Cytosolic group IVA phospholipase A2 inhibitors, AVX001 and AVX002, ameliorate collagen-induced arthritis

Background

Cytosolic phospholipase A2 group IVA (cPLA2α)-deficient mice are resistant to collagen-induced arthritis, suggesting that cPLA2α is an important therapeutic target. Here, the anti-inflammatory effects of the AVX001 and AVX002 cPLA2α inhibitors were investigated.

Methods

In vitro enzyme activity was assessed by a modified Dole assay. Effects on inhibiting IL-1β-induced release of arachidonic acid (AA) and prostaglandin E2 (PGE2) were measured using SW982 synoviocyte cells. In vivo effects were studied in prophylactic and therapetic murine collagen-induced arthritis models and compared to methotrexate (MTX) and Enbrel, commonly used anti-rheumatic drugs. The in vivo response to treatment was evaluated in terms of the arthritis index (AI), histopathology scores and by plasma levels of PGE2 following 14 and 21 days of treatment.

Results

Both cPLA2α inhibitors are potent inhibitors of cPLA2α in vitro. In synoviocytes, AVX001 and AVX002 reduce, but do not block, release of AA or PGE2 synthesis. In both CIA models, the AI and progression of arthritis were significantly lower in the mice treated with AVX001, AVX002, Enbrel and MTX than in non- treated mice. Several histopathology parameters of joint damage were found to be significantly reduced by AVX001 and AVX002 in both prophylactic and therapeutic study modes; namely articular cavity and peripheral tissue inflammatory cell infiltration; capillary and synovial hyperplasia; articular cartilage surface damage; and periostal and endochondral ossification. In comparison, MTX did not significantly improve any histopathology parameters and Enbrel only improved ossification. Finally, as a biomarker of inflammation and as an indication that AVX001 and AVX002 blocked the cPLA2α target, we determined that plasma levels of PGE2 were significantly reduced in response to the AVX inhibitors and MTX, but not Enbrel.

Conclusions

AVX001 and AVX002 display potent anti-inflammatory activity and disease-modifying properties in cellular and in vivo models. The in vivo effects of AVX001 and AVX002 were comparable to, or superior, to those of MTX and Enbrel. Taken together, this study suggests that cPLA2α inhibitors AVX001 and AVX002 are promising small molecule disease-modifying anti-rheumatic therapies.

Broadband photocurrent enhancement and light-trapping in thin film Si solar cells with periodic Al nanoparticle arrays on the front

Plasmonic resonances in metal nanoparticles are considered candidates for improved thin film Si photovoltaics. In periodic arrays the influence of collective modes can enhance the resonant properties of such arrays. We have investigated the use of periodic arrays of Al nanoparticles placed on the front of a thin film Si test solar cell. It is demonstrated that the resonances from the Al nanoparticle array causes a broadband photocurrent enhancement ranging from the ultraviolet to the infrared with respect to a reference cell. From the experimental results as well as from numerical simulations it is shown that this broadband enhancement is due to single particle resonances that give rise to light-trapping in the infrared spectral range and to collective resonances that ensure an efficient in-coupling of light in the ultraviolet-blue spectral range.

Abstract P6-04-08: Cytosolic phospholipase A2 (cPLA2) as a therapeutic target in basal-like breast cancer

Introduction: Basal-like breast cancer is frequently associated with triple negative phenotype, and there is a need for novel therapeutic strategies for this patient population. Inhibitors of cytosolic phospholipase A2 (cPLA2) have been suggested to block both MAPK and PI3K signalling and have a high potential for activity in basal-like breast cancer (Lin 1993, Wen 2013). In this study, we compared the expression of PLA2G4A between luminal B and basal-like breast cancer, both in patient-derived xenograft models (PDX) and human cancer tissue. In addition, we studied the effect of the novel cPLA2 inhibitor AVX235 on tumor growth in a basal-like PDX model.

Materials and methods: Tumor tissue specimens were obtained from PDX models (n = 26) and a clinical breast cancer biobank (n = 32). Gene expression analysis was carried out on Agilent 8×60K microarrays. The expression of 54 genes directly involved in choline metabolism was examined. Differential expression of choline genes between basal-like and luminal B tumors was calculated by subtraction of log2 expression values. Mice carrying bilateral MAS98.12 basal-like xenografts (Bergamaschi 2009) were treated with the cPLA2 inhibitor AVX235 (30 mg/kg i.p. daily for 7 days then every second day for 14 days, n = 6) or drug-free vehicle (control group, n = 6).

Results: The PDX models were subtyped into basal-like (n = 19) and luminal B (n = 7) subtypes based on the expression of 500 intrinsic genes [Sørlie 2003]. For the human cancer tissue, there were 18 basal-like and 14 luminal B tumors. There was a significant correlation between differential choline gene expression in basal-like vs luminal B tumors in PDX models and human cancer tissue (p<1.3*10−12). Both in PDX models (p<0.04) and human cancer tissue (p<0.0003), PLA2G4A was significantly higher expressed in basal-like than luminal B tumors. Treatment with AVX235 markedly reduced the growth rate of MAS98.12 xenografts compared to controls. After 19 treatmment days, the mean tumor volume (normalised to volume at start of treatment) in the treatment group was 36% of the tumor volume in the control group, the difference being statistically significant (p = 0.023). No signs of treatment-related adverse effects were observed.

