The use of erythropoietin-stimulating agents versus supportive care in newborns with hereditary spherocytosis: a single centre's experience

Hereditary Spherocytosis (HS) is a common haemolytic anaemia in which 75% of cases are autosomal dominant. As most newborns with HS have a family history of disease, haematologists often see these infants before their physiologic haemoglobin nadir, which is exaggerated in comparison with healthy infants. The objective of this study was to evaluate the frequency of implementation and cost of erythropoietin-stimulating agents (EPO) versus transfusion in infants with HS at a single paediatric programme. In the last decade, only 15% of infants with HS at our centre have been treated with EPO, which costs twice that of a single transfusion and EPO treated infants did not always avoid transfusion. Infrequent prescription of EPO therapy to infants with HS at our centre may be related to the incomplete data supporting its use.

Asymptotic scaling in turbulent pipe flow

The streamwise velocity component in turbulent pipe flow is assessed to determine whether it exhibits asymptotic behaviour that is indicative of high Reynolds numbers. The asymptotic behaviour of both the mean velocity (in the form of the log law) and that of the second moment of the streamwise component of velocity in the outer and overlap regions is consistent with the development of spectral regions which indicate inertial scaling. It is shown that an 'inertial sublayer' in physical space may be considered as a spatial analogue of the inertial subrange in the velocity spectrum and such behaviour only appears for Reynolds numbers R+>5 x 10(3), approximately, much higher than was generally thought.

The mechanism of the reaction catalysed by adenosine triphosphate-creatine phosphotransferase

1. The forward and reverse reactions catalysed by ATP-creatine phosphotransferase have been studied kinetically at pH8.0 in the presence and absence of products, under conditions in which the free Mg(2+) concentration was maintained constant at 1mm. Thus at fixed pH the reaction may be considered as being bireactant and expressed as:MgATP(2-)+creatine(0)right harpoon over left harpoonMgADP(-)+phosphocreatine(2-)2. The initial-velocity pattern in the absence of products and the product-inhibition pattern have been determined. These are consistent with a random mechanism in which all steps are in rapid equilibrium except that concerned with the interconversion of the central ternary complexes, and in which two dead-end complexes (enzyme-MgADP-creatine and enzyme-MgATP-phosphocreatine) are formed. The results are in accord with previous suggestions that the enzyme possesses distinct sites for the combination of the nucleotide and guanidino substrates. 3. Values have been determined for the Michaelis and dissociation constants involved in the combination of each substrate with various enzyme forms. Although these values cannot be regarded as absolute, they appear to indicate that the presence of one substrate on the enzyme enhances the combination of the second substrate. In addition, it would seem that in the formation of the enzyme-MgADP-creatine complex the concentration of one reactant does not affect the combination of the other. This contrasts with the formation of the enzyme-MgATP-phosphocreatine complex, where each reactant hinders the combination of the other.

Reynolds number dependence of streamwise velocity spectra in turbulent pipe flow

Spectra of the streamwise velocity component in fully developed turbulent pipe flow are presented for Reynolds numbers up to 5.7x10(6). Even at the highest Reynolds number, streamwise velocity spectra exhibit incomplete similarity only: while spectra collapse with both classical inner and outer scaling for limited ranges of wave number, these ranges do not overlap. Thus similarity may not be described as complete, and a region varying with the inverse of the streamwise wave number, k(1), is not expected, and any apparent k(-1)(1) range does not attract any special significance and does not involve a universal constant. Reasons for this are suggested.

Catecholamines in the heart and adrenal gland of the STZ-diabetic rat

The concentrations of noradrenaline (NA), adrenaline (ADR), 5-hydroxyindoleacetic acid (5-HIAA), serotonin (5-HT) and dopamine (DOP) have been studied in the left ventricle and the left adrenal gland of control and streptozotocin (STZ) - treated rats at various intervals (12, 24, 30, 34, 38 and 42 weeks) after the induction of diabetes. The only amines detected in the heart were NA, 5-HIAA and DOP, whereas those detected in the adrenal gland were NA and ADR. Differential changes in the catecholamine concentrations occurred in the heart and the adrenal gland at different stages of the metabolic disorder. In the heart the initial changes in short-term diabetes included an increase in NA concentration but this did not persist in the longer term diabetic animals (30-38 weeks following STZ injection). In the adrenal gland there was an initial reduction followed by a steady increase in the concentration of NA and ADR throughout the period of the study.

The interaction of nitric oxide and prostaglandins in the control of corporal smooth muscle tone: evidence for production of a cyclooxygenase-derived endothelium-contracting factor

OBJECTIVE

To investigate the interaction of endothelium-derived nitric oxide (NO) and prostaglandins (PGs) in regulating corporal smooth muscle tone in vitro. Materials and methods Strips of rabbit corpus cavernosum were mounted in organ chambers for the measurement of isometric tension. Strips were submaximally contracted with noradrenaline and concentration-response curves (CRCs) to acetylcholine (ACh) were constructed before and after treatment with 5 micromol/L atropine, 20 micromol of the cyclooxygenase inhibitor indomethacin and 10 micromol of the PGH2/thromboxane A2 receptor antagonist SQ29548. The NO synthase (NOS) inhibitors L-NG-monomethyl arginine (L-NMMA) and L-NG-nitroarginine (L-NOARG) were added to strips at tonic tension in the presence and absence of indomethacin, and after this CRCs to ACh were constructed.

RESULTS

The addition of ACh to strips produced a concentration-dependent relaxation which was inhibited by atropine. Indomethacin, but not SQ29548, significantly increased relaxation to ACh. Relaxation to ACh was impaired by L-NMMA, but adding ACh to strips treated with L-NOARG resulted in contractile responses, whilst both effects were reversed by indomethacin. L-NMMA and L-NOARG led to increases in tonic tone which were unaffected by indomethacin.

CONCLUSIONS

In rabbit corpus cavernosum there is a tonic release of NO which does not appear to be inhibited by a vasoconstrictor prostanoid. Endothelium-dependent relaxation to ACh results in the dual production of NO and a cyclooxygenase-derived endothelium contracting factor which acts in opposition to NO; this factor is unlikely to act on PGH2/TXA2 receptors.

Nitric oxide-mediated corpus cavernosal smooth muscle relaxation is impaired in ageing and diabetes

OBJECTIVE

To examine nitric-oxide (NO)-mediated relaxation in cavernosal smooth muscle in a rat model of diabetes, as previous experiments showed that HbA1c (an isoform of glycosylated haemoglobin and a marker of long-term diabetic control) impaired NO-mediated relaxation of normal corpus cavernosal tissue through the generation of superoxide anions.

MATERIALS AND METHODS

Eight weeks after the induction of diabetes, male Wistar rats were killed and cavernosal tissue obtained. Strips were contracted with 1 micromol/L noradrenaline before applying acetylcholine or electrical field stimulation (EFS) or sodium nitroprusside (SNP). Relaxation responses were repeated in the presence of L-arginine (100 micromol/L), indomethacin (10 micromol/L) or superoxide dismutase (SOD, 120 IU/mL). Young and age-matched control animals were examined in the same way.

RESULTS

Eight weeks of uncontrolled diabetes caused a significant impairment in mean relaxation responses to acetylcholine (P < 0.05) and to EFS (P < 0.05), but not to SNP, compared with young and age-matched controls, respectively. L-arginine, indomethacin and SOD had no significant effect on this impairment. Ageing caused a lesser but significant impairment in EFS-mediated cavernosal smooth muscle relaxation (P < 0.05).

