Acetaminophen influences musculoskeletal signaling but not adaptations to endurance exercise training

Acetaminophen (ACE) is a widely used analgesic and antipyretic drug with various applications, from pain relief to fever reduction. Recent studies have reported equivocal effects of habitual ACE intake on exercise performance, muscle growth, and risks to bone health. Thus, this study aimed to assess the impact of a 6-week, low-dose ACE regimen on muscle and bone adaptations in exercising and non-exercising rats. Nine-week-old Wistar rats (n = 40) were randomized to an exercise or control (no exercise) condition with ACE or without (placebo). For the exercise condition, rats ran 5 days per week for 6 weeks at a 5% incline for 2 min at 15 cm/s, 2 min at 20 cm/s, and 26 min at 25 cm/s. A human equivalent dose of ACE was administered (379 mg/kg body weight) in drinking water and adjusted each week based on body weight. Food, water intake, and body weight were measured daily. At the beginning of week 6, animals in the exercise group completed a maximal treadmill test. At the end of week 6, rats were euthanized, and muscle cross-sectional area (CSA), fiber type, and signaling pathways were measured. Additionally, three-point bending and microcomputer tomography were measured in the femur. Follow-up experiments in human primary muscle cells were used to explore supra-physiological effects of ACE. Data were analyzed using a two-way ANOVA for treatment (ACE or placebo) and condition (exercise or non-exercise) for all animal outcomes. Data for cell culture experiments were analyzed via ANOVA. If omnibus significance was found in either ANOVA, a post hoc analysis was completed, and a Tukey's adjustment was used. ACE did not alter body weight, water intake, food intake, or treadmill performance (p > .05). There was a treatment-by-condition effect for Young's Modulus where placebo exercise was significantly lower than placebo control (p < .05). There was no treatment by condition effects for microCT measures, muscle CSA, fiber type, or mRNA expression. Phosphorylated-AMPK was significantly increased with exercise (p < .05) and this was attenuated with ACE treatment. Furthermore, phospho-4EBP1 was depressed in the exercise group compared to the control (p < .05) and increased in the ACE control and ACE exercise group compared to placebo exercise (p < .05). A low dose of ACE did not influence chronic musculoskeletal adaptations in exercising rodents but acutely attenuated AMPK phosphorylation and 4EBP1 dephosphorylation post-exercise.

A qualitative evaluation of internet information on hip and knee osteoarthritis

BACKGROUND

Hip and knee arthritis are two of the most common conditions that result in referral to orthopaedic outpatient clinics. Many patients now use the internet to research their condition and to inform their decision about treatment options. This has implications for the process of informed consent.

AIM

To assess the quality of patient information on the internet regarding hip and knee arthritis.

METHODS

'Hip arthritis' and 'Knee arthritis' were entered as search terms into a popular search engine. To adjust for temporal variation, the process was repeated one month and one year later. Of the 200 results analysed, 83 websites met the inclusion criteria. The quality of patient information presented on these websites was assessed using a validated scoring instrument by two independent observers.

RESULTS

Most websites assessed were of poor quality; nearly half of all websites did not mention any risks or complications associated with surgical intervention for these conditions.

CONCLUSIONS

As part of their professional obligation to provide a robust process of informed consent, clinicians should be aware of the variable quality of patient information available on the internet. As such, they should be prepared to advise their patients about quality websites where reliable information can be sought.

Long-term impact of early non-infectious complications at the initiation of peritoneal dialysis

BACKGROUND

Early non-infectious complications at initiation of peritoneal dialysis (PD) are a major burden with unknown long-term impacts on individuals.

METHODS

Prospective multicentre cohort study using univariable and multivariable Cox regression to identity mortality risk and PD discontinuation risk in those with and without non-infectious complications. All individuals commencing PD between 1 January 2014 and 31 December 2018, registered in the New Zealand Peritoneal Dialysis Registry (NZPDR) were followed up to 31 December 2020. Early non-infectious complications defined as functional, catheter-related, exit-site dialysate leak or anatomical leak complications occurring within 30 days of initiation of PD. Primary outcomes were patient survival and time on PD therapy. Secondary outcomes were peritonitis free survival, first PD catheter survival and catheter tunnel infection free survival.

RESULTS

Of 1596 individuals included in the study, 102 experienced an early non-infectious complication. Multivariable analysis demonstrated these complications were associated with higher risk of overall mortality (hazard ratio (HR) 1.71; 95% confidence interval (CI) 1.21-2.44), PD discontinuation (HR 1.84; 95% CI 1.41-2.41) and first catheter failure (HR 2.89; 95% CI 2.28-3.66). No difference was found for risk of development of first peritonitis episode or catheter tunnel infection. Mortality risk was associated with functional and exit-site dialysate leak complications and continued beyond 180 days. Risk of PD discontinuation and first catheter loss were associated with catheter and functional complications in the first 180 days.

CONCLUSION

Early non-infectious complications are associated with long-term mortality risk. Further research in risk factors and causes of early non-infectious complications are required.

Podocyte GSK3 is an evolutionarily conserved critical regulator of kidney function

Albuminuria affects millions of people, and is an independent risk factor for kidney failure, cardiovascular morbidity and death. The key cell that prevents albuminuria is the terminally differentiated glomerular podocyte. Here we report the evolutionary importance of the enzyme Glycogen Synthase Kinase 3 (GSK3) for maintaining podocyte function in mice and the equivalent nephrocyte cell in Drosophila. Developmental deletion of both GSK3 isoforms (α and β) in murine podocytes causes late neonatal death associated with massive albuminuria and renal failure. Similarly, silencing GSK3 in nephrocytes is developmentally lethal for this cell. Mature genetic or pharmacological podocyte/nephrocyte GSK3 inhibition is also detrimental; producing albuminuric kidney disease in mice and nephrocyte depletion in Drosophila. Mechanistically, GSK3 loss causes differentiated podocytes to re-enter the cell cycle and undergo mitotic catastrophe, modulated via the Hippo pathway but independent of Wnt-β-catenin. This work clearly identifies GSK3 as a critical regulator of podocyte and hence kidney function.