Conclusion: PLA2G4A is higher expressed in basal-like than in luminal B breast cancer. Treatment with the cPLA2 inhibitor AVX235 significantly inhibits tumor growth. These data suggest that cPLA2 inhibitors may be of particular value in treatment of basal-like breast cancer.

References: Lin LL et al: cPLA2 is phosphorylated and activated by MAP kinase. Cell 1993; 72; 269-278. Wen ZH et al: Critical role of arachidonic acid-activated mTOR signaling in breast carcinogenesis and angiogenesis. Oncogene 2013; 32; 160-170. Bergamaschi A et al: Molecular profiling and characterization of luminal-like and basal-like in vivo breast cancer xenograft models. Mol Oncol 2009; 3; 469-482. Sørlie T et al: Repeated observation of breast tumor subtypes in independent gene expression data sets. Proc Natl Acad Sci USA 2003; 100; 8418-8423.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-04-08.

Diffractive coupling and plasmon-enhanced photocurrent generation in silicon

Arrays of metal nanoparticles are considered candidates for improved light-coupling into silicon. In periodic arrays the coherent diffractive coupling of particles can have a large impact on the resonant properties of the particles. We have investigated the photocurrent enhancement properties of Al nanoparticles placed on top of a silicon diode in periodic as well as in random arrays. The photocurrent of the periodic array sample is enhanced relative to that of the random array due to the presence of a Fano-like resonance not observed for the random array. Measurements of the photocurrent as a function of angle, reveal that the Fano-like enhancement is caused by diffractive coupling in the periodic array, which is accordingly identified as an important design parameter for plasmon-enhanced light-coupling into silicon.

Self-assembled Al nanoparticles on Si and fused silica, and their application for Si solar cells

This paper presents a novel method for the self-assembly of aluminum nanoparticles on Si and fused silica. Due to high reactivity with oxygen, ex-vacuo annealing of thin deposited metal films, a method used extensively with other metals, does not work with aluminum. In the present experiment this problem was overcome by annealing the samples in-vacuo in the deposition chamber. Aluminum was thermally evaporated onto substrates at elevated temperatures (200-400 ° C) and annealed for 60 min without breaking the vacuum. It is shown that at 300 and 400 ° C the average particle size can be controlled by adjusting the amount of evaporated aluminum. Particle diameters ranging from 20 to 130 nm are demonstrated. These particles support localized surface plasmon resonances, a property that can be utilized for enhancing the efficiency of thin Si solar cells. This is explored here, and an increase in external quantum efficiency of up to 15% in a thin-film Si solar cell is demonstrated.

Aluminum nanoparticles for plasmon-improved coupling of light into silicon

This paper investigates the improved photo-current response obtained by depositing Al nanoparticles on top of a Si diode. Well defined Al nanodiscs with a diameter and height of 100 nm are produced on the surface of a Si diode using electron-beam lithography, and the change in photo-current generation is characterized. A blue shift of the photo-current response is demonstrated, substantially improving the relation between gains and losses compared to what is typically observed in similar schemes using Ag nanoparticles. Enhanced photo-current response is observed in diodes with Al particles on the surface at all wavelengths larger than ≈465 nm, thereby minimizing the losses in the blue range usually reported with Ag nanoparticles on the surface.

Multiple phospholipase A2 enzymes participate in the inflammatory process in osteoarthritic cartilage

OBJECTIVE

The aim of this study was to determine the involvement of pro-inflammatory phospholipase A2 (PLA2) enzymes in human chondrocytes from patients with osteoarthritis (OA).

METHODS

PLA2 involvement in OA chondrocytes was analysed by (a) arachidonic acid (AA) and oleic acid release, (b) PLA2 mRNA analysis, and (c) prostaglandin E2 (PGE2) production in cultured OA chondrocytes in response to various cytokines and platelet activating factor (PAF).

RESULTS

Pro-inflammatory cytokines and PAF stimulation led to increased AA release, interleukin (IL)-1β and tumour necrosis factor (TNF) being the strongest inducers. The pattern of oleic acid release was similar to but less prominent than AA release, suggesting that predominantly arachidonyl selective enzymes were activated. IL-1β, TNF, IL-6, and IL-8 upregulated secretory group IIA, IID, and V phospholipase A2 (sPLA2-IIA, -IID, -V) and cytosolic group IVA phospholipase A2 (cPLA2-IVA) expression, where induction of chondrocyte sPLA2-IID is a novel finding. Furthermore, IL-1β, TNF, and IL-6 also induced COX2 expression. PAF induced expression of group IIA, IID and IVA PLA2, and COX2. In line with its anti-inflammatory properties, IL-4 was unable to induce either AA release or expression of PLA2s or COX2. IL-1β and TNF strongly increased PGE2 production, with IL-1β as the most prominent inducer.