CONCLUSION

Diabetes impairs endothelial and neuronal NO-mediated cavernosal smooth muscle relaxation in rats in vitro. This effect is not mediated by an alteration in the intracellular action of NO, the availability of NO, superoxide anion inactivation of NO or the generation of constrictor prostanoids. It is possible that cholesterol or advanced glycation end products are responsible for the effect of diabetes on penile smooth function.

Advanced glycation end-products are responsible for the impairment of corpus cavernosal smooth muscle relaxation seen in diabetes

OBJECTIVE

To determine if advanced glycation end-products (AGEs) are responsible for the lower neuronal and endothelial-derived nitric oxide (NO)-mediated relaxation of corpus cavernosum in tissue in diabetic rats than in control rats.

MATERIALS AND METHODS

Diabetes was induced in male Wistar rats by an intraperitoneal injection with streptozotocin (60 mg/kg). One group of diabetic rats was given free access to water and standard diet. A second group was given standard diet and aminoguanidine with their water (50 mg/100 mL) from the initiation of diabetes. Two groups of rats that were not diabetic acted as age-matched controls. After 8 weeks animals were killed by cervical dislocation, corpus cavernosal tissue strips harvested and mounted in an organ bath to measure isometric tension. After 90 min of equilibration at optimal resting tension and contraction with 1 micromol/L noradrenaline, the response to either acetylcholine or electrical field stimulation (EFS) after adding guanethidine (5 micromol/L) and atropine (1 micromol/L) was determined for each group.

RESULTS

There was no difference between the baseline characteristics of all the experimental groups. After 8 weeks the mean body mass and glycosylated haemoglobin (HbA1c) were significantly greater in the diabetic than in control animals. Aminoguanidine had no effect on the recorded body mass or HbA1c. The in vitro relaxation response to the application of acetylcholine or EFS of tissue strips from age-matched control animals fed a standard diet and those supplemented with aminoguanidine were the same. The administration of aminoguanidine to diabetic animals for 8 weeks reversed the expected impaired relaxation response to acetylcholine; the response to EFS was similar.

CONCLUSION

AGEs are more prevalent in erectile tissue from diabetic than in control animals. Aminoguanidine reversed the impairment in neuronal and endothelial NO-mediated penile smooth muscle relaxation seen in diabetes. As aminoguanidine prevents AGE formation, erectile dysfunction in diabetes is probably caused partly by the generation of AGEs.

Evidence for a role of HLA DRB1 alleles in the control of IgE levels, strengthened by interacting TCR A/D marker alleles

BACKGROUND

MHC class II alleles at human chromosome 6p21.1 and alleles in the TCR A/D locus at human chromosome 14q11.2 have been implicated in susceptibility to specific allergies and the modulation of total serum IgE. It has also been hypothesized that HLA and TCR allelic interactions may have a strong influence on predisposition to allergic disease.

OBJECTIVE

This study was performed to investigate the influence of HLA-DRB and DQB1 alleles and D14S50 alleles (adjacent to TCR A/D locus on 14q11.2), individually and in-combination, on total serum IgE levels, and on the development of specific allergies.

METHODS

We performed an association study between HLA-DRB, HLA-DQB1 polymorphisms, D14S50 alleles, total serum IgE expression and specific allergies to house dust mite, grass pollens and cat fur. A sample of 181 individuals was drawn from a larger set of 2415 adults, sampled at random from a district in Nottingham.

RESULTS

Strong association was observed between HLA-DRB1*0701 allele and high total serum IgE expression (P < 0.001). D14S50 alleles alone showed no evidence for independent association. However, there was a significant interaction between DRB1*0701 and D14S50 allele 170 such that, when both were present, there was a further increase in total serum IgE levels.

CONCLUSION

This study suggests that DRB1*0701 allele is involved in the modulation of total serum IgE, and that there is an interaction between DRB1*0701 and a marker adjacent to TCR A/D in the control of IgE expression.

Endothelial and neuronal-derived nitric oxide mediated relaxation of corpus cavernosal smooth muscle in a rat, in vitro, model of erectile function

We set out to establish a simple, reproducible, rat in vitro model of erectile function and to use this to demonstrate the functional importance of both neuronal- and endothelial-derived nitric oxide within this animal. Two corpora cavernosal smooth muscle strips were harvested from sexually mature male Wistar rats and mounted in an organ bath for measurement of isometric tension. Following contraction with noradrenaline the strips were relaxed by the addition of either acetylcholine or sodium nitroprusside. Electrical field stimulation was performed in the presence of atropine and guanethidine. Relaxation responses were repeated in the presence of methylene blue, L-arginine, L-NNA and haemoglobin +/- L-arginine. Methylene blue abolishes the relaxation to acetylcholine and EFS; L-NNA and haemoglobin cause a significant impairment in the relaxation response. L-arginine reverses the effect of haemoglobin. In conclusion, the inhibitory, relaxant stimulus of rat corpora cavernosa is due to both neuronal nitric oxide and endothelial-derived nitric oxide released in response to cholinergic stimulation.

Lack of linkage between chromosome 5q23-33 markers and IgE/bronchial hyperreactivity in 67 Scottish families

BACKGROUND

Raised serum immunoglobulin E (IgE) and bronchial hyperreactivity (BHR) are risk factors for the expression of the asthma phenotype. Previous studies have reported evidence for linkage between these traits and markers on the 5q23-33 cytokine gene cluster.

OBJECTIVE

To test for linkage between total serum IgE/BHR and microsatellite markers which map to the 5q23-33 region in an ethnically distinct cohort of families from Aberdeen, Scotland.

METHODS

We performed a linkage study between five polymorphic markers (spanning the chromosome 5q23-33 region) and total serum IgE and BHR traits. A cohort of 67 families, who were recruited originally to study the natural history of wheeze, were clinically characterized and genotyped for D5S404, IL4, IRF-1, IL9, D5S436 markers. Linkage analyses were performed using the nonparametric Haseman-Elston algorithm for the quantitative trait log IgE, and the nonparametric LOD score (NPL-score) of the GENEHUNTER package for the qualitative traits serum IgE and BHR.

RESULTS

The results of the nonparametric linkage analysis using either the Haseman-Elston algorithm or NPL-score were consistent and showed no evidence for linkage with IgE. There was also no evidence for linkage between the BHR traits (at cut-off values of PD20FEV1 < 8 mmol and 16 mmol) and any of the tested five microsatellite markers.

CONCLUSIONS

This study presents evidence against the presence of a gene with a major effect on total serum IgE or BHR in the 5q23-33 region, in this ethnic group.

Impairment of corpus cavernosal smooth muscle relaxation by glycosylated human haemoglobin

OBJECTIVE

To examine the effect of HbA1c, an isoform of glycosylated haemoglobin (GHb, a product of non-enzymatic reactions between elevated blood glucose and haemoglobin), on nitric oxide-mediated corpus cavernosal smooth muscle relaxation, and to categorize the mechanisms involved.

