Discrete-trial alternation in the rat

The acquisition and maintenance by rats of single alternation, double alternation, and four other repeating patterns of reinforced and non-reinforced trials was studied in a discrete-trial lever-pressing situation. The rats learned all these patterns in a small number of experimental sessions. Single alternation was learned more rapidly than the more complex patterns. Rate of learning single and double alternation decreased moderately as inter-trial interval increased. Abrupt changes in the scheduling of trials, either by doubling the inter-trial interval or by shifting from fixed to variable trial spacing, temporarily disrupted the patterned performance. Two hypotheses concerned with the means by which the rats could have learned to conform to the pattern were examined: (1) "timing" of the interval between successive reinforcements; and (2) control of responding on a trial by the outcome of preceding trials, depending on the consistency with which these outcomes were associated with reinforced or non-reinforced trials in the pattern and on how many trials back these outcomes occurred. The second hypothesis accounted for the relative frequency of errors on trials at various locations in the sequences, and predicted most of the changes in error frequency observed in experiments in which "inter-trial stimuli" were added to the sequences.

Pulmonary effects of bupivacaine, ropivacaine, and levobupivacaine in parturients undergoing spinal anaesthesia for elective caesarean delivery: a randomised controlled study

BACKGROUND

Spinal anaesthesia is the method of choice for elective caesarean delivery, but has been reported to worsen dynamic pulmonary function when using bupivacaine. Similar investigations are lacking for ropivacaine and levobupivacaine. We have therefore compared the pulmonary effects of intrathecal bupivacaine, ropivacaine and levobupivacaine used for caesarean delivery.

METHODS

Forced vital capacity, forced expiratory volume in the first second, and peak expiratory flow rate were measured in 48 parturients before and after onset of spinal anaesthesia using either 0.5% bupivacaine 10 mg, 1% ropivacaine 20 mg, or 0.5% levobupivacaine 10 mg. Apgar scores and umbilical arterial pH were recorded.

RESULTS

The final level of sensory blockade was not different between groups. Forced vital capacity was significantly decreased with bupivacaine (3.6+/-0.5 L to 3.5+/-0.4 L, P<0.05) and ropivacaine (3.2+/-0.4 L to 3.1+/-0.5 L, P<0.05), but not with levobupivacaine (3.6+/-0.5 L to 3.4+/-0.6 L). Forced expiratory volume during the first second was not decreased in any group. Peak expiratory flow rate was significantly decreased with ropivacaine (5.5+/-1.5 L/s to 5.0+/-1.1 L/s, P<0.05) and levobupivacaine (from 6.0+/-1.1 L/s to 5.2+/-0.9 L/s, P<0.01). Neonatal vital parameters did not differ between the three groups.

CONCLUSIONS

Decreases in maternal pulmonary function tests were similar following spinal anaesthesia with bupivacaine, ropivacaine, or levobupivacaine for caesarean delivery. The clinical maternal and neonatal effects of these alterations appeared negligible.

Copine-III interacts with ErbB2 and promotes tumor cell migration

ErbB2 amplification and overexpression in breast cancer correlates with aggressive disease and poor prognosis. To find novel ErbB2-interacting proteins, we used stable isotope labeling of amino acids in cell culture followed by peptide affinity pull-downs and identified specific binders using relative quantification by mass spectrometry. Copine-III, a member of a Ca(2+)-dependent phospholipid-binding protein family, was identified as binding to phosphorylated Tyr1248 of ErbB2. In breast cancer cells, Copine-III requires Ca(2+) for binding to the plasma membrane, where it interacts with ErbB2 upon receptor stimulation, an interaction that is dependent on receptor activity. Copine-III also binds receptor of activated C kinase 1 and colocalizes with phosphorylated focal adhesion kinase at the leading edge of migrating cells. Importantly, knockdown of Copine-III in T47D breast cancer cells causes a decrease in Src kinase activation and ErbB2-dependent wound healing. Our data suggest that Copine-III is a novel player in the regulation of ErbB2-dependent cancer cell motility. In primary breast tumors, high CPNE3 RNA levels significantly correlate with ERBB2 amplification. Moreover, in an in situ tissue microarray analysis, we detected differential protein expression of Copine-III in normal versus breast, prostate and ovarian tumors, suggesting a more general role for Copine-III in carcinogenesis.