CONCLUSION

Multiple PLA2 isoforms are expressed and influenced by pro-inflammatory stimuli in OA chondrocytes. Hence, several PLA2 enzymes may contribute to chondrocyte function by their upregulation and activation, and increased AA release and PGE2 production may therefore be important effectors in OA pathophysiology. PLA2 enzymes and cPLA2-IVA in particular are thus possible therapeutic targets in OA.

Airway limitation and exercise intolerance in well-regulated myasthenia gravis patients

OBJECTIVES

Myasthenia gravis (MG) is an autoimmune disease of neuromuscular synapses, characterized by muscular weakness and reduced endurance. Remission can be obtained in many patients. However, some of these patients complain of fatigue. The aim of this study was to assess exercise capacity and lung function in well-regulated MG patients.

PATIENTS AND METHODS

Ten otherwise healthy MG patients and 10 matched controls underwent dynamic spirometry, and a ramped symptom-limited bicycle exercise test. Spirometric variables included forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and maximum voluntary ventilation (MVV). Exercise variables included maximal oxygen uptake (VO(2) max), anaerobic threshold (VO(2) AT) maximum work load (W), maximum ventilation (VE max), and limiting symptom.

RESULTS

Myasthenia gravis patients had significantly lower FEV1/FVC ratio than controls. This was more marked in patients on acetylcholine esterase inhibitors. On the contrary, patients not using acetylcholine esterase inhibitors had a significantly lower exercise endurance time.

CONCLUSION

Well-regulated MG patients, especially those using pyridostigmine, tend to have an airway obstruction. The modest airway limitation might be a contributing factor to their fatigue. Patients who are not using acetylcholinesterase inhibitor seem to have diminished exercise endurance in spite of their clinically complete remission.

Chest abnormalities in juvenile-onset mixed connective tissue disease: assessment with high-resolution computed tomography and pulmonary function tests

BACKGROUND

Mixed connective tissue disease (MCTD) is associated with several chest manifestations. Only a few studies have focused on chest manifestations in juvenile-onset MCTD (jMCTD), and the true prevalence of pulmonary abnormalities on high-resolution computed tomography (HRCT) in these patients is unknown.

PURPOSE

To investigate the occurrence of pulmonary abnormalities in jMCTD with particular reference to interstitial lung disease (ILD), and to evaluate a possible association between pulmonary findings and disease-related variables.

MATERIAL AND METHODS

Twenty-four childhood-onset MCTD patients with median disease duration of 10.5 years (range 1-21 years) were investigated in a cross-sectional study by means of HRCT, pulmonary function tests (PFT), and clinical assessment.

RESULTS

Discrete ILD was identified in six patients (25%). Median extent of ILD was 2.0%, and all except one of the patients had very mild disease in which 5% or less of the parenchyma was affected. The CT features of fibrosis were mainly microcystic and fine intralobular. The most frequently abnormal PFT was carbon monoxide uptake from the lung, which was abnormal in 33% of the patients. PFT and disease duration were not significantly associated with HRCT findings of ILD.

CONCLUSION

The prevalence of ILD in childhood-onset MCTD patients was lower than previously believed. In most of the patients with ILD, the findings were subtle and without clinical correlation. The results suggest a low extent of ILD in childhood-onset MCTD, even after long-term disease duration.

Pulmonary involvement in patients with childhood-onset systemic lupus erythematosus

OBJECTIVE

Pulmonary involvement is a common finding in adults with systemic lupus erythematosus (SLE). The aim of this study was to investigate the frequency of pulmonary abnormalities in patients with childhood-onset SLE, with particular reference to interstitial lung disease (ILD), and to examine any association between pulmonary abnormalities and other disease-related variables.

METHODS

A cohort of 60 Norwegian patients with childhood-onset SLE was examined in a cross-sectional study by high-resolution computed chest tomography (HRCT) and pulmonary function tests (PFT). Median disease duration was 11.2 years. Disease activity, cumulative organ damage and immunological markers were also assessed.

RESULTS

Five patients (8%) had abnormal HRCT findings, including micronodules in four patients and bronchiectasis in one. None of the patients had radiographic evidence of ILD. PFT results were impaired in 37% of the patients, the most frequent pulmonary dysfunction was reduced carbon monoxide diffusing capacity (26%). HRCT findings, disease activity or serology did not correlate with PFTs. Reduced diffusion capacity was associated with smoking (p-value < 0.05).

CONCLUSION

Lung function was moderately impaired, while the frequency of pulmonary parenchymal involvement was low. There was no radiographic evidence of ILD, which is an unexpected finding given the high frequencies reported in adult SLE patients assessed with HRCT. The results suggests that PFT values are often abnormal, but these are infrequently associated with development of ILD or other substantial parenchymal alterations in childhood-onset SLE, and do not require further HRCT investigation in asymptomatic patients.

Trends in symptoms of obstructive lung disease in Norway

SETTING

Evidence is accumulating that there has been an increase in the adult population burden of obstructive lung disease. Has this increased the burden of symptoms? It is possible that diagnostic efficiency has improved, so that milder asthma cases are being diagnosed.

OBJECTIVE

To investigate changes in symptom burden by asthma diagnosis, age and sex.