MATERIALS AND METHODS

Corpus cavernosal tissue from Wistar rats (300-350 g body weight) was prepared for the measurement of isometric tension. After equilibration in Krebs solution gassed with 95% O2/5% CO2 at 37 degrees C for 90 min, optimal resting tension was applied. Tissue was precontracted with 1 micromol/L noradrenaline (NAd) and either relaxed with incremental doses of acetylcholine (ACh) or sodium nitroprusside (SNP). After washout, strips were again precontracted with NAd and then incubated with pyrogallol (100 micromol/L), 100 microL of haemoglobin or 100 microL of GHb in the presence of either L-arginine (100 micromol/L), indomethacin (10 micromol/L), allopurinol (100 micromol/L), deferoxamine (100 micromol/L), catalase (600 IU/mL), or superoxide dismutase (SOD) (120 IU/mL) before ACh- or SNP-induced relaxation responses were repeated.

RESULTS

Haemoglobin and GHb significantly impaired the relaxation of rat corpus cavernosum to ACh in a dose-dependent manner. L-arginine reversed the impairment caused by Hb, but not GHb. A donor of superoxide anions, pyrogallol, mimicked this impairment to ACh when added to control strips. Catalase, deferoxamine, indomethacin and allopurinol had no significant effect on the impaired relaxation response to ACh, whilst L-arginine partially reversed it. SOD completely reversed the GHb-induced impaired relaxation; GHb did not alter the relaxation response to SNP.

CONCLUSION

GHb significantly impairs endothelial NO-mediated corpus cavernosal relaxation in the rat, in vitro. This effect is caused partly by the generation of superoxide anions and the extracellular inactivation of NO.

Purinergic sensory neurotransmission in the urinary bladder: an in vitro study in the rat

OBJECTIVES

To determine the response of mechanosensitive pelvic nerve afferents, arising from the rat urinary bladder, to the purinergic agonist alpha,beta-methylene ATP and to the purinergic antagonist suramin.

MATERIALS AND METHODS

Using a newly developed in vitro bladder-pelvic nerve afferent model, multiunit recordings were taken from mechanosensitive pelvic nerve afferents arising from the rat urinary bladder, in response to bladder distension. Control experiments were performed by distending the bladder with saline at 0.04 mL/min, and recording the total afferent nerve activity and the bladder pressure response to the distension. Bladder distensions were then repeated using a solution of the stable purinergic agonist alpha,beta-methylene ATP (10 micromol/L), which is known to desensitize P2X-purinoceptors after prolonged exposure, and the total afferent activity and bladder pressure response were again measured. In a separate series of experiments the afferent nerve activity and bladder pressure response to bladder distension with saline was determined in the presence of the purinergic antagonist suramin (10 micromol/L) and repeated after washout of the drug. In both series of experiments, afferent nerve responses were compared with control using the paired t-test, whilst the bladder pressure responses were compared using one-way analysis of variance.

RESULTS

Bladder distension with alpha,beta-methylene-ATP produced a statistically significant reduction in afferent nerve activity, by up to 75% compared with the control, whilst having no significant effect on the bladder pressure response. Bladder distension with saline in the presence of suramin (10 micromol/L) produced a significant reduction in the resultant afferent nerve activity, by 50%, which returned to normal after washout of the drug.

CONCLUSION

These findings are consistent with the notion that ATP is released endogenously during bladder distension in the rat and is involved significantly in the activation of pelvic nerve afferents arising from the rat urinary bladder.

Association between - 308 tumour necrosis factor promoter polymorphism and bronchial hyperreactivity in asthma

BACKGROUND

Tumour necrosis factor (TNF) is a pivotal cytokine in the inflammation underlying asthma. The TNF gene is located in the polymorphic HLA class 3 region on chromosome 6p. Several polymorphisms in this region have been described and associated with alteration of TNF secretion in vitro.

OBJECTIVE

In this study we tested the hypothesis that two such polymorphisms, lymphotoxin alpha NcoI B*1 and -308 TNF2 may be components of the genetic predisposition to asthma.

METHODS

Five hundred and fifty-six random individuals were studied, comprising approximately equal numbers of asthmatic subjects, with or without atopy, and a nonatopic nonasthmatic control group. In addition, 355 subjects (172 asthmatics) from 60 multiplex families were typed at the LTalpha NcoI locus.

RESULTS

There was an association between allele two of the -308 TNF polymorphism and bronchial hyperreactivity (OR 2.12, 95% CI 1.04-4.32, P = 0.036). However, there was no association with LTalpha NcoI alleles. To determine whether this was influenced by linkage disequilibrium within the MHC, 91 subjects with bronchial hyperreactivity and 85 control subjects were typed for class 2 and 3 alleles. Following identification of the extended TNF2 haplotype, we found no independent association of these alleles with BHR.

CONCLUSIONS

We conclude that the -308 TNF2 promoter polymorphism may form a component of the genetic predisposition to BHR in asthma.

CCR7 (EBI1) receptor down-regulation in asthma: differential gene expression in human CD4+ T lymphocytes

Asthma is an inflammatory disorder, and the CD4+ T lymphocyte plays a key role in mediating the inflammatory response. We used a high-density grid, hybridization-based, differential gene expression technology to analyse molecular mechanisms underlying in vivo CD4+ T-cell activation in both steroid-resistant asthma (SRA) and steroid-sensitive asthma (SSA). Hybridization of radioactively-labelled first-strand cDNAs prepared from different biological samples, to identical high-density gridded arrays of PCR amplicons derived from cDNA clone inserts immobilized on nylon membranes, was compared by phosphorimaging. Hybridization data were captured and processed using image analysis software that can identify the location and signal intensity of each hybridized cDNA. This produces a hierarchy of signals of differing intensities between the two grids, representing differential gene expression in the two different RNA samples. CCR7 (EBI1), a lymphocyte-specific G-protein-coupled receptor, was down-regulated in the CD4+ T cells of SRA and SSA non-atopic, compared to non-asthmatic non-atopic individuals. This observation is intriguing given that CCR7 and its ligand EBI1-Ligand Chemokine (ELC), may play a role in the migration and homing of normal lymphocytes. Also, TNFR2 is up-regulated in both SSA non-atopic and SRA atopic as compared to non-asthmatic controls. LAMR1 is down-regulated in CD4+ T cells of SRA compared to non-asthmatic individuals, irrespective of their atopic status. These could be general phenomena resulting from cytokine release.

Suggestive evidence for genetic linkage between IgE phenotypes and chromosome 14q markers

Chromosome 14q was screened for loci modulating immunoglobulin E (IgE) phenotypes in 15 extended and 45 nuclear asthmatic families using a panel of 14 microsatellite markers. We examined the reported linkage between the TCR A/D locus on 14q11.2 and specific (cognate) allergic responses and observed supportive evidence for linkage between a general skin prick test reactivity trait (but not with total serum IgE) and TCRA microsatellite (in the total sample of informative sib-pairs p = 0.039, in selected sample of one or zero affected parent p = 0.017). We also show suggestive evidence for a novel linkage between markers D14S75 and D14S63 on 14q13-23 and log total serum IgE (p = 0.034 and p = 0.0029). The evidence for linkage with marker D14S63 on 14q23 is strengthened by the finding of association of allele 165 to log IgE (p = 0.0029). We conclude that chromosome 14q may contain a locus close to TCR A/D at 14q11.2 linked to skin prick reactivity and a locus at 14q13- 23 linked to total serum IgE.