The differential impact of adverse childhood experiences in the development of pre-diabetes in a longitudinal cohort of US adults

BACKGROUND

ACEs have a dose-response relationship with diabetes. The relationship between ACEs and pre-diabetes is not well known and may represent an effective area for prevention efforts.

METHODS

Data from 1054 participants from two waves of the longitudinal MIDUS study were used. Multivariate general linear regression models assessed the relationship between ACEs and biomarker outcomes. Correlation tests and mediation models investigated the relationship between ACE and pre-diabetes.

RESULTS

Individuals reporting ACEs were statistically significantly more likely to have higher BMI (1.13 (0.34-1.92)), higher waist circumference (2.74 (0.72-4.76)), elevated blood fasting insulin levels (2.36 (0.71-4.02)) and higher insulin resistance (HOMA-IR (0.57 (0.08-1.06)). BMI/waist circumference and insulin resistance did not maintain independent relationships with ACEs once HOMA-IR was included in the dichotomized ACE model (p = 0.05 and p = 0.06, respectively), suggesting the relationship between BMI and ACEs may be mediated by insulin resistance.

CONCLUSIONS

These results represent one of the first studies to examine the differential impact of ACEs on a diverse set of clinical pre-diabetes measures. Findings suggest sexual and physical abuse, and financial strain during childhood are important factors associated with higher risk for pre-diabetes, and should be considered during intervention development.

Coalescence of Macroscopic Flux Ropes at the Subsolar Magnetopause: Magnetospheric Multiscale Observations

We report unambiguous in situ observation of the coalescence of macroscopic flux ropes by the magnetospheric multiscale (MMS) mission. Two coalescing flux ropes with sizes of ∼1  R_{E} were identified at the subsolar magnetopause by the occurrence of an asymmetric quadrupolar signature in the normal component of the magnetic field measured by the MMS spacecraft. An electron diffusion region (EDR) with a width of four local electron inertial lengths was embedded within the merging current sheet. The EDR was characterized by an intense parallel electric field, significant energy dissipation, and suprathermal electrons. Although the electrons were organized by a large guide field, the small observed electron pressure nongyrotropy may be sufficient to support a significant fraction of the parallel electric field within the EDR. Since the flux ropes are observed in the exhaust region, we suggest that secondary EDRs are formed further downstream of the primary reconnection line between the magnetosheath and magnetospheric fields.

An ovine hepatorenal fibrocystic model of a Meckel-like syndrome associated with dysmorphic primary cilia and TMEM67 mutations

Meckel syndrome (MKS) is an inherited autosomal recessive hepatorenal fibrocystic syndrome, caused by mutations in TMEM67, characterized by occipital encephalocoele, renal cysts, hepatic fibrosis, and polydactyly. Here we describe an ovine model of MKS, with kidney and liver abnormalities, without polydactyly or occipital encephalocoele. Homozygous missense p.(Ile681Asn; Ile687Ser) mutations identified in ovine TMEM67 were pathogenic in zebrafish phenotype rescue assays. Meckelin protein was expressed in affected and unaffected kidney epithelial cells by immunoblotting, and in primary cilia of lamb kidney cyst epithelial cells by immunofluorescence. In contrast to primary cilia of relatively consistent length and morphology in unaffected kidney cells, those of affected cyst-lining cells displayed a range of short and extremely long cilia, as well as abnormal morphologies, such as bulbous regions along the axoneme. Putative cilia fragments were also consistently located within the cyst luminal contents. The abnormal ciliary phenotype was further confirmed in cultured interstitial fibroblasts from affected kidneys. These primary cilia dysmorphologies and length control defects were significantly greater in affected cells compared to unaffected controls. In conclusion, we describe abnormalities involving primary cilia length and morphology in the first reported example of a large animal model of MKS, in which we have identified TMEM67 mutations.

Protracted core formation and rapid accretion of protoplanets

Understanding core formation in meteorite parent bodies is critical for constraining the fundamental processes of protoplanet accretion and differentiation within the solar protoplanetary disk. We report variations of 5 to 20 parts per million in (182)W, resulting from the decay of now-extinct (182)Hf, among five magmatic iron meteorite groups. These (182)W variations indicate that core formation occurred over an interval of ~1 million years and may have involved an early segregation of Fe-FeS and a later segregation of Fe melts. Despite this protracted interval of core formation, the iron meteorite parent bodies probably accreted concurrently ~0.1 to 0.3 million years after the formation of Ca-Al-rich inclusions. Variations in volatile contents among these bodies, therefore, did not result from accretion at different times from an incompletely condensed solar nebula but must reflect local processes within the nebula.

The effect of lipoic acid and vitamin E therapies in individuals with the metabolic syndrome

The metabolic syndrome is associated with abnormal glucose and lipid metabolism, insulin resistance, increased oxidative stress and pro-inflammatory activity that increase the risk of type 2 diabetes and cardiovascular disease. The aim of this study was to investigate the effect of treatment with the antioxidant α-lipoic acid (ALA) with or without vitamin E supplementation, on markers of insulin resistance and systemic inflammation and plasma nonesterified fatty acid (NEFA) concentrations in individuals with the metabolic syndrome. In a randomized, double-blind, placebo-controlled trial, subjects with the metabolic syndrome received ALA (600 mg/day, n = 34), vitamin E (100 IU/day, n = 36), both ALA and vitamin E (n = 41), or matching placebo (n = 40) for 1 year. Fasting circulating concentrations of glucose and insulin were measure every 3 months and NEFA, markers of inflammation, adiponectin and vitamin E were measured at 6 monthly intervals. Plasma NEFA concentrations decreased [-10 (-18, 0)%] at a marginal level of significance (p = 0.05) in those who received ALA alone compared with placebo and decreased [-8 (-14, -1)% (95% CI)] significantly (P = 0.02) in participants who were randomised to ALA with and without vitamin E compared with those who did not receive ALA. Fasting glucose, insulin, homeostatic model assessment of insulin resistance, adiponectin, and markers of inflammation did not change significantly during the study. These data suggest that prolonged treatment with ALA may modestly reduce plasma NEFA concentrations but does not alter insulin or glucose levels in individuals with the metabolic syndrome.

