Carriage of Extended-Spectrum-Beta-Lactamase- and AmpC Beta-Lactamase-Producing Escherichia coli Strains from Humans and Pets in the Same Households.

Extended-spectrum-beta-lactamase (ESBL)- or AmpC beta-lactamase (ACBL)-producing Escherichia coli bacteria are the most common cause of community-acquired multidrug-resistant urinary tract infections (UTIs) in New Zealand. The carriage of antimicrobial-resistant bacteria has been found in both people and pets from the same household; thus, the home environment may be a place where antimicrobial-resistant bacteria are shared between humans and pets. In this study, we sought to determine whether members (pets and people) of the households of human index cases with a UTI caused by an ESBL- or ACBL-producing E. coli strain also carried an ESBL- or ACBL-producing Enterobacteriaceae strain and, if so, whether it was a clonal match to the index case clinical strain. Index cases with a community-acquired UTI were recruited based on antimicrobial susceptibility testing of urine isolates. Fecal samples were collected from 18 non-index case people and 36 pets across 27 households. Eleven of the 27 households screened had non-index case household members (8/18 people and 5/36 animals) positive for ESBL- and/or ACBL-producing E. coli strains. Whole-genome sequence analysis of 125 E. coli isolates (including the clinical urine isolates) from these 11 households showed that within seven households, the same strain of ESBL-/ACBL-producing E. coli was cultured from both the index case and another person (5/11 households) or pet dog (2/11 households). These results suggest that transmission within the household may contribute to the community spread of ESBL- or ACBL-producing E. coliIMPORTANCEEnterobacteriaceae that produce extended-spectrum beta-lactamases (ESBLs) and AmpC beta-lactamases (ACBLs) are important pathogens and can cause community-acquired illnesses, such as urinary tract infections (UTIs). Fecal carriage of these resistant bacteria by companion animals may pose a risk for transmission to humans. Our work evaluated the sharing of ESBL- and ACBL-producing E. coli isolates between humans and companion animals. We found that in some households, dogs carried the same strain of ESBL-producing E. coli as the household member with a UTI. This suggests that transmission events between humans and animals (or vice versa) are likely occurring within the home environment and, therefore, the community as a whole. This is significant from a health perspective, when considering measures to minimize community transmission, and highlights that in order to manage community spread, we need to consider interventions at the household level.

Pharmacological and non-pharmacological treatments for neuropathic pain: Systematic review and French recommendations.

Neuropathic pain remains a significant unmet medical need. Several recommendations have recently been proposed concerning pharmacotherapy, neurostimulation techniques and interventional management, but no comprehensive guideline encompassing all these treatments has yet been issued. We performed a systematic review of pharmacotherapy, neurostimulation, surgery, psychotherapies and other types of therapy for peripheral or central neuropathic pain, based on studies published in peer-reviewed journals before January 2018. The main inclusion criteria were chronic neuropathic pain for at least three months, a randomized controlled methodology, at least three weeks of follow-up, at least 10 patients per group, and a double-blind design for drug therapy. Based on the GRADE system, we provide weak-to-strong recommendations for use and proposal as a first-line treatment for SNRIs (duloxetine and venlafaxine), gabapentin and tricyclic antidepressants and, for topical lidocaine and transcutaneous electrical nerve stimulation specifically for peripheral neuropathic pain; a weak recommendation for use and proposal as a second-line treatment for pregabalin, tramadol, combination therapy (antidepressant combined with gabapentinoids), and for high-concentration capsaicin patches and botulinum toxin A specifically for peripheral neuropathic pain; a weak recommendation for use and proposal as a third-line treatment for high-frequency rTMS of the motor cortex, spinal cord stimulation (failed back surgery syndrome and painful diabetic polyneuropathy) and strong opioids (in the absence of an alternative). Psychotherapy (cognitive behavioral therapy and mindfulness) is recommended as a second-line therapy, as an add-on to other therapies. An algorithm encompassing all the recommended treatments is proposed.

Neonatal and obstetric outcomes in diet- and insulin-treated women with gestational diabetes mellitus: a retrospective study.