Prospective randomized controlled multi-centre trial of cuffed or uncuffed endotracheal tubes in small children

BACKGROUND

The use of cuffed tracheal tubes (TTs) in small children is still controversial. The aim of this study was to compare post-extubation morbidity and TT exchange rates when using cuffed vs uncuffed tubes in small children.

METHODS

Patients aged from birth to 5 yr requiring general anaesthesia with TT intubation were included in 24 European paediatric anaesthesia centres. Patients were prospectively randomized into a cuffed TT group (Microcuff PET) and an uncuffed TT group (Mallinckrodt, Portex, Rüsch, Sheridan). Endpoints were incidence of post-extubation stridor and the number of TT exchanges to find an appropriate-sized tube. For cuffed TTs, minimal cuff pressure required to seal the airway was noted; maximal cuff pressure was limited at 20 cm H(2)O with a pressure release valve. Data are mean (SD).

RESULTS

A total of 2246 children were studied (1119/1127 cuffed/uncuffed). The age was 1.93 (1.48) yr in the cuffed and 1.87 (1.45) yr in the uncuffed groups. Post-extubation stridor was noted in 4.4% of patients with cuffed and in 4.7% with uncuffed TTs (P=0.543). TT exchange rate was 2.1% in the cuffed and 30.8% in the uncuffed groups (P<0.0001). Minimal cuff pressure required to seal the trachea was 10.6 (4.3) cm H(2)O.

CONCLUSIONS

The use of cuffed TTs in small children provides a reliably sealed airway at cuff pressures of <or=20 cm H(2)O, reduces the need for TT exchanges, and does not increase the risk for post-extubation stridor compared with uncuffed TTs.

Comparison of wheat and rye flour solutions for skin prick testing: a multi-centre study (Stad 1)

BACKGROUND

Skin prick testing (SPT) is the basic method for diagnosing IgE-mediated allergies. However, skin reactivity is related to the quality of allergen extracts, which are often poorly defined for occupational allergens.

OBJECTIVE

To compare wheat and rye flour SPT solutions from different producers.

MATERIALS AND METHODS

Standardized SPTs were performed in seven allergy centres with wheat and rye flour solutions from four producers in 125 symptomatic bakers. Optimal cut-off levels for weal sizes were assessed with the Youden Index. Comparisons between SPT results of different solutions were made with flour-specific IgE (sIgE) as the gold standard. Sensitivities, specificities, positive and negative predictive values, and test efficiencies were calculated and compared with McNemar and chi(2)-tests. The influence of the choice of the gold standard (sIgE or challenge) test was examined for 95 subjects. Additionally, SPT solutions were analysed for protein and antigen content.

RESULTS

The optimal cut-off level for all SPT solutions was a weal size of >or=1.5 mm. While differences between wheat and rye flours were small, differences between producers were important. Variability of sensitivities (0.31-0.96), negative predictive values (0.42-0.91), and test efficiencies (0.54-0.90) were higher than variations of specificities (0.74-1.00) and positive predictive values (0.88-1.00). Similar results were obtained when using challenge test results as the gold standard. Variability could be explained by the different antigen contents of the SPT solutions.

CONCLUSION

There is a wide variability of SPT solutions for wheat and rye flour from different producers, mainly with respect to sensitivities, negative predictive values, and test efficiencies. Improvement and standardization of SPT solutions used for the diagnosis of baker's asthma are highly recommended.

[Pancytopenia, fever, and splenomegaly in a 2-year-old boy]

HISTORY

Suspected of having a systemic malignancy a 22-month-old boy was admitted to hospital with fever, pancytopenia and hepatosplenomegaly. The boy was of ethnically German origin and no travel abroad was reported.

DIAGNOSIS

Intensive search for a focus of infection, laboratory tests and bone marrow microscopy failed to be diagnostic. Serological findings and detection of Leishmania DNA in bone marrow by polymerase chain reaction (PCR) led to the diagnosis of visceral leishmaniasis. On explicit questioning the child's parents reported a stay in Greece 18 months before onset of symptoms.