Rapid passage signals from a vibrationally excited target molecule: a pump and probe experiment with continuous wave quantum cascade lasers

Two 5 µm continuous wave quantum cascade lasers are used to perform a counterpropagating pump and probe experiment on a low pressure sample of nitric oxide. The strong pump field excites a fundamental rovibrational transition and the weaker probe field is tuned to the corresponding rotationally resolved hot band transition. When both light fields are in resonance, rapid passage is observed in the hot band absorption lineshape arising from a minimally damped and velocity-selected sample of molecules in the v=1 state. The measured rapid passage signals are well described by a two-level model based on the optical Bloch equations.

Limits on the spin-dependent WIMP-nucleon cross sections from the first science run of the ZEPLIN-III experiment

We present new experimental constraints on the WIMP-nucleon spin-dependent elastic cross sections using data from the first science run of ZEPLIN-III, a two-phase xenon experiment searching for galactic dark matter weakly interacting massive particles based at the Boulby mine. Analysis of approximately 450 kg x days fiducial exposure allow us to place a 90%-confidence upper limit on the pure WIMP-neutron cross section of sigma(n)=1.9x10(-2) pb at 55 GeV/c(2) WIMP mass. Recent calculations of the nuclear spin structure based on the Bonn charge-dependent nucleon-nucleon potential were used for the odd-neutron isotopes 129Xe and 131Xe. These indicate that the sensitivity of xenon targets to the spin-dependent WIMP-proton interaction could be much lower than implied by previous calculations, whereas the WIMP-neutron sensitivity is impaired only by a factor of approximately 2.

The actions of Caenorhabditis elegans neuropeptide-like peptides (NLPs) on body wall muscle of Ascaris suum and pharyngeal muscle of C. elegans

The actions of six Neuropeptide-like Peptides (NLPs) were investigated on Ascaris suum dorsal body wall muscle and Caenorhabditis elegans pharyngeal muscle. The NLPs tested on A. suum muscle, viz, NLP-1A, NLP-2A and B, had no direct effect on the muscle but all reversibly reduced acetylcholine (ACh)-induced contractions of the muscle, NLP-2A being the most potent, with an IC50 value of 78 microM. NLP-2A also reversibly reduced ACh-induced depolarizations of A. suum muscle resting membrane potential. NLP-1A, NLP-2A, NLP-3C and NLP-10A all increased pharyngeal pumping in C. elegans, NLP-8A weakly inhibited pumping while NLP-2B was inactive. NLP-10A induced a concentration-dependent increase in pumping activity with a threshold of 10-100 nM. Since genes encoding NLPs (nlp genes) are expressed in C. elegans pharyngeal neurons it is likely these peptides play a role in feeding behaviour.

Actions of glutamate and ivermectin on the pharyngeal muscle of Ascaridia galli: a comparative study with Caenorhabditis elegans

The actions of glutamate and ivermectin were examined in the pharynx of Ascaridia galli and the results compared with those on the pharynx of Caenorhabditis elegans. In both preparations glutamate elicits a depolarization and inhibition of pharyngeal pumping, but the response of the pharynx of A. galli was much less than for C. elegans. This may be either because the pharyngeal membrane potential of the former is closely linked to the equilibrium potential for chloride ions (E(Cl)) while that of C. elegans is independent of E(Cl), or that there is a lower density of glutamate receptors on the pharyngeal muscle of A. galli compared with C. elegans. The maximum depolarization to glutamate of the pharyngeal muscle was 4.5+/-0.8 mV in A. galli while it was >25 mV in C. elegans. Picrotoxin was a weak antagonist of the glutamate response in both species. Flufenamic acid, pentobarbitone and flurazepam had no significant effect on either preparation at concentrations up to 100 microM. Three glutamate receptor agonists, ibotenate, kainate and quisqualate were all more potent than glutamate on the A. galli pharyngeal muscle. In contrast, only ibotenate was more potent than glutamate in C. elegans pharynx, the other two agonists being approximately 20 times less potent. The potency of ivermectin differed markedly between the two species, being approximately three orders of magnitude less potent on the pharynx of A. galli compared with C. elegans. This study demonstrates clear differences between the properties of the pharyngeal muscle of the two species and shows that care must be taken when extrapolating data from free-living to parasitic species of nematode.

Interventions for protecting renal function in the perioperative period

BACKGROUND

A number of methods have been used to try to protect kidney function in patients undergoing surgery. These include the administration of dopamine, diuretics, calcium channel blockers, angiotensin converting enzyme inhibitors and hydration fluids.

OBJECTIVES

For this review, we selected randomized controlled trials, which employed different methods to protect renal function during the perioperative period. In examining these trials, we looked at outcomes such as renal failure and mortality, as well as changes in the renal function tests, including urine output, creatinine clearance, free water clearance, fractional excretion of sodium and renal plasma flow.

SEARCH STRATEGY

We searched the Cochrane Central register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 4, 2004), MEDLINE (1966 to 2004) and EMBASE (1988 to 2004) and hand searched six journals (British Journal of Anaesthesia; Anesthesia and Analgesia; Anesthesiology; Annals of Surgery; Journal of Thoracic and Cardiovascular Surgery and Journal of Vascular Surgery).

SELECTION CRITERIA

We selected all randomized controlled trials in adult population undergoing surgery where a treatment measure was used for the purpose of renal protection in the perioperative period.