BACKGROUND: To evaluate the neonatal and obstetric outcomes of pregnancies complicated by gestational diabetes mellitus (GDM). Screening and treatment - diet-only versus additional insulin therapy - were based on the 2010 national Dutch guidelines. METHODS: Retrospective study of the electronic medical files of 820 singleton GDM pregnancies treated between January 2011 and September 2014 in a university and non-university hospital. Pregnancy outcomes were compared between regular care treatment regimens -diet-only versus additional insulin therapy- and pregnancy outcomes of the Northern region of the Netherlands served as a reference population. RESULTS: A total of 460 women (56 %) met glycaemic control on diet-only and 360 women (44 %) required additional insulin therapy. Between the groups, there were no differences in perinatal complications (mortality, birth trauma, hyperbilirubinaemia, hypoglycaemia), small for gestational age, large for gestational age (LGA), neonate weighing >4200 g, neonate weighing ≥4500 g, Apgar score <7 at 5 min, respiratory support, preterm delivery, and admission to the neonatology department. Neonates born in the insulin-group had a lower birth weight compared with the diet-group (3364 vs. 3467 g, p = 0.005) and a lower gestational age at birth (p = 0.001). However, birth weight was not different between the groups when expressed in percentiles, adjusted for gestational age, gender, parity, and ethnicity. The occurrence of preeclampsia and gestational hypertension was comparable between the groups. In the insulin-group, labour was more often induced and more planned caesarean sections were performed (p = 0.001). Compared with the general obstetric population, the percentage of LGA neonates was higher in the GDM population (11.0 % vs.19.9 %, p = <0.001). CONCLUSIONS: Neonatal and obstetric outcomes were comparable either with diet-only or additional insulin therapy. However, compared with the general obstetric population, the incidence of LGA neonates was significantly increased in this GDM cohort.

Extended-spectrum ß-lactamase- and AmpC ß-lactamase-producing Enterobacterales associated with urinary tract infections in the New Zealand community: a case-control study.

OBJECTIVES: To assess whether having a pet in the home is a risk factor for community-acquired urinary tract infections associated with extended-spectrum ß-lactamase (ESBL)- or AmpC ß-lactamase (ACBL)- producing Enterobacterales. METHODS: An unmatched case-control study was conducted between August 2015 and September 2017. Cases (n = 141) were people with community-acquired urinary tract infection (UTI) caused by ESBL- or ACBL-producing Enterobacterales. Controls (n = 525) were recruited from the community. A telephone questionnaire on pet ownership and other factors was administered, and associations were assessed using logistic regression. RESULTS: Pet ownership was not associated with ESBL- or ACBL-producing Enterobacterales-related human UTIs. A positive association was observed for recent antimicrobial treatment, travel to Asia in the previous year, and a doctor's visit in the last 6 months. Among isolates with an ESBL-/ACBL-producing phenotype, 126/134 (94%) were Escherichia coli, with sequence type 131 being the most common (47/126). CONCLUSIONS: Companion animals in the home were not found to be associated with ESBL- or ACBL-producing Enterobacterales-related community-acquired UTIs in New Zealand. Risk factors included overseas travel, recent antibiotic use, and doctor visits.

Modelling the evolution and spread of HIV immune escape mutants.

During infection with human immunodeficiency virus (HIV), immune pressure from cytotoxic T-lymphocytes (CTLs) selects for viral mutants that confer escape from CTL recognition. These escape variants can be transmitted between individuals where, depending upon their cost to viral fitness and the CTL responses made by the recipient, they may revert. The rates of within-host evolution and their concordant impact upon the rate of spread of escape mutants at the population level are uncertain. Here we present a mathematical model of within-host evolution of escape mutants, transmission of these variants between hosts and subsequent reversion in new hosts. The model is an extension of the well-known SI model of disease transmission and includes three further parameters that describe host immunogenetic heterogeneity and rates of within host viral evolution. We use the model to explain why some escape mutants appear to have stable prevalence whilst others are spreading through the population. Further, we use it to compare diverse datasets on CTL escape, highlighting where different sources agree or disagree on within-host evolutionary rates. The several dozen CTL epitopes we survey from HIV-1 gag, RT and nef reveal a relatively sedate rate of evolution with average rates of escape measured in years and reversion in decades. For many epitopes in HIV, occasional rapid within-host evolution is not reflected in fast evolution at the population level.

Early dosing and efficacy of triptans in acute migraine treatment: the TEMPO study.