TREATMENT AND COURSE

On the fourth day of i.v. therapy with liposomal amphotericin B, 3mg/kg/d for 10 days, the fever subsided. Platelets and leukocytes regained normal levels. The child was discharged after 10 days of treatment and received two more doses on days 14 and 21.

CONCLUSION

Negative results on microscopic bone marrow inspection do not rule out visceral leishmaniasis. Detection of anti-Leishmania antibodies may support the suspected diagnosis and provide the indication for PCR technique.

Association of genetic polymorphisms in the ACE, ApoE, and TGF beta genes with early onset ischemic heart disease

BACKGROUND

The genetic factors that contribute to ischemic heart disease (IHD) are poorly understood, and it is likely that multiple genes acting independently or synergistically contribute to the risk of IHD and outcome. The genes for angiotensin-converting enzyme (ACE) and apolipoprotein E (ApoE) have been implicated independently in the risk of IHD.

HYPOTHESIS

This study examined whether genetic polymorphisms in the ACE and ApoE genes are associated with early onset IHD. Polymorphisms in a third gene, transforming growth factor beta 2 (TGF beta 2), with a known role in wound repair and cardiac development, are also examined with respect to early onset IHD.

METHODS

In all, 101 patients with IHD and onset of disease before 55 years for men and 60 years for women, and 100 controls with angiographically confirmed normal coronary arteries were recruited for this study. The ACE, ApoE, and TGF beta 2 genotypes were determined by polymerase chain reaction amplification or Southern blotting and were compared with the patient's clinical and family histories.

RESULTS AND CONCLUSION

The frequency of the ACE D allele was significantly lower in the patient group (0.475) than in the control group (0.59, p = 0.03), which was attributed to a reduction in the number of patients with the DD genotype (patients: 24% DD, controls: 33% DD). Sudden cardiac death was also associated with the DD genotype. These data are consistent with the ACE D allele contributing to a fatal outcome. No association between the DD genotype and risk of myocardial infarction, presenting age, extent of vessel disease, family history, hypertension, or hypercholesterolemia was seen. Analysis of the ApoE genotype showed no association with early onset IHD. There was no evidence for a synergistic effect between the ACE and ApoE genotypes on the risk of early onset IHD. A polymorphism in the TGF beta 2 gene was rare and not associated with early onset IHD.

PDGFR-A is a therapeutic target in alveolar rhabdomyosarcoma

Alveolar rhabdomyosarcoma is an aggressive skeletal muscle cancer of childhood. Our initial studies of rhabdomyosarcoma gene expression for patients enrolled in a national clinical trial suggested that platelet-derived growth factor receptor A (PDGFR-A) may be a mediator of disease progression and metastasis. Using our conditional mouse tumor models that authentically recapitulate the primary mutations and metastatic progression of alveolar rhabdomyosarcomas in humans, we found by immunoblotting and immunokinase assays that PDGFR-A and its downstream effectors, mitogen-activated protein kinase and Akt, were highly activated in both primary and metastatic tumors. Inhibition of PDGFR-A by RNA interference, small molecule inhibitor or neutralizing antibody had a dramatic effect on tumor cell growth both in vitro and in vivo, although resistance evolved in one-third of tumors. These results establish proof-of-principal for PDGFR-A as a therapeutic target in alveolar rhabdomyosarcoma.

Prediction of challenge test results by flour-specific IgE and skin prick test in symptomatic bakers

BACKGROUND

Wheat and rye flours are among the most important allergens causing occupational asthma. Usually, the diagnosis of baker's asthma is based on inhalation challenge tests with flours.

AIMS OF THE STUDY

To evaluate the relevance of flour-specific serum immunoglobulin E (IgE) and skin prick test (SPT) in the diagnosis of baker's asthma and to define flour-specific IgE concentrations and wheal sizes that allow a prediction of the outcome of challenge testing.

METHODS

Bronchial and nasal challenge tests with wheat (rye) flour were performed in 71 (95) symptomatic bakers. Determinations of flour-specific IgE as well as SPTs were performed in all subjects. Analyses included the calculation of sensitivity, specificity, positive (PPV) and negative predictive values (NPV) at different IgE concentrations and different wheal sizes, and receiver-operating characteristics (ROC) plots with the challenge result as gold standard.