DATA COLLECTION AND ANALYSIS

We selected 37 studies for inclusion in this review. As well as analysis of the data from all the studies, we also performed subgroup analysis for type of interventions, types of surgical procedures and those with pre-existing renal dysfunction. We undertook sensitivity analysis on studies with high methodological quality.

MAIN RESULTS

The review included data from 37 studies, comprising a total of 1227 patients. Of these, 658 received some form of treatment and 569 acted as controls. The interventions were mostly employing different pharmaceutical agents such as dopamine, diuretics, calcium channel blockers. ACE inhibitors or selected hydration fluids. The results indicated that certain interventions showed some benefits, but all the results suffered from significant heterogeneity. Hence we can draw no conclusions about the effectiveness of these interventions in protecting the kidneys during surgery.

AUTHORS' CONCLUSIONS

There is no reliable evidence from available literature to suggest that interventions during surgery can protect the kidneys from damage. However, there is a need for more studies of high methodological quality. One particular area for further studies may be on patients with pre-existing renal dysfunction undergoing surgery.

Nematode neuropeptides: Localization, isolation and functions

Historically, peptidergic substances (in the form of neurosecretions) were linked to moulting in nematodes. More recently, there has been a renewal of interest in nematode neurobiology, initially triggered by studies demonstrating the localization of peptide immunoreactivities to the nervous system. Here, David Brownlee, Ian Fairweather, Lindy Holden-Dye and Robert Walker will review progress on the isolation of nematode neuropeptides and efforts to unravel their physiological actions and inactivation mechanisms. Future avenues for research are suggested and the potential exploitation of peptidergic pathways in future therapeutic strategies highlighted.

A structure-activity study of the neuropeptide PF1, SDPNFLRFamide, using the dorsal body wall muscle of the chicken nematode, Ascaridia galli

The action of a range of N terminally modified peptides structurally related to the nematode peptide PF1, SDPNFLRFamide, has been investigated using a dorsal muscle strip preparation from the chicken nematode, Ascaridia galli. Acetylcholine contracts this muscle preparation in a concentration-dependent manner when applied in the range 1-100 microM with an EC50 value of 9 microM. These contractions are reduced in the presence of PF1 and its analogues, with a threshold effect of PF1 of around 1 nM and an IC50 value of 470 nM against 10 microM acetylcholine. All the PF1 analogues tested were less potent than PF1 in reducing the acetylcholine contractions, indicating the importance of the N terminal amino acids in the action of PF1 in this preparation.

Effect of changing from a cellulose acetate to a polysulphone dialysis membrane on protein oxidation and inflammation markers

BACKGROUND

In vitro, synthetic dialysis membranes induce less activation of blood components to produce pro-inflammatory cytokines and reactive oxygen species compared with cellulose acetate membranes. However, the long-term effect of switching from a cellulose-based dialysis membrane to a synthetic membrane on protein oxidation and systemic inflammation in hemodialysis patients is not well defined.

METHODS

Nineteen patients receiving hemodialysis were followed prospectively after changing from a low-flux cellulose acetate membrane to a low-flux polysulphone membrane for 11-17 months (n = 15) and then returning to the cellulose acetate membrane for 1 month (n = 13). Plasma markers of protein oxidation, cell activation and systemic inflammation and concentrations of soluble cell adhesion molecules were measured at baseline and at the end of each intervention period.

RESULTS

Plasma levels of protein thiols (18%), IL-6 (34%), VCAM-1 (33%), ICAM-1 (21%) and beta2-microglobulin (21%) increased significantly and dityrosine fluorescence (-36%), protein lipofuscin-like fluorophores (-18%) and TNF-alpha (-20%) decreased significantly in the patients after they switched to the polysulphone membrane. After reverting to the cellulose acetate membrane for 1 month, plasma levels of protein thiols and IL-6 returned to baseline while levels of other variables were not significantly different from values at the end of the polysulphone dialysis period. There was substantial intra-individual variation between 2 baseline measurements of plasma cytokines.

CONCLUSIONS

Switching from a cellulose acetate membrane to a low-flux polysulphone dialysis membrane for a year or more may decrease the level of protein oxidation suggesting a decrease in oxidant stress and greater biocompatibility of the polysulphone membrane. The effect of this change in dialysis membrane on systemic inflammation is uncertain due to increases in some but not other inflammation-sensitive molecules.

Evidence for a possible role for nitric oxide in the modulation of heart activity in Achatina fulica and Helix aspersa

The effects of nitric oxide (NO) donors, S-nitroso-N-acetylpenicillamine, S-nitroso-l-glutathione, sodium nitroprusside and sodium nitrite were investigated on the activity of the isolated hearts of Achatina fulica and Helix aspersa. NO donors inhibited heart activity in a concentration-dependent manner. The only exception was sodium nitroprusside, which excited H. aspersa heart. The inhibitory effects of these NO donors were reduced by the NO scavenger, methylene blue, the guanylyl cyclase inhibitor, 1H-(1,2,4) Oxadiazolo(4,3-a)quinoxalin-1-one (ODQ), and potentiated by 8-Br-cGMP and the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX). Acetylcholine also inhibited the heart activity, and this inhibition was reduced by methylene blue and ODQ. Positive NADPH-diaphorase staining was located in the outer pericardial layer of the heart of A. fulica. The present results provide evidence that NO may modulate the activity of gastropod hearts, and this modulation may modify the inhibitory action of acetylcholine on heart activity.

