Exhaled nitric oxide correlates with airway eosinophils in childhood asthma

BACKGROUND

Exhaled nitric oxide has been proposed as a marker for airway inflammation in asthma. The aim of this study was to compare exhaled nitric oxide levels with inflammatory cells and mediators in bronchoalveolar lavage fluid from asthmatic and normal children.

METHODS

Children were recruited from elective surgical lists and a non-bronchoscopic bronchoalveolar lavage (BAL) was performed after induction of anaesthesia. Exhaled nitric oxide (parts per billion) was measured by two techniques: tidal breathing and restricted breath.

RESULTS

Median (interquartile range) exhaled nitric oxide measured by restricted breath was increased in asthmatics compared with normal children (24.3 (10.5-66.5) v 9.7 (6.5-16.5), difference between medians 14.6 (95% CI 5.1 to 29.9), p=0.001). In asthmatic children exhaled nitric oxide correlated significantly with percentage eosinophils (r=0.78, p<0.001 (tidal breathing) and r=0.78, p<0.001 (restricted breath)) and with eosinophilic cationic protein (r=0.53, p<0.01 (restricted breath)), but not with other inflammatory cells in the BAL fluid. The area under the receiver operator characteristic curves for the prediction of the presence of eosinophilic airways inflammation by exhaled nitric oxide (tidal and restricted) was 0.80 and 0.87, respectively.

CONCLUSIONS

Exhaled nitric oxide correlates closely with percentage eosinophils in BAL fluid in asthmatic children and is therefore likely to be a useful non-invasive marker of airway inflammation.

Outgrown asthma does not mean no airways inflammation

Although some asthmatic children seem to recover from their asthma, 30-80% develop asthma again in later life. The underlying risk factors are unknown. The hypothesis for this study was that children with apparently outgrown asthma would have underlying airway inflammation. Nonbronchoscopic bronchoalveolar lavage was performed on normal children (n=35) and children who had wheezed previously (n=35). Eosinophils were raised in the lavage fluid of atopic children who had apparently outgrown asthma (median (interquartile range) 0.36 (0.05-0.74) compared to controls 0.10 (0-0.18), p=0.002). There was no relationship between length of remission and degree of airways eosinophilia. Thus, there is persistent airways inflammation in some children with outgrown asthma and this may be a risk factor for future relapse.

Fasting insulin and outcome in early-stage breast cancer: results of a prospective cohort study

PURPOSE

Insulin, a member of a family of growth factors that includes insulin-like growth factor (IGF)-I and IGF-II, exerts mitogenic effects on normal and malignant breast epithelial cells, acting via insulin and IGF-I receptors. Because of this and because of its recognized association with obesity, an adverse prognostic factor in breast cancer, we examined the prognostic associations of insulin in early-stage breast cancer.

PATIENTS AND METHODS

A cohort of 512 women without known diabetes, who had early-stage (T1 to T3, N0 to N1, and M0) breast cancer, was assembled and observed prospectively. Information on traditional prognostic factors and body size was collected, and fasting blood was obtained.

RESULTS

Fasting insulin was associated with distant recurrence and death; the hazard ratios and 95% confidence intervals (CI) for those in the highest (> 51.9 pmol/L) versus the lowest (< 27.0 pmol/L) insulin quartile were 2.0 (95% CI, 1.2 to 3.3) and 3.1 (95% CI, 1.7 to 5.7), respectively. There was some evidence to suggest that the association of insulin with breast cancer outcomes may be nonlinear. Insulin was correlated with body mass index (Spearman r = 0.59, P <.001), which, in turn, was associated with distant recurrence and death (P <.001). In multivariate analyses that included fasting insulin and available tumor- and treatment-related variables, adjusted hazard ratios for the upper versus lower insulin quartile were 2.1 (95% CI, 1.2 to 3.6) and 3.3 (95% CI, 1.5 to 7.0) for distant recurrence and death, respectively.

CONCLUSION

Fasting insulin level is associated with outcome in women with early breast cancer. High levels of fasting insulin identify women with poor outcomes in whom more effective treatment strategies should be explored.

The effect of group psychosocial support on survival in metastatic breast cancer

BACKGROUND

Supportive-expressive group therapy has been reported to prolong survival among women with metastatic breast cancer. However, in recent studies, various psychosocial interventions have not prolonged survival.

METHODS

In a multicenter trial, we randomly assigned 235 women with metastatic breast cancer who were expected to survive at least three months in a 2:1 ratio to an intervention group that participated in weekly supportive-expressive group therapy (158 women) or to a control group that received no such intervention (77 women). All the women received educational materials and any medical or psychosocial care that was deemed necessary. The primary outcome was survival; psychosocial function was assessed by self-reported questionnaires.

RESULTS

Women assigned to supportive-expressive therapy had greater improvement in psychological symptoms and reported less pain (P=0.04) than women in the control group. A significant interaction of treatment-group assignment with base-line psychological score was found (P</=0.003 for the comparison of mood variables; P=0.04 for the comparison of pain); women who were more distressed benefited, whereas those who were less distressed did not. The psychological intervention did not prolong survival (median survival, 17.9 months in the intervention group and 17.6 months in the control group; hazard ratio for death according to the univariate analysis, 1.06 [95 percent confidence interval, 0.78 to 1.45]; hazard ratio according to the multivariate analysis, 1.23 [95 percent confidence interval, 0.88 to 1.72]).

CONCLUSIONS

Supportive-expressive group therapy does not prolong survival in women with metastatic breast cancer. It improves mood and the perception of pain, particularly in women who are initially more distressed.

Oxidative stress in lavage fluid of preterm infants at risk of chronic lung disease

There is evidence that oxidative stress plays a role in the development of chronic lung disease (CLD), with immature lungs being particularly sensitive to the injurious effect of oxygen and mechanical ventilation. We analyzed total ascorbate, urate, and protein carbonyls in 102 bronchoalveolar lavage fluid samples from 38 babies (33 preterm, 24-36 wk gestation; 5 term, 37-39 wk gestation). Preterm babies had significantly decreasing concentrations of ascorbate, urate, and protein carbonyls during the first 9 days of life (days 1-3, 4-6, and 7-9, Kruskal-Wallis ANOVA: P = 0.016, P < 0.0001, and P = 0.010, respectively). Preterm babies had significantly higher protein carbonyl concentrations at days 1-3 and 4-6 (P = 0.005 and P = 0.044) compared with term babies. Very preterm babies (24-28 wk gestation) had increased concentrations of protein carbonyls at days 4-6 (P = 0.056) and significantly decreased ascorbate concentrations at days 4-6 (P = 0.004) compared with preterm babies (29-36 wk gestation). Urate concentrations were significantly elevated at days 1-3 (P = 0.023) in preterm babies who subsequently developed CLD. This study has shown the presence of oxidative stress in the lungs of preterm babies during ventilation, especially in those who subsequently developed CLD.