RESULTS

Thirty-seven bakers were positive in the challenge with wheat flour, while 63 were positive with rye flour. Depending on the flour-specific IgE concentrations (wheal size), PPV was 74-100% (74-100%) for wheat and 82-100% (91-100%) for rye flour, respectively. The minimal cut-off values with a PPV of 100% were 2.32 kU/l (5.0 mm) for wheat flour and 9.64 kU/l (4.5 mm) for rye flour. The shapes of the ROC plots were similar for wheat and rye flour.

CONCLUSION

High concentrations of flour-specific IgE and clear SPT results in symptomatic bakers are good predictors for a positive challenge test. Challenge tests with flours may be avoided in strongly sensitized bakers.

Wave-particle duality of C(60) molecules

Quantum superposition lies at the heart of quantum mechanics and gives rise to many of its paradoxes. Superposition of de Broglie matter waves' has been observed for massive particles such as electrons, atoms and dimers, small van der Waals clusters, and neutrons. But matter wave interferometry with larger objects has remained experimentally challenging, despite the development of powerful atom interferometric techniques for experiments in fundamental quantum mechanics, metrology and lithography. Here we report the observation of de Broglie wave interference of C(60) molecules by diffraction at a material absorption grating. This molecule is the most massive and complex object in which wave behaviour has been observed. Of particular interest is the fact that C(60) is almost a classical body, because of its many excited internal degrees of freedom and their possible couplings to the environment. Such couplings are essential for the appearance of decoherence, suggesting that interference experiments with large molecules should facilitate detailed studies of this process.

Comparison of high- and low-dose intrathecal morphine for spinal fusion in children

BACKGROUND

The purpose of this prospective study was to assess the blood-sparing effect, the quality of analgesia, and the incidence of side-effects of a low-dose regime of intrathecal opioids (ITO) when compared with those of a high-dose regime in scoliosis surgery in children.

METHODS

Forty-six children were randomly included into one of the three groups to receive morphine 5 microg kg(-1) plus sufentanil 1 microg kg(-1) [low-dose intrathecal opioid (LITO)], morphine 15 microg kg(-1) plus sufentanil 1 microg kg(-1) [high-dose intrathecal opioid (HITO)] intrathecally, or no intrathecal opioid. Postoperative analgesia was provided by i.v. opioids. Intraoperative blood loss, postoperative quality of analgesia, opioid requirements, and the incidence of side-effects were recorded for 3 days.

RESULTS

Intraoperative blood loss was significantly reduced by ITOs [LITO: 41.4 (sd 18.8) ml kg(-1); HITO: 37.5 (6.9) ml kg(-1); control: 76.9 (15.3) ml kg(-1), P<0.001], with no difference between the two intrathecal opioid groups. Mean pain scores on the day of surgery were lower in both intrathecal opioid groups (LITO: 2.2 and HITO: 2.1) when compared with the control group (4.1, P<0.03) and opioid consumption was significantly decreased [LITO: 304.3 (65.0) microg kg(-1); HITO: 224.1 (51.8) microg kg(-1); control: 667.7 (89.5) microg kg(-1), P<0.002]. Side-effects of intrathecally administered opioids were similarly frequent in all groups.

CONCLUSIONS

Intrathecal administration of opioids significantly reduces blood loss and postoperative opioid demand, thereby showing side-effects comparable with the control group. These effects were already seen with the low-dose regimen and high dose did not further improve efficacy.

Fatal errors in nitrous oxide delivery

Nitrous oxide continues to be used frequently and the possibility of inadvertent fatal hypoxaemia resulting from technical errors with its administration still exists. A Medline analysis revealed only a few case reports over the last 30 years, and a closed claim analysis only reported 'claims involving oxygen supply lines' predating 1990. The aim of this study was to assess the frequency of nitrous oxide-related catastrophes during general anaesthesia in Germany, Austria, and Switzerland. As nitrous oxide-related anaesthesia casualties are rare but generally prosecuted, they almost invariably attract significant media attention. We scanned mass media archives from April 2004 until October 2006 for nitrous oxide-related disasters during general anaesthesia. This approach detected six incidents which were almost certainly nitrous oxide ventilation-related deaths. Searching non-scientific data bases demonstrates that severe incidents involving oxygen supply lines occurred after 1990, and may be much more frequent than previously thought.

