriate.

4.Systolic, mean arterial and diastolic blood pressures decreased with increasing hepatic damage (P = 0.031, P = 0.01 and P = 0.038 respectively). Nitric oxide synthase activity increased with the degree of liver dysfunction (P = 0.033) and was highest in patients with Child-Pugh score C. Systolic blood pressure correlated with nitric oxide synthase activity in patients with Child-Pugh score C (P = 0.029).

5.Our results show that nitric oxide synthase activity increases with increasing Child-Pugh score and is associated with the development of systemic hypotension. These data may support the involvement of nitric oxide in the haemodynamic disturbances seen in liver disease.
Non-invasive measurements of arterial structure and function: repeatability, interrelationships and trial sample size
Authors: LIANG Yu-Lu , TEEDE Helena , KOTSOPOULOS Dimitra , SHIEL Louise , CAMERON James D. , DART Anthony M. , McGRATH Barry P.
Published: August 2015

1. Repeatability of measurements of arterial compliance and flow-mediated dilation of the brachial artery has been infrequently reported, despite increasing use in interventional and risk-factor modification studies. Furthermore, little is known about the interrelationships of the various indices. The purposes of this study were to determine the repeatability and interrelationships of a range of arterial indices.

2. Fifty healthy volunteers, 20 men and 30 women, aged 20–70 (mean 46.5) years, were studied on two occasions, using an identical protocol, at a mean interval of 2.5 weeks. Tonometry, ultrasound and Doppler technique were used to measure the following: carotid wall intima-media thickness (IMT), total systemic artery compliance (SAC), arterial pulse wave velocity [PWV aorto-femoral (A-F), and femoral-dorsalis pedis (F-D)], carotid distensibility coefficient (DC) and carotid augmentation index (AI). Brachial flow-mediated dilation was measured in 30 subjects with analysis of diameter change for 4 min post ischaemia.

3. There were no systematic differences over the observed range of measurements for any of the reported parameters. Coefficients of variation were as follows: IMT 2.8%, SAC 9.2%, PWV(A-F) 3.2%, PWV(F-D) 5.0%, DC 10.0%, AI 1.3%. Brachial flow-mediated dilation curves were not different between visits; changes were maximum 60-s post ischaemia. All indices of arterial compliance were significantly correlated with age. The three different indices of central arterial compliance [SAC, PWV(A-F) and AI] were significantly correlated with carotid intima-media thickness.

4. Under controlled experimental conditions there was good repeatability of measurements of indices between sessions of both intrinsic and functional arterial mechanical properties (central and carotid arterial compliance, intima-media thickness and brachial flow-mediated dilation). Sample size tables for clinical trials using these indices are presented.
Effect of β-blockade on baroreceptor and autonomic function in heart failure
Authors: SANDERSON John E. , YEUNG Leata Y. , CHAN Skiva , TOMLINSON Brian , KAY Richard , WOO Kam S. , BERNARDI Luciano
Published: August 2015

Although β-adrenoreceptor antagonists appear to be beneficial in chronic heart failure there is little information on their effects on autonomic and baroreceptor function which may have important prognostic implications. We sought to determine first whether β-adrenoreceptor blockade will improve baroreceptor function and vagal tone in chronic heart failure, and second whether there were any differences between standard therapy with metoprolol and the second-generation vasodilating β-blocker celiprolol. In this double-blind randomized placebo-controlled study 50 patients with stable chronic heart failure received either celiprolol 200 mg daily, metoprolol 50 mg twice daily or placebo for 12 weeks after a 4-week dose titration period. Thirty-five healthy normal subjects were also studied. Baroreceptor gain was assessed non-invasively by cross-spectral analysis of R–R and systolic blood pressure low- and high-frequency components (the α angle) during controlled respiration. High-frequency power was used as a measure of vagal modulation. Satisfactory recordings for analysis were obtained in 31 patients with heart failure. The results showed that at baseline baroreceptor gain (αHF) was significantly depressed in patients with heart failure compared with the normal control group (4.95±0.55 versus 11.73±1.32 ms/mmHg, P< 0.0001). After 12 weeks of treatment with metoprolol baroreceptor gain improved significantly whether measured while supine (P = 0.03) or standing (P = 0.009), and this was associated with a significant increase in R–R HF power (P = 0.008). There were no significant changes after treatment with celiprolol or placebo. We conclude that metoprolol but not celiprolol therapy restores baroreceptor gain towards normal and increases vagal tone in chronic heart failure. The ancillary properties of celiprolol do not appear to provide any advantages over metoprolol for the restoration of autonomic and baroreceptor function in heart failure.
Differential expression of mRNA in human thyroid cells depleted of mitochondrial DNA by ethidium bromide treatment
Authors: THOMAS A. W. , MAJID A. , SHERRATT E. J. , GAGG J. W. , ALCOLADO J. C.
Published: August 2015