The repeatability of nonbronchoscopic bronchoalveolar lavage differential cell counts

Airway inflammation in children can be assessed by nonbronchoscopic bronchoalveolar lavage (BAL). Little is known about the repeatability of cell counts in the BAL obtained. Children (n=43) attending for elective surgery were studied. Cell counts were obtained following a nonbronchoscopic lavage. Two samples were obtained with either: 1) the catheter wedged in the same position (n=21) or 2) the catheter reinserted and wedged again (n=22). Slides (n=30) from nonbronchoscopic lavage samples were selected at random and two independent observers counted 500 cells on each slide on two occasions. The repeatability of the lavage sampling and cell counting was assessed for different cell types. The inter- and intra-observer repeatability for the differential cell counting demonstrated that there was good repeatability for all cell types except lymphocytes (interobserver: Lin's concordance coefficient 0.42; repeatability coefficient 0.66). Quantification of eosinophil (%) was highly repeatable using either method (Lin's concordance coefficient 1) 0.99, 2) 0.95; repeatability coefficient 1) 0.58, 2) 1.36). Nonbronchoscopic lavage is a repeatable technique for the quantification of eosinophils. Variation in the sampling method can be reduced by taking two separate samples and averaging the differential cell counts. Furthermore, increasing the number of cells counted should ensure accurate quantification of lymphocytes.

Dopamine D2 receptor-mediated presynaptic inhibition of olfactory nerve terminals

Olfactory receptor neurons of the nasal epithelium project via the olfactory nerve (ON) to the glomeruli of the main olfactory bulb, where they form glutamatergic synapses with the apical dendrites of mitral and tufted cells, the output cells of the olfactory bulb, and with juxtaglomerular interneurons. The glomerular layer contains one of the largest population of dopamine (DA) neurons in the brain, and DA in the olfactory bulb is found exclusively in juxtaglomerular neurons. D2 receptors, the predominant DA receptor subtype in the olfactory bulb, are found in the ON and glomerular layers, and are present on ON terminals. In the present study, field potential and single-unit recordings, as well as whole cell patch-clamp techniques, were used to investigate the role of DA and D2 receptors in glomerular synaptic processing in rat and mouse olfactory bulb slices. DA and D2 receptor agonists reduced ON-evoked synaptic responses in mitral/tufted and juxtaglomerular cells. Spontaneous and ON-evoked spiking of mitral cells was also reduced by DA and D2 agonists, and enhanced by D2 antagonists. DA did not produce measurable postsynaptic changes in juxtaglomerular cells, nor did it alter their responses to mitral/tufted cell inputs. DA also reduced 1) paired-pulse depression of ON-evoked synaptic responses in mitral/tufted and juxtaglomerular cells and 2) the amplitude and frequency of spontaneous, but not miniature, excitatory postsynaptic currents in juxtaglomerular cells. Taken together, these findings are consistent with the hypothesis that activation of D2 receptors presynaptically inhibits ON terminals. DA and D2 agonists had no effect in D2 receptor knockout mice, suggesting that D2 receptors are the only type of DA receptors that affect signal transmission from the ON to the rodent olfactory bulb.

Direct excitation of mitral cells via activation of alpha1-noradrenergic receptors in rat olfactory bulb slices

The main olfactory bulb receives a significant modulatory noradrenergic input from the locus coeruleus. Previous in vivo and in vitro studies showed that norepinephrine (NE) inputs increase the sensitivity of mitral cells to weak olfactory inputs. The cellular basis for this action of NE is not understood. The goal of this study was to investigate the effect of NE and noradrenergic agonists on the excitability of mitral cells, the main output cells of the olfactory bulb, using whole cell patch-clamp recording in vitro. The noradrenergic agonists, phenylephrine (PE, 10 microM), isoproterenol (Isop, 10 microM), and clonidine (3 microM), were used to test for the functional presence of alpha1-, beta-, and alpha2-receptors, respectively, on mitral cells. None of these agonists affected olfactory nerve (ON)-evoked field potentials recorded in the glomerular layer, or ON-evoked postsynaptic currents recorded in mitral cells. In whole cell voltage-clamp recordings, NE (30 microM) induced an inward current (54 +/- 7 pA, n = 16) with an EC(50) of 4.7 microM. Both PE and Isop also produced inward currents (22 +/- 4 pA, n = 19, and 29 +/- 9 pA, n = 8, respectively), while clonidine produced no effect (n = 6). In the presence of TTX (1 microM), and blockers of excitatory and inhibitory fast synaptic transmission [gabazine 5 microM, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) 10 microM, and (+/-)-2-amino-5-phosphonopentanoic acid (APV) 50 microM], the inward current induced by PE persisted (EC(50) = 9 microM), whereas that of Isop was absent. The effect of PE was also observed in the presence of the Ca(2+) channel blockers, cadmium (100 microM) and nickel (100 microM). The inward current caused by PE was blocked when the interior of the cell was perfused with the nonhydrolyzable GDP analogue, GDPbetaS, indicating that the alpha1 effect is mediated by G-protein coupling. The current-voltage relationship in the absence and presence of PE indicated that the current induced by PE decreased near the equilibrium potential for potassium ions. In current-clamp recordings from bistable mitral cells, PE shifted the membrane potential from the downstate (-52 mV) toward the upstate (-40 mV), and significantly increased spike generation in response to perithreshold ON input. These findings indicate that NE excites mitral cells directly via alpha1 receptors, an effect that may underlie, at least in part, increased mitral cell responses to weak ON input during locus coeruleus activation in vivo.

Ephaptic interactions in the mammalian olfactory system

Ephaptic coupling refers to interactions between neurons mediated by current flow through the extracellular space. Ephaptic interactions between axons are considered negligible, because of the relatively large extracellular space and the layers of myelin that separate most axons. By contrast, olfactory nerve axons are unmyelinated and arranged in tightly packed bundles, features that may enhance ephaptic coupling. We tested the hypothesis that ephaptic interactions occur in the mammalian olfactory nerve with the use of a computational approach. Numerical solutions of models of axon fascicles show that significant ephaptic interactions occur for a range of physiologically relevant parameters. An action potential in a single axon can evoke action potentials in all other axons in the fascicle. Ephaptic interactions can also lead to synchronized firing of independently stimulated axons. Our findings suggest that ephaptic interactions may be significant determinants of the olfactory code and that such interactions may occur in other, similarly organized axonal or dendritic bundles.

Membrane bistability in olfactory bulb mitral cells

Whole-cell patch-clamp recordings were used to investigate the electrophysiological properties of mitral cells in rat main olfactory bulb brain slice preparations. The majority of mitral cells are bistable. These cells spontaneously alternate between two membrane potentials, separated by approximately 10 mV: a relatively depolarized potential (upstate), which is perithreshold for spike generation, and a relatively hyperpolarized potential (downstate), in which spikes do not occur. Bistability occurs spontaneously in the absence of ionotropic excitatory or inhibitory synaptic inputs. Bistability is voltage dependent; transition from the downstate to the upstate is a regenerative event activated by brief depolarization. A brief hyperpolarization can switch the membrane potential from the upstate to the downstate. In response to olfactory nerve (ON) stimulation, mitral cells in the upstate are more likely to fire an action potential than are those in the downstate. ON stimulation can switch the membrane potential from the downstate to the upstate, producing a prolonged and amplified depolarization in response to a brief synaptic input. We conclude that bistability is an intrinsic property of mitral cells that is a major determinant of their responses to ON input.