AIM: To compare the effectiveness of early or late triptan intake in the treatment of acute migraine attacks. METHODS: The TEMPO study was a French prospective, multicentre, two-phase study conducted in neurological practice. Two-hundred-and-ten migraine patients who were regular triptan users were enrolled. In the first phase, patients treated three attacks as they usually did. In the second phase, those who initially practiced late dosing ( ≥ 1 hour after headache onset) were instructed to change to early dosing ( < 1 hour). RESULTS: A total of 144 patients completed the first phase. Seventy-nine patients constituted the 'early dosers' group and 65 patients the 'late dosers' group. In this phase, early dosing produced higher rates (n = 38; 52.8%) of freedom from pain at 2 hours in at least two of three attacks compared with late dosing (n = 19; 30.2%; p < 0.01). In the second phase, switching from late to early dosing following the physician's instruction (n = 42 patients) also improved the rates of freedom from pain at 2 hours (from 38.1% (n = 16) to 53.7% (n = 22); p < 0.05). CONCLUSION: This suggests that advising patients on the importance of early triptan intake after headache onset may help improve the efficacy of acute migraine treatments.

Brainstem changes in 5-HT1A receptor availability during migraine attack.

BACKGROUND: Among serotonin receptors, 5-HT(1A) receptors are implicated in the regulation of central serotoninergic tone and could be involved in the abnormal brain 5-HT turnover suspected in migraineurs. The aim of this study was to investigate 5-HT(1A) receptors' availability during migraine attacks. METHODS: Ten patients suffering from odor-triggered migraine attacks and 10 control subjects were investigated using positron emission tomography (PET) and [(18)F]MPPF PET tracer, a selective 5-HT(1A) antagonist. All subjects underwent calibrated olfactory stimulations prior to the PET study. RESULTS: Four patients developed a migraine attack during the PET study. In these patients, statistical parametrical mapping and region of interest analyses showed an increased [(18)F]MPPF binding potential (BP(ND)) in the pontine raphe when compared to headache-free migraineurs and control subjects. This ictal change was confirmed at the individual level in each of the four affected patients. In comparison with the headache-free migraineurs, patients with a migraine attack also showed significantly increased [(18)F]MPPF BP(ND) in the left orbitofrontal cortex, precentral gyrus and temporal pole. No significant change in [(18)F]MPPF BP(ND) was observed between headache-free migraineurs and controls. CONCLUSIONS: Our results emphasize the role of 5HT(1A) receptors in the pontine raphe nuclei during the early stage of migraine attacks.

Development and validation of a movement and activity in physical space score as a functional outcome measure.

OBJECTIVE: To develop and validate a functional measure, the Movement and Activity in Physical Space (MAPS) score, that encompasses both physical activity and environmental interaction. DESIGN: Observational matched-pair cohort with 2-month follow-up. SETTING: General community under free-living conditions. PARTICIPANTS: Adult participants (N=18; n=9 postsurgical, n=9 matched control; mean age ± SD, 28.9 ± 12.0y) were monitored by an accelerometer and global positioning system receiver for 3 days within 1 week (4.1 ± 2.8d) after knee surgery (T=0) and 2 months later (T+2). The healthy controls were matched for age, sex, smoking, perceived physical activity level, and occupation of a postsurgical participant. Correlation, t test (with Bonferroni adjustment: α=.05/2), analysis of variance, and intraclass correlation coefficient were used to establish validity and reliability evidence. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: MAPS scores. RESULTS: MAPS scores were moderately correlated with the Knee Injury and Osteoarthritis Outcome Score (P<.05). There was a significant group difference at T = 0 for MAPS (t(9.9)=-3.60; P=.01). Analysis of variance results for the MAPS indicated a time and group interaction (F(1,12)=4.60, P=.05). Reliability of 3 days of MAPS scores ranged from 0.75 to 0.81 (postsurgical and control), and 2-month test-retest reliability in the control group was 0.94. CONCLUSIONS: The results provide a foundation of convergent and known-group difference validity evidence along with reliability evidence for the use of MAPS as a functional outcome measure.

Guidance of magnetic resonance imaging and placement of skin-marker localization devices.

