bluuebunny/crossref_metadata_2025 huggingface dataset:
β
2-Adrenoceptor polymorphism and bronchoprotective sensitivity with regular short- and long-acting β2-agonist therapy
Authors: LIPWORTH B. J. , HALL I. P. , AZIZ I. , TAN K. S. , WHEATLEY A.
Published: August 2015

The aim of the present study was to investigate bronchoprotective sensitivity in patients receiving regular treatment with short- and long-acting β2-agonists and to evaluate any possible association with genetic polymorphism. Thirty-eight patients with stable mild to moderate asthma and receiving inhaled corticosteroids were randomized in a parallel group, double-blind, double-dummy fashion to receive 2 weeks of treatment with either formoterol (12μg once daily, 6μg twice daily or 24μg twice daily) or terbutaline (500μg four times daily). Bronchoprotection against methacholine challenge (as a provocative dose to produce a 20% fall in forced expiratory volume in 1.0 ;s: PD20) was measured at baseline (unprotected) after an initial 1 week run-in without β2-agonist, and at 1 ;h after the first and last doses of each treatment. The PD20 values were log-transformed and calculated as change from baseline. Percentage desensitization of log PD20 for first- versus last-dose bronchoprotection was calculated and analysed according to effects of treatment and β2-adrenoceptor polymorphism at codon 16 or 27. The mean degree of desensitization for bronchoprotection was comparable with all four treatments and there were no significant differences in absolute PD20 values after 2 weeks of chronic dosing. The PD20 values were (as μg of methacholine, geometric means±S.E.M.): formoterol, 12μg once daily, 99±42μg; formoterol, 6μg twice daily, 107±44μg; formoterol, 24μg twice daily, 108±45μg; terbutaline, 500μg four times daily, 88±37μg. All patients receiving formoterol, 24μg twice daily, exhibited a loss of protection greater than 30% which was unrelated to polymorphism at codon 16 or 27. For codon 16, the use of lower doses of formoterol (12μg once daily or 6μg twice daily) showed wider variability in the propensity for protection loss in patients who were heterozygous, in contrast to a more uniform protection loss seen with homozygous glycine patients. The amount of protection loss was not significantly related to polymorphism at codon 16 or 27, expressed as values (mean±S.E.M.) for percentage desensitization according to each genotype (pooled treatments): Gly-16, 66±11%; Het-16, 53±8%; Arg-16, 69±18%; Glu-27, 68±12%; Het-27, 58±8%; Gln-27, 52±12%. The results of this preliminary study showed that bronchoprotective desensitization occurred readily in response to short- or long-acting β2-agonist exposure irrespective of β2-adrenoceptor polymorphism at codon 16 or 27. Further studies with larger patient numbers are required to further evaluate the effects of polymorphisms with lower doses of regular formoterol.
Inhibition of carbohydrate-mediated glucagon-like peptide-I (7–36)amide secretion by circulating non-esterified fatty acids
Authors: RANGANATH L. , NORRIS F. , MORGAN L. , WRIGHT J. , MARKS V.
Published: August 2015

Two studies were performed to assess the entero-insular axis in simple obesity and the possible effect of variations in the level of circulating non-esterified fatty acids (NEFA) on one of the components of the entero-insular axis, glucagon-like peptide-1 [(7–36) amide]. In the first study, we compared the entero-pancreatic hormone response to oral carbohydrate in obese and lean women. Obese subjects demonstrated hyperinsulinaemia and impaired glucose tolerance but this was not associated with an increased secretion of either glucose-dependent insulinotropic polypeptide or glucagon-like peptide-1 (GLP-1). These findings therefore provide no support for the hypothesis that overactivity of the entero-insular axis contributes to the hyperinsulinaemia seen in obesity. Indeed, the plasma GLP-1 response to carbohydrate was markedly attenuated in obese subjects, confirming previous observations. In the second study, in which carbohydrate-stimulated GLP-1 responses were again evaluated in obese and lean women, circulating NEFA levels were modulated using either heparin (to increase serum NEFA) or acipimox (to reduce serum NEFA). Treatment with acipimox resulted in complete suppression of NEFA levels and in a markedly higher GLP-1 response than the response to carbohydrate alone or to carbohydrate plus heparin. We suggest that higher fasting and postprandial NEFA levels in obesity may tonically inhibit nutrient-mediated GLP-1 secretion, and that this results in attenuation of the GLP-1 response to carbohydrate. However, although serum NEFA levels post-acipimox were similarly suppressed in both lean and obese subjects, the GLP-1 response was again significantly lower in obese subjects, suggesting the possibility of an intrinsic defect of GLP-1 secretion in obesity. The reduction of GLP-1 levels in obesity may be important both in relation to its insulinotropic effect and to its postulated role as a satiety factor.
Serum leptin is associated with the perception of palatability during a standardized high-carbohydrate breakfast test
Authors: RAYNAUD Eric , BRUN Jean-Frédéric , PEREZ-MARTIN Antonia , SAGNES Colette , BOULARAN Anne-Marie , FEDOU Christine , MERCIER Jacques
Published: August 2015

Leptin is an adipocyte-derived signalling molecule which plays a key role in the regulation of body weight and energy expenditure. Since its involvement in human eating behaviour is still poorly understood, we investigated whether the perception of palatability of food was related to fasting serum leptin levels. Twenty-six non-diabetic subjects, six men and twenty women of widely ranging age and body mass index, performed a standardized high-carbohydrate breakfast test. Palatability was evaluated with a visual analogue scale, body composition by bioelectrical impedance, serum leptin and plasma insulin by radioimmunoassay. Palatability was correlated to fasting serum leptin levels independently of body mass index, body fat mass and percentage of body fat (P< 0.01). No significant relation was observed with peaks of insulinaemia, integrated concentrations of insulin or insulin resistance indices. A stepwise regression analysis indicated that serum leptin gave the strongest predictive association with palatability. These results suggest that the leptin system may be involved in the regulation of human eating behaviour in relation to the perception of palatability of food.
Soccer players under regular training show oxidative stress but an improved plasma antioxidant status
Authors: BRITES Fernando D. , EVELSON Pablo A. , CHRISTIANSEN Marina García , NICOL María F. , BASÍLICO María José , WIKINSKI Regina W. , LLESUY Susana F.
Published: August 2015