A wide variety of human diseases have been associated with defects in mitochondrial DNA (mtDNA). The exact mechanism by which specific mtDNA mutations cause disease is unknown and, although the disparate phenotypes might be explained on the basis of impaired mitochondrial gene function alone, the role of altered nuclear gene expression must also be considered. In recent years, the experimental technique of depleting cells of mtDNA by culturing them with ethidium bromide has become a popular method of studying mitochondrial disorders. However, apart from depleting mtDNA, ethidium bromide may have many other intracellular and nuclear effects. The aim of the present study was to investigate the effects of ethidium bromide treatment on nuclear gene expression. A simian-virus-40-transformed human thyroid cell line was depleted of mtDNA by culture in ethidium bromide, and differential display reverse transcriptase–PCR (DDRT-PCR) was then employed to compare mRNA expression between wild-type, mtDNA-replete (ρ+) and ethidium bromide-treated, mtDNA-depleted (ρ0) cells. Expression of the majority of nuclear-encoded genes, including those for subunits involved in oxidative phosphorylation, remained unaffected by the treatment. Seven clones were found to be underexpressed; three of the clones showed significant similarity with sequences of the human genes encoding RNase L inhibitor, human tissue factor and ARCN1 (archain vesicle transport protein 1), a highly conserved species which is related to vesicle structure and trafficking proteins. We conclude that the effects of ethidium bromide treatment on nuclear gene expression are not simply limited to changes in pathways directly associated with known mitochondrial function. Further studies will be required to elucidate which of these changes are due to mtDNA depletion, ATP deficiency or other disparate effects of ethidium bromide exposure. Given that most genes appear unaffected, the results suggest that depleting cells of mtDNA by ethidium bromide treatment is a valuable approach for the study of mitochondrial mutations by cybrid techniques.
Post-operative effects on insulin resistance and specific tension of single human skeletal muscle fibres
Authors: DEGENS Hans , SOOP Mattias , HÖÖK Peter , LJUNGQVIST Olle , LARSSON Lars
Published: August 2015

Surgery and accidental trauma are associated with a transient period of insulin resistance, substrate catabolism and muscle weakness. In the present study, we evaluated the changes in the force-generating capacity of chemically skinned single muscle fibres following abdominal surgery. Biopsies of the m. vastus lateralis were obtained in three patients 1 day before and 3 or 6 days after surgery. Part of the biopsy was frozen for histochemical analysis of the fibre cross-sectional area (FCSA) and myofibrillar protein content, and another part was used for single-fibre contractile measurements. All patients developed insulin resistance following surgery. The maximum velocity of unloaded shortening of single muscle fibres did not change following surgery. The FCSA did not decrease after surgery, as determined either from histochemical sections or from single fibres measured at a fixed sarcomere length of 2.76±0.09 μm (mean±S.D.). Further, the force-generating capacity of the single fibres, measured as maximal Ca2+-activated force (P0) or as P0 normalized to FCSA (specific tension), remained unchanged, as did the myofibrillar protein content of the muscle. In conclusion, the muscle weakness associated with post-operative insulin resistance is not related to a decreased specific tension or a loss of myofibrillar proteins. Other potential cellular mechanisms underlying post-operative weakness are discussed.
Non-steroidal anti-inflammatory drugs and renal response to exercise: a comparison of indomethacin and nabumetone
Authors: OLSEN Niels Vidiendal , JENSEN Niels Georg , HANSEN Jesper Melchior , CHRISTENSEN Niels Juel , FOGH-ANDERSEN Niels , KANSTRUP Inge-Lis
Published: August 2015