Oxidative stress and increased type-IV collagenase levels in bronchoalveolar lavage fluid from newborn babies

Oxidative stress may increase lung permeability by up-regulation of matrix-metalloproteinase-9 (MMP-9), a type-IV collagenase that can disrupt alveolar basement membranes. We have compared a marker of oxidative stress (protein carbonyl residues) with levels of MMP-9 and its inhibitor, tissue inhibitor of metalloproteinase-1 (TIMP-1), in bronchoalveolar lavage samples from newborn babies. Bronchoalveolar lavage samples (n = 87, two from each time point) were taken in the first 6 postnatal days from 41 ventilated babies: 18 of <29 wk gestation, 10 of 29-36 wk, 9 term with persistent fetal circulation, and 4 term without lung disease. Respiratory disease severity at the time of bronchoalveolar lavage was assessed using the arterial-alveolar oxygen tension ratio. One sample from each time point was used for the measurement of MMP-9 by zymography and TIMP-1 by ELISA. The second sample was used to measure carbonyl group concentrations, also using an ELISA. Correlations were calculated between protein carbonyls, arterial-alveolar oxygen tension ratio, and MMP-9 and TIMP-1 concentrations. Significant correlations were found between carbonyl concentrations and arterial-alveolar oxygen tension ratio (r = -0.325, p = 0.0031, n = 81), MMP-9 (r = 0.331, p < 0.0029, n = 79), and TIMP-1 (r = 0.436, p < 0.0001, n = 87). Worsening respiratory disease in newborn babies is associated with increased carbonyl concentrations in neonatal bronchoalveolar lavage fluid, and these correlated with MMP-9 and TIMP-1 levels. Increased oxidative stress may damage the lung by increasing type-IV collagenase activity, causing disruption of the extracellular matrix.

Antioxidants and protein carbonyls in bronchoalveolar lavage fluid of children: normal data

Antioxidant-oxidant imbalances in bronchoalveolar lavage fluid (BAL) are thought to contribute to oxidative stress in respiratory disease. However, normal reference ranges for BAL antioxidants and oxidized proteins in children are not available. In this study, we recruited 124 children attending for elective surgery for a noninflammatory condition; 83 were nonasthmatic, nonatopic (N) and 41 were nonasthmatic, atopic (NA). A nonbronchoscopic lavage was performed and ascorbate, uric acid, alpha-tocopherol, and protein carbonyl (as a measure of oxidative damage) concentrations were determined in BAL fluid. The 95% reference range was 0.112-1.897 micromol/L for ascorbate, 0.149-2.163 micromol/L for urate, 0.0029-0.066 micromol/L for alpha-tocopherol, and 0.280-4.529 nmol/mg for protein carbonyls in BAL fluid. Age, gender, and exposure to environmental tobacco smoke did not affect the concentration of ascorbate, urate, alpha-tocopherol, or protein carbonyls. However, in multiple linear regression analyses, the type of home heating (glass-fronted fires or oil-fired central heating) was found to influence ascorbate and urate concentrations in the BAL fluid (ss-coefficient for ascorbate: 0.445, p = 0.031; for urate: 0.114, p = 0.001). There was no significant difference between the N and NA group in BAL fluid concentrations of ascorbate, urate, or protein carbonyls. The alpha-tocopherol concentration was significantly increased in the NA group (p = 0.037). Uric acid and alpha-tocopherol concentrations in BAL fluid and serum were not correlated. Intriguingly, serum and BAL ascorbate concentrations were significantly correlated (r = 0.297, p = 0.018, n = 63), which may offer an explanation for why supplementing the diet with vitamin C can improve asthma symptoms. Further studies will investigate the role of BAL antioxidant concentrations in children with inflammatory respiratory diseases.

Isolation and purification of human mast cells and basophils

Mast cells were once thought to represent a single population of highly granulated secretory cells. However, with the development of mast cell isolation techniques for a diverse range of tissues, it became apparent that mast cells from different species and those from different tissues within the same species exhibit variations in their biochemical, histochemical, and functional properties. The functional heterogeneity of mast cells has important implications for studies of the response of mast cells to secretory stimuli, antiallergic drugs, or drugs that have the potential to produce adverse responses.

Anxiety is a good indicator for somatic symptom reduction through behavioral medicine intervention in a mind/body medicine clinic

BACKGROUND

This study examined the effect of anxiety on symptom reduction through a behavioral medicine intervention in a Mind/Body Medicine Clinic.

METHOD

Participants were 1,312 outpatients attending a 10-week behavioral medicine intervention which included training in the relaxation response, cognitive restructuring, exercise and nutrition. All of the patients had physical symptoms and were referred to the clinic by their physician. The Medical Symptom Checklist (12 major symptoms), Symptom Checklist 90 Revised (SCL-90R), Stress Perception Scale and the Health-Promoting Lifestyle Profile were administered before and after the program.

RESULTS

Of the sample, 1,012 patients completed the program, and 911 completed the posttreatment assessment. Self-reported frequency of medical symptoms, degree of discomfort and interference with daily activities were significantly reduced as a result of the program. Anxiety and other psychological distress as measured by the SCL-90R and stress perception scales also showed significant reductions. Furthermore, health-promoting lifestyle functioning significantly improved. High levels of pretreatment anxiety predicted a decrease in the total number of medical symptoms endorsed.

CONCLUSIONS

Behavioral medicine interventions are effective in reducing medical symptoms coinciding with improvement in anxiety. High anxiety at program entry may predict better outcome.

Chronic cough in children: bronchoalveolar lavage findings

Isolated chronic cough in childhood is a common complaint. Although the symptom cough is included in the definition of clildhood asthma, there is debate as to whether the majoritv of these children have asthma. The authors studied children with isolated chronic cough looking for evidence of airway inflammation typical of asthma, with increased numbers of airway eosinophils as assessed from bronchoalveolar lavage (BAL). The investigations were carried out on 23 children (median age: 6.7 yrs; range: 1.7-12.75 yrs), attending the Royal Belfast Hospital for Sick Children for elective surgery, who also had a chronic unexplained cough. Written informed consent was obtained from the parent(s) and a nonbronchoscopic BAL was performed. BAL samples were analysed for total and differential white cell counts and also for the inflammatory mediators, eosinophil cationic protein (ECP) and histamine. Results were compared with a group of normal nonatopic children and also a group of atopic asthmatic children, who had been recruited for other studies on airway inflammation. There was a small but statistically significant increase in BAL percentage eosinophils in the children with chronic cough compared with nonasthmatic controls (0.28% versus 0.10%, p=0.03). However, the children with cough had lower percentage eosinophils than the atopic asthmatic controls (0.28% versus 0.66%, p=0.01). Three out of 23 children with chronic cough had BAL eosinophils greater than the normal upper 95% reference interval in BAL. There was a small but statistically significant increase in percentage neutrophils in the children with cough compared with the nonasthmatic controls (5.85% versus 3.21%, p=0.03). Four out of the 23 children had BAL neutrophils greater than the normal upper 95% reference interval in BAL. The authors conclude that only a minority of children with chronic unexplained cough have asthmatic-type airway inflammation. It is speculated that the increased percentage neutrophils in bronchoalveolar lavage from children with cough could relate to underlying persistent airways infection.