Effects of SEPYLRFamide on acetylcholine-induced currents of Helix aspersa neurones: role of ryanodine receptors

The possible participation of ryanodine receptors in the modulatory effects of the endogenous Helix heptapeptide, SEPYLRFamide, on the acetylcholine-induced currents (ACh-currents) of Helix aspersa neurones was studied using the two-electrode voltage clamp technique. SEPYLRFamide (bath application) caused a reduction of the ACh-currents of D1, D2, F1, F2, F76 and F77 neurones. Ryanodine (10 microM; bath application), which modifies ryanodine-controlled Ca(2+) channels, potentiated the inhibitory effect of SEPYLRFamide on the ACh-current. An antagonist of cyclic adenosine diphosphate ribose (cADPR) and ryanodine receptors, ruthenium red (1 mM; intracellular injection), reduced the inhibitory effects of SEPYLRFamide on the ACh-current. Ryanodine (10 microM) did not change the inhibitory effect of SEPYLRFamide on the ACh-current after intracellular injection of ruthenium red. An agonist of ryanodine receptors, caffeine (5 mM; bath application), reduced the ACh-current. Ryanodine (10 microM) did not change the reduction of ACh-currents induced by the first application of caffeine but decreased the reduction of ACh-currents induced by subsequent applications of caffeine. It is proposed that ryanodine receptors are involved in the inhibitory modulatory effects of SEPYLRFamide on somatic cholinergic receptors of Helix aspersa neurones.

The effect of the anthelmintic emodepside at the neuromuscular junction of the parasitic nematode Ascaris suum

Here we report on the action of the novel cyclo-depsipeptide anthelmintic, emodepside, on the body wall muscle of the parasitic nematode, Ascaris suum. Emodepside caused (i) muscle relaxation, (ii) inhibition of muscle contraction elicited by either acetylcholine (ACh), or the neuropeptide, AF2 (KHEYLRFamide) and (iii) a rapid relaxation of muscle tonically contracted by ACh. The inhibitory action of emodepside on the response to ACh was not observed in a denervated muscle strip, indicating that it may exert this action through the nerve cord, and not directly on the muscle. Electrophysiological recordings showed emodepside elicited a Ca(++)-dependent hyperpolarization of muscle cells. Furthermore, the response to emodepside was dependent on extracellular K+, similar to the action of the inhibitory neuropeptides PF1 and PF2 (SDPNFLRFamide and SADPNFLRFamide). Thus emodepside may act at the neuromuscular junction to stimulate release of an inhibitory neurotransmitter or neuromodulator, with a similar action to the PF1/PF2 neuropeptides.

The dusk flank of Jupiter's magnetosphere

Limited single-spacecraft observations of Jupiter's magnetopause have been used to infer that the boundary moves inward or outward in response to variations in the dynamic pressure of the solar wind. At Earth, multiple-spacecraft observations have been implemented to understand the physics of how this motion occurs, because they can provide a snapshot of a transient event in progress. Here we present a set of nearly simultaneous two-point measurements of the jovian magnetopause at a time when the jovian magnetopause was in a state of transition from a relatively larger to a relatively smaller size in response to an increase in solar-wind pressure. The response of Jupiter's magnetopause is very similar to that of the Earth, confirming that the understanding built on studies of the Earth's magnetosphere is valid. The data also reveal evidence for a well-developed boundary layer just inside the magnetopause.

Regulation of the pharynx of Caenorhabditis elegans by 5-HT, octopamine, and FMRFamide-like neuropeptides

More than fifty FMRFamide-like neuropeptides have been identified in nematodes. We addressed the role of a subset of these in the control of nematode feeding by electrophysiological recording of the activity of C. elegans pharynx. AF1 (KNEFIRFamide), AF2 (KHEYLRFamide), AF8 (KSAYMRFamide), and GAKFIRFamide (encoded by the C. elegans genes flp-8, flp-14, flp-6, and flp-5, respectively) increased pharyngeal action potential frequency, in a manner similar to 5-HT. In contrast, SDPNFLRFamide, SADPNFLRFamide, SAEPFGTMRFamide, KPSVRFamide, APEASPFIRFamide, and AQTVRFamide (encoded by the C. elegans genes flp-1; flp-1; flp-3; flp-9; flp-13, and flp-16, respectively) inhibited the pharynx in a manner similar to octopamine. Only three of the neuropeptides had potent effects at low nanomolar concentrations, consistent with a physiological role in pharyngeal regulation. Therefore, we assessed whether these three peptides mediated their actions either directly on the pharynx or indirectly via the neural circuit controlling its activity by comparing actions between wild-type and mutants with deficits in synaptic signaling. Our data support the conclusion that AF1 and SAEPFGTMRFamide regulate the activity of the pharynx indirectly, whereas APEASPFIRFamide exerts its action directly. These results are in agreement with the expression pattern for the genes encoding the neuropeptides (Kim and Li, 1999) as both flp-8 and flp-3 are expressed in extrapharyngeal neurons, whereas flp-13 is expressed in I5, a neuron with synaptic output to the pharyngeal muscle. These results provide the first, direct, functional information on the action of neuropeptides in C. elegans. Furthermore, we provide evidence for a putative inhibitory peptidergic synapse, which is likely to have a role in the control of feeding.

Four cases of CMV ureteritis: emergence of a new pattern of disease?

Although cytomegalovirus (CMV) infection is common in renal transplant recipients, urinary tract involvement has been rare. Only six cases of symptomatic ureteritis have been reported in renal transplant recipients and all within the last five years. We describe an additional four cases of CMV ureteritis. The presentation of CMV ureteritis is obstructive nephropathy often in the absence of systemic illness. Presentation may also mimic allograft rejection with minimal obstructive symptoms. We hypothesize that CMV ureteritis is an emerging complication of CMV disease, possibly due to changes in transplant practice.

Structure-activity and possible mode of action of S-Iamide neuropeptides on identified central neurons of Helix aspersa

Intracellular recordings were made from identified neurons from the suboesophageal ganglia of Helix aspersa. The inhibitory action of nine S-Iamide peptides was investigated. Structure-activity studies suggest that all act through a common receptor, which normally requires FVRIamide at the C terminal, with a preferred length of seven amino acids. Substitution at the N-terminal with alanine (A), threonine (T), proline (P) or leucine (L) results in little change in potency, suggesting the N-terminal requirements are relatively flexible. Ion substitution experiments suggest that potassium is the main ion involved in the inhibitory response to S-Iamide application. Studies using a range of compounds, which modify second messenger systems, would suggest that S-Iamide peptides may interact with adenylate cyclase. No evidence was found for an interaction with either guanylate cyclase or nitric oxide synthase.