Nabumetone, a newer non-steroidal anti-inflammatory drug (NSAID) which preferentially blocks cyclo-oxygenase-2 activity, may be less nephrotoxic than indomethacin. This study tested whether nabumetone has effects different from those of indomethacin on exercise-induced changes in renal function and the renin–aldosterone system. In a randomized fashion, ten subjects were studied after indomethacin (100 mg), nabumetone (1 g) or no medication (control) administered orally at 22.00 hours on the day before each study day, and again at 8.00 hours upon arrival at the laboratory. Renal function was studied at baseline, during graded 20-min exercise sessions at 25%, 50% and 75% of the maximal oxygen uptake rate, and subsequently during two 1-h recovery periods. Heart rate, arterial blood pressure, cardiac output and plasma catecholamines at rest and during exercise were not altered by indomethacin or nabumetone. Indomethacin decreased urinary rates of excretion of 6-oxo-prostaglandin F1α (6-oxo-PGF1α) and thromboxane B2 in all study periods. Nabumetone decreased 6-oxo-PGF1α excretion during and after exercise. Excretion rates for PGE2 did not change. Neither indomethacin nor nabumetone changed baseline values or exercise-induced decreases in renal plasma flow or glomerular filtration rate. Indomethacin, but not nabumetone, decreased sodium excretion, urine flow rate and free water clearance. The renal response to exercise, however, remained unchanged. In contrast with nabumatone, indomethacin decreased the plasma renin concentration. Thus, during exercise, nabumetone may decrease the excretion of 6-oxo-PGF1α by inhibition of cyclo-oxygenase-1 or by inhibition of specific exercise-induced activation of cyclo-oxygenase-2, or both. None of the drugs changed the renal response to exercise. Inhibition by indomethacin of angiotensin II and thromboxane A2 synthesis may, during exercise, counterbalance renal vasoconstriction caused by blockade of vasodilatory prostaglandins.
Androgen deprivation facilitates acetylcholine-induced relaxation by superoxide anion generation
Authors: FERRER Mercedes , TEJERA Nuria , MARÍN Jesús , BALFAGÓN Gloria
Published: August 2015

The aim of the present study was to assess the role of superoxide anions in the relaxation induced by acetylcholine (ACh) in aortic segments from male rats, and to investigate if their production is altered by sex hormone deprivation. In segments precontracted with 10 nmol/l noradrenaline, ACh (0.1 nmol/–10 μmol/l) induced concentration-dependent relaxation, which was greater in segments from castrated compared with control animals. ACh-induced relaxation was abolished in segments from control rats, and reduced in those from castrated rats, by 0.1 mmol/l NG-nitro-L-arginine methyl ester (L-NAME; a nitric oxide synthase inhibitor). Indomethacin (1 μmol/l; a cyclo-oxygenase blocker) decreased the ACh-induced relaxation in arteries from control males only. Incubation of segments with superoxide dismutase (SOD; 100 units/ml; a superoxide anion scavenger) enhanced and reduced relaxation in segments from control and castrated animals respectively. For arteries from castrated animals, the presence of SOD plus L-NAME abolished such responses. In these arteries, incubation with L-NAME abolished the relaxation caused by ACh when the segments were precontracted with 30 mmol/l KCl. In segments obtained from castrated rats and pretreated with L-NAME, 1 mmol/l tetraethylammonium or 0.4 μmol/l charybdotoxin [blockers of Ca2+-sensitive and large-conductance Ca2+-sensitive (BKCa) K+ channels respectively] abolished the relaxation induced by ACh. These results suggest that ACh generates endothelial NO and superoxide anions from the arterial wall in both control and castrated animals; these agents negatively modulate ACh-induced relaxation in control rats by destruction of NO, and positively modulate ACh-induced relaxation in castrated rats by activation of BKCa channels.
Low paraoxonase activity in type II diabetes mellitus complicated by retinopathy
Authors: MACKNESS Bharti , DURRINGTON Paul N. , ABUASHIA Bashir , BOULTON Andrew J. M. , MACKNESS Michael I.
Published: August 2015