Physical activity is known to induce oxidative stress in individuals subjected to intense exercise. In this study, we investigated the lipoprotein profile and the plasma antioxidant status in a group of soccer players engaged in a regular training programme. As was expected for aerobic exercise, high-density lipoprotein-cholesterol (HDL-C) and HDL3-C levels were significantly increased in the sportsmen (P< 0.05). Total plasma antioxidant capacity was 25% higher in sportsmen than in controls (P< 0.005). Accordingly, plasma hydrosoluble antioxidant levels (ascorbic acid and uric acid) were found to be significantly elevated in the soccer players (P< 0.005). In addition, these subjects showed high concentrations of α-tocopherol in plasma compared with controls (P< 0.005). Furthermore, an increase in plasma superoxide dismutase activity was also observed in relation to exercise (P< 0.01). The elevation in plasma activities of antioxidant enzymes and the higher levels of free radical scavengers of low molecular mass may compensate the oxidative stress caused by physical activity. High levels of high-density lipoprotein in plasma may offer additional protection by inhibiting low-density lipoprotein oxidation and thus liposoluble antioxidant consumption. Therefore, soccer players under regular training show an improved plasma antioxidant status in comparison to sedentary controls.
Pharmacological and molecular biological evidence for ETA endothelin receptor subtype mediating mechanical responses in the detrusor smooth muscle of the human urinary bladder
Authors: OKAMOTO-KOIZUMI Takako , TAKEDA Masayuki , KOMEYAMA Takeshi , HATANO Akihiko , TAMAKI Makoto , MIZUSAWA Takaki , TSUTSUI Toshiki , OBARA Kenji , TOMITA Yoshihiko , ARAI Kei , TAKAHASHI Kota
Published: August 2015

The aim of this study was to characterize endothelin receptor subtypes of the detrusor muscle of the human urinary bladder. The receptor subtypes mediating endothelin (ET)-1-induced activity in the human detrusor smooth muscles have been characterized using isometric contraction and reverse transcription–polymerase chain reaction (RT–PCR). ET-1 (a non-selective ET receptor agonist; 10-10 M to 10-6 M) exhibited concentration-dependent contractions in human urinary bladder with a plateau at concentrations above 3×10-7 M. Neither IRL1620 nor sarafotoxin S6c (both ETB-selective agonists; 10-10 M to 10-6 M) elicited contractile activity in the human urinary bladder detrusor smooth muscle. FR139317 (an ETA-selective antagonist; 10-7 M to 10-5 M) produced a marked shift to the right of the ET-1 concentration–response curve in human urinary bladder detrusor smooth muscle (from the Schild plot TpA2 = 7.96; slope = 0.95). In contrast, RES701-1 (an ETB-selective antagonist; 10-7 M to 10-5 M) had no effect on the ET-1 concentration–response curve. RT–PCR revealed positive amplification of ETA receptor mRNA fragment, but not ETB. These results indicate that the ET-1-induced contractile effects of urinary bladder detrusor smooth muscle seem to be mediated mainly by the ETA receptor, not by the ETB receptor.
Coronary sinus adrenomedullin rises in response to myocardial injury
Authors: VIJAY Palaniswamy , SZEKELY Laszlo , AUFIERO Thomas X. , SHARP Thomas G.
Published: August 2015

Human adrenomedullin (ADM), a peptide comprising 52 amino acids, is a circulating hormone with vasodilator properties. We have evaluated its release by the heart following ischaemic myocardial damage, as indicated by elevated levels of the cardiospecific protein troponin-T (Tn-T) during cardiopulmonary bypass. ADM (pg/ml) and Tn-T (ng/ml) were measured in coronary sinus blood before and after aortic cross-clamp and in venous blood 6 ;h after surgery in 22 coronary-bypass patients. Based on the pre- and post-clamp Tn-T levels in the coronary sinus, the patients were divided into group I (no change; n = 10) and group II (two times increase; n = 12). Baseline ADM (362.7±106.2 and 303±58.7 pg/ml in groups I and II respectively; means±S.D.) and Tn-T (0.66±0.14 and 0.57±0.13 ng/ml respectively) levels were similar in both groups. In group I, the post-clamp ADM (317.6±80.8 pg/ml) and Tn-T (0.68±0.15 ng/ml) levels did not change significantly. In group II, the post-clamp ADM levels rose significantly above the baseline, mimicking the change in Tn-T (ADM, 541.4±89.4 pg/ml; Tn-T, 1.37±0.31 ng/ml; P = 0.009). After 6 h, the systemic Tn-T levels were similar in both groups (2.09±0.44 and 1.95±0.52 ng/ml in groups I and II respectively). We suggest that: (1) minor degrees of myocardial ischaemic damage result in release of ADM by the heart, and (2) ADM may play a protective role in the myocardium during an ischaemic insult. This suggests a possible therapeutic role for ADM in the management of intra-operative myocardial ischaemia.
Effects of ursodeoxycholic acid on systemic, renal and forearm haemodynamics and sodium homoeostasis in cirrhotic patients with refractory ascites
Authors: WONG Florence , BOMZON Arieh , ALLARD Johane , LIU Peter , BLENDIS Laurence
Published: August 2015