Stimulation of the inflammatory system by reamed and unreamed nailing of femoral fractures. An analysis of the second hit

It has been suggested that reamed intramedullary nailing of the femur should be avoided in some patients with multiple injuries. We have studied prospectively the effect of femoral reaming on the inflammatory process as implicated in the pathogenesis of acute respiratory distress syndrome (ARDS) and multiple-organ failure (MOF). We studied changes in the levels of serum interleukin-6 (IL-6) (proinflammatory cytokine), neutrophil CD11b (C3) receptor expression (activated neutrophil adhesion molecule), serum soluble intracellular adhesion molecule (s-ICAM-1), serum soluble E-selectin (the soluble products of endothelial adhesion molecules) and plasma elastase (neutrophil protease) in a series of patients with femoral fractures treated by nailing. We have also compared reamed nailing with unreamed nailing. We found that the levels of serum IL-6 and elastase rose significantly during the nailing procedure indicating a measurable 'second hit'. There was no clear response in leukocyte activation and no difference in the release of endothelial adhesion molecule markers. There was no significant difference between groups treated by reamed and unreamed nailing. Although clinically unremarkable, the one patient who died from ARDS was shown to be hyperstimulated after injury and again after nailing, suggesting the importance of an excessive inflammatory reaction in the pathogenesis of these serious problems. Our findings have shown that there is a second hit associated with femoral nailing and suggest that the degree of the inflammatory reaction may be important in the pathogenesis of ARDS and MOF.

A novel in vitro bladder pelvic nerve afferent model in the rat

OBJECTIVE

To develop an in vitro model to allow electrophysiological recordings from pelvic nerve afferents of the urinary bladder in the rat and to ascertain the stability and reproducibility of the model with time.

MATERIALS AND METHODS

Six male Wistar rats (body weight approximately 100 g) were used in the study. The bladder (complete with accessory organs of prostate and seminal vesicles), urethra and penis, together with the attached pelvic nerve and L6/S1 nerve trunk, were removed intact and placed in a specially designed recording chamber containing oxygenated Krebs solution maintained at 30 degrees C. The bladder was catheterized urethrally and attached to a continuous-infusion pump and a pressure transducer. The L6/S1 nerve trunk was placed across a silicone-gel wall into a separate chamber containing liquid paraffin, in which multiunit recordings from pelvic nerve afferents originating from the bladder were made. The afferent nerve activities in response to repeated bladder distension with saline, at 0.04 mL/min for 8 min over 3 h, were compared using the paired t-test to assess the reproducibility of the model. Conduction velocity studies were also carried out to ascertain the proportion of C- and A delta-fibres in the multiunit recordings.

RESULTS

Repeated bladder distension with saline over 3 h produced consistent and reproducible afferent nerve responses, signifying that the afferent nerves recorded in this study neither sensitize nor desensitize over time. This is an essential prerequisite when using this model to study the effects of pharmacological manipulation of the bladder on its afferent nerve response. Conduction velocity studies showed that approximately 30% of the afferent fibres recorded from were C-fibres with the remaining being A delta-fibres.

CONCLUSIONS

An in vitro bladder pelvic nerve afferent model for the rat was developed successfully; it is stable and produces reproducible results with repeated bladder distension over at least 3 h.

Relationship between exhaled nitric oxide and childhood asthma

The purpose of the study was to determine if exhaled nitric oxide levels in children varied according to their asthmatic and atopic status. Exhaled nitric oxide was measured in a sample of 93 children attending the North West Lung Centre, Manchester, United Kingdom, for the clinical evaluation of a respiratory questionnaire being developed as a screening tool in general practice. The clinical assessment included full lung function, skin prick testing, and exercise challenge. Children were said to be asthmatic either by consensus decision of three independent consultant pediatricians, who reviewed all the clinical results except the nitric oxide measurements, or by positive exercise test. Atopic asthmatic children had higher geometric mean exhaled nitric oxide levels (consensus decision, 12.5 ppb [parts per billion] 95% CI, 8.3 to 18. 8; positive exercise test, 12.2 ppb 95% CI, 7.6 to 19.7) than did nonatopic asthmatic children (3.2 ppb 95% CI, 2.3 to 4.6; 3.2 ppb 95% CI, 2.0 to 5.0), atopic nonasthmatic children (3.8 ppb 95% CI, 2. 7 to 5.5; 5.7 ppb 95% CI, 4.1 to 8.0), or nonatopic nonasthmatic children (3.4 ppb 95% CI, 2.8 to 4.1; 3.5 ppb 95% CI, 3.0 to 4.1). Thus, exhaled nitric oxide was raised in atopic asthmatics but not in nonatopic asthmatics, and these nonatopic asthmatics had levels of exhaled nitric oxide similar to those of the nonasthmatics whether atopic or not.

The CD4+ T lymphocyte is a site of steroid resistance in asthma

Phytohaemagglutinin (PHA)-induced T-cell proliferation is suppressed completely in steroid-sensitive asthma (SSA) by fluticasone propionate (FP). By contrast, in patients with steroid-resistant asthma (SRA), this proliferative response is only partially attenuated by steroids, which suggests that the T lymphocyte may harbour a key molecular defect in these patients. Both CD4+ and CD8+ T cells may be involved in orchestrating the inflammation underlying asthma. We examined whether CD4+ or CD8+ T cells isolated from SRA and SSA patients are equally susceptible to steroid suppression of PHA-induced proliferation. Complete suppression of CD4+ T-lymphocyte proliferation was seen in both SSA and control subjects at concentrations of 10(-9) M FP. In contrast, proliferation of CD4+ T cells from SRA patients was only partially inhibited, even at 10(-6) M FP. CD8+ responses from SRA, SSA and controls were all similar, with only a partial suppression of proliferation at 10(-6) M FP. Differential suppression by FP of CD4+ T cells has thus been demonstrated between SRA and SSA patients.

Beta2-adrenoceptor polymorphisms are in linkage disequilibrium, but are not associated with asthma in an adult population

OBJECTIVE

To determine the association between the beta2-adrenoceptor polymorphisms at amino acids 16 and 27 and markers of allergic disease and asthma per se in a random adult population, and to determine the degree of linkage disequilibrium existing between polymorphisms at amino acid positions 16, 27, 164 and nucleic acid residue 523.

METHODS

We measured serum IgE, skin-prick test positivity, atopy, bronchial hyperreactivity, wheeze and asthma (self-reported and doctor-diagnosed), and determined beta2-adrenoceptor genotype by allele specific oligonucleotide hybridization, in 630 adults aged between 18 and 70, selected from the electoral role in a local health authority in Nottingham.

RESULTS

Homozygotes for the Glycine 16 polymorphism had a significantly higher incidence of atopy (chi2=6.44 (Pearson's), P=0.04). We also observed a significant association between the Glycine 16 allele and atopy (chi2=4.13 (Pearson's), P=0.04), when we assumed the Glycine 16 allele to operate in a dominant mode. No other significant associations between beta2-adrenoceptor polymorphisms and markers of allergic disease and asthma per se were observed. Marked linkage disequilibrium exists between the beta2-adrenoceptor polymorphisms at amino acid 16 and 27 (D=0.38, chi2 P<0.0001), and between the beta2-adrenoceptor polymorphisms at amino acid 27 and nucleic acid residue 523 (C-A) (D=0.36, chi2 P<0.0001).