Human serum paraoxonase 1 (PON1) is located on high-density lipoprotein and has been implicated in the detoxification of organophosphates, and possibly in the prevention of lipid peroxidation of low-density lipoprotein. PON1 has two genetic polymorphisms, both due to amino acid substitutions: one involving glutamine (Q genotype) and arginine (R genotype) at position 192, and the other involving leucine (L genotype) and methionine (M genotype) at position 55. We investigated the effects of these polymorphisms, and of a polymorphism of the PON2 gene at position 310 (Cys/Ser; C and S genotypes respectively), on serum PON1 activity and concentration, plasma lipids and lipoproteins and glycaemic control in 93 individuals with type II diabetes with no complications and in 101 individuals with type II diabetes with retinopathy. Serum PON1 activity in the group with no complications [median 164.1 nmol·min-1·ml-1 (range 8.0–467.8)] was significantly higher than in the group with retinopathy [113.4 nmol·min-1·ml-1 (3.0–414.6)] (P< 0.001), but the serum PON1 concentration was not different between the groups. The gene frequencies of the PON1-55 and PON1-192 polymorphisms and of the PON2-310 polymorphism were not different between the study populations. The PON1-55 and PON1-192 polymorphisms affected PON1 activity in the way described in a previous study of a control group and subjects with type II diabetes. The PON2-310 polymorphism also significantly affected serum PON1. PON1 activity was significantly higher in individuals with the PON2-310 CC genotype in both groups with type II diabetes, and the PON1 concentration was significantly higher in PON2-310 CC homozygotes with no complications than in the group with retinopathy. Neither the PON1-55 nor the PON1-192 polymorphism was correlated with the serum lipid or lipoprotein concentration in either group. In the group with retinopathy (but not the group with no complications), all three PON polymorphisms were correlated with glycaemic control, which was worse for the PON1-55 genotypes in the order MM > LM > LL (P = 0.0032), for the PON1-192 genotypes in the order RR > QR > QQ (P = 0.011) and for the PON2-310 genotypes in the order CC > CS > SS (P = 0.010). Low serum PON1 activity in retinopathy may be related to an increased tendency for lipid peroxidation. Our findings thus raise the possibility that, in retinopathy, the PON2 gene may influence PON1, and that an inter-relationship between the PON1 and PON2 genes may influence glycaemic control in subjects with type II diabetes complicated by retinopathy.
Abnormal venous function in patients with homozygous sickle cell (SS) disease and chronic leg ulcers
Authors: MOHAN Junette S. , VIGILANCE Jacqueline E. , MARSHALL Janice M. , HAMBLETON Ian R. , REID Harvey L. , SERJEANT Graham R.
Published: August 2015

Chronic leg ulceration is a major cause of morbidity in homozygous sickle cell (SS) disease in Jamaica. These ulcers have features in common with venous ulcers in patients with a normal haemoglobin genotype (AA). Thus we sought to determine whether there is abnormal venous function in the legs of patients with SS disease who have ulcers. Experiments were performed on 15 SS patients with ulcers, and on 15 SS patients and 15 AA subjects with no history of leg ulcers. Changes in venous blood volume of the bottom one-third of the leg induced by venous occlusion and release were studied by air plethysmography, providing indices of segmental venous capacitance (SVC), maximal venous outflow (MVO) and venous emptying time (VET). The changes in volume (ambulatory volume change; AVC) induced by a period of leg exercise were also measured at the ankle (AVCa) and calf (AVCc); venous refilling times at these sites (RTa and RTc respectively) were also measured. Finally, cutaneous red blood cell flux recovery time (FRT) after ankle exercise was assessed by laser Doppler flowmetry. Measurements were also made of haematological variables. SVC, MVO and VET did not differ between the groups, indicating no deep venous obstruction in the SS patients with ulcers. AVCc, AVCa and RTc did not differ among the three subject groups. However, compared with AA subjects, SS patients with ulcers had reduced RTa and FRT. Moreover, RTa and FRT were further shortened in SS patients with ulcers relative to SS patients without ulcers. Since the levels of anaemia were similar in SS patients with and without ulcers, these differences cannot be attributed to differences in arterial flow secondary to anaemia. These results suggest abnormal venous function in SS patients with ulcers, relative to both AA subjects and SS patients without ulcers. We propose that there is incompetence of venous valves draining the ankle region of SS patients with ulcers: the consequent raised venous pressure contributes to the slow healing and, possibly, to the onset of leg ulceration in SS disease.
S-Adenosylmethionine prevents hepatic tocopherol depletion in carbon tetrachloride-injured rats
Authors: DEULOFEU Ramón , PARÉS Albert , RUBIO Mireia , GASSÓ Marta , ROMÁN Juan , GIMÉNEZ América , VARELA-MOREIRAS Gregorio , CABALLERIA Joan , BALLESTA Antonio M. , MATO José M. , RODÉS Joan
Published: August 2015