Systemic arterial vasodilatation has been implicated in the pathogenesis of sodium retention in cirrhosis. Hydrophobic bile acids, which have vasodilatory actions, may be involved. Ursodeoxycholic acid, a hydrophilic bile acid, could potentially decrease systemic arterial vasodilatation, possibly due to its antioxidant effects, and improve sodium handling in cirrhosis. The effects of ursodeoxycholic acid on systemic, renal and forearm haemodynamics, liver function and renal sodium handling were assessed in vasodilated cirrhotic patients with refractory ascites treated with a transjugular intrahepatic porto-systemic shunt (TIPS). Eight cirrhotic patients with refractory ascites without TIPS placement served as controls for the sodium handling effects of ursodeoxycholic acid. From 1 month post TIPS, seven patients were studied before, after 1 month of treatment with ursodeoxycholic acid (15 mg·day-1·kg-1) and at 1 month follow-up. Lipid peroxidation products were used as indices of its antioxidant effects. Ursodeoxycholic acid caused a significant reduction in sodium excretion in both groups (P< 0.05). This, in the post-TIPS patients (urinary sodium excretion: 35±8 mmol/day at 1 month versus 93±21 mmol/day at baseline, P< 0.05), was due to a significant increase in sodium reabsorption proximal to the distal tubule (P< 0.05), without any significant changes in systemic, renal or forearm haemodynamics, or in liver function. No significant change in lipid peroxidation products was observed. We conclude that: (i) in cirrhotic patients with refractory ascites, ursodeoxycholic acid causes sodium retention, (ii) the abnormality in sodium handling in the post-TIPS cirrhotic patients appears to be the result of a direct effect on the proximal nephron, suggesting that factors other than systemic vasodilatation also contribute to sodium retention in cirrhosis, (iii) caution should be exercised in administering ursodeoxycholic acid in cirrhotic patients with ascites.
Acute effect of ephedrine on 24-h energy balance
Authors: SHANNON John R. , GOTTESDIENER Keith , JORDAN Jens , CHEN Kong , FLATTERY Stacey , LARSON Patrick J. , CANDELORE Mari Rios , GERTZ Barry , ROBERTSON David , SUN Ming
Published: August 2015

Ephedrine is used to help achieve weight control. Data on its true efficacy and mechanisms in altering energy balance in human subjects are limited. We aimed to determine the acute effect of ephedrine on 24-h energy expenditure, mechanical work and urinary catecholamines in a double-blind, randomized, placebo-controlled, two-period crossover study. Ten healthy volunteers were given ephedrine (50 mg) or placebo thrice daily during each of two 24-h periods (ephedrine and placebo) in a whole-room indirect calorimeter, which accurately measures minute-by-minute energy expenditure and mechanical work. Measurements were taken of 24-h energy expenditure, mechanical work, urinary catecholamines and binding of (±)ephedrine in vitro to human β1-, β2- and β3-adrenoreceptors. Twenty-four-hour energy expenditure was 3.6% greater (8965±1301 versus 8648±1347 kJ, P< 0.05) with ephedrine than with placebo, but mechanical work was not different between the ephedrine and placebo periods. Noradrenaline excretion was lower with ephedrine (0.032±0.011 μg/mg creatinine) compared with placebo (0.044±0.012 μg/mg creatinine) (P< 0.05). (±)Ephedrine is a relatively weak partial agonist of human β1- and β2-adrenoreceptors, and had no detectable activity at human β3-adrenoreceptors. Ephedrine (50 mg thrice daily) modestly increases energy expenditure in normal human subjects. A lack of binding of ephedrine to β3-adrenoreceptors and the observed decrease in urinary noradrenaline during ephedrine treatment suggest that the thermogenic effect of ephedrine results from direct β1-/β2-adrenoreceptor agonism. An indirect β3-adrenergic effect through the release of noradrenaline seems unlikely as urinary noradrenaline decreased significantly with ephedrine.
Impaired skin vasomotor reflexes in patients with erythromelalgia
Authors: LITTLEFORD Roberta C. , KHAN Faisel , BELCH Jill J. F.
Published: August 2015

Erythromelalgia (EM) is a chronic disorder characterized by intermittent burning pain, warmth and erythema of the extremities. Increasing the local temperature and dependency of the affected limb(s) precipitates the symptoms, whereas direct cooling and elevation of the limb(s) can provide partial relief. Our previous findings showed that patients with EM have enhanced cutaneous vascular tone at rest and during stimulation, which may be due to an increase in sympathetic neural activity. To test this, we measured skin vasoconstrictor responses to contralateral arm cold challenge (CC) and inspiratory gasp (IG) using laser Doppler flowmetry at the toe pulp and fingertip. These areas were chosen because of their dense sympathetic innervation. An index of the vasoconstrictor response (between 0 and 1) was calculated from the change in skin perfusion from baseline following CC and IG. In control subjects, vasoconstrictor responses to CC at the toe and fingertip were both 0.70±0.02 (mean±S.E.M.), which were significantly greater (P < 0.001) than corresponding values in patients with EM (0.37±0.04 and 0.45±0.04 respectively). Similarly, vasoconstrictor responses to IG were significantly greater (P < 0.001) at the toe and fingertip in control subjects (0.70±0.03 and 0.70±0.02 respectively) compared with values in EM patients (0.27±0.03 and 0.45±0.15 respectively). These data show that, in contrast with control subjects, patients with EM have diminished sympathetic vasoconstrictor responses to both CC and IG. Denervation supersensitivity may play a part by increasing vasoconstrictor responses to circulating catecholamines, leading to a reduction in skin blood flow. Therefore an interplay between neural and vasoactive agents may be involved in the pathophysiology of EM.
Effects of adrenaline on glucose and glutamine metabolism and superoxide production by rat neutrophils
Authors: GARCIA Carolina , PITHON-CURI Tania C. , DE LOURDES FIRMANO Maria , PIRES DE MELO Mariza , NEWSHOLME Philip , CURI Rui
Published: August 2015