CONCLUSION

There is no consistent association between beta2-adrenoceptor polymorphisms and the risk of developing allergic disease or asthma per se in this adult sample. Marked linkage disequilibrium exists between the amino acid 16 and 27 polymorphisms, and also between the amino acid 27 polymorphism and the nucleic acid residue 523 (C-A) polymorphism. This polymorphism accounts for the Ban 1 RFLP previously described at the beta2-adrenoceptor locus on chromosome 5q 31.

Association study of asthma and atopy traits and chromosome 5q cytokine cluster markers

BACKGROUND

Linkage studies have provided evidence for the presence of gene(s) in the 5q cytokine cluster region which control total serum immunoglobulin E (IgE) concentration, and bronchial hyperreactivity (BHR). However, the identification of the gene(s) involved has been confounded by the lack of power of the published linkage studies and the presence of multiple candidate genes mapped to the region.

OBJECTIVE

To define the important loci on 5q31-33 which are implicated in the control of total serum IgE and BHR through a case/control study of association.

METHODS

We performed an association study between 11 polymorphic markers (spanning the region 5q31.1-33.1) and total serum IgE and BHR traits. A case/control sample of 181 individuals was drawn from a larger set of 2415 adults, sampled at random from a district in Nottingham, UK. Half of the subjects in this case/control sample were hyperreactive to methacholine and asthmatic (cases), while the other half were non-reactive and non-asthmatic (controls). Association analysis was performed using the non-parametric chi-squared and Mann-Whitney U-tests.

RESULTS

We observed no evidence of strong allelic association between any of the above markers and the studied traits. Markers D5S404, interferon regulatory factor 1 (IRF-1) and D5S210 showed evidence of borderline association with BHR (P = 0.04, 0.03 and 0.04 respectively), and D5S404 showed borderline significance with IgE levels (P = 0.029).

CONCLUSIONS

This study presents evidence against the presence of a strong association between markers mapped to 5q31-33 and either BHR or total serum IgE. The significance of the weaker associations observed with markers D4S404, IRF-1 and D5S210 is not clear. Whether this represents a type I error secondary to multiple hypothesis testing or a true association is uncertain.

Matrix and modifier effects in the supercritical fluid extraction of cocaine and benzoylecgonine from human hair

The supercritical fluid extraction (SFE) behavior of cocaine and its major metabolite benzoylecgonine (BZE) was investigated and found to be highly dependent upon the chemical nature of the matrix and the manner in which the target drug analytes are incorporated into or on the matrix. The recovery of cocaine from Teflon wool, filter paper, drug-fortified hair, and drug user hair was studied using a variety of CO2/modifier mixtures. Incorporation of a triethylamine (TEA)/water modifier mixture provided dramatic improvements in the recovery of cocaine from interactive matrixes. The results suggest that the SF extractability of cocaine is not limited by analyte solubility; rather, desorption of cocaine from hair binding sites is a rate-limiting step in the SFE process. A displacement SFE mechanism is hypothesized in which TEA (as the triethylammonium cation) competes with cocaine for negatively charged hair binding sites. The dependence of extractability on hair/drug binding interactions allows the differentiation of cocaine present at different discrete sites in hair based on differences in SFE behavior. These findings suggest the potential for distinguishing exogenous (i.e., environmental) from endogenous (i.e., physiological) sources of drugs in hair. In contrast to the results observed for cocaine, SFE recoveries of BZE were poor from all matrixes and under all conditions studied. Its increased polarity, the presence of an additional binding site, and the possibility of multiple charged states suggest that poor BZE recoveries may be due to both poor analyte solubility and failure to desorb the analyte from hair binding sites under the conditions employed.

Characterization of human SHC p66 cDNA and its processed pseudogene mapping to Xq12-q13.1

SHC is an adapter protein in the Ras-MAPkinase pathway that is involved in the regulation of cell growth and differentiation. The p46 and p52 isoforms are thought to be produced by the use of two alternative translation initiation sites in a 3.4-kb transcript from the SHCA gene, which maps to chromosome 1q21. The p66 isoform could be encoded by a different 3.8- or 2.8-kb transcript of the same gene or alternatively by a SHC-related gene. To characterize other putative genes coding for SHC-like proteins, primers from the 3' UTR of the SHCA gene were used to screen a yeast artificial chromosome (YAC) library by polymerase chain reaction (PCR). Two YAC clones, 20D11B and 36D1D, were isolated and used as probes for fluorescence in situ hybridization analysis. Both these probes hybridized to chromosome Xq12-q13.1. This novel SHC-related sequence was characterized by direct sequencing of vectorette library PCR products produced from clone 20D11B. A transcript of 3.2 kb that was 85% identical to the mouse Shc cDNA encoding the p66 isoform was identified. Sequence analysis demonstrated the presence of multiple stop codons identifying this isoform of SHC as a processed pseudogene. Using primers designed on the basis of the nucleotide sequence of the pseudogene, we have now amplified and sequenced a human cDNA that encodes the SHC p66 protein. Thus, we have characterized the human SHC p66 isoform cDNA and identified a processed SHC pseudogene that maps to chromosome Xq12-q13.1.

Slow-binding inhibition: the general case

Two basic kinetic mechanisms have been described to account for the slow-binding inhibition of enzyme-catalyzed reactions. One mechanism involves the slow interaction of an inhibitor with enzyme (Mechanism A), while the other involves the rapid formation of an enzyme-inhibitor complex that undergoes a slow isomerization reaction (Mechanism B). But the initial interaction of enzyme and inhibitor may not necessarily be fast so that the free enzyme and the two forms of enzyme inhibitor complex are in steady-state equilibrium. This assumption would give rise to a more general form of Mechanism B. The present study has been concerned with attempts to determine whether it might be possible to distinguish between the three possible inhibition mechanisms by steady-state kinetic techniques. The approach to the investigation has been to derive theoretical data for the most general mechanism by using three different ratios for the two rate constants that determine which mechanism applies. The progress curve data were then fitted to the rate equations that describe the other two mechanisms. The results draw attention to the difficulties of deducing that experimental data conform to the most general mechanism. They also show how the values for the kinetic parameters, as determined from fits of the data to the equations that describe Mechanisms A and B, can be considerably in error.

Excitatory and inhibitory A- and C-reflexes in pelvic parasympathetic efferent nerves elicited by single shock to A and C afferent fibers of perineal and limb somatic nerves in anesthetized rats

The effects of single electrical shocks to myelinated A and unmyelinated C afferent fibers of perineal and limb somatic nerves on the reflex discharges in pelvic parasympathetic (L6/S1) efferent nerves to the bladder were examined in anesthetized central nervous system (CNS)-intact and acute spinal rats. When the bladder was empty, stimulation of perineal somatic inputs to the L6 and S1 segments from the perineo-femoral branch of a pudendal nerve produced excitatory A- and C-reflex discharge components in postganglionic parasympathetic efferent nerve branches on the bladder surface. When the bladder was expanded and pelvic efferent neurons were rhythmically active, additional inhibitory A- and C-reflex components could be seen. After acute spinal transection, the same stimuli elicited excitatory A- and C-reflex discharges of similar latency as those observed before the spinal transection, but were of larger amplitude and longer duration; resting activity in the pelvic nerve was low, and no evoked inhibitory reflex components could be observed. Electrical stimulation of afferents in the tibial nerve had no effect when the bladder pressure was low, but when the bladder was distended, early and late components of reflex inhibition and excitation of parasympathetic activity were visible in CNS-intact rats; these reflex responses were abolished following spinalization.