In various experimental models, S-adenosylmethionine (SAMe) has been shown to reduce liver injury by preventing depletion of glutathione, one of the antioxidant systems that plays a critical role in defence against oxidative stress. On the other hand, α-tocopherol may be decreased in liver diseases, and treatment with this vitamin reduces liver injury in CCl4-treated rats. Since there is a close relationship among the different antioxidant systems (mainly glutathione, α-tocopherol and ascorbic acid), we have assessed whether, as well as restoring hepatic glutathione content, SAMe has any effect on liver α-tocopherol and ascorbic acid levels in CCl4-injured rats. Four groups of seven male Wistar rats treated for 9 weeks were studied: rats induced to cirrhosis with CCl4, rats induced to cirrhosis plus SAMe administration (10 mgċkg-1ċday-1) and their respective controls. Liver samples were obtained for measuring levels of glutathione, α-tocopherol, ascorbic acid and thiobarbituric acid-reactive substances (TBARS), and hydroxyproline concentration as an index of collagen content. The hydroxyproline content was higher in CCl4-injured rats than in the control group (4.4±1.8 and 1.1±0.3 μmol/g respectively; P < 0.05). In CCl4-injured rats, SAMe administration decreased collagen content (2.7±1.0 μmol/g; P < 0.05) and TBARS, and corrected glutathione depletion. α-Tocopherol was significantly lower in CCl4-injured rats than in controls (17.3±4.9 and 23.0±4.0 μmol/g respectively; P < 0.05). By contrast, α-tocopherol levels were similar (23.8±5.1 μmol/g) in CCl4-injured rats receiving SAMe and in controls. In CCl4-injured rats, liver ascorbic acid was decreased in comparison with controls (4.9±1.8 and 8.2±1.0 μmol/g respectively; P < 0.05), levels which were not replenished by SAMe (4.6±0.4 μmol/g). In conclusion, SAMe not only decreases fibrosis and protects against hepatic glutathione depletion, but has a further antioxidant effect of preventing α-tocopherol depletion in CCl4-injured rats.
Relationship between the concentrations of plasma phospholipid stearic acid and plasma lipoprotein lipids in healthy men
Authors: LI Duo
Published: August 2015