Despite the large body of information on the role of corticosteroids in regulating lymphocyte and phagocyte function, the role of the hormone adrenaline in immunoregulation is an under-investigated topic. The present study has addressed the effects of adrenaline on the rates of utilization and oxidation of glucose and glutamine, the phagocytic capacity and the rate of superoxide production by rat neutrophils. Incubation of rat neutrophils in the presence of 50 µM adrenaline caused a marked elevation in glucose metabolism, an effect that could be blocked by propranolol. Adrenaline caused a partial inhibition of glutamine utilization by neutrophils, an effect that was also blocked by propranolol. These effects of adrenaline could be mimicked by 100 µM dibutyryl cAMP. Phosphate-dependent glutaminase activity was significantly elevated in neutrophils incubated in the presence of 50 µM adrenaline or 100 µM dibutyryl cAMP for 1 h, whereas glutamine oxidation was significantly depressed (P < 0.05) under these conditions. The elevation in enzyme activity was only partially blocked by propranolol. The phagocytic activity of rat neutrophils was not altered by adrenaline in the presence of either glucose or glutamine. The rate of phorbol 12-myristate 13-acetate-induced superoxide production in the presence of glucose was potently reduced by the addition of 5 nM or 50 µM adrenaline. This effect could be mimicked by dibutyryl cAMP. However, when rat neutrophils were incubated in the presence of glutamine plus adrenaline (5 nM or 50 µM), the rate of superoxide production was only marginally reduced. These findings support the proposition that adrenaline may deviate the flux of glucose from the NADPH-producing pentose phosphate pathway, thus reducing substrate availability for the superoxide-generating NADPH oxidase. However, glutamine metabolism may still give rise to substantial quantities of NADPH from the glutaminolysis pathway. We postulate that glutamine metabolism may thus provide a protective mechanism against the inhibitory effect of adrenaline on superoxide production by neutrophils.
Endothelial haemostatic factors are associated with progression of urinary albumin excretion in clinically healthy subjects: a 4-year prospective study
Authors: CLAUSEN Peter , FELDT-RASMUSSEN Bo , JENSEN Gorm , JENSEN JanSkov
Published: August 2015

A slightly elevated urinary albumin excretion rate (UAER), above 5-10 µg/min, is a predictor of atherosclerotic cardiovascular disease. Endothelial dysfunction is an important early feature of atherosclerosis. The plasma concentration of von Willebrand factor (vWF), a potential marker of endothelial dysfunction, predicts a subsequent increase of UAER in patients with diabetes. The aim of this study is to test the hypothesis that high concentrations of vWF as well as other haemostatic factors predict progression of UAER in clinically healthy subjects. UAER was measured together with selected markers of haemostatic function - vWF, tissue plasminogen activator (tPA), plasminogen activator inhibitor, factor VII and fibrinogen - in healthy volunteers aged 40-65 years. After a mean follow-up of 4.1 years, 64 of 74 agreed to a re-examination including re-measurement of UAER. Baseline vWF and tPA were both positively correlated to the change in UAER during follow-up (r = 0.26, P = 0.04 and r = 0.40, P = 0.001 respectively). The mean UAER increased significantly by 7.6 µg/min and 7.5 µg/min respectively in subjects with vWF and tPA above the medians at baseline (P = 0.01 and P = 0.003 respectively), whereas no changes in UAER were seen in subjects with vWF and tPA below the medians. Subjects with high tPA were also characterized by an excess of other cardiovascular risk factors at baseline. No significant differences in these risk factors were present between subjects with high or low vWF. High plasma concentrations of vWF and tPA are associated with progression of UAER in clinically healthy subjects. Both vWF and tPA are secreted by endothelial cells and the results suggest that endothelial dysfunction leads to progression of UAER.
Contractile properties of rat skeletal muscles following storage at 4 °C
Authors: VAN DER HEIJDEN E. P. A. , KROESE A. B. A. , STREMEL R. W. , BÄR P. R. , KON M. , WERKER P.M. N.
Published: August 2015

The purpose of this study was to assess the potential of preservation solutions for protecting skeletal muscle function during storage at 4 °C. The soleus and the cutaneus trunci (CT) from the rat were stored for 2, 8 or 16 h at 4 °C in University of Wisconsin solution (UW), HTK–Bretschneider solution (HTK) or Krebs–Henseleit solution (KH). After storage, muscles were stimulated electrically to analyse the isometric contractile properties, such as the maximum tetanic tension (P0). Histological analysis was also performed. In separate experiments, the effect of the diffusion distance on muscle preservation was studied by bisecting the soleus. After 8 h of storage in UW or HTK, the contractile properties of the CT were similar to those of the control, whereas those of the soleus were reduced (P0 values of 16% and 69% of control in UW and HTK respectively). At 16 h, the contractile properties of the CT (P0 28%) were again better preserved than those of the soleus (P0 9%). Muscle function deteriorated most after storage in KH (P0 at 16 h: soleus, 3%; CT, 17%). The bisected soleus was equally well preserved as the CT (P0 of bisected soleus at 8 h in UW and HTK: 86%). The functional data corresponded well with the histological data, which showed increasing muscle fibre derangement with increasing storage time. For both muscles and all solutions, the threshold stimulus current increased with increasing storage time (control, 0.1 mA; 16 h, 1.2 mA) and was strongly correlated with the deterioration in contractile properties. It is concluded that, at 4 °C, muscle is preserved better in UW and HTK (intracellular-like solutions) than in KH (extracellular-like solution). The soleus and CT were best protected in HTK. The diffusion distance is a critical factor for successful preservation of muscle function at 4 °C. The reduced function after 16 h of storage at 4 °C was caused by hypercontraction and necrosis of about 25% of the muscle fibres, and by deterioration of the electrical component of excitation–contraction coupling of the remaining fibres.
Effect of externally applied focused acoustic energy on clot disruption in vitro
Authors: WESTERMARK Sara , WIKSELL Hans , ELMQVIST Håkan , HULTENBY Kjell , BERGLUND Hans
Published: August 2015