DESIGN

We performed two postal cross-sectional studies among adults aged 15-70 years in Oslo, Norway, in 1972 and again in 1998/1999 (total = 39998). Changes in 11 self-reported respiratory symptoms were investigated.

RESULTS

The prevalence of having at least one symptom increased from 50% to 60% (P < 0.001), and the distribution of symptoms showed an overall increase. Nine symptoms increased in prevalence. The increase was largest among the young and females, and was present in both those with and those without asthma. For any given number of reported symptoms, asthma prevalence was higher in 1998 than in 1972, suggesting increased case finding.

CONCLUSION

There has been an increase in the population burden of respiratory symptoms matching the observed increase in young adult asthma, together with a probable increase in the clinical willingness to give an asthma diagnosis.

Enzymatically modified low-density lipoprotein upregulates CD36 in low-differentiated monocytic cells in a peroxisome proliferator-activated receptor-γ-dependent way

Peroxisome proliferator-activated receptor-gamma (PPARgamma) has been suggested to upregulate CD36. Since free oxidized polyunsaturated fatty acids are PPARgamma ligands, we studied the effects of LDL modified by the simultaneous action of sPLA2 and 15-lipoxygenase (15LO) on CD36 expression and PPARgamma activation in monocytic cells. Exposure of MM6 cells, which do not express CD36 or other scavenger receptors, to such enzymatically modified LDL (enzLDL) resulted in upregulation of CD36 surface protein and mRNA expression. Similar effects were observed with free 13-hydroperoxyoctadecadienoic acid but not its esterified counterpart. Less pronounced effects were observed with LDL modified by 15LO alone. Upregulation of CD36 was inversely correlated to the state of cell differentiation, as showed by lower response to enzLDL of the scavenger receptor-expressing MM6-sr and THP1 cells. Importantly, LDL modified by sPLA2 and 15LO did not efficiently induce upregulation CD36 in PPARgamma-deficient macrophage-differentiated embryonic stem cells confirming a role of PPARgamma in CD36 expression in cells stimulated with enzLDL. Our data show that LDL modified with physiologically relevant enzymes stimulates CD36 expression in non-differentiated monocytes and that this process involves PPARgamma activation. These effects of enzLDL can be considered pro-atherogenic in the context of early atherosclerosis.

Long-term changes in adult asthma prevalence

There has been an increase in asthma prevalence among children. Little evidence is available regarding long-term changes in asthma prevalence in adults. Two cross-sectional studies were performed among adults aged 15-70 yrs in Oslo, Norway, in 1972 and again in 1998-1999 (n=39,998). A postal self-completed questionnaire was used. Exactly the same questions and survey methods were used in both studies. In 1998-1999, additional telephone follow-up was included for postal nonresponders. The crude prevalence of ever having had a doctor's diagnosis of asthma increased from 3.4 to 9.3%. The prevalence of wheezing increased from 17.8 to 25.8% and attacks of breathlessness from 12.6 to 16.7%. After controlling for smoking, the risk of asthma among those aged <40 yrs had tripled. The increase in asthma was 50% greater in females than males. The prevalence of symptoms increased less than asthma diagnosis. Wheezing increased by 50% in those aged <40 yrs, with smaller increases at greater ages. The increase in symptoms was seen among both asthmatics and nonasthmatics. There has been a large increase in the prevalence of asthma diagnosis and asthma-like symptoms in adults. The increase is less pronounced among those aged >40 yrs.

Simian virus 40 large T-antigen, but not small T-antigen, trans-activates the human cytomegalovirus major immediate early promoter

Cytomegalovirus infection is a major cause of morbidity in immunocompromised patients. The major immediate early promoter/enhancer (MIEP) of the human cytomegalovirus controls the expression of the immediate early genes 1 and 2 which play a central role both in primary and reactivated human cytomegalovirus (HCMV)-infections. Our previous studies have shown that co-infection of A549 cells with human cytomegalovirus and human polyomavirus BK resulted in enhanced expression of the immediate early genes 1 and 2 and that the early gene products of BK virus trans-activated the MIEP. However, neither the MIEP sequences required for mediating this trans-activation, nor the contribution of the individual BK virus early gene products were examined. The MIEP contains multiple binding sites for the transcription factors CREB, AP1, Sp1 and NFkappaB, which may mediate polyomavirus large T- or small t-antigens-induced promoter activation. Transient transfection studies in A549 cells demonstrated that SV40 large T-antigen, but not small t-antigen, trans-activated MIEP activity approximately 9-fold. Mutations in individual binding motifs in the context of the complete MIEP did not impair traits-activation by large T-antigen. The level of induction of a truncated MIEP consisting of a single set of CRE/AP1, NFkappaB, and Sp1 binding motifs by large T-antigen was reduced 2-fold compared to the full length MIEP. Extended truncations diminished trans-activation by large T-antigen. To determine the contribution of a single binding motif in the trans-activation by large T-antigen, a CRE/AP1, an NFkappaB, an Sp1, or a non-consensus Sp1-motif, respectively, was linked to the MIEP TATA-sequence respecting the natural spacing between the two transcription regulatory elements. Only the MIEP TATA-box with the correctly spaced non-consensus Sp1 binding site (GT-motif) was stimulated by large T-antigen. These results suggest that an isolated non-consensus Sp1-motif is important for trans-activation of the MIEP by large T-antigen, but that other cis-acting elements can compensate for this element in the context of the whole MIEP.