Prognostic awareness and the terminally ill

The authors rated patients who were in advanced stages of cancer and in their final few weeks of life on their level of awareness of their medical prognosis (N = 200, mean age = 71.0 years). The authors measured prognostic awareness with a semistructured interview, dividing patients into those acknowledging No Awareness, Partial Awareness, and Complete Awareness. The authors also administered a semistructured interview for depressive disorders, along with an assessment of various demographic and social support measures. Nineteen patients (9.5%) denied awareness of both their terminal prognosis and foreshortened life expectancy. Thirty-four patients (17%) were placed in the partial awareness category, with the remaining 147 patients (73.5%) reporting complete awareness. Depression was nearly three times greater among patients who did not acknowledge their prognosis, as compared with those who demonstrated partial or complete acknowledgment (chi2 = 7.094), P = 0.029). In addition to depression, male patients, older patients, and those having "intense social contact" were associated with lower ratings of prognostic awareness. Dying patients differ in respect to their capacity to acknowledge their prognosis. Prognostic disavowal is most likely to arise in patients with underlying psychological distress and emotional turmoil.

Is there an association between angiotensin-converting enzyme gene variants and chronic nonproductive cough?

BACKGROUND

It is unclear why some patients develop a chronic nonproductive cough. Angiotensin-converting enzyme (ACE) inactivates tussive peptides in the airways such as bradykinin and tachykinins. An insertion/deletion polymorphism in the ACE gene accounts for variation in ACE levels, and patients with the II genotype have lowest serum ACE levels compared with ID and DD genotypes. We hypothesized that the II genotype would be associated with increased risk of developing a chronic cough.

MATERIALS AND METHODS

We recruited 47 patients (33 women), referred for evaluation of cough (median cough duration, 24 months; range, 2 to 240 months). Cough patients were evaluated using a comprehensive diagnostic protocol, and cough reflex sensitivity was measured using a capsaicin inhalation challenge. ACE genotyping was performed on DNA samples from patients using the polymerase chain reaction followed by agarose gel electrophoresis. ACE genotypes in patients with chronic cough were compared with those in 199 healthy control subjects. Serum ACE levels were determined using a colorimetric assay.

RESULTS

Genotype frequencies for the ACE gene were similar between patients and control subjects. There was no correlation between capsaicin sensitivity and ACE genotypes or serum ACE levels.

CONCLUSION

Susceptibility to develop chronic cough is not associated with ACE genotype.

Tonic and synaptically evoked presynaptic inhibition of sensory input to the rat olfactory bulb via GABA(B) heteroreceptors

Olfactory receptor neurons of the nasal epithelium send their axons, via the olfactory nerve (ON), to the glomeruli of the olfactory bulb (OB), where the axon terminals form glutamatergic synapses with the apical dendrites of mitral and tufted cells, the output cells of the OB, and with juxtaglomerular (JG) interneurons. Many JG cells are GABAergic. Here we show that, despite the absence of conventional synapses, GABA released from JG cells activates GABA(B) receptors on ON terminals and inhibits glutamate release both tonically and in response to ON stimulation. Field potential recordings and current-source density analysis, as well as intracellular and whole cell recording techniques were used in rat OB slices. Baclofen (2-5 microM), a GABA(B) agonist, completely suppressed ON-evoked synaptic responses of both mitral/tufted cells and JG cells, with no evidence for postsynaptic effects. Baclofen (0.5-1 microM) also reversed paired-pulse depression (PPD) of mitral/tufted cell responses to paired-pulse facilitation (PPF), and reduced depression of JG cell excitatory postsynaptic currents (EPSCs) during repetitive ON stimulation. These results suggest that baclofen reduced the probability of glutamate release from ON terminals. The GABA(B) antagonists CGP35348 or CGP55845A increased mitral/tufted cell responses evoked by single-pulse ON stimulation, suggesting that glutamate release from ON terminals is tonically suppressed via GABA(B) receptors. The same antagonists reduced PPD of ON-evoked mitral/tufted cell responses at interstimulus intervals 50-400 ms. This finding suggests that a single ON impulse evokes sufficient GABA release, presumably from JG cells, to activate GABA(B) receptors on ON terminals. Thus GABA(B) heteroreceptors on ON terminals are activated by ambient levels of extrasynaptic GABA, and by ON input to the OB. The time course of ON-evoked, GABA(B) presynaptic inhibition suggests that neurotransmission to M/T cells and JG cells will be significantly suppressed when ON impulses arrive in glomeruli at 2.5-20 Hz. GABA(B) receptor-mediated presynaptic inhibition of sensory input to the OB may play an important role in shaping the activation pattern of the OB glomeruli during olfactory coding.

Ultrastructural characteristics and conduction velocity of olfactory receptor neuron axons in the olfactory marker protein-null mouse

Olfactory receptor neuron (ORN) axon diameters and the conduction velocity of the compound action potential along ORN axons were studied in olfactory marker protein (OMP)-null mice and genotypically matched controls. The compound action potential was distinguished from postsynaptic field potentials by its shorter latency, its persistence following application of cobalt or kynurenic acid that blocked postsynaptic responses, and its ability to follow paired-pulse stimulation at 300 Hz. Blockade of the postsynaptic field responses by kynurenic acid indicates that in the mouse, as in the rat, glutamate is the olfactory nerve transmitter. The mean conduction velocity of ORNs in wild-type control mice was 0. 47+/-0.19 (S.E.M.) m/s (n=5), similar to the conduction velocity reported for other mammals. The mean diameter of ORN axons in control mice was 0.202+/-0.005 and 0.261+/-0.006 microm in the OMP-null mice. This increase in fiber diameter in the OMP-nulls predicts an increase in impulse conduction velocity. However, the mean conduction velocity of OMP-null mice, 0.38+/-0.03 m/s (n=6), was not significantly different from control (P>0.1). The conduction velocity predicted by the increase in fiber diameter in OMP-null mice was within the 95% confidence interval of the measured value. Thus, OMP-null ORNs are normal with respect to the conduction velocity of their axons. The number of axodendritic synapses in the glomeruli of OMP-null mice is higher than in congenic wild-type mice.