Application of low-frequency ultrasound for clot disruption has been suggested as a potential therapy to enhance thrombus dissolution, but the optimal mode for delivery of ultrasound with clot-disruptive properties has not yet been extensively explored. Target-specific effects are desirable and may be accomplished by focusing the ultrasound. Adequate focusing, however, requires a short wavelength. The aim of this study was to compare the clot-disruptive effects of different modalities of focused acoustic energy. An in vitro model (10 blood clots for each modality) was used to test the clot-disruptive capacity of (i) shock waves generated in an electrohydraulic lithotriptor; (ii) focused continuous ultrasound of frequency 1.1 MHz, delivered from a specially constructed piezoelectric transducer; and (iii) focused pulse-modulated ultrasound of frequency 1.1 MHz delivered from the same transducer. Exposure to 30 s of focused pulse-modulated ultrasound caused a marked reduction (99±2%) in clot weight compared with 30 shock waves (11±5%) or 30 s exposure to focused continuous wave ultrasound (11±6%) (P< 0.0001). The observed marked and rapid disruptive effect on blood clots of focused high-frequency ultrasound indicates an alternative approach for external ultrasound-mediated thrombus destruction in vivo. The focused pulse-modulated technique has potential to exhibit the desired effect in a well-defined target volume and provides the means for control of the average power.
Hypophosphatasia: diagnostic application of linked DNA markers in the dominantly inherited adult form
Authors: IQBAL S. J. , PLAHA D. S. , LINFORTH G. H. , DALGLEISH R.
Published: August 2015

Hypophosphatasia is a rare disease characterized by low serum levels of tissue non-specific alkaline phosphatase (TNSALP) and a spectrum of skeletal disease varying from the severest form with death in utero to mild with no clinical abnormality in adults. Currently, the diagnosis of hypophosphatasia is made on the basis of clinical findings, radiography, low serum alkaline phosphatase levels and raised abnormal phosphorylated metabolites; there are elevations in serum pyridoxal 5′-phosphate, urinary phosphoethanolamine and inorganic pyrophosphate. In borderline cases the biochemical diagnosis remains uncertain. Prenatally, diagnosis is made using radiography and ultrasonography together with chorionic villus tissue biopsy, in which TNSALP levels are measured using an antibody-based assay. Since hypophosphatasia results from mutations in the TNSALP gene we have, for the first time in two U.K. families, undertaken restriction fragment length polymorphism (RFLP) analysis using three intragenic RFLPs for BclI and MspI at the ALPL locus. One family was informative, and a mutant-allele-specific haplotype with respect to three RFLPs was defined. In the other family the disease was shown to segregate with one allele of the BclI RFLP, but the MspI RFLPs were not informative. The disease segregated in the two families with different alleles of the BclI RFLP, suggesting that the mutations are likely to be different. We confirm that DNA analysis is likely to be the way ahead for diagnosing hypophosphatasia, and that standardized screening methods need to be developed for detecting mutations in these and other families.
Human placental nitric oxide synthase activity is not altered in diabetes
Authors: DI IULIO J. L. , GUDE N. M. , KING R. G. , LI C. G. , RAND M.J. , BRENNECKE S. P.
Published: August 2015

Endothelial nitric oxide synthase (NOS) protein and mRNA have been identified and calcium-dependent NOS activity has been measured in human placentae during normal pregnancy. Recently, mRNA and protein for the inducible isoform of NOS have been detected in placentae of women with gestational diabetes. The aim of this study was to determine whether calcium-independent (ciNOS) and/or total (tNOS) NOS activities were increased in placentae obtained after vaginal delivery or Caesarean section from women assigned to the following groups according to standard obstetric criteria: gestational diabetes, diabetes before pregnancy and non-diabetic controls. tNOS and ciNOS were assessed by measuring the conversion of [3H]⌊-arginine to [3H]⌊-citrulline in the three groups. Michaelis–Menten constants (Km) and maximum velocities of reaction (Vmax) were calculated using Lineweaver–Burk analysis for tNOS. There were no significant differences in either ciNOS, Vmax or Km values between any of the three groups (normal, ciNOS 12.7±1.6%, Vmax 16.6±3.3 pmol⋅min-1⋅mg-1 protein, Km 15.30±2.6 µmol/l; gestational diabetes, ciNOS 15.4±1.4%, Vmax 14.8±5.2 pmol⋅min-1⋅mg-1 protein, Km 10.5±1.7 µmol/l; diabetes before pregnancy, ciNOS 13.4±1.1%, Vmax 14.9±3.4 pmol⋅min-1⋅mg-1 protein, Km 17.7±2.2 µmol/l). The presence of macrosomia did not affect tNOS activity in those with diabetes before pregnancy, and glycosylated haemoglobin levels measured between weeks 27 and 39 were not correlated with ciNOS activity. The results from the present study do not provide evidence for increased placental tNOS or ciNOS activities in pregnancies complicated by gestational diabetes or diabetes present before pregnancy.
Impaired postprandial clearance of squalene and apolipoprotein B-48 in post-menopausal women with coronary artery disease
Authors: RAJARATNAM Radhakrishnan A. , GYLLING Helena , MIETTINEN Tatu A.
Published: August 2015