Normal endothelial function after meals rich in olive or safflower oil previously used for deep frying

BACKGROUND AND AIM

Polyunsaturated fats are more susceptible to oxidation during heating than monounsaturated fats but their effects on endothelial function when heated are unknown. The aim of this study was to compare the effect of meals rich in heat-modified safflower and olive oils on postprandial flow-mediated endothelium-dependent dilation (EDD) in healthy men.

METHODS AND RESULTS

Flow-mediated EDD and glyceryltrinitrate-induced endothelium-independent dilation of the brachial artery were investigated in 14 subjects before and 4 hours after meals rich in olive oil and safflower oil used hourly for deep-frying for 8 hours in a double-blind crossover study design. There were high levels of lipid oxidation products (peroxides and carbonyls) in both heated oils. Plasma triglycerides were markedly increased at 4 hours after heated olive oil (1.26 +/- 0.43 vs 2.06 +/- 0.97 mmol/L) and heated safflower oil (1.44 +/- 0.63 vs 1.99 +/- 0.88 mmol/L). There was no change in EDD between fasting and postprandial studies and the response during the postprandial period was not significantly (p = 0.51) different between the meals (heated olive oil: 4.9 +/- 2.2% vs 4.9 +/- 2.5%; heated safflower oil: 5.1 +/- 3.1% vs 5.6 +/- 3.4%).

CONCLUSIONS

Meals rich in olive and safflower oils previously used for deep frying and containing high levels of lipid oxidation products increase postprandial serum triglycerides without affecting endothelial function. These findings suggest that relatively short-term use of these vegetable oils for frying may not adversely affect postprandial endothelial function when foods containing the heat-modified oils are consumed.

Vitamin C improves endothelial dysfunction in renal allograft recipients

BACKGROUND

Endothelial function is impaired in renal allograft recipients but the effects of antioxidant vitamin therapy on endothelial function in such patients is unknown.

METHODS

Thirteen renal allograft recipients were randomized to vitamin C or placebo in a double blind cross-over study design. Flow-mediated endothelium-dependent dilation and glyceryltrinitrate-induced endothelium-independent dilation of the brachial artery were assessed before and 2 h after oral administration of 2 g vitamin C or placebo.

RESULTS

Plasma vitamin C levels increased from 33.5+/-17.0 micromol/l to 98.8+/-60.2 micromol/l after treatment (P=0.0001). Endothelium-dependent dilation improved (from 1.6+/-2.6 to 4.5+/-2.5%) after vitamin C administration but was unchanged after placebo (1.9+/-1.5 to 1.8+/-2.5%; P=0.003 for vitamin C vs placebo). There was no significant change in endothelium-independent dilation in response to vitamin C. Vitamin C was also associated with a significant increase in the lag time in dilute serum oxidation (P=0.001).

CONCLUSIONS

Vitamin C acutely improves flow-mediated, endothelium-dependent dilation and increases the resistance of lipoproteins in dilute serum to oxidation in renal transplant recipients.

Characterization of glutamate-gated chloride channels in the pharynx of wild-type and mutant Caenorhabditis elegans delineates the role of the subunit GluCl-alpha2 in the function of the native receptor

Glutamate-gated chloride (GluCl) channels are the site of action of the anthelmintic ivermectin. Previously, the Xenopus laevis oocyte expression system has been used to characterize GluCl channels cloned from Caenorhabditis elegans. However, information on the native, pharmacologically relevant receptors is lacking. Here, we have used a quantitative pharmacological approach and intracellular recording techniques of C. elegans pharynx to characterize them. The glutamate response was a rapidly desensitizing, reversible, chloride-dependent depolarization (EC(50) = 166 microM), only weakly antagonized by picrotoxin. The order of potency of agonists was ibotenate > L-glutamate > kainate = quisqualate. Ivermectin potently and irreversibly depolarized the muscle (EC(50) = 2.7 nM). No further depolarization was seen with coapplication of maximal glutamate during the maximal ivermectin response, indicating that ivermectin depolarizes the muscle by the same ionic mechanism as glutamate (i.e., chloride). The potency of ivermectin on the pharynx was greater than at any of the GluCl subunits expressed in X. laevis oocytes. This effect of ivermectin was abolished in the mutant avr-15, which lacks a functional GluCl-alpha2 subunit. However, a chloride-dependent, nondesensitizing response to glutamate persisted. Therefore, the GluCl-alpha2 subunit confers ivermectin sensitivity and a high-affinity desensitizing glutamate response on the native pharyngeal GluCl receptor.

An auroral flare at Jupiter

Jupiter's aurora is the most powerful in the Solar System. It is powered largely by energy extracted from planetary rotation, although there seems also to be a contribution from the solar wind. This contrasts with Earth's aurora, which is generated through the interaction of the solar wind with the magnetosphere. The major features of Jupiter's aurora (based on far-ultraviolet, near-infrared and visible-wavelength observations) include a main oval that generally corotates with the planet and a region of patchy, diffuse emission inside the oval on Jupiter's dusk side. Here we report the discovery of a rapidly evolving, very bright and localized emission poleward of the northern main oval, in a region connected magnetically to Jupiter's outer magnetosphere. The intensity of the emission increased by a factor of 30 within 70 s, and then decreased on a similar timescale, all captured during a single four-minute exposure. This type of flaring emission has not previously been reported for Jupiter (similar, but smaller, transient events have been observed at Earth), and it may be related directly to changes in the solar wind.