A study of airway management using the ProSeal LMA laryngeal mask airway compared with the tracheal tube on postoperative analgesia requirements following gynaecological laparoscopic surgery

In a randomised double blind prospective study, we tested the hypothesis that postoperative pain is lower in patients who receive an ProSeal LMA laryngeal mask airway compared with a tracheal tube. One hundred consecutive female patients (ASA I-II, 18-75 years) undergoing laparoscopic gynaecological surgery were divided into two equal-sized groups for airway management with the ProSeal LMA or tracheal tube. Anaesthesia management was identical for both groups and included induction of anaesthesia using propofol/fentanyl, and maintenance with propofol/remifentanil, muscle relaxation with rocuronium, positive pressure ventilation, gastric tube insertion, dexamethasone/tropisetron for anti-emetic prophylaxis, and diclofenac for pain prophylaxis. All types of postoperative pain were treated using intravenous patient-controlled analgesia (PCA) morphine. Patients and postoperative staff were unaware of the airway device used. Data were collected by a single blinded observer. We found that pain scores were lower for the ProSeal LMA at 2 h and 6 h but not at 24 h. Morphine requirements were lower for the ProSeal LMA by 30.4%, 30.6% and 23.3% at 2, 6 and 24 h, respectively. Nausea was less common with the ProSeal LMA than with the tracheal tube at 2 h and 6 h but not at 24 h. There were no differences in the frequency of vomiting, sore throat, dysphonia or dysphagia. We conclude that postoperative pain is lower for the ProSeal LMA than the tracheal tube in females undergoing gynaecological laparoscopic surgery.

Postoperative nausea, vomiting, airway morbidity, and analgesic requirements are lower for the ProSeal laryngeal mask airway than the tracheal tube in females undergoing breast and gynaecological surgery

BACKGROUND

We test the hypothesis that the frequency of postoperative nausea and vomiting is similar for the ProSeal laryngeal mask airway (LMA) and the tracheal tube.

METHODS

Two hundred consecutive female patients (ASA I-II, 18-75 yr) undergoing routine breast and gynaecological surgery were divided into two equal-sized groups for airway management with the ProSeal LMA or tracheal tube.

RESULTS

Ventilation was better and airway trauma less frequent for the ProSeal LMA. For the ProSeal group, the time spent in the post-anaesthesia care unit was shorter (69 vs 88 min, P < 0.0001); fewer doses of tropisetron were required in the post-anaesthesia care unit (P < or = 0.001) and ward (P = 0.004); morphine requirements were lower in the post-anaesthesia care unit (6.0 vs 8.1 mg, P = 0.005) and ward (6.1 vs 8.9, P = 0.004); nausea was less frequent at all times (overall: 13% vs 53%, P < 0.0001); vomiting was less frequent at 2 h (4% vs 18%, P = 0.003) and 24 h (5% vs 19%, P = 0.004); and sore throat was less frequent at all times (overall: 12% vs 38%, P < 0.0001).

CONCLUSIONS

The ProSeal LMA reduced the absolute risk of postoperative nausea and vomiting by 40% (53-13%). In patients without the need for morphine, the ProSeal LMA reduced the absolute risk of postoperative nausea and vomiting by 23% (37-14%). We conclude that the frequency of postoperative nausea, vomiting, airway morbidity, and analgesic requirements is lower for the ProSeal LMA than the tracheal tube in females undergoing breast and gynaecological surgery.

Effect of total intravenous anaesthesia and balanced anaesthesia on the frequency of coughing during emergence from the anaesthesia

BACKGROUND

The effects of total intravenous anaesthesia (TIVA) and balanced anaesthesia (BAL) on coughing during emergence from the general anaesthesia have not yet been compared.

METHODS

Fifty patients, aged 18-60 yr, undergoing elective lumbar disk surgery were randomly allocated to undergo TIVA (propofol-remifentanil) or BAL (fentanyl-nitrous oxide-sevoflurane). Extubation was performed in the knee-elbow position, documented on video, and subsequently evaluated by blinded examiners.