AIM: A variety of magnetic resonance imaging (MRI)-compatible skin-marker localization devices are available on the market. MRI protocols call for the liberal use of the skin markers over the specific site of symptoms or over any palpable mass. This study investigates the usefulness of patient-assisted placement of 1 000-mg fish oil capsules as skin markers over the area of maximum localized pain, signs, or symptoms and correlates this placement with any potential underlying neuropathology or potential pain generator. METHODS: One-hundred symptomatic patients undergoing MRI were assessed for focal or localized signs or symptoms. Under the direction of a physician and with guidance from the patient, the MRI technician placed a 1 000-mg fish-oil capsule over the area of maximum pain or signs and symptoms. Patients with poorly localized, diffuse symptoms or an area of maximal signs and symptoms outside the field of view of the MRI were not included in this study. All MRI exams were reviewed by clinical physicians and radiologists or neuroimaging physicians. RESULTS: In all 100 cases, the images show clearly visible MRI-compatible skin-surface markers that correlate with potential underlying neuropathology. CONCLUSION: Our results show that 1 000-mg fish-oil capsules can be used as MRI localization devices as a cost-effective alternative to more expensive commercially available devices.

The Eurolight project: the impact of primary headache disorders in Europe. Description of methods.

The Eurolight project is the first at European Union level to assess the impact of headache disorders, and also the first of its scale performed by collaboration between professional and lay organizations and individuals. Here are reported the methods developed for it. The project took the form of surveys, by structured questionnaire, conducted in ten countries of Europe which together represented 60% of the adult population of the European Union. In Lithuania, the survey was population-based. Elsewhere, truly population-based studies were impractical for reasons of cost, and various compromises were developed. Closest to being population-based were the surveys in Germany, Luxembourg, the Netherlands, Italy and Spain. In Austria, France and UK, samples were taken from health-care settings. In addition in the Netherlands, Spain and Ireland, samples were drawn from members of national headache patient organizations and their relatives. Independent double data-entry was performed prior to analysis. Returned questionnaires from 9,269 respondents showed a moderate female bias (58%); of respondents from patients' organizations (n = 992), 61% were female. Mean age of all respondents was 44 years; samples from patients' organizations were slightly older (mean 47 years). The different sampling methods worked with differing degrees of effectiveness, as evidenced by the responder-rates, which varied from 10.8 to 90.7%. In the more population-based surveys, responder-rates varied from 11.3 to 58.8%. We conclude that the methodology, although with differences born of necessity in the ten countries, was sound overall, and will provide robust data on the public ill-health that results from headache in Europe.

[Burden of herpes zoster and postherpetic neuralgia: Incidence, proportion, and associated costs in the French population aged 50 or over]. / Évaluation de l'incidence du zona, de la proportion des douleurs post-zostériennes, et des coûts associés dans la population française de 50 ans ou plus.

BACKGROUND: Despite the perspective of vaccination against herpes zoster, there are few recent data available on the incidence of this disease, the proportion of postherpetic neuralgia cases, and associated disease management costs. This study was performed to evaluate these parameters in a representative sample of French physicians. METHODS: It was a retrospective, declarative study conducted from the medical files of patients who presented with herpes zoster and consulted in 2005, based on a random sample of GPs, dermatologists, neurologists, and physicians in pain clinics, weighted by demographic departmental distribution of patients aged 50 years and above. The analysis was performed on cases diagnosed by physicians themselves (incident cases). RESULTS: The annual incidence of herpes zoster was estimated at 8.99/1000 [8.34-9.64], all types of physicians pooled and at 8.67/1000 for GPs. This represents about 182,500 cases of herpes zoster in France in 2005 in patients aged 50 years and above. Incidence was slightly higher amongst women (1.3 times) and increased with age. Amongst the 777 cases of incident herpes zoster, 343 were complicated by postherpetic neuralgia one month after diagnosis. The proportion of patients presenting postherpetic neuralgia at 3 and 6 months was 32.1% and 17.6%, respectively. The annual cost of management of herpes zoster and postherpetic neuralgia was estimated at 170 [109-249] million euros, of which 61.0 million euros were covered by the national health insurance. CONCLUSION: In this study, the incidence of herpes zoster observed in France in subjects aged 50 years and above is close to that already estimated in France and Europe. The proportion of postherpetic neuralgia is high and this painful complication may persist for several months after diagnosis of herpes zoster. To our knowledge, EPIZOD is the first study conducted in France to assess the cost of herpes zoster and of postherpetic neuralgia, the most frequent complication of this viral disease.