The nitric oxide synthase inhibitor L-NAME reduces inhibitory components of somato-vesical parasympathetic reflexes in the rat

Reflex discharges of pelvic postganglionic parasympathetic efferent fibers on the bladder surface induced by afferent volleys in the hindlimb nerve have been recorded in anesthetized rats, and the effects of the nitric oxide synthase inhibitor, N omega-nitro-L-arginine methyl ester (L-NAME) on the reflex discharges have been investigated. Single electrical stimulation of the tibial nerve at intensities supramaximal for excitation of A- and C-afferents evoked a reflex discharge in the postganglionic parasympathetic efferents with four distinct components, i.e., two inhibitory components with latencies of 49 and 203 ms, respectively, and two excitatory components with latencies of 126 and 308 ms, respectively. These reflexes could be observed when the bladder was expanded, but not markedly when the bladder was empty. Intravenous administration of L-NAME resulted in (a) a reduction in the level of resting discharge, (b) a reduction in the size of the first inhibitory component, (c) the disappearance of the second inhibitory component and (d) the exaggeration of the late excitatory component. Intracisternal injection of L-NAME caused changes similar to those observed following intravenous injection. The results suggest that inhibitory components of the somato-pelvic parasympathetic reflex are mediated by pathways that utilize nitric oxide as a neurotransmitter or neuromodulator at the level of the brainstem.

Non random usage of T cell receptor alpha gene expression in atopy using anchored PCR

The T cell receptor (TCR) alpha beta heterodimer recognises antigenic peptide fragments presented by Class II MHC. This interaction initiates T cell activation and cytokine release with subsequent recruitment of inflammatory cells. Previous work from our group suggests a qualitative difference in variable alpha gene expression in atopy as compared to non atopic controls. In this study we examine TCR alpha repertoire using anchored PCR to provide a quantitative assessment of the V alpha and J alpha repertoire. One atopic (DRB1*0701,DRB1*15: DRB4*0101, DRB5*01: DQB1* 0303, DQB1*601/2) and one non-atopic (DRB1*0701,DRB1*03011/2: DRB4*01, DRB3*0x: DQB1* 0303, DQB1*0201/2) control were studied. Variable gene usage was markedly limited in the atopic individual. V alpha 1, 3, 8 accounted for 60% and J alpha 12, 31 30% of the gene usage. There was evidence of preferential V alpha-J alpha gene pairing and clonal expansion. We conclude that there is a marked non random TCR alpha gene distribution in atopy using both V alpha family and anchored PCR. This may be due in part to antigen driven clonal expansion.

Multiple mechanisms of heterologous beta-adrenoceptor regulation in rat uterus

The inhibitory effects of catecholamines on rat myometrium mediated by beta-adrenoceptors are modulated by ovarian steroids. Previously reported findings of radioligand binding studies on myometrial membranes have demonstrated changes in the numbers of beta-adrenergic binding sites following ovarian steroid treatment. However, these changes were not accompanied by parallel functional changes. In the present study, we have investigated possible mechanisms of heterologous beta-adrenoceptor regulation by ovarian steroids. Binding studies were performed on myometrial membrane and cytosolic preparations from rats which had been ovariectomized and subsequently received no hormonal treatment or had been treated with oestradiol, progesterone or combined oestradiol and progesterone. The beta-adrenergic antagonist [125I]iodocyanopindolol and the unlabelled competing agonist, isoprenaline, were used in the present studies. Hormonal treatment had no effect on the concentration of beta-adrenergic binding sites in the myometrium (i.e. the number of membrane-bound and cytosolic binding sites per mg protein). However, significant changes were found in the total number of binding sites; these were associated with the hormone-induced tissue hypertrophy. In myometrium from ovariectomized-alone rats, approximately 50% of beta-adrenergic binding sites were present in the cytosolic fraction. Oestradiol treatment, either on its own or in combination with progesterone, resulted in the translocation of binding sites to the cell membrane. However, in the absence of progesterone only 33% of the membrane-bound binding sites bound the beta-adrenergic agonist, isoprenaline, with a high affinity, suggesting that the majority of these membrane-bound binding sites represented non-functional beta-adrenoceptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytokine expression in normal, atopic, and asthmatic subjects using the combination of sputum induction and the polymerase chain reaction

BACKGROUND

The importance of cytokines in the asthmatic inflammatory response is becoming apparent. The aim of this study was to determine whether the non-invasive method of induced sputum combined with the polymerase chain reaction would allow the detection of messenger RNA (mRNA) encoding a range of cytokines on a qualitative basis.

METHODS

Four groups were studied comprising 10 normal subjects, six atopic, 10 mild and five moderately severe asthmatic subjects. Sputum was induced by the inhalation of nebulised 3.5% saline and total RNA extracted from the expectorated cells. Expression of cytokine message within induced sputum was examined by reverse transcription and the polymerase chain reaction (PCR) using primers specific for a range of cytokines (IL-1 alpha, IL-2, IL-3, IL-4, IL-5, IL-6, IL-8, RANTES, TNF alpha, IFN alpha, IFN gamma). Presence or absence of the signal was determined at 35 and 70 cycles of PCR by electrophoretic size fractionation on ethidium bromide stained agarose gels.

RESULTS

Cytokine message was detectable in sputum by this method. All samples showed a positive result for actin control. Analysis of signal for the cytokines in all subjects showed that, at 70 cycles, IL-1, IL-5, IL-8, and TNF alpha were detected in more subjects than would be expected by chance. IL-5 mRNA was detected in more of the asthmatic patients (moderate 80%, mild 40%) than in the atopic subjects (33%), who in turn showed expression of this cytokine in more individuals than nonatopic subjects (10%).

CONCLUSIONS

The combination of sputum induction and PCR appears to be a useful, non-invasive tool to explore the chronic inflammation of asthma and possibly other lung disorders. It should enable differences between normal and asthmatic subjects to be identified for future confirmation by quantitative techniques.

Effects of denervation on muscarinic receptors in the rat bladder

OBJECTIVE

To demonstrate the specific distribution of muscarinic receptors in the rat urinary bladder and to investigate the effects of afferent and efferent denervation on the density and distribution of muscarinic receptors.

MATERIALS AND METHODS

Urinary bladders were obtained from female rats which had been injected with vehicle (control), or neonatally with capsaicin (NC, afferent denervation) or which had their pelvic plexus removed (post-ganglionic denervation, PGD, efferent denervation). Tissue sections were used in radioligand-binding studies and for autoradiography with the muscarinic receptor ligand l-quinuclidinyl[phenyl-4-3H]benzilate (QNB).

RESULTS

Binding of QNB was saturable and specific to a single population of binding sites, with a mean dissociation constant (Kd) of 1.05 +/- 0.14 nM in controls and 0.90 +/- 0.13 nM in rats with PGD. Post-ganglionic denervation caused a 37% increase in maximal binding (Bmax) of QNB from 437.1 +/- 39.1 fmol/mg protein (control group) to 599.1 +/- 4.5 fmol/mg protein (P < 0.02). Autoradiograms revealed muscarinic binding sites over the smooth muscle, but none over the epithelium. Smooth muscle binding sites were doubled after PGD but were unchanged after NC treatment.

CONCLUSION

Muscarinic receptors were localized over the smooth muscle of the rat bladder and were increased after post-ganglionic denervation. This increase may be responsible for the increased sensitivity to muscarinic agonists reported to occur after bladder denervation.