RESULTS

There was no difference between TIVA and BAL patients with respect to patient characteristics, proportion of smokers, surgical time, or time of emergence. The median number of coughs was significantly lower in the TIVA group (1, range 0-9) than in the BAL group (4, range 0-20, P = 0.007). Mean maximal heart rate and mean maximal arterial pressure measured during emergence were also significantly lower in the TIVA group (P = 0.009 and P = 0.006, respectively).

CONCLUSIONS

During emergence from anaesthesia in the knee-elbow position, TIVA is associated with significantly less coughing and reduced haemodynamic response when compared with BAL.

Differential neurotoxicity of tricyclic antidepressants and novel derivatives in vitro in a dorsal root ganglion cell culture model

BACKGROUND AND OBJECTIVE

Tricyclic antidepressants are commonly employed orally to treat major depressive disorders and have been shown to be of substantial benefit in various chronic pain conditions. Among other properties they are potent Na+ channel blockers in vitro and show local anaesthetic properties in vivo. The present study aimed to determine their differential neurotoxicity, and that of novel derivatives as prerequisite for their potential use in regional anaesthesia.

METHODS

To directly test neurotoxicity in adult peripheral neurons, the culture model of dissociated adult rat primary sensory neurons was employed. Neurons were incubated for 24 h with amitriptyline, N-methyl-amitriptyline, doxepin, N-methyl-doxepin, N-propyl-doxepin, desipramine, imipramine and trimipramine at 100 mumol, and at concentrations correlating to their respective potency in blocking sodium channels.

RESULTS

All investigated substances showed considerable neurotoxic potency as represented in significantly decreased neuron numbers in cultures as compared to controls. Specifically, doxepin was more neurotoxic than amitriptyline, and both imipramine and trimipramine were more toxic than desipramine or amitriptyline. Novel derivatives of tricyclic antidepressants were, in general, more toxic than the parent compound.

CONCLUSIONS

Tricyclic antidepressants and novel derivatives thereof show differential neurotoxic potential in vitro. The rank order of toxicity relative to sodium channel blocking potency was desipramine < amitriptyline < N-methyl amitriptyline < doxepin < trimipramine < imipramine < N-methyl doxepin < N-propyl doxepin.

The metabolic role of IL-6 produced during exercise: is IL-6 an exercise factor?

For most of the last century, researchers have searched for a muscle contraction-induced factor that mediates some of the exercise effects in other tissues such as the liver and the adipose tissue. It has been called the ‘work stimulus’, the ‘work factor’ or the ‘exercise factor’. In the search for such a factor, a cytokine, IL-6, was found to be produced by contracting muscles and released into the blood. It has been demonstrated that IL-6 has many biological roles such as: (1) induction of lipolysis; (2) suppression of TNF production; (3) stimulation of cortisol production. The IL-6 gene is rapidly activated during exercise, and the activation of this gene is further enhanced when muscle glycogen content is low. In addition, carbohydrate supplementation during exercise has been shown to inhibit the release of IL-6 from contracting muscle. Thus, it is suggested that muscle-derived IL-6 fulfils the criteria of an exercise factor and that such classes of cytokines could be termed ‘myokines’.

Oxygen status of lung granulomas in Mycobacterium tuberculosis-infected mice

It is often assumed that Mycobacterium tuberculosis (Mtb)-induced granulomatous lesions, particularly those undergoing central caseation, are anoxic, and that the survival of Mtb in these lesions requires the integrity of its non-oxidative respiratory pathways. Using the hypoxia marker pimonidazole, we now provide immunohistochemical evidence that in the most frequently used animal model system of inbred mice Mtb-induced granulomas, even after more than one year of aerogenic infection, are not severely hypoxic. In contrast, chronic aerosol infection with M. avium strain TMC724 was associated with hypoxia surrounding necrotizing granuloma centres. Direct measurements of oxygen tension with a flexible microelectrode in mouse lungs chronically infected with Mtb disclosed a wide range of oxygen partial pressures in different parts of the lungs which, however, rarely approached the anoxic conditions consistently found in necrotizing tumours. We further show that an Mtb mutant, defective in nitrate reductase (narG) necessary for survival under anaerobic conditions in vitro, can persist in the lungs of chronically infected mice to a similar extent as wild-type Mtb. These findings have important implications for the use of the mouse model of Mtb infection in developing eradication chemotherapy and for evaluating putative mechanisms of chronic persistence and latency of Mtb.