Distension-induced duodenal contractions vary with the phases of the canine interdigestive migrating motility complex

BACKGROUND

The aim of the study was to evaluate whether the sensitivity for distension-induced contractions in the duodenum varied with the phases of the interdigestive migrating motility complex (MMC).

METHODS

Four beagles (12-17 kg) with gastric fistulas were studied by means of perfused low-compliance manometry. A 2.5-cm-long balloon was placed in the third part of the duodenum. Side holes for pressure measurements were placed inside the balloon, 2cm proximal to the balloon, and in the antrum. Two-minute distensions with balloon pressures of 10 cmH2O were repeated in 10-min intervals during 17 MMCs. Twelve MMCs were also recorded without doing distensions.

RESULTS

Balloon distension did not affect the duration of phase III and the MMC. In the beginning of phase I, distension did not significantly affect duodenal motility whereas distension induced contractile responses in late phase I, early phase II and late phase II (p < 0.05). The highest increase from the pre-distension to distension period was observed in early phase II (average 4 contractions min(-1)). However, considering the level of pre-distension contraction frequency, the fractional increase was by far the highest in late phase I. In phase III no difference was found between the periods before and during distension (15.8 +/- 0.7 versus 15.8 +/- 0.5 contractions min(-1)). The effect of balloon distension in phase IV was difficult to evaluate due to the inconsistent nature and sometimes rapidly decreasing activity in phase IV. Duodenal distension did not change frequency and amplitude of antral phase II contractions (p > 0.5).

CONCLUSIONS

Duodenal balloon distension elicited ascending contractions in the canine duodenum in late phase I and in phase II. A refractory phase was demonstrated in the beginning of phase I while in phase III the frequency of contraction could not be increased further.

Atypical lambda/iota PKC conveys 5-lipoxygenase/leukotriene B4-mediated cross-talk between phospholipase A2s regulating NF-kappa B activation in response to tumor necrosis factor-alpha and interleukin-1beta

The transcription factor nuclear factor kappaB (NF-kappaB) plays crucial roles in a wide variety of biological functions such as inflammation, stress, and immune responses. We have shown previously that secretory nonpancreatic (snp) and cytosolic (c) phospholipase A(2) (PLA(2)) regulate NF-kappaB activation in response to tumor necrosis factor (TNF)-alpha or interleukin (IL)-1beta activation and that a functional coupling mediated by the 5-lipoxygenase (5-LO) metabolite leukotriene B(4) (LTB(4)) exists between snpPLA(2) and cPLA(2) in human keratinocytes. In this study, we have further investigated the mechanisms of PLA(2)-modulated NF-kappaB activation with respect to specific kinases involved in TNF-alpha/IL-1beta-stimulated cPLA(2) phosphorylation and NF-kappaB activation. The protein kinase C (PKC) inhibitors RO 31-8220, Gö 6976, and a pseudosubstrate peptide inhibitor of atypical PKCs attenuated arachidonic acid release, cPLA(2) phosphorylation, and NF-kappaB activation induced by TNF-alpha or IL-1beta, thus indicating atypical PKCs in cPLA(2) regulation and transcription factor activation. Transfection of a kinase-inactive mutant of lambda/iotaPKC in NIH-3T3 fibroblasts completely abolished TNF-alpha/IL-1beta-stimulated cellular arachidonic acid release and cPLA(2) activation assayed in vitro, confirming the role of lambda/iotaPKC in cPLA(2) regulation. Furthermore, lambda/iotaPKC and cPLA(2) phosphorylation was attenuated by phosphatidyinositol 3-kinase (PI3-kinase) inhibitors, which also reduced NF-kappaB activation in response to TNF-alpha and IL-1beta, indicating a role for PI3-kinase in these processes in human keratinocytes. TNF-alpha- and IL-1beta-induced phosphorylation of lambda/iotaPKC was attenuated by inhibitors toward snpPLA(2) and 5-LO and by an LTB(4) receptor antagonist, suggesting lambda/iotaPKC as a downstream effector of snpPLA(2) and 5-LO/LTB(4) the LTB(4) receptor. Hence, lambda/iotaPKC regulates snpPLA(2)/LTB(4)-mediated cPLA(2) activation, cellular arachidonic acid release, and NF-kappaB activation induced by TNF-alpha and IL-1beta. In addition, our results demonstrate that PI3-kinase and lambda/iotaPKC are involved in cytokine-induced cPLA(2) and NF-kappaB activation, thus identifying lambda/iotaPKC as a novel regulator of cPLA(2).

[General practitioners' knowledge of and attitude to assessment and treatment of women with urinary incontinence. A questionnaire among general practitioners in Denmark]

INTRODUCTION

Urinary incontinence is a common problem for adult women, and the need for assessment and treatment of incontinence is expected to increase in the future. The aim of this study was to elucidate the general practitioners' (GPs) knowledge about and attitude to women with urinary incontinence.