Physiological and pharmacological studies on nematodes

Classical transmitters and neuroactive peptides act as transmitters or modulators within the central and peripheral nervous systems of nematodes, for example Ascaris suum and Caenorhabditis elegans. Acetylcholine (ACh) and gamma-aminobutyric acid (GABA) are respectively the excitatory and inhibitory transmitters onto somatic body wall muscle while 5-hydroxytrypamine (5-HT) is the excitatory transmitter onto pharyngeal muscle. 5-HT also reduces ACh-induced contractions of somatic muscle and this action of 5-HT is mediated through activation of adenylate cyclase while that on pharyngeal muscle is mediated through inositol phosphate activation. Glutamate, dopamine and octopamine also have transmitter roles in nematodes. Neuroactive peptides of the RFamide family can excite somatic muscle, for example, AF-1 (KNEFIRFamide), AF-2 (KHEYLRFamide), AF-3 (AVPGVLRFamide) and AF-4 (GDVPGVLRFamide) or inhibit and relax this muscle, for example, PF-1 (SDPNFLRFamide), PF-2 (SADPNFLRFamide) and PF-4 (KPNlRFamide). In addition PF-3 (AF-8) (KSAYMRFamide) has a biphasic action on pharyngeal muscle, excitation followed by inhibition while AF-1 only inhibits this muscle. The peptide effects can be either pre- or postsynaptic or both and are likely to be mediated through second messenger systems. In addition these peptides modulate the action of classical transmitters, particularly ACh.

Diagnosing insulin resistance in the general population

OBJECTIVE

Difficulties in measuring insulin sensitivity prevent the identification of insulin-resistant individuals in the general population. Therefore, we compared fasting insulin, homeostasis model assessment (HOMA), insulin-to-glucose ratio, Bennett index, and a score based on weighted combinations of fasting insulin, BMI, and fasting triglycerides with the euglycemic insulin clamp to determine the most appropriate method for assessing insulin resistance in the general population.

RESEARCH DESIGN AND METHODS

Family history of diabetes, BMI, blood pressure, waist and hip circumference, fasting lipids, glucose, insulin, liver enzymes, and insulin sensitivity index (ISI) using the euglycemic insulin clamp were obtained for 178 normoglycemic individuals aged 25-68 years. Product-moment correlations were used to examine the association between ISI and various surrogate measurements of insulin sensitivity. Regression models were used to devise weights for each variable and to identify cutoff points for individual components of the score. A bootstrap procedure was used to identify the most useful predictors of ISI.

RESULTS

Correlation coefficients between ISI and fasting insulin, HOMA, insulin-to-glucose ratio, and the Bennett index were similar in magnitude. The variables that best predicted insulin sensitivity were fasting insulin and fasting triglycerides. The use of a score based on Mffm/I = exp[2.63 - 0.28ln(insulin) - 0.31ln(TAG)] rather than the use of fasting insulin alone resulted in a higher sensitivity and a maintained specificity when predicting insulin sensitivity.

CONCLUSIONS

A weighted combination of two routine laboratory measurements, i.e., fasting insulin and triglycerides, provides a simple means of screening for insulin resistance in the general population.

Characterization of 5-HT receptors in the parasitic nematode, Ascaris suum

The pharmacological profiles of the 5-hydroxytryptamine (5-HT) receptors on Ascaris suum pharyngeal and somatic body wall muscles were investigated. The mechanisms involved following activation of these receptors were also studied. 5-HT activated and maintained pumping in isolated pharynxes with an EC-50 value of 44+/-1.7 microM. The 5-HT agonists, tryptamine, sumatriptan 8-OH-DPAT and 5-carboxyamidotryptamine all failed to stimulate pumping. The 5-HT2 antagonist, ketanserin, initially excited and then inhibited pumping while the 5-HT3 antagonist, ondansetron, had no effect. 5-HT and 5-HT agonists, 8-OH-DPAT, 5-carboxyamidotryptamine, alpha-methyl-5-HT and tryptamine all inhibited ACh-induced contractions of a somatic body wall muscle strip. Ketanserin partially blocked the inhibitory effect of alpha-methyl-5-HT and ACh-induced contractions while the 5-HT uptake blocker, fluoxetine, potentiated the effect of 5-HT on ACh-induced contractions. Basal levels of cAMP, 1540+/-232 pmol/mg, in pharyngeal muscle and 1721+/-134 pmol/mg, somatic body wall muscle, were both increased by forskolin. 5-HT had no effect on pharyngeal muscle cAMP levels but raised cAMP levels in somatic body wall muscle, e.g. 100 micron 5-HT, raised the level to 2851+/-212 pmol/mg and 1000 microM raised levels to 4578+/-1234 pmol/mg. 5-HT, 1000 microM, increased inositol phosphate levels in pharyngeal muscle. These results provide some evidence for a 5-HT2-like receptor on pharyngeal muscle. In contrast, the situation on somatic body wall muscle is more confusing since the pharmacological profile partly indicates a 5-HT2-like receptor but this receptor is linked to a rise in cAMP levels. Further studies are required to resolve the position but they must be based on the rational design of ligands specifically for nematode 5-HT receptors and not simply using ligands developed for the classification of mammalian 5-HT receptors. Such a design must take into account data from molecular biology studies of nematode 5-HT receptors.

Characterization of a putative nitric oxide synthase in the neuromuscular system of the parasitic nematode, Ascaris suum

In this paper we report on the biochemical presence of nitric oxide synthase (NOS)-like activity in Ascaris suum tissue and examine the pharmacological effect of NO donors on A. suum muscle strip preparation. NOS activity was determined by monitoring the formation of [3H]citrulline from [3H]L-arginine and NO formation via the oxyhaemoglobin assay. Neuromuscular tissue from A. suum which stained positively for NADPH diaphorase, contained NOS activity. Neither NOS activity nor NADPH diaphorase staining was detected in intestinal tissue. The absence of Ca2+, NADPH and other co-factors normally required for mammalian neuronal NOS activity only partially reduced the formation of both citrulline and NO by A. suum neuromuscular homogenate. The results of the biochemical assays indicate the presence of an enzyme capable of producing NO and citrulline, but with a different profile from that of rat neuronal NOS. We also present preliminary evidence for the action of NO (NO donors) in the neuromuscular system of A. suum.