Strategies for the diagnosis and treatment of neuropathic pain secondary to diabetic peripheral sensory polyneuropathy.

This article proposes a strategy for the diagnosis and treatment of neuropathic pain due to diabetic peripheral sensory neuropathy, based on 15 years of experience in French pain-management centres and on the available literature. In the diabetic patient with chronic pain in the lower limbs, the first step in the diagnostic process is to identify the neuropathic origin of the pain. The second step is to evaluate the patient's medical history and make a rigorous baseline assessment of the neuropathic pain symptoms to determine an effective pain-management strategy. In the third step, adequate and well-tolerated treatment directed towards a variety of painful symptoms is selected, taking into account other co-morbidities such as anxiety and depression. This report reports on the clinical aspects of neuropathic pain exhibited by patients with diabetic sensory polyneuropathy, and the key factors in their diagnosis and treatment, based on the results of meta-analyses and on a recent expert consensus.

Generalised probability mass function for the final epidemic size of an SIR model on a line of triangles network.

We explore the feasibility of deriving generalised expressions for the probability mass function (PMF) of the final epidemic size of a Susceptible - Infected - Recovered (SIR) model on a finite network of an arbitrary number of nodes. Expressions for the probability that the infection progresses along a given pathway in a line of triangles (LoT) network are presented. Deriving expressions for the probability that the infection ends at any given node allows us to determine the corresponding final size of the epidemic, and hence produce PMFs of the final epidemic size. We illustrate how we can use the results from small networks derived in a previous study to describe how an infection spreads through a LoT network. The key here is to correctly decompose the larger network into an appropriate assemblage of small networks.

Olfactory hypersensitivity in migraineurs: a H(2)(15)O-PET study.

Olfactory hypersensitivity (OHS) may occur during migraine attacks and seems to be very specific to this form of headache. OHS is also observed during migraine-free periods and is associated with the presence of odour-triggered attacks. Yet the pathophysiology of OHS remains unknown. The aim of our study was to evaluate olfactory processing in migraineurs with OHS and to investigate whether regional cerebral blood flow (rCBF) associated with olfactory stimulation is modified in these patients compared with controls. Eleven migraineurs with OHS and 12 controls participated in a H(2)(15)O-positron emission tomography study, including three scans in which odours were delivered and three scans where only odourless air was delivered. rCBF during olfactory condition was compared with that for the odourless baseline condition. Between-group analyses were performed using voxel-based and region-of-interest analyses. During both olfactory and non-olfactory conditions, we observed higher rCBF in the left piriform cortex and antero-superior temporal gyrus in migraineurs compared with controls. During odour stimulation, migraineurs also showed significantly higher activation than controls in the left temporal pole and significantly lower activation in the frontal (left inferior as well as left and right middle frontal gyri) and temporo-parietal (left and right angular, and right posterior superior temporal gyri) regions, posterior cingulate gyrus and right locus coeruleus. These results could reflect a particular role of both the piriform cortex and antero-superior temporal gyrus in OHS and odour-triggered migraine. Whether these rCBF changes are the cause or a consequence of odour-triggered migraines and interictal OHS remains unknown. Further comparisons between migraineurs with and without OHS are warranted to address this issue. The abnormal cerebral activation patterns during olfactory stimulation might reflect altered cerebrovascular response to olfactory stimulation due to the migraine disease, or an abnormal top-down regulation process related to OHS.

Efficacy and safety of a T-type calcium channel blocker in patients with neuropathic pain: A proof-of-concept, randomized, double-blind and controlled trial.