It is not known in detail whether postprandial lipaemia is associated with coronary artery disease (CAD) in women. To investigate this, we administered an oral vitamin A/squalene/fat meal to 24 post-menopausal women with angiographically proven CAD who were not taking hormone replacement therapy, and to 30 healthy controls (18 without and 12 with hormone replacement therapy) to evaluate the effects of CAD on postprandial lipoprotein metabolism. This was done by assessing squalene, triacylglycerols, retinyl palmitate and apolipoprotein B-48 (apoB-48) during the subsequent 24 h. The subjects with CAD had significantly higher fasting concentrations of squalene and apoB-48 in triacylglycerol-rich lipoproteins (TGRL) compared with the controls. The postprandial areas under the incremental curve of TGRL apoB-48, chylomicrons, very-low-density lipoprotein (VLDL) and TGRL squalene, and of retinyl palmitate in VLDL only, were significantly higher in women with CAD than in controls. Adjustment for fasting values did not eliminate the differences in postprandial squalene and apoB-48 between CAD and controls. The postprandial responses of control subjects were not influenced by hormone replacement therapy. The peaks of squalene and retinyl palmitate of the controls, but not of the women with CAD, occurred significantly earlier (P < 0.01 for both) in chylomicrons than in VLDL. The findings suggest that lipoproteins that accumulate postprandially are labelled by dietary squalene, and that these lipoproteins may be atherogenic in post-menopausal women.
Acute administration of 17β-oestradiol does not improve endothelium-dependent vasodilatation in young men
Authors: NEW Gishel , DUFFY Stephen J. , BERRY Karen L. , HARPER Richard W. , MEREDITH Ian T.
Published: August 2015

Studies have recently demonstrated that long-term oestrogen therapy improves endothelium-dependent and endothelium-independent vasodilatation in the conductance vessels of biological males. We sought to determine if an acute single dose of oestrogen might similarly improve vasodilator function in young males. In a randomized, double-blind, placebo-controlled, crossover study, we compared the effects of 1 mg of sublingual 17β-oestradiol (E2) and placebo on endothelium-dependent and endothelium-independent vasodilatation in the brachial artery using a non-invasive ultrasound technique. We recruited 30 young males based on a power calculation. Neither acute sublingual oestrogen nor placebo affected flow-mediated vasodilatation [5.32±0.78% and 5.28±0.60% respectively (mean±S.E.M.), P = 0.94]. Responses to nitroglycerine were similar after oestrogen or placebo (16.01±0.86% and 15.29±1.19%, P = 0.47). Basal blood flow and flow during reactive hyperaemia did not differ after oestrogen or placebo. Heart rate and blood pressure were similar during both treatment phases of the study. The absolute change in serum oestradiol levels was greater after the oestrogen treatment phase than after placebo (1509±87 versus -13±4 pmol/l, P < 0.0001). Despite achieving supra-physiological oestradiol levels, the acute administration of sublingual E2 does not appear to improve endothelium-dependent or endothelium-independent vasodilatation, at least acutely, in the brachial artery of young males. In keeping with our previous study, these data suggest that a period of oestrogen ‘priming’ (possibly to induce receptor-mediated nitric oxide synthesis) may be required to yield an improvement in vascular function in males.
Lack of effect of clinical doses of cyclosporin A on erythrocyte Na+/K+-ATPase activity
Authors: FERRER-MARTÍNEZ Andreu , FELIPE Antonio , BARCELÓ Pedro , CASADO Francisco J. , BALLARÍN José , PASTOR-ANGLADA Marçal
Published: August 2015

Cyclosporin A (CsA) may exert its cytotoxic effects by altering the activity of different plasma membrane transport systems. Although CsA may act at the gene level, it has been also suggested that it can directly alter transport processes at the plasma membrane. To examine this possibility in a physiological context, we determined Na+/K+-ATPase activity in erythrocytes from two groups of subjects receiving CsA treatment: group I consisted of kidney transplant patients, and group II comprised patients with steroid-resistant idiopathic nephrotic syndrome. Group I patients showed a marked decrease (35%) in the activity of the Na+/K+-ATPase in erythrocytes immediately after surgery, before the initiation of CsA treatment. The activity remained low 2 days after the introduction of CsA, but had recovered to the original (pre-surgery) value 1 month later. Group II patients showed the same pattern of erythrocyte Na+/K+-ATPase activity as those in group I. When the blood CsA levels from all patients were plotted against the corresponding erythrocyte Na+/K+-ATPase transport activity, a significant linear correlation was found. Higher levels of CsA in the blood were correlated significantly with increased Na+/K+-ATPase activities. The blood sodium concentration was also correlated positively with both erythrocyte Na+/K+-ATPase activity and blood CsA concentration. Thus CsA treatment is not associated with inhibition of the Na+/K+-ATPase in erythrocytes.
Continuous stroke volume monitoring by modelling flow from non-invasive measurement of arterial pressure in humans under orthostatic stress
Authors: HARMS Mark P. M. , WESSELING Karel H. , POTT Frank , JENSTRUP Morten , VAN GOUDOEVER Jeroen , SECHER Niels H. , VAN LIESHOUT Johannes J.
Published: August 2015