Clinical consequences of mast cell heterogeneity

The heterogeneous morphological, biochemical and functional characteristics of mast cells from different species and from different tissue sites in the same species have been described for over 30 years. Far from being mere histochemical or pharmacological curiosities these differences have far reaching implications for therapeutic practice. This review concentrates on two important areas affected by mast cell heterogeneity, those of adverse reactions to therapeutic agents and the efficacy of anti-allergy therapy. In vitro studies of preformed and de novo synthesised mediator release have demonstrated a wide variability in the response of basophils and isolated mast cells to anti-allergy drugs and therapeutic agents such as radiographic contrast media, general anaesthetics, opioids and muscle relaxants. This heterogeneity is not limited to the mast cell's tissue of origin as there is also variability in the response of basophils and mast cells from different donors to the same drug or agent. These data have considerable clinical implications for the study of adverse drug reactions and the design of novel anti-allergic drugs.

Sensory neuropeptides induce histamine release from bronchoalveolar lavage cells in both nonasthmatic coughers and cough variant asthmatics

BACKGROUND

Sensory neuropeptides have been suggested to play a role in the pathogenesis of a number of respiratory diseases including asthma and chronic non-productive cough.

OBJECTIVES

To investigate the action of sensory neuropeptides on airway mast cells obtained by bronchoalveolar lavage (BAL).

METHODS

BAL was performed on 23 nonasthmatic patients with cough (NAC), 11 patients with cough variant asthma (CVA) and 10 nonatopic controls. Washed lavage cells were stimulated (20 min, 37 degrees C) with calcitonin gene-related peptide (CGRP), neurokinin A (NKA) and substance P (25 and 50 micromol/L).

RESULTS

The neuropeptides tested induced histamine release in all groups studied. Only CGRP (50 micromol/L) induced significantly more histamine release from both NAC and CVA patients compared with control subjects (P = 0.038 and 0.045, respectively).

CONCLUSION

Regardless of aetiology, mast cells from patients with chronic cough appear to have an increased responsiveness to CGRP compared with controls. The results of the present study suggest that the role of CGRP in chronic cough should be further investigated.

Serum eosinophil cationic protein (ECP): reference values in healthy nonatopic children

BACKGROUND

Although serum ECP concentrations have been reported in normal children, there are currently no published upper cutoff reference limits for serum ECP in normal, nonatopic, nonasthmatic children aged 1-15 years.

METHODS

We recruited 123 nonatopic, nonasthmatic normal children attending the Royal Belfast Hospital for Sick Children for elective surgery and measured serum ECP concentrations. The effects of age and exposure to environmental tobacco smoke (ETS) on the upper reference limits were studied by multiple regression and fractional polynomials.

RESULTS

The median serum ECP concentration was 6.5 microg/l and the 95th and 97.5 th percentiles were 18.8 and 19.9 microg/l. The median and 95th percentile did not vary with age. Exposure to ETS was not associated with altered serum ECP concentrations (P = 0.14).

CONCLUSIONS

The 95th and 97.5 th percentiles for serum ECP for normal, nonatopic, nonasthmatic children (aged 1-15 years) were 19 and 20 microg/l, respectively. Age and exposure to parental ETS did not significantly alter serum ECP concentrations or the normal upper reference limits. Our data provide cutoff upper reference limits for normal children for use of serum ECP in a clinical or research setting.

Serum eosinophilic cationic protein and blood eosinophil counts for the prediction of the presence of airways inflammation in children with wheezing

BACKGROUND

Serum eosinophilic cationic protein (ECP) concentrations may be useful noninvasive markers of airways inflammation in atopic asthma. However, the usefulness of serum ECP measurement for the prediction of airways inflammation in children with a history of wheezing is unknown.

OBJECTIVE

To determine the test accuracy of serum ECP and blood eosinophil percentage as noninvasive markers of eosinophilic airways inflammation.

METHODS

Bronchoalveolar lavage (BAL) fluid and peripheral blood samples for eosinophil percentages and serum ECP were obtained from children undergoing elective surgery and who gave a history of wheezing in the previous year. Sensitivity, specificity and likelihood ratios (LH) and the area under the curve (AUC) for the receiver operator characteristic (ROC) curve were calculated for each blood marker for the prediction of airways inflammation defined by a BAL eosinophil percentage > 0.86. Data were analysed on the basis of how recently symptoms had occurred.

RESULTS

Seventy-seven children (median age 6.75 years) were studied. An AUC of 0.75 (log serum ECP concentration) and 0.76 (log blood eosinophil percentage) was obtained for predicting airways inflammation. A serum ECP > 13 microg/L yielded a LH of 4.4, whereas using a cutoff blood eosinophils > 4% yielded a LH of 1.9, for the prediction of elevated eosinophils in BAL. Serum ECP and eosinophil percentages in BAL and blood were lowest (not statistically significant) when last symptoms had occurred more than 12 weeks previously.

CONCLUSIONS

Serum ECP and blood eosinophil percentages are useful markers for predicting eosinophilic airways inflammation in wheezing children.

Promoter analysis of the murine T-cell protein tyrosine phosphatase gene

The T-cell protein tyrosine phosphatase (TC PTP) is expressed ubiquitously at all stages of mammalian development. However, mRNA levels fluctuate in a cell-cycle-dependent manner, reaching peak levels in late G1, and rapidly decreasing in S phase. Furthermore, TC PTP being present in higher amounts in lymphoid tissues, we have recently shown that it is essential for proper maintenance of both the bone marrow micro-environment and B- and T-cell functions. In order to better understand the elements controlling the expression pattern of this gene, we have isolated and characterized approx. 4kb of the murine TC PTP promoter. DNA sequencing of the proximal 5' region revealed the absence of both TATAA and CAAT boxes. Primer extension analysis and S1 nuclease mapping techniques identified multiple transcription initiation sites. Functional promoter activity was determined using transfection experiments of promoter deletion constructs fused to a CAT reporter construct. Our results indicate that the minimal promoter sequence required for functional expression is contained within the first 147bp of the TC PTP promoter. In addition, consistent with the cell-cycle-dependent expression of TC PTP, we localized a domain between 492 and 1976bp from the transcription initiation site through which repression occurs. In conclusion, although initiator-driven transcription allows for ubiquitous expression of TC PTP, we define general transcription motifs present within the promoter that may mediate specific modulations of the TC PTP gene.