METHODS

A questionnaire was posted to 1700 randomly selected GPs in 1998 and 1999.

RESULTS

A total of 1071 (63%) GPs responded at least once. Five hundred (29%) returned the questionnaire both years. About 50% expressed a positive interest in the management of urinary incontinence. Only 24% felt that their knowledge was sufficient to manage incontinence. About 50% and 66% of the GPs would probably refer a patient with stress incontinence or urge incontinence to a specialist. The GPs' proposals for assessment and treatment were mainly consistent with good clinical practice. There were only minor changes in knowledge and attitude from 1998 to 1999.

DISCUSSION

GPs' interest in urinary incontinence is moderate and management is characterised by a high referral rate to a specialist. Most GPs. consider their knowledge to be inadequate. There is need for education to ensure sufficient knowledge and to change the attitude, so that first-line assessment and treatment of urinary incontinence is carried out in general practice.

Functional coupling between secretory and cytosolic phospholipase A2 modulates tumor necrosis factor-alpha- and interleukin-1beta-induced NF-kappa B activation

Tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta are potent activators of the transcription factor NF-kappaB, induced during inflammatory conditions. We have previously shown that both secretory and cytosolic phospholipase A(2) (PLA(2)) are involved in TNF-alpha- and IL-1beta-induced NF-kappaB activation. In this study, we have addressed the mechanism of PLA(2) involvement with respect to downstream arachidonic acid (AA) metabolites and the functional coupling between PLA(2)s mediating NF-kappaB activation. We show that in addition to inhibitors of secretory and cytosolic PLA(2)s, 5-lipoxygenase inhibitors attenuate TNF-alpha- and IL-1beta-stimulated NF-kappaB activation. Exogenous addition of leukotriene B(4) (LTB(4)) restored NF-kappaB activation reduced by 5-lipoxygenase inhibitors or an LTB(4) receptor antagonist, thus identifying LTB(4) as a mediator in signaling to NF-kappaB. TNF-alpha- and IL-1beta-induced AA release from cellular membranes was accompanied by phosphorylation of cytosolic PLA(2). Inhibitors of secretory PLA(2) and of 5-lipoxygenase/LTB(4) functionality markedly reduced AA release and nearly completely abolished cytosolic PLA(2) phosphorylation. This demonstrates that secretory PLA(2), through 5-lipoxygenase metabolites, is an essential upstream regulator of cytosolic PLA(2) and AA release. Our results therefore suggest the existence of a functional link between secretory and cytosolic PLA(2) in cytokine-activated keratinocytes, providing a molecular explanation for the participation of both secretory and cytosolic PLA(2) in arachidonic acid signaling and NF-kappaB activation in response to proinflammatory cytokines.

[Vaginal hysterectomy in non-prolapsed uterus]

INTRODUCTION

There is an increasing number of methods available for removing the uterus, but no multicentre, randomised, clinical trials are available to show which type of operation ensures the best outcome for the patient. The charts of 207 vaginal hysterectomies were reviewed in this descriptive study. The aim was to examine whether vaginal hysterectomy might be an alternative for a group of patients.

MATERIAL AND METHODS

Only patients with a previous, vaginal birth were entered in the study (four patients had not given birth). A uterus weight of 500-600 g was the upper limit set by our group for the use of the vaginal route. Patient characteristics, data from the operations, complications, and histological examinations of the uterus were analysed.

RESULTS

The mean operation time was 61 min (95% CI 58-64 min), range 25-115 min. The difference between preoperative and postoperative haemoglobin was 1.1 mmol/l (95% CI 1.0-1.2 mmol/l). The mean length of hospital stay was 2.9 days (95% CI 2.7-3.1 days). The complications were 1) febrile morbidity; 17 (8%) (95% CI 4-12%); 2) urinary tract injury, 3 (2%) (95% CI 0-3%); 3) unforeseen need for major surgery (including conversion to abdominal hysterectomy), 3 (2%) (95% CI 0-3%).

DISCUSSION

In some patients, vaginal hysterectomy is a good alternative.

Expression of a membrane-anchored endo-1,4-beta-glucanase from Brassica napus, orthologous to KOR from Arabidopsis thaliana, is inversely correlated to elongation in light-grown plants

A PCR fragment derived from a membrane-anchored endo-1,4-beta-glucanase cDNA was amplified using degenerated oligonucleotides and mRNA from oilseed rape (Brassica napus L.) siliques. Sequence analysis of the corresponding gene, Cel16, showed that the predicted Cel16 protein has high identity with the Arabidopsis KOR protein (94%). High-stringency genomic Southern analysis further revealed that Cel16 and KOR are most likely orthologous genes performing a similar function in both species. Northern blot and GUS analysis of transgenic Arabidopsis containing a fusion between a 2.0 kb Cel16 promoter fragment and the GUS reporter gene showed that Cel16 was expressed at a low level in the primary raceme, the young lateral stems, the elongation zone of the primary root and the older root base. By contrast, a high level of Cel16 mRNA accumulation was found in the young root and in the main stem carrying flowers and young siliques. Cel16 transcripts were localized to the apical meristem, cambium, primary xylem and cortex of oilseed rape stem tissue by in situ RT-PCR. A similar pattern of activity was found in the GUS analysis of transgenic Arabidopsis. Cel16 mRNA accumulation in the main stem was lower in the zone of most rapid cell elongation than in the subjacent, fully elongated internodes. Similarly, Cel16 transcripts accumulated to a higher level in leaves as they reached full size than during early leaf expansion. Analysis of the expression pattern in elongating, light-grown seedlings showed that Cel16 mRNA accumulated at a lower level in the elongating upper third than elsewhere in the hypocotyl. This is contrary to etiolated hypocotyls, where we found a higher expression level in the rapidly elongating upper part. This difference in expression most probably reflects a difference in cell wall assembly between light- and dark-grown seedlings.