The relationship between aortic flow and pressure is described by a three-element model of the arterial input impedance, including continuous correction for variations in the diameter and the compliance of the aorta (Modelflow). We computed the aortic flow from arterial pressure by this model, and evaluated whether, under orthostatic stress, flow may be derived from both an invasive and a non-invasive determination of arterial pressure. In 10 young adults, Modelflow stroke volume (MFSV) was computed from both intra-brachial arterial pressure (IAP) and non-invasive finger pressure (FINAP) measurements. For comparison, a computer-controlled series of four thermodilution estimates (thermodilution-determined stroke volume; TDSV) were averaged for the following positions: supine, standing, head-down tilt at 20 ° (HDT20) and head-up tilt at 30 ° and 70 ° (HUT30 and HUT70 respectively). Data from one subject were discarded due to malfunctioning thermodilution injections. A total of 155 recordings from 160 series were available for comparison. The supine TDSV of 113±13 ml (mean±S.D.) dropped by 40% to 68±14 ml during standing, by 24% to 86±12 ml during HUT30, and by 51% to 55±15 ml during HUT70. During HDT20, TDSV was 114±13 ml. MFSV for IAP underestimated TDSV during HDT20 (-6±6 ml; P < 0.05), but that for FINAP did not (-4±7 ml; not significant). For HUT70 and standing, MFSV for IAP overestimated TDSV by 11±10 ml (HUT70; P < 0.01) and 12±9 ml (standing; P < 0.01). However, the offset of MFSV for FINAP was not significant for either HUT70 (3±8 ml) or standing (3±9 ml). In conclusion, due to orthostasis, changes in the aortic transmural pressure may lead to an offset in MFSV from IAP. However, Modelflow correctly calculated aortic flow from non-invasively determined finger pressure during orthostasis.
Heterogeneous vascular endothelial growth factor (VEGF) isoform mRNA and receptor mRNA expression in human glomeruli, and the identification of VEGF148 mRNA, a novel truncated splice variant
Authors: WHITTLE Catheryne , GILLESPIE Kathleen , HARRISON Rebecca , MATHIESON Peter W. , HARPER Steve J.
Published: August 2015

Vascular endothelial growth factor (VEGF) mediates increased vascular permeability and endothelial mitogenesis, and may orchestrate normal glomerular permselectivity and proteinuria. Distinct isoforms result from differential gene splicing. VEGF binds to two cell surface tyrosine-kinase receptors, KDR (kinase domain region) and Flt-1 (fms-like tyrosine kinase-1). The latter also exists in a soluble form (sFlt), which is inhibitory. We have studied patterns of VEGF-isoform and VEGF-receptor expression in isolated single normal human glomeruli. mRNA from 190 glomeruli (from 20 individuals) was harvested on to magnetic beads, and nested reverse transcription–PCR was performed using primers for the VEGF isoforms and VEGF receptors. Simultaneous nested reverse transcription–PCR for CD45 was conducted in order to exclude leucocyte contamination. Unexpected products were isolated, cloned and sequenced. Multiple patterns of glomerular VEGF mRNA isoform expression were identified. Most frequently (58%), all three common forms were expressed. VEGF189 (i.e. 189-amino-acid form of VEGF) was expressed in 63%, VEGF165 in 85% and VEGF121 in 84% of glomeruli. Two unexpected PCR products were also identified: 18% of glomeruli expressed VEGF145, and 27% of glomeruli expressed a new truncated VEGF splice variant, VEGF148, lacking exon 6, the terminal part of exon 7 and exon 8. Multiple patterns of VEGF-receptor expression were also identified, the most common being expression of all three isoforms (28%). Overall, KDR was seen in 59% of glomeruli, Flt-1 in 45% and sFlt in 57%. Thus the expression of VEGF within normal glomeruli is complex and variable, with inter- and intra-individual variation. Furthermore, sFlt appears to be the co-dominant form of VEGF receptor expressed within glomeruli, suggesting that, in healthy individuals, a degree of VEGF autoregulation is the norm. The physiological importance of VEGF148 remains to be confirmed.
Interleukin-8 stimulates the migration of human colonic epithelial cells in vitro
Authors: WILSON Andrew J. , BYRON Keith , GIBSON Peter R.
Published: August 2015

The migration of colonic epithelial cells (restitution) is an important event in the repair of mucosal injuries. Interleukin-8 (IL-8) is a physiological initiator of the chemotactic migration of leucocytes. This study aimed to determine whether IL-8 had a similar effect on migration in an in vitro model of wounded colonic epithelium. Cell migration over 24 h was assessed in circular wounds made in confluent monolayers of the human colon cancer cell line LIM1215. This migration was stimulated in a concentration-dependent manner by IL-8, with maximal effects of approx. 1.75-fold above basal migration. The motogenic effect of IL-8 was mediated independently of effects on cell proliferation. In contrast, it was partially dependent upon gene transcription and protein synthesis and involved the activation of pertussis-toxin-sensitive G-proteins. The short-chain fatty acids, acetate, propionate, butyrate and valerate, the activator of protein kinase C (phorbol-12-myristate-13-acetate) and tumour necrosis factor-α (TNF-α) all stimulated the secretion of IL-8. However, only the motogenic effect of TNF-α was dependent upon IL-8. In conclusion, IL-8 stimulated cell migration in an in vitro model of colonic epithelium, whereas the motogenic effect of at least one physiologically relevant factor was dependent upon an increase in its endogenous levels. If IL-8 stimulates colonic epithelial restitution in vivo, this would have ramifications for the control of repair processes following wounding of the colonic mucosa.
Uptake and antioxidant effects of ergothioneine in human erythrocytes
Authors: MITSUYAMA Hiroki , MAY James M.
Published: August 2015