This study investigated the correlation between the plasma phospholipid (PL) saturated fatty acid (SFA) concentration (as a surrogate marker of SFA intake) and plasma lipid and lipoprotein lipid concentrations in 139 healthy Australian men aged 20–55 years old with widely varying intakes of saturated fat (vegans, n = 18; ovolacto vegetarians, n = 43; moderate meat eaters, n = 60; high meat eaters, n = 18). Both the ovolacto vegetarian and vegan groups demonstrated significant decreases in plasma total cholesterol (TC), low-density-lipoprotein cholesterol (LDL-C) and triacylglycerol concentrations compared with both the high-meat-eater and moderate-meat-eater groups. Total SFA and individual SFA [palmitic acid (16:0), stearic acid (18:0) and arachidic acid (20:0)] in the plasma PL were significantly lower in both the ovolacto vegetarian and vegan groups than in both the high- and moderate-meat-eater groups, while myristic acid (14:0) was significantly lower in the vegans than in the high-meat-eaters. Bivariate analysis of the results showed that the plasma PL stearic acid concentration was strongly positively correlated with plasma TC (P < 0.0001), LDL-C (P < 0.0001) and triacylglycerol (P < 0.0001), with r2 values of 0.655, 0.518 and 0.43 respectively. In multiple linear regression, after controlling for potential confounding factors (such as exercise, dietary group, age, body mass index, plasma PL myristic acid, palmitic acid and arachidic acid, and dietary total fat, saturated fat, cholesterol, carbohydrate and fibre intake), the plasma PL stearic acid concentration was still strongly positively correlated with plasma TC (P < 0.0001) and LDL-C (P = 0.006) concentrations. Based on the present data, it would seem appropriate for the population to reduce their dietary total SFA intake rather than to replace other SFA with stearic acid.
Assessment of baroreflex sensitivity in patients with preserved and impaired left ventricular function by means of the Valsalva manoeuvre and the phenylephrine test
Authors: RACZAK Grzegorz , LA ROVERE Maria Teresa , PINNA Gian Domenico , MAESTRI Roberto , ŚWITECKA Grayna
Published: August 2015

The purpose of the present study was to assess the agreement between measurements of baroreflex sensitivity (BRS) obtained by the Valsalva manoeuvre and by the phenylephrine test in patients with previous myocardial infarction and different degrees of left ventricular dysfunction. Patients with a previous myocardial infarction were enrolled consecutively into two groups according to their left ventricular ejection fraction (LVEF): ⩽ 40% (n = 52) or > 40% (n = 52). All patients underwent BRS assessment by the phenylephrine technique (Phe-BRS) and by the Valsalva manoeuvre, with the latter using both the overshoot part of phase IV (Ov-VM-BRS) and the whole of phase IV (IV-VM-BRS). The linear association between methods was assessed by correlation analysis and the agreement was evaluated by computing the bias and the limits of agreement. IV-VM-BRS and Ov-VM-BRS could not be computed in 26% and 39% of patients respectively. For both indices a much higher percentage of non-computable Valsalva manoeuvre slopes was found in the group of patients with LVEF ⩽ 40%. Phe-BRS was significantly lower in patients with non-computable Valsalva manoeuvre slopes; 55% and 59% of patients with non-computable Ov-VM-BRS and IV-VM-BRS respectively had a markedly depressed Phe-BRS (i.e. < 3 ms/mmHg, as defined by the ATRAMI study). On comparing Phe-BRS and Ov-VM-BRS in patients with LVEF ⩽ 40%, we obtained the following results: r = 0.75 (P < 0.001), bias = 0.5 ms/mmHg (P = 0.5) and limits of agreement from -6.7 to 7.8 ms/mmHg. In patients with LVEF > 40% the results were: r = 0.91 (P < 0.001), bias = 0.1 ms/mmHg (P = 0.84) and limits of agreement from -4.8 to 5 ms/mmHg. When comparing Phe-BRS and IV-VM-BRS, we found r = 0.67 (P = 0.001), bias =-1.5 ms/mmHg (P = 0.06) and limits of agreement from -8.8 to 5.7 ms/mmHg in the group of patients with LVEF ⩽ 40%; and r = 0.66 (P < 0.001), bias =-3.1 ms/mmHg (P < 0.001) and limits of agreement from -12.1 to 5.9 ms/mmHg in the group of patients with LVEF > 40%. Dichotomizing Ov-VM-BRS, the best cut-off value to identify patients with a Phe-BRS of < 3 ms/mmHg was found to be 7 ms/mmHg, giving 100% sensitivity and 69% specificity. In conclusion, estimation of BRS by the Valsalva manoeuvre in post-myocardial infarction patients is limited by a large number of non-measurable results. When computable, measurements are well correlated with those obtained by Phe-BRS, but, because of large limits of agreement, the two methods cannot be used interchangeably. If used as a screening test for risk stratification, the Valsalva manoeuvre could reduce by about one-third the need for phenylephrine injection.