BACKGROUND: T-type calcium channels have been shown to play an important role in the initiation and maintenance of neuropathic pain and represent a promising therapeutic target for new analgesic treatments. Ethosuximide (ETX), an anticonvulsant and a T-type channel blocker has shown analgesic effect in several chronic pain models but has not yet been evaluated in patients with neuropathic pain. METHODS: This proof-of-concept, multicentre, double-blind, controlled and randomized trial compared the efficacy and safety of ETX (given as add-on therapy) to an inactive control (IC) in 114 patients with non-diabetic peripheral neuropathic pain. After a 7-day run-in period, eligible patients aged over 18 years were randomly assigned (1:1) to ETX or IC for 6 weeks. The primary outcome was the difference between groups in the pain intensity (% of change from the baseline to end of treatment) assessed in the intention-to-treat population. This study is registered with EudraCT (2013-004801-26) and ClinicalTrials.gov (NCT02100046). RESULTS: The study was stopped during the interim analysis due to the high number of adverse events in the active treatment group. ETX failed to reduce total pain and showed a poor tolerance in comparison to IC. In the per-protocol analysis, ETX significantly reduced pain intensity by 15.6% (95% CI -25.8; -5.4) from baseline compared to IC (-7.8%, 95% CI -14.3; -1.3; p = 0.033), but this result must be interpreted with caution because of a small subgroup of patients. CONCLUSION: Ethosuximide did not reduce the severity of neuropathic pain and induces, at the doses used, many adverse events. SIGNIFICANCE: This article shows that ETX is not effective to treat neuropathic pain. Nevertheless, per-protocol analysis suggests a possible analgesic effect of ETX. Thus, our work adds significant knowledge to preclinical and clinical data on the benefits of T-type calcium channel inhibition for the treatment of neuropathic pain.

Chronic cluster headache: a French clinical descriptive study.

BACKGROUND: Cluster headache (CH) is a relatively rare disease and episodic CH is more frequent than chronic CH. Few studies have described the characteristics of patients with chronic CH. METHODS: This was a descriptive study carried out by eight tertiary care specialist headache centres in France participating in the Observatory of Migraine and Headaches (OMH). From 2002 to 2005, OMH collected data from 2074 patients with CH, of whom 316 had chronic CH. From January to June 2005, 113 patients with chronic CH were interviewed using standardised questionnaires during a consultation. RESULTS: The male to female ratio was 4.65:1. Median age was 42 years. The majority of patients were smokers or former smokers (87%). 46% had primary chronic CH (chronic at onset) and 54% secondary chronic CH (evolving from episodic CH). Most patients had unilateral pain during attacks and 7% had sometimes bilateral pain during an attack. 48% reported a persisting painful state between attacks. Symptoms anteceding pain onset (mainly discomfort/diffuse pain, exhaustion, mood disorders) and auras were reported by 55% and 20% of patients, respectively. The functional impact of chronic CH was estimated as severe by 74% of patients, and 75.7% suffered from anxiety, as assessed by the Hospital Anxiety and Depression scale. There was no substantial difference in clinical presentation between primary and secondary CH. DISCUSSION: This study confirms the existence of auras and interictal signs and symptoms in patients with chronic CH, and male sex and smoking as CH risk factors. Primary and secondary chronic CH appear equally prevalent. Male sex does not appear to favour the shift from episodic to chronic CH.

Key transmission parameters of an institutional outbreak during the 1918 influenza pandemic estimated by mathematical modelling.

AIM: To estimate the key transmission parameters associated with an outbreak of pandemic influenza in an institutional setting (New Zealand 1918). METHODS: Historical morbidity and mortality data were obtained from the report of the medical officer for a large military camp. A susceptible-exposed-infectious-recovered epidemiological model was solved numerically to find a range of best-fit estimates for key epidemic parameters and an incidence curve. Mortality data were subsequently modelled by performing a convolution of incidence distribution with a best-fit incidence-mortality lag distribution. RESULTS: Basic reproduction number (R0) values for three possible scenarios ranged between 1.3, and 3.1, and corresponding average latent period and infectious period estimates ranged between 0.7 and 1.3 days, and 0.2 and 0.3 days respectively. The mean and median best-estimate incidence-mortality lag periods were 6.9 and 6.6 days respectively. This delay is consistent with secondary bacterial pneumonia being a relatively important cause of death in this predominantly young male population. CONCLUSION: These R0 estimates are broadly consistent with others made for the 1918 influenza pandemic and are not particularly large relative to some other infectious diseases. This finding suggests that if a novel influenza strain of similar virulence emerged then it could potentially be controlled through the prompt use of major public health measures.

Selective stimulation of in situ intermediary metabolism by free calcium in permeabilized rat adipocytes.