The effects of sequential combined oral 17beta-estradiol norethisterone acetate on insulin sensitivity and body composition in healthy postmenopausal women: a randomized single blind placebo-controlled study

OBJECTIVE

The androgenic effect of progestogen, necessary in early postmenopausal hormone replacement therapy (HRT), may adversely affect insulin sensitivity as well as body fat distribution and thereby increase the cardiovascular risk profile. The impact of HRT with sequential combined oral 17beta-estradiol and norethisterone acetate on insulin sensitivity and body composition in early menopause has not been studied.

DESIGN

A randomized single blind placebo-controlled 6-month study of sequential combined 17beta-estradiol norethisterone acetate on insulin sensitivity and body composition was carried out. Thirty fit healthy postmenopausal women were enrolled and completed this 6-month study. Body composition was measured by dual-energy x-ray absorptiometry scanning, and insulin sensitivity was measured using the euglycemic hyperinsulinemic clamp. Studies were undertaken at baseline and after 6 months of therapy. The studies were performed during the estrogen-only phase of therapy.

RESULTS

All women demonstrated a degree of decreased insulin sensitivity that was not modified by 6 months of hormone replacement therapy. Body composition remained unchanged over 6 months. There was no alteration in total body fat or the distribution of body fat. The percentage of central abdominal fat (android) was not altered.

CONCLUSION

Six months of HRT with sequential combined oral 17beta-estradiol norethisterone acetate does not have an adverse effect on insulin sensitivity and does not promote an increase in weight or the more android distribution of body fat, which could contribute to the increased cardiovascular risk profile that is evident in postmenopausal women.

The management of alcohol-related seizures: an overview

Alcohol-withdrawal seizures are one of the common medical emergencies. The seizures are generalized and usually occur abruptly between 6-8 hours after cessation of alcohol use (peak 12-24 hours). These patients are often uncooperative and therefore need careful assessment. Lorazepam is the first-line drug for termination and prophylaxis of alcohol-withdrawal seizures.

Galileo magnetometer measurements: a stronger case for a subsurface ocean at Europa

On 3 January 2000, the Galileo spacecraft passed close to Europa when it was located far south of Jupiter's magnetic equator in a region where the radial component of the magnetospheric magnetic field points inward toward Jupiter. This pass with a previously unexamined orientation of the external forcing field distinguished between an induced and a permanent magnetic dipole moment model of Europa's internal field. The Galileo magnetometer measured changes in the magnetic field predicted if a current-carrying outer shell, such as a planet-scale liquid ocean, is present beneath the icy surface. The evidence that Europa's field varies temporally strengthens the argument that a liquid ocean exists beneath the present-day surface.

Plasma cholesteryl ester fatty acid composition, insulin sensitivity, the menopause and hormone replacement therapy

This study was designed to determine the effect of menopause and hormone replacement therapy (HRT) on plasma cholesteryl ester fatty acid (CEFA) composition and insulin sensitivity and the relationships between these variables in perimenopausal women (aged 40-55 years) including 49 who were premenopausal and 32 who were postmenopausal. Plasma cholesteryl ester proportions of dihomo-gamma-linolenic acid (20:3 n-6) were correlated significantly with insulin sensitivity index (r=-0.319, P=0.005), fasting serum insulin levels (r=0.230, P=0.038), body mass index (r=0.242, P=0.03) and per cent body fat (r=0.329, P=0.003) in perimenopausal women (n=81). Similar associations were observed in premenopausal women. Regression analysis suggested the relationships between 20:3 n-6 proportions and indices of insulin action may be partly mediated by levels of adiposity. In postmenopausal women, 6 months of HRT significantly (P=0.008) increased the ratio of arachidonic acid (20:4 n-6) to linoleic acid (18:2 n-6), which is an indicator of activity in the pathway of 20:4 n-6 synthesis, compared with placebo. These findings suggest that the type of fat in the diet indicated by plasma CEFA composition is linked to adiposity and insulin action. They also suggest that in postmenopausal women, HRT may increase the synthesis of 20:4 n-6, which is the precursor for eicosanoids with important cardiovascular functions.

Involvement of ryanodine receptors in EPYLRFamide-mediated reduction of acetylcholine-induced inward currents in helix lucorum identified neurones

The effects of several modulators of ryanodine receptors (RYRs) on the reduction of acetylcholine induced inward current (ACh-current) evoked by EPYLRFamide (5 microM, bath application), the potent N-terminally modified analogue of the endogenous Helix heptapeptide SEPYLRFamide, were investigated. These modulators were applied intracellularly. Inward currents were recorded from identified Helix lucorum LPa2, LPa3, RPa3, RPa2 neurones in ganglia preparations using the two-electrode voltage clamp technique. ACh was applied ionophoretically. BAPTA (0.1 mM), chelator of intracellular Ca(2+), ryanodine (0.1 mM), agonist/antagonist of RYRs and dantrolene (0.1 mM), antagonist of RYRs decrease the effect of EPYLRFamide. Adenosine (1 mM), alpha,beta-methylene ATP (0.1 mM), the nonhydrolisable ATP analogue and cyclic adenosine diphosphate ribose (0.1 mM) (agonists of RYRs) potentiate the modulatory effect of EPYLRFamide. Ruthenium red (1 mM), antagonist of RYRs and caffeine (1 mM), agonist of RYRs do not change the modulatory effect of EPYLRFamide. These data suggest that intracellular Ca(2+) and RYRs are involved in the modulatory effect of EPYLRFamide on ACh-currents. It was concluded that EPYLRFamide decreases ACh-current through elevation of basal intracellular level of a putative endogenous agonist of RYRs which activates RYR-dependent mobilization of Ca(2+) by binding to the adenine nucleotide site of the ryanodine receptor-channel complex and does not bind the site activated by caffeine.