Long-lasting facilitation and depression of periurethral skeletal muscle following acupuncture-like stimulation in anesthetized rats

The effects of acupuncture-like stimulation on the tone of the partially filled bladder and on the periurethral electromyogram (EMG) were examined in urethane-anesthetized rats. Acupuncture-like stimuli were usually applied to the skin and underlying muscles (or other structures), either separately or together, for a period of 1 min; the effects were studied in spinal cord intact and in spinalized animals. Maps have been constructed showing the effects of acupuncture-like stimulation at different sites on the body surface and of similar stimulation applied to individual muscles, the urethra and the testis. When acupuncture-like stimuli were applied to the skin and underlying structures, in the rostral half of the body and the hindpaw, testis or urethra, these stimuli usually induced excitation of periurethral EMG activity. Depression of EMG activity was seen predominantly during stimulation of structures close to the urethra, but not opposed to it. When acupuncture-like stimuli were applied only to structure beneath the skin, depression of EMG activity usually occurred. Acupuncture-like stimulation of the bulbocavernosus, which partly overlies the proximal urethra produced depression of EMG activity in 50% of trials, but the incidence of similar effects from the more distant pubococcygeus, or the dorsal or ventral sacrococcygeal muscles was about 90-100%. Acupuncture-like stimulation for 1 min could produce either excitation or depression of periurethral EMG activity lasting about 5 or 6 min, depending on the site of insertion and rotation of the acupuncture needles. Excitation of short duration (less than 3 min) was consistently observed from areas of the body distant to the bladder, i.e. the nose, forepaw, forelimb, chest, abdominal wall and hindpaw. Longer lasting excitation of EMG activity was often seen from the penile urethra, perineal area and hindlimb. Depression of EMG activity with a duration of more than 3 min was consistently seen from the muscles at the base of the tail (sacrococcygeus) and perineal area (pubococcygeus and bulbocavernosus). The bladder was partially filled in these experiments, so that micturition contractions were never seen; acupuncture-like stimulation of the perineal area induced some increase in bladder tone in 40% of trials. In spinalized animals, the pattern of activity induced by acupuncture-like stimulation was similar to that seen in spinal cord intact animals and the durations of the effects were not significantly different in these two groups. The distribution of sites from which acupuncture-like stimuli can influence the activity of the lower urinary tract is discussed.

The influence of afferent inputs from skin and viscera on the activity of the bladder and the skeletal muscle surrounding the urethra in the rat

(1) Somato-visceral and viscero-visceral reflex interactions have been studied in the bladder branches of the pelvic nerve and in the electromyographic (EMG) activity of the periurethral skeletal muscles of the anesthetized rat, and by observations of changes in bladder motility. (2) Slow distensions of the bladder caused some elevation of intravesical pressure, and culminated in a micturition contraction. Periurethral EMG activity increased gradually during the bladder distension, and showed an oscillatory marked increase during the bladder contraction. There was a small increase in pelvic nerve efferent activity during slow distension, and there was a substantial increase before, or at the start, of a micturition contraction. (3) Oscillatory bursting activity occurred in recordings of the EMG activity from periurethral skeletal muscle during the rising phase of micturition contraction; this was particularly so during the most rapid rise in intravesical pressure, and periods of electrical silence lasting 80-270 ms alternated with bursts of activity in the periurethral EMG. (4) In the present experiments, the switching mechanism activated by pelvic afferent signals related to intravesical pressure reversed the behavior of a number of reflex pathways. When the bladder pressure was low, nociceptive pinching of the perineal skin usually caused bladder contraction and a rise in pelvic nerve efferent activity and in periurethral EMG activity. When the bladder was full, micturition contractions were present and reduced in size and frequency by pinching of the perineal skin. The pelvic nerve efferent activity was correspondingly reduced, while the EMG activity increased during and following the nociceptive stimulus. Cooling the scrotal skin with ice also decreased the frequency of bladder contractions. (5) When the bladder pressure was low, distension of the anus and colon increased periurethral EMG activity, but did not affect bladder tone. However, when the bladder was full, these stimuli reduced the size and frequency of bladder contractions, associated with a reduction in the pelvic nerve efferent activity. There was usually a simultaneous reduction in the EMG activity in periurethral muscles. Similar results were obtained during distension of the seminal vesicles or vagina, or following injection of 20-60 microliters of saline into the lumen of the vas deferens. Reversal of the responses at extremes of intravesical pressure was observed in every case. (6) Following spinal transection at the upper cervical or thoracic level, micturition contractions were absent at high bladder volumes. However the effects described when the neuraxis was intact and the bladder pressure was low were still observed.(ABSTRACT TRUNCATED AT 400 WORDS)

The effects of pregnancy and parturition on the substance P content of the rat uterus: uterine growth is accompanied by hypertrophy of its afferent innervation

The afferent innervation of the uterus might be expected to grow during pregnancy as the size of the uterus increases. Substance P-like immunoreactivity (SPLI) has been measured as a means of monitoring the changes in the afferent innervation of the urogenital tract of rats during pregnancy and following parturition. The great growth of uterine tissue during pregnancy causes an overall decrease in SPLI concentrations during pregnancy, but it has been found that the amount of SPLI present per uterine horn increases nearly 3-fold by the end of pregnancy. This increase is greater in uterine horns that contain more fetuses, suggesting that the SPLI innervation expands to a greater extent in uterine horns that undergo greater degrees of hypertrophy. There is a significant correlation between SPLI content and the number or total weight of fetuses throughout the latter two-thirds of pregnancy. There is a fall in SPLI content of uterine horns following parturition, but not to a statistically significant degree, and this may be related to the release of the peptide during parturition.

The effects of pregnancy and parturition on the levels of substance P-like immunoreactivity in different areas of the hypothalamus

1. The concentrations of substance P-like immunoreactivity (SPLI) have been measured in the rostral and caudal areas of the hypothalamus of male rats and of virgin, pregnant and puerperal female rats. 2. The rostral:caudal ratio of SPLI is similar in males and virgin females, but diminishes in pregnancy and decreases further during the puerperium. In the pre-optic area, the SPLI concentration fell significantly during parturition, from 241.8 to 177.2 pmols/g wet weight (P < 0.05), and in the medio-basal hypothalamus, the concentration rose during pregnancy and parturition, from 87.4 to 145.5 pmols/g wet weight (P < 0.001). 3. The results are discussed in relation to the endocrine and nociceptive aspects of pregnancy and parturition.

The temporal and cellular expression of c-fos and c-jun in mechanically stimulated rabbit latissimus dorsi muscle

The levels of c-fos and c-jun mRNA were measured by reverse transcription PCR in the rabbit latissimus dorsi muscle following three separate training regimes, i.e. passive stretch, 10 Hz electrical stimulation or a combination of the two. Both c-fos and c-jun mRNA expression peaked at around 1 h after imposing stretch and at around 4.5-6 h after the initiation of electrical stimulation. The combined stretch/electrical stimulation regime induced biphasic expression of both c-fos and c-jun mRNA, with peaks coinciding temporally with those for the individual regimes. Immunostaining with anti-Fos and anti-Jun antibodies revealed the accumulation of these proteins in both myofibre and interstitial cell nuclei following passive stretch. In contrast, following electrical stimulation the localization of immunoreactive c-Fos and c-Jun proteins was predominantly in interstitial cell nuclei. c-Fos and c-Jun immunoreactivity was also clearly colocalized in a proportion of myonuclei from stretched muscle. These findings suggest that the rapid induction of c-fos and c-jun is an early event in response to mechanical stretch and might trigger [via activator protein-1 (AP-1) transcriptional factors] events leading to muscle fibre hypertrophy. However, the involvement of AP-1 in inducing the phenotypic changes in muscle fibres as a result of electrical stimulation appears less clear.