The hypothesis that ionized calcium [Ca2+]i may stimulate in situ rat adipocyte intermediary metabolism distal to glucose transport was tested. A metabolically active porous adipocyte model was employed in which pathway metabolism is exclusively pore-dependent using glucose 6-phosphate (G6P) as substrate. Cellular [Ca2+]i was, furthermore, directly adjusted to between 0-2.5 microM via the membrane pores. Three metabolic fluxes were examined, (1) glycolysis-Krebs ([6-14C]G6P oxidation), (2) glycolysis to lactate ([U-14C]G6P to [14C]lactate) and (3) pentose pathway ([1-14C]G6P oxidation). Glycolysis-Krebs oxidation was was found to be selectively (33% above basal P less than 0.001) stimulated by 0.625 microM free calcium. In contrast, there was no effect of [Ca2+]i on the other, exclusively cytoplasmic, pathways. The stimulation of glycolysis-Krebs by [Ca2+]i was inhibited by a mitochondrial calcium channel blocker (Ruthenium red) and persisted over a range of ATP/ADP ratios. Separate studies demonstrated that 2-[1-14C]ketoglutarate oxidation was also calcium-stimulated in the porous adipocytes (160% over baseline at 1 microM [Ca2+]i). These studies thus demonstrate that physiologically relevant increments in porous adipocyte [Ca2+]i enhance overall in situ glycolytic-Krebs pathway oxidation by a mechanism which entails mitochondrial calcium uptake. Methodologically, this metabolically active porous adipocyte model presents a novel experimental approach to investigations regarding the effects of ionized calcium on intermediary metabolism beyond glucose transport.

Inhibitory effects of cerulenin on protein palmitoylation and insulin internalization in rat adipocytes.

Protein acylation by long-chain fatty acids has been suggested as a necessary step in membrane trafficking. Because several insulin effects are dependent upon membrane trafficking, the cellular effects of the protein acylation inhibitor cerulenin were examined. Cerulenin blocked palmitoylation of selected rat adipocyte proteins including CD36, the dominant marker for palmitoylation in adipocytes. To measure cerulenin's effects on insulin internalization, rat adipocytes were incubated with 125I-insulin at 37 degrees C in the presence or absence of cerulenin. Surface-bound and intracellular insulin were discriminated by the sensitivity of the former to rapid dissociation by a pH 3 buffer at 4 degrees C. Insulin internalization was inhibited 85% by 0.3 mM cerulenin. Inhibition required preincubation with the agent, was irreversible, was not dependent upon protein synthesis, and was not the result of ATP depletion. Cerulenin was also found to inhibit insulin-stimulated glucose uptake and acetyl-CoA carboxylase activity. Cerulenin had no effect on basal glucose uptake and utilization or on the uptake and retention of fatty acids. In summary, protein acylation may be an important step in insulin-regulated cellular functions dependent upon membrane trafficking, such as insulin internalization.

Persistence of disturbed adipocyte metabolism in streptozocin-induced diabetic rats despite near-euglycemia with phlorizin.

It is widely accepted that hyperglycemia per se incites and perpetuates the diabetic state by adverse effects on beta cell insulin secretion and peripheral insulin action. Examination of the latter locus has revealed glucose-related abnormalities in facilitated glucose transport. Beyond the plasma membrane, however, there is scant data examining whether hyperglycemia influences important intracellular metabolic events. We recently described a sizable reduction in post-transport, in situ metabolism in permeabilized fat cells from streptozocin-induced diabetic rats. Of importance, the diabetes-related deficit was entirely ameliorated by insulin therapy. In this study we examined whether hyperglycemia per se contributes to this altered intracellular metabolic effect. By infusing phlorizin, near euglycemia was achieved for at least four days in streptozocin-induced diabetic rats. The phlorizin-treated diabetic rats had improved (intact cell) rates of insulin-stimulated 2-deoxyglucose uptake. Despite this, permeabilized fat cell studies revealed no improvement or deterioration in diabetic intracellular metabolism as measured by both the oxidation of [6-14C]glucose-6-phosphate via the citric acid cycle or its incorporation into triglyceride. We conclude that hypoinsulinemia, and not hyperglycemia, mediates the disturbance in porous diabetic adipocyte cellular metabolism.