Ergothioneine is a fungal metabolite that may have antioxidant functions in mammalian cells. Although it accumulates to low millimolar concentrations in liver and other tissues, it is not thought to be taken up by mature erythrocytes. During a study of the function of ergothioneine as an antioxidant in human erythrocytes, we found that these cells do take up ergothioneine from the surrounding medium. Ergothioneine concentrations in freshly prepared erythrocytes were 2–9-fold higher than in plasma from the same donor. Slow but progressive accumulation of ergothioneine to about 125% of basal levels was observed in erythrocytes over a 4 h incubation. After a 2 h incubation, intracellular ergothioneine concentrations rose on addition of increasing amounts of ergothioneine to the incubation medium, although saturation was not evident in cells from all donors. Both initial levels and rates of ergothioneine uptake varied in erythrocytes from different donors. Intracellular ergothioneine was stable to depletion of GSH by N-ethylmaleimide and to a more severe oxidant stress induced by hydrogen peroxide in the presence of catalase. These results show that human erythrocytes do take up ergothioneine; however, the GSH results do not support an antioxidant role for ergothioneine in erythrocytes.
Increased intracellular calcium and decreased activities of leucocyte Na+,K+-ATPase and Ca2+-ATPase in asthma
Authors: CHHABRA Sunil Kumar , KHANDUJA Anita , JAIN Deepika
Published: August 2015

The present study was carried out to determine the intracellular free calcium concentration ([Ca2+]i) and the activity of its regulatory enzymes (Na+,K+-ATPase and Ca2+-ATPase) in leucocytes. Levels of plasma lysophosphatidylcholine (LPC) were also measured. Then the relationship between these parameters and the clinical severity of asthma and bronchial reactivity was studied. Patients with asthma were divided into three groups: acute asthma (subjects in acute exacerbation), uncontrolled asthma (subjects currently symptomatic) and stable asthma (subjects currently asymptomatic). A group of normal subjects was also studied. Spirometry, specific airway conductance and bronchial reactivity measurements were carried out. The following biochemical parameters were studied in venous blood: leucocyte [Ca2+]i, Na+,K+-ATPase and Ca2+-ATPase activities, and plasma LPC. Leucocyte [Ca2+]i was increased and the activities of Na+,K+-ATPase and Ca2+-ATPase were decreased in patients with asthma. Plasma levels of LPC were also increased. These changes were observed to be greatest among asthmatics in acute exacerbation of asthma, and lesser in magnitude in patients with less severe asthma. The activities of both ATPases were found to have a significant positive correlation, and [Ca2+]i and the levels of plasma LPC a significant negative correlation, with predicted forced expiratory volume in 1 s (FEV1). No significant correlation was observed between the biochemical parameters and bronchial reactivity. It is concluded that intracellular calcium homoeostasis is abnormal in asthma; specifically, the activities of Na+,K+-ATPase and Ca2+-ATPase are decreased. These abnormalities may modulate the clinical severity of asthma.
Role of erythropoietin and nitric oxide in modulating the tone of human renal interlobular and subcutaneous arteries from uraemic subjects
Authors: WU Xiao Chun , RICHARDS Nicholas T. , JOHNS Edward J.
Published: August 2015

This study investigated potential reasons why erythropoietin (EPO) given therapeutically to patients with renal failure may increase peripheral, but not renal, vascular resistance. This was done by comparing the effects of EPO on resting tension in normal renal interlobular and subcutaneous vessels from uraemic patients. In human subcutaneous arteries from uraemic subjects, noradrenaline- and KCl-induced vasoconstrictions were enhanced when nitric oxide (NO) production was blocked with NG-nitro-L-arginine methyl ester (L-NAME), but were unaffected by EPO, while acetylcholine- and bradykinin-induced concentration-dependent relaxations were markedly attenuated by L-NAME, but not by EPO. The noradrenaline- and KCl-induced vasoconstrictions of human renal interlobular arteries were unaffected by the presence of L-NAME, but were attenuated by EPO (20 units·ml-1) by some 33% (P< 0.01); this effect was enhanced by the co-administration of L-NAME. Acetylcholine and bradykinin caused comparable dilatations of the interlobular arteries; the response to the former was attenuated by L-NAME, but none of these responses were changed by EPO. EPO given alone, at a concentration of either 0.1 or 20 units·ml-1, had no effect on basal resting tone. NO production mediated both acetylcholine- and bradykinin-induced relaxation in this vessel type. In contrast, in the interlobular arteries there was no indication of NO modulating the level of vasoconstriction, and it only mediated acetylcholine-induced dilation. These acute responses to EPO only partially explain its differential effects on the vasculature in renal failure.
Comparable vasorelaxant effects of 17α- and 17β-oestradiol on rat mesenteric resistance arteries: an action independent of the oestrogen receptor
Authors: NADERALI Ebrahim K. , WALKER Adrian B. , DOYLE Patrick , WILLIAMS Gareth
Published: August 2015

17β-Oestradiol (17βE2) has vasorelaxant properties that may contribute to its beneficial cardiovascular effects. The mechanism of vasorelaxation remains controversial, but does not appear to involve interaction of 17βE2 with its nuclear receptor. The present study examined the effects on resistance arteries of 17βE2 and its isomer, 17α-oestradiol (17αE2), which does not bind to the classical oestrogen receptor. In arteries precontracted with either noradrenaline or KCl, 17βE2 and 17αE2 caused comparable relaxation in a concentration-dependent manner over the concentration range 0.1–10 μmol/l, with no significant difference in the maximal effect obtained. Pre-incubation of the arteries with 17βE2 or 17αE2 for 15 min reduced the magnitude and duration of the force generated with both noradrenaline and KCl to a comparable degree. Vasorelaxation induced by either 17βE2 or 17αE2 was not blocked by an inhibitor of NO synthase or by protein synthesis inhibitors, indicating that vasodilatation is not dependent upon either NO generation or protein synthesis. In the absence of extracellular calcium, both oestradiols still relaxed arteries precontracted with NA, suggesting that they inhibit intracellular calcium release. Both 17βE2 and 17αE2 therefore have important and comparable vasorelaxant properties that do not require interaction with the nuclear oestrogen receptor. Direct interactions with the cell membrane or with ion-channel proteins may be responsible.