Evidence for cholinergic regulation of basal norepinephrine release in the rat olfactory bulb

The effects of locally infused cholinergic agonists on extracellular levels of norepinephrine in the olfactory bulb of anesthetized rats were determined using in vivo microdialysis coupled with high-performance liquid chromatography and electrochemical detection. Using chronically implanted microdialysis probes, the basal norepinephrine level in the olfactory bulb was 0.55 pg/10 microl dialysate. Local infusion of K+ (30 mM) or the norepinephrine re-uptake inhibitor desipramine (1 microM) through the dialysis probe significantly increased basal norepinephrine levels. Focal activation of noradrenergic locus coeruleus neurons, the sole source of norepinephrine innervation of the olfactory bulb, increased norepinephrine levels by 247% of control. Local infusion of the acetylcholinesterase inhibitor soman (0.4 mM) into the olfactory bulb increased basal norepinephrine levels by 134% of control, suggesting that endogenously released acetylcholine modulates norepinephrine release. Intrabulbar infusion of acetylcholine (40 mM) or nicotine (40 mM) increased norepinephrine levels (317% and 178% of control, respectively), while infusion of the muscarinic receptor agonist pilocarpine (40 mM) reduced norepinephrine levels (54% of control). These results demonstrate that basal norepinephrine release in the olfactory bulb is potently modulated by stimulation of local cholinergic receptors. Nicotinic receptors stimulate, and muscarinic receptors inhibit, norepinephrine release from locus coeruleus terminals.

Risk of menopause during the first year after breast cancer diagnosis

PURPOSE

Premenopausal women with breast cancer often enter a premature menopause during initial treatment of their malignancy, with resulting loss of childbearing capacity, onset of menopausal symptoms, and subsequent prolonged exposure to long-term risks of menopause. Adjuvant therapy is believed to contribute to this early menopause.

PATIENTS AND METHODS

One hundred eighty-three premenopausal women with locoregional breast cancer (tumor-node-metastasis staging system classification, T1-3 N0-1 M0) who had undergone surgical treatment and provided information on menopausal status at diagnosis and 1 year later were enrolled. Systemic adjuvant therapy was recorded. Univariate and multivariate predictors of menopause were examined.

RESULTS

Age, weight gain, tumor stage, nodal stage, and systemic adjuvant therapy (chemotherapy, tamoxifen) were all significant univariate correlates of menopause. In multivariate analysis, age, chemotherapy, and hormone therapy (tamoxifen) made significant independent contributions to the onset of menopause.

CONCLUSION

Age and systemic chemotherapy are the strongest predictors of menopause in women with locoregional breast cancer. They independently contribute to menopause. A graphic representation of our multivariate model allows an estimation of risk of menopause according to patient age and planned adjuvant treatment, and it may facilitate clinical decision-making.

Diagonal band stimulation increases piriform cortex neuronal excitability in vivo

The effects of diagonal band (NDB) stimulation on the spontaneous discharge of pyramidal cells and evoked field potentials (FPs) in piriform cortex (PC) were investigated in vivo. NDB stimulation increased the spontaneous firing rate of PC cells, and increased the disynaptic excitatory (B1) and decreased the disynaptic inhibitory (P2) FP components following lateral olfactory tract (LOT) stimulation. NDB stimulation decreased the P2 component following activation of association fibers in caudal PC. NDB stimulation reduced the paired-pulse inhibition of the P2 component following LOT and caudal PC shocks. The effects of NDB stimulation were reversed by scopolamine, suggesting the involvement of muscarinic receptors. These results suggest that activation of cholinergic inputs to PC increases the excitability of pyramidal cells, probably by a disinhibitory mechanism.

The organization of preoptic-medullary circuits in the male rat: evidence for interconnectivity of neural structures involved in reproductive behavior, antinociception and cardiovascular regulation

The present studies used anatomical tract-tracing techniques to delineate the organization of pathways linking the medial preoptic area and the ventral medulla, two key regions involved in neuroendocrine, autonomic and sensory regulation. Wheatgerm agglutinin-horseradish peroxidase injections into the ventromedial medulla retrogradely labeled a large number of neurons in the medial preoptic area, including both the median and medial preoptic nuclei. The termination pattern of preoptic projections to the medulla was mapped using the anterograde tracers Phaseolus vulgaris leucoagglutinin and biotinylated dextran amine. Tracer injections into the preoptic area produced a dense plexus of labeled fibers and terminals in the ventromedial and ventrolateral pons and medulla. Within the caudal pons/rostral medulla, medial preoptic projections terminated heavily in the nucleus raphe magnus; strong anterograde labeling was also present in the pontine reticular field. At mid-medullary levels, labeled fibers focally targeted the nucleus paragigantocellularis, in addition to the heavy fiber labeling present in the midline raphe nuclei. By contrast, very little labeling was observed in the caudal third of the medulla. Experiments were also conducted to map the distribution of ventral pontine and medullary neurons that project to the medial preoptic area. Wheatgerm agglutinin-horseradish peroxidase injections in the preoptic area retrogradely labeled a significant population of neurons in the ventromedial and ventrolateral medulla. Ascending projections from the medulla to the preoptic area were organized along rostral-caudal, medial-lateral gradients. In the caudal pons/rostral medulla, retrogradely labeled cells were aggregated along the midline raphe nuclei; no retrograde labeling was present laterally at this level. By contrast, in the caudal half of the medulla, cells retrogradely labeled from the medial preoptic area were concentrated as a discrete zone dorsal to the lateral reticular nucleus; labeled cells were not present in the ventromedial medulla at this level. The present findings suggest that the medial preoptic area and ventral midline raphe nuclei share reciprocal connections that are organized in a highly symmetrical fashion. By contrast, preoptic-lateral medullary pathways are not reciprocal. These preoptic-brainstem circuits may participate in antinociceptive, autonomic and reproductive behaviors.

Dendrodendritic recurrent excitation in mitral cells of the rat olfactory bulb

Most neuronal interactions within the olfactory bulb network are mediated by dendrodendritic synapses. Dendritic transmitter release potentially could affect the parent dendrite as well as local neuronal elements that have receptors for the released transmitter. Here we report that under conditions that facilitate N-methyl-D-aspartate (NMDA) receptor activity (reduced GABAA inhibition and extracellular Mg2+), a single action potential evoked by brief intracellular current pulses in mitral cells is followed by a prolonged depolarization, which is blocked by an NMDA receptor antagonist. This depolarization also is evoked by a presumed calcium spike in the presence of tetrodotoxin. A similar NMDA-receptor-dependent prolonged depolarization is elicited by stimulation of the lateral olfactory tract at current intensities subthreshold for antidromic activation of the recorded neuron. These observations suggest that glutamate released from the dendrites of mitral cells excites the same and neighboring mitral cell dendrites. Further evidence suggests that both the apical and lateral dendrites of mitral cells participate in this recurrent excitation. These dendrodendritic interactions may play a role in the prolonged, NMDA-receptor-dependent depolarization of mitral/tufted cells evoked by olfactory nerve stimulation.