Yeast artificial chromosome cloning of the beta-catenin locus on human chromosome 3p21-22

beta-Catenin has emerged as an important component of the adherens junctions between epithelial cells. As a result of studies of its interaction with the APC gene product, it has been implicated in the development of colorectal cancer. alpha-Catenin, beta-catenin, E-cadherin and APC appear to mediate contact inhibition in epithelia. As part of the study of the organization of the beta-catenin gene, we have isolated yeast artificial chromosomes (YACs) to characterize its intron/exon structure. YAC fluorescence in situ hybridization analysis and polymerase chain reaction analysis of somatic cell hybrid DNAs show that beta-catenin maps in the 3p21-22 region, the location of tumour-suppressor genes deleted in small-cell lung cancer (SCLC) and other disorders. beta-Catenin YACs will provide a source of microsatellite markers useful in loss of heterozygosity studies to assess the importance of beta-catenin deletions in SCLC.

The effects of aging on the rat bladder and its innervation

1) Measurements of the cystometrogram, of the responsiveness of bladder muscle to pelvic nerve efferent stimulation and of the sensitivity of the pelvic nerve afferents to pressure and volume during distensions have been made in the bladders of young adult (2-3 months) and aged (26-29 months) rats, anesthetized with mixtures of urethane and chloralose. 2) The pressure-volume relationship differed in young adult and aged rats. The bladders of the aged rats held up to nearly six times the volume of the young animals, and these volumes were accommodated at lower pressures in the aged animals. The pressure at which micturition contractions appeared was similar in young adult and aged animals. 3) The passive pressure associated with each of a series of distending volumes was recorded when a pelvic nerve was cut unilaterally. The distal cut end of this cut pelvic nerve was stimulated for 10 s at 20 Hz, using square wave pulses of 10 V and 1.0 ms. The active pressure-volume relationship was constructed from this data. Both the active and the passive relationships were shifted to the right in the aged animals, and it was evident that aging was associated with a reduction in the maximal pressure generated during pelvic nerve stimulation. Also the change in intravesical pressure induced by bladder contraction was less in aged animals. 4) The most sensitive mechanoreceptor afferents appear to have pressure and volume thresholds that do not change significantly during aging. While the distension-sensitive afferents in the pelvic nerve appear to have a similar sensitivity to intravesical pressure in young adult and aged rats, they were less able to monitor volume in the aged animals. The stimulus response relationship for volume was often less steep in the aged animals. 5) In this study, aging was shown to be associated with a large increase in bladder volume and a reduced sensitivity of pelvic nerve afferents to volume, and a reduced ability to raise bladder pressure during contraction of bladder smooth muscle. The changes in bladder function associated with aging are discussed.

Effect of mechanical stimulation of the skin on the external urethral sphincter muscles in anesthetized cats

Experiments were performed using anesthetized cats to examine the effects of cutaneous stimuli on the external urethral sphincter (EUS) activity and bladder motility, 1) when the bladder volume was changed from low to high, and in the latter case, in the presence or absence of micturition contractions, 2) in different neurological states, viz., in animals with an intact neuraxis and in acute or chronic spinal preparations. In animals with an intact neuraxis, when the volume of the bladder was low, the bladder was quiescent and noxious mechanical stimulation of the perineal skin produced abrupt and marked increases both in vesical pressure and EUS activity. Similar results were observed in acute spinal as well as chronic spinal animals. The effect of the stimulus was particularly potent in chronic spinal animals. In animals with an intact neuraxis, when the volume of the bladder was increased, rhythmic micturition contractions were produced and noxious stimulation of the perineal skin slowed the frequency of the large rhythmic micturition contractions of the bladder and increased the EUS activity. These effects in animals with an intact neuraxis were substantially similar to those in chronic spinal cats showing synergic states. The effects of these somatic stimuli on the integration and coordination of bladder motility (controlled mainly by the parasympathetic pelvic efferent nerves) and EUS activity (controlled by somatic pudendal efferent nerves) are discussed.

Bambuterol: effective in nocturnal asthma

Bambuterol was compared with placebo in 28 patients with nocturnal asthma in a randomized, double-blind cross-over study. All patients were symptomatic despite taking inhaled beta 2-agonists, inhaled corticosteroids (in 26 patients the median daily dose was 1500 micrograms) and oral corticosteroids (in eight patients the median daily dose was 10 mg). Patients demonstrated > or = 20% overnight fall in peak expiratory flow (PEF) for at least half of the 14-day run-in period. They then entered two treatment periods lasting 14 days when bambuterol 20 mg nocte and placebo were given in random order. Compared to placebo, bambuterol produced a 16% improvement in mean PEF on waking (271 l min-1 vs. 239 l min-1 P = 0.0002) and a 10% improvement in evening PEF measured 24 h after drug intake (318 l min-1 vs. 296 l min-1 P = 0.01). Bambuterol significantly reduced frequency of nocturnal awakening from 1.1 to 0.7 per night (P = 0.01) and nocturnal beta 2-agonist use from 2.7 to 2.1 puffs (P = 0.0004). Other nocturnal symptoms: cough, wheeze and dyspnoea were also significantly reduced during bambuterol treatment and patients quality of sleep was improved. The results indicate bambuterol (20 mg nocte) provides effective nocturnal bronchodilation with sustained effect for 24 h and may have a useful therapeutic role in the control of symptomatic nocturnal asthma.

Effects of inhaled capsaicin in heart-lung transplant patients and asthmatic subjects

We have studied the effects on FEV1 of inhaled capsaicin in concentrations of 3 x 10(-6) to 3 x 10(-1) mg/ml and methacholine (1 to 16 mg/ml) in 15 heart-lung transplant (HLT) patients who had undergone recent transbronchial lung biopsy to determine the relationships in chronically denervated lungs between these different forms of airway hyperreactivity and inflammation. A total of 10 normal subjects and 17 asthmatic subjects were included for comparison. Capsaicin caused bronchodilation in eight HLT patients (FEV1 rising by 6.4 to 26.8%) and bronchoconstriction in two (fall in FEV1 of 7.2 and 7.6%). By contrast, seven asthmatic subjects developed bronchoconstriction after capsaicin (fall in FEV1 5.6 to 40.4%); the remaining 10 asthmatic subjects showed no response. Bronchial hyperresponsiveness to methacholine was most evident in the asthmatic subjects, but six HLT patients demonstrated a > or = to 20% fall in FEV1 with < or = 8 mg/ml of methacholine. All normal subjects were nonresponsive to both agents, and all normal and asthmatic subjects, unlike HLT patients, coughed with capsaicin. No relationship existed between the methacholine and capsaicin responses. In the HLT patients neither form of airway responsiveness was related to the degree of inflammation seen on transbronchial lung biopsy. The results suggest that in normal subjects, although it provokes cough, inhaled capsaicin causes little airway narrowing.(ABSTRACT TRUNCATED AT 250 WORDS)