Ceramide binds to the CaLB domain of cytosolic phospholipase A2 and facilitates its membrane docking and arachidonic acid release

Excessive production of eicosanoids is characteristic of many inflammatory diseases. In this study we show that ceramide, which is an early messenger of inflammatory cytokine action, exerts a dual effect on the cytosolic phospholipase A2 (cPLA2), the rate-limiting enzyme in arachidonic acid release and subsequent eicosanoid formation. Stimulation of renal mesangial cells with exogenous short-chain ceramide analogs for 30 and 60 min leads to a concentration-dependent increase in arachidonic acid release that is not blocked by specific inhibitors of mitogen-activated protein kinase pathways. This suggests that these established upstream activators of cPLA2 are not involved in ceramide-induced arachidonic acid release. By use of photoactivatable ceramide analogs, D- and L-[125I]3-trifluoromethyl-3-(m-iodophenyl)diazirine-ceramides (TID-ceramides), we observed a direct interaction of ceramide with cPLA2. This interaction was independent of the absolute configuration as D- and L-TID-ceramide were equally effective in binding to cPLA2. Moreover, recombinant CaLB domain of cPLA2 as well as a mutant deficient in the connecting 'hinge' domain of cPLA2, efficiently bound D- and L-TID-ceramides, whereas the catalytic domain did not interact with TID-ceramides. In vitro binding assays reveal that stearoyl-arachidonyl-phosphatidylcholine (SAPC)-liposomes containing increasing mol% of ceramide lead to an increased association of recombinant cPLA2 to the liposomes. Furthermore, measurement of cPLA2 activity in vitro shows that the presence of SAPC-liposomes resulted in only weak cPLA2 activity. However, the activity dramatically increases by addition of ceramide to the liposomes. Furthermore, liposomes containing SAPC and sphingomyelin resulted in no better substrate than SAPC liposomes, unless bacterial sphingomyelinase was added to generate ceramide, which then causes a marked increase in cPLA2 activity. These results demonstrate that ceramide can interact directly with cPLA2 via the CaLB domain and thereby serves as a membrane-docking device that facilitates cPLA2 action in inflammatory diseases.

Arabidopsis map kinase 4 negatively regulates systemic acquired resistance

Transposon inactivation of Arabidopsis MAP kinase 4 produced the mpk4 mutant exhibiting constitutive systemic acquired resistance (SAR) including elevated salicylic acid (SA) levels, increased resistance to virulent pathogens, and constitutive pathogenesis-related gene expression shown by Northern and microarray hybridizations. MPK4 kinase activity is required to repress SAR, as an inactive MPK4 form failed to complement mpk4. Analysis of mpk4 expressing the SA hydroxylase NahG and of mpk4/npr1 double mutants indicated that SAR expression in mpk4 is dependent upon elevated SA levels but is independent of NPR1. PDF1.2 and THI2.1 gene induction by jasmonate was blocked in mpk4 expressing NahG, suggesting that MPK4 is required for jasmonic acid-responsive gene expression.

Presence of group IIa secretory phospholipase A2 in mast cells and macrophages in normal human ileal submucosa and in Crohn's disease

Secretory group IIa phospholipase A2 (PLA2-II) is an important regulator of proinflammatory lipid mediator production and may play a role in ileal inflammation in Crohn's disease. The enzyme has previously only been detected in epithelial Paneth cells. However, one characteristic feature of Crohn's disease is the transmural inflammation. Full thickness ileal sections from nine patients with Crohn's disease, and histologically normal sections from patients with colonic cancer (n=7) and chronic severe constipation (n=1) as controls, were used in this study. PLA2-II-positive cells were detected by immunofluorescence and in situ hybridization. Metachromatic staining and esterase staining were used to identify mast cells and macrophages, respectively. It was shown that mast cells and macrophages in the ileal submucosa in both patients and controls showed positive PLA2-II staining. The number of PLA2-II-labeled cells that did not react with metachromasia, e.g. macrophages, was significantly greater in inflamed Crohn's disease compared to controls. This is, to our knowledge, the first study that has described the presence in healthy, while presence and upregulation of PLA2-II-positive cells in inflamed human ileal submucosa. Our findings suggest a proinflammatory potential for secretory PLA2-II in submucosa, while proinflammatory stimulation of mast cells and macrophages in vitro has shown that the enzyme is responsible for delayed prostaglandin formation.