Adenosine, mast cells and asthma

The aim of this article is to review the interplay between adenosine and mast cells in asthma. Adenosine is an endogenous nucleoside released from metabolically active cells and generated extracellularly via the degradation of released ATP. It is a potent biological mediator that modulates the activity of numerous cell types including platelets, neutrophils and mast cells via action at specific adenosine receptors (A1, A2a, A2b, A3). These receptors are expressed on mast cells but the exact pattern of receptor subtype expression depends on the source of the mast cells. Adenosine is also a potent bronchoconstricting agent and is suggested to contribute to the pathophysiology of asthma. Evidence is provided to suggest that the nucleoside exerts its influence on the asthmatic condition through its ability to modulate the release of mast cell derived mediators. However, the mechanism of adenosine/mast cell interaction which contributes to asthma remains unclear. Progress in the area has been hampered by the heterogeneity of mast cell responses and a lack of highly specific receptor agonists and antagonists. The expression of different adenosine receptor subtypes on mast cells is described. The final section of the review presents data to suggest that BAL mast cells may provide an accurate and relevant model for future investigations and together with the development of superior pharmacological tools, may aid the realisation of the therapeutic potential of adenosine/mast cell interactions in asthma. In conclusion, the role of adenosine in asthma is clearly complex. A better understanding of the contribution of adenosine to the asthmatic condition may lead to novel therapeutic approaches in the treatment of the disease.

A Huntington's disease CAG expansion at the murine Hdh locus is unstable and associated with behavioural abnormalities in mice

Huntington's disease (HD) is a dominant disorder characterized by premature and progressive neurodegeneration. In order to generate an accurate model of the disease, we introduced an HD-like mutation (an extended stretch of 72-80 CAG repeats) into the endogenous mouse Hdh gene. Analysis of the mutation in vivo reveals significant levels of germline instability, with expansions, contractions and sex-of-origin effects in evidence. Mice expressing full-length mutant protein display abnormal social behaviour in the absence of acute neurodegeneration. Given that psychiatric changes, including irritability and aggression, are common findings in HD patients, our data are consistent with the hypothesis that some clinical features of HD may be caused by pathological processes that precede gross neuronal cell death. This implies that effective treatment of HD may require an understanding and amelioration of these dysfunctional processes, rather than simply preventing the premature death of neurons in the brain. These mice should facilitate the investigation of the molecular mechanisms that underpin the pathway from genotype to phenotype in HD.

Norepinephrine increases rat mitral cell excitatory responses to weak olfactory nerve input via alpha-1 receptors in vitro

A rat olfactory bulb in vitro slice preparation was used to investigate the actions of norepinephrine on spontaneous and afferent (olfactory nerve) evoked activity of mitral cells. Single olfactory nerve shocks elicited a characteristic mitral cell response consisting of distinct, early and late spiking components separated by a brief inhibitory epoch. Bath-applied norepinephrine (1 microM) increased the early spiking component elicited by perithreshold (79% increase, P<0.02), but not by suprathreshold (3% decrease, P>0.05), intensity olfactory nerve shocks. The facilitatory effect of norepinephrine was due to a reduction in the incidence of response failures to perithreshold intensity shocks. Norepinephrine also decreased the inhibitory epoch separating the early and late spiking components by 44% (P<0.05). By contrast, norepinephrine had no consistent effect on the spontaneous discharge rate of the mitral cells. The effects of norepinephrine were mimicked by the al receptor agonist phenylephrine (1 microM, P<0.001). Both norepinephrine and phenylephrine modulation of mitral cell responses were blocked by the al adrenergic antagonist WB-4101 (1 microM). These findings are consistent with observations that the main olfactory bulb exhibits the highest density of alpha1 receptors in the brain. The alpha2 receptor agonist clonidine (100 nM) and the beta receptor agonist isoproterenol (1 microM) had inconsistent effects on mitral cell spontaneous and olfactory nerve-evoked activity. These results indicate that norepinephrine increases mitral cell excitatory responses to weak but not strong olfactory nerve inputs in vitro via activation of al receptors. This is consistent with recent findings in vivo that synaptically released norepinephrine preferentially increases mitral cell excitatory responses to weak olfactory nerve inputs. Taken together, these results suggest that the release of norepinephrine in the olfactory bulb may increase the sensitivity of mitral cells to weak odors. Olfactory cues evoke norepinephrine release in the main olfactory bulb, and norepinephrine plays important roles in early olfactory learning and reproductive/maternal behaviors. By increasing mitral cell responses to olfactory nerve input, norepinephrine may play a critical role in modulating olfactory function, including formation and/or recall of specific olfactory memories.

Comparisons of urinary versus serum cortisol in older persons

The present analysis compared urine- versus serum-based amounts of the stress hormone cortisol in two older adult samples, given that urine as a sample medium is a less expensive and less invasive method of determining cortisol amounts relative to serum. Seventy-three older adults provided urine samples as part of an ongoing study to assess levels of cortisol as a function of intellectual efficacy/performance; these data were compared to serum cortisol levels obtained from 96 older adults in a separate study examining health beliefs and cortisol levels. Analyses indicated that the cortisol levels did not differ across samples, i.e., cortisol amounts measured in serum or urine yielded similar, typical (within normal ranges) results. The data, though preliminary, indicate that urine may provide an alternative to serum when assessing cortisol in older persons.

Adenosine induces histamine release from human bronchoalveolar lavage mast cells

Previous studies have shown that in vitro adenosine enhances histamine release from activated human lung mast cells obtained by enzymic dispersion of lung parenchyma. However, adenosine alone has no effect on histamine release from these cells. Given the evidence for direct activation of mast cells after endobronchial challenge with adenosine and previous studies indicating that mast cells obtained at bronchoalveolar lavage are a better model for asthma studies than those obtained by enzymic dispersion of lung tissue, the histamine-releasing effect of adenosine was examined on lavage mast cells. Bronchoalveolar lavage fluid was obtained from patients attending hospital for routine bronchoscopy (n=54). Lavage cells were challenged with adenosine or adenosine receptor agonists (20 min, 37 degrees C) and histamine release determined using an automated fluorometric assay. Endogenous adenosine levels were also measured in lavage fluid (n=9) via an HPLC method. Adenosine alone caused histamine release from lavage mast cells in 37 of 54 patients with a maximal histamine release of 20.56+/-2.52% (range 5.2-61%). The adenosine receptor agonists (R)-N6-(2-phenylisopropyl)adenosine, 5'-N-ethylcarboxamidoadenosine and CGS21680 also induced histamine release from lavage mast cells. Preincubation of lavage mast cells with the adenosine receptor antagonist xanthine amine congener caused significant inhibition of the response to adenosine (P=0.007). There was an inverse correlation between endogenous adenosine levels in the lavage fluid and the maximal response to in vitro adenosine challenge of the lavage cells. The findings of the present study indicate a means by which adenosine challenge of the airways can induce bronchoconstriction and support a role for adenosine in the pathophysiology of asthma. The results also suggest that cells obtained from bronchoalveolar lavage fluid may provide the ideal model for the testing of novel, adenosine receptor, targeted therapies for asthma.

Inflammatory mediators in bronchoalveolar lavage samples from children with and without asthma

BACKGROUND

We investigated whether eosinophils and mast cells, found in the airways of children with wheeze, were activated during relatively asymptomatic periods.

METHODS

A nonbronchoscopic bronchoalveolar lavage (BAL) procedure was performed on children presenting for an elective surgical procedure. Eosinophil-derived (eosinophil cationic protein, ECP) and mast cell-derived (histamine/tryptase) mediator concentrations were measured in the BAL fluid. A detailed history and serum immunoglobulin E were used to classify the children into four groups: atopic with and without asthma, viral-associated wheeze and normal controls.

RESULTS

The ECP concentrations in BAL from atopic asthmatic subjects were significantly higher than those measured in BAL from normal controls (P < 0.01), no other groups differed significantly. Histamine concentrations were elevated in both the atopic asthmatic and viral-associated wheeze groups compared with controls (P < 0.02) and additionally higher concentrations were obtained in atopics with asthma compared with atopics without asthma (P < 0.03). Tryptase concentrations did not differ between groups, although the tryptase and histamine concentrations correlated significantly (r = 0.78, P < 0.0001).

CONCLUSIONS

Elevated histamine concentrations were found in children with wheeze regardless of the aetiology, whereas ECP was only elevated in those asthmatics with atopy. This suggests that even in relatively quiescent periods, there is some on going activation of airway eosinophils in children with atopic asthma.

Bronchoalveolar lavage findings in patients with chronic nonproductive cough

Mast cells and eosinophils may play a role in the pathophysiology of chronic cough in nonasthmatics. It is unknown, however, whether degranulation of these cells occurs in the airways of such patients. Thirty-five nonsmoking patients referred with a chronic nonproductive cough (mean cough duration 76.2 months) were evaluated using a comprehensive diagnostic protocol. Bronchoalveolar lavage (BAL) cell differentials and BAL histamine, tryptase and eosinophilic cationic protein (ECP) concentrations were determined. Ten nonsmoking healthy volunteers served as controls. Diagnostic subgroups were identified: eight postnasal drip syndrome (PNDS), seven cough variant asthma (CVA), seven gastro-esophageal reflux (GOR), seven dual aetiology and six idiopathic. Nonasthmatic coughers (NAC) were characterized as those patients without bronchial hyperresponsiveness on histamine challenge and whose cough had either responded to therapy for PNDS or GOR or failed to improve with antiasthma therapy. There was a significant increase in both eosinophil and mast cell numbers (p<0.05) and in histamine levels (p = 0.027) when NAC patients were compared with controls. Tryptase and ECP levels were elevated in 7 of 23 and 6 of 23 NAC patients, respectively. In conclusion, airway inflammatory cell numbers are not only increased but also activated, suggesting an important role for airways inflammation in the pathophysiology of chronic nonproductive cough.

Adjuvant treatment and onset of menopause predict weight gain after breast cancer diagnosis

PURPOSE

Weight gain is common during the first year after breast cancer diagnosis. In this study, we examined clinical factors associated with body size at diagnosis and weight gain during the subsequent year.

PATIENTS AND METHODS

An inception cohort of 535 women with newly diagnosed locoregional breast cancer underwent anthropometric measurements at baseline and 1 year. Information was collected on tumor- and treatment-related variables, as well as diet and physical activity.

RESULTS

Mean age was 50.3 years; 57% of women were premenopausal. Mean baseline body mass index (weight [kg] divided by height [m] squared) was 25.5 kg/m2. Overall, 84.1% of the patients gained weight. Mean weight gain was 1.6 kg (95% confidence interval, 1.2 to 1.9 kg), 2.5 kg (95% confidence interval, 1.8 to 3.2 kg) in those receiving chemotherapy, 1.3 kg (95% confidence interval, 0.7 to 1.8 kg) in those receiving tamoxifen only, and 0.6 kg (95% confidence interval, 0.01 to 1.3 kg) in those receiving no adjuvant treatment. Menopausal status at diagnosis (P = .02), change in menopausal status over the subsequent year (P = .002), axillary nodal status (P = .009), and adjuvant treatment (P = .0002) predicted weight gain in univariate analysis. In multivariate analysis, onset of menopause and administration of chemotherapy were independent predictors of weight gain (all P < or = .05). Caloric intake decreased (P < .01) and physical activity increased (P < .05) during the year after diagnosis; these factors did not explain the observed weight gain.

CONCLUSION

Weight gain is common after breast cancer diagnosis; use of adjuvant chemotherapy and onset of menopause are the strongest clinical predictors of this weight gain.

Current-source density analysis in the rat olfactory bulb: laminar distribution of kainate/AMPA- and NMDA-receptor-mediated currents

The one-dimensional current-source density method was used to analyze laminar field potential profiles evoked in rat olfactory bulb slices by stimulation in the olfactory nerve (ON) layer or mitral cell layer (MCL) and to identify the field potential generators and the characteristics of synaptic activity in this network. Single pulses to the ON evoked a prolonged (>/=400 ms) sink (S1ON) in the glomerular layer (GL) with corresponding sources in the external plexiform layer (EPL) and MCL and a relatively brief sink (S2ON) in the EPL, reversing in the internal plexiform and granule cell layers. These sink/source distributions suggested that S1ON and S2ON were generated in the apical dendrites of mitral/tufted cells and granule cells, respectively. The kainate/AMPA-receptor antagonist CNQX (10 microM) reduced the early phase of S1ON, blocked S2ON, and revealed a low amplitude, prolonged sink at the location of S2ON in the EPL. Reduction of Mg2+, in CNQX, enhanced both the CNQX-resistant component of S1ON and the EPL sink. This EPL sink reversed below the MCL, suggesting it was produced in granule cells. The NMDA-receptor antagonist APV (50 microM) reversibly blocked the CNQX-resistant field potentials in all layers. Single pulses were applied to the MCL to antidromically depolarize the dendrites of mitral/tufted cells. In addition to synaptic currents of granule cells, a low-amplitude, prolonged sink (S1mcl) was evoked in the GL. Corresponding sources were in the EPL, suggesting that S1mcl was generated in the glomerular dendritic tufts of mitral/tufted cells. Both S1mcl and the granule cell currents were nearly blocked by CNQX (10 microM) but enhanced by subsequent reduction of Mg2+; these currents were blocked by APV. S1mcl also was enhanced by gamma-aminobutyric acid-A-receptor antagonists applied to standard medium; this enhancement was reduced by APV. ON activation produces prolonged excitation in the apical dendrites of mitral/tufted cells, via kainate/AMPA and NMDA receptors, providing the opportunity for modulation and integration of sensory information at the first level of synaptic processing in the olfactory system. Granule cells respond to input from the lateral dendrites of mitral/tufted cells via both kainate/AMPA and NMDA receptors; however, in physiological concentrations of extracellular Mg2+, NMDA-receptor activation does not contribute significantly to the granule cell responses. The glomerular sink evoked by antidromic depolarization of mitral/tufted cell dendrites suggests that glutamate released from the apical dendrites of mitral/tufted cells may excite the same or neighboring mitral/tufted cell dendrites.