Secretory and cytosolic phospholipase A(2)regulate the long-term cytokine-induced eicosanoid production in human keratinocytes

The involvement of cytosolic phospholipase A(2)(cPLA(2)) and secretory non-pancreatic PLA(2)(npPLA(2)) in release of arachidonic acid (AA) preceding eicosanoid formation in the human keratinocyte cell line HaCaT was examined. Interleukin 1beta (IL-1beta) and tumour necrosis factor-alpha (TNF), phorbol myristate acetate (PMA) and calcium ionophore A(23187)increased the extracellular AA release, and stimulated eicosanoid synthesis as determined by HPLC analysis. The main metabolites after stimulation with IL-1beta, PMA or A(23187)were PGE(2), an unidentified PG and LTB(4), while TNF stimulated HETE-production. Both cPLA(2)and npPLA(2)message and enzyme activity were detected in unstimulated HaCaT cells. IL-1beta, PMA and TNF increased both cPLA(2)enzyme activity and expression, but did not lead to any increase in npPLA(2)expression or activity. The selective npPLA(2)inhibitors LY311727 and 12-epi-scalaradial, or the cPLA(2)inhibitor arachidonyl trifluoro methyl ketone (AACOCF(3)) reduced IL-1beta-induced eicosanoid production in a concentration dependent manner. The results presented strongly suggest that both cPLA(2)and npPLA(2)contribute to the long-term generation of AA preceding eicosanoid production in differentiated, human keratinocytes. Inhibitors against npPLA2 or cPLA2 enzymes should be useful in treating inflammatory skin diseases, such as psoriasis.

Molecular genetic analysis of severe protein C deficiency

Severe protein C deficiency is a rare, early onset, venous thrombotic condition that is inherited as an autosomal recessive trait. The protein C (PROC) genes of nine unrelated individuals with severe protein C deficiency were sequenced yielding a total of 13 different lesions. Eight of these were novel, including a gross gene deletion, three missense mutations, two micro-deletions, a splicing mutation and a single base-pair substitution in the HNF-3 binding site in the PROC gene promoter. Evidence for the pathogenicity of the mutations detected was obtained by molecular modelling, in vitro splicing assay and reporter gene assay. Neither the plasma protein C activity level nor the nature of the PROC gene lesions detected were found to be a good prognostic indicator of the age of onset or clinical severity of thrombotic symptoms. Other factors may thus complicate the relationship between genotype and clinical phenotype. Indeed, in two patients, the inheritance of either one or two Factor V Leiden alleles in addition to two PROC gene lesions could have served to precipitate the thrombotic events. No association was however apparent between clinical severity and the possession of a particular promoter polymorphism genotype. Despite the absence of a clear genotype-phenotype relationship, the molecular genetic analysis of the severe recessive form of protein C deficiency potentiates both the counselling of affected families and the provision of antenatal exclusion diagnosis.

Mildly oxidized LDL induces expression of group IIa secretory phospholipase A(2) in human monocyte-derived macrophages

Phospholipase A(2)s (PLA(2)s) constitute a family of enzymes that hydrolyze fatty acids of membrane phospholipids, thus initiating the synthesis of proinflammatory mediators. Various PLA(2)s have been detected in human atherosclerotic arteries (advanced lesions); however, only the secretory group of PLA(2) has been shown to specifically hydrolyze low density lipoprotein (LDL)-associated phospholipids and, as such, may play a potential role in atherogenesis. In the present study, we investigated the expression pattern of group IIa, IV, and V PLA(2)s in human macrophages, which are the key cells involved in the onset and perpetuation of atherosclerosis. Immunohistochemical staining by double labeling showed that the secretory nonpancreatic PLA(2) (snpPLA(2)) is detectable in macrophages in the intima of early atherosclerotic lesions. Reverse transcription-polymerase chain reaction analysis of RNA extracted from human monocytes clearly showed that expression of group IV PLA(2) was enhanced during differentiation into macrophages, with an onset of induction at days 2 to 3 of differentiation. Group V snpPLA(2) was constitutively expressed on differentiation, whereas the detection of group IIa snpPLA(2) was dependent on both differentiation and subsequent stimulation of macrophages. Indeed, the transcription of group IIa snpPLA(2) in macrophages was induced by treatment with minimally modified or mildly oxidized LDL, whereas native, extensively oxidized, or acetylated LDL had no effect. To our knowledge, this is the first report describing induction of group IIa snpPLA(2) expression in human monocyte-derived macrophages. The mRNA levels of cytosolic PLA(2) group IV and snpPLA(2) group V remained unchanged on LDL treatment. Thus, our results show that the expression of distinct PLA(2) enzymes is regulated not only during differentiation of monocytes into macrophages but also on exposure of macrophages to distinct LDL species. Consequently, our results indicate a potential role for both cytosolic and secretory PLA(2) enzymes in inflammation and in macrophage functions related to atherosclerosis, with a specific role for group IIa snpPLA2 in LDL scavenging.

Molecular basis for the association of group IIA phospholipase A(2) and decorin in human atherosclerotic lesions

Group IIA secretory nonpancreatic phospholipase A(2) (snpPLA(2)) is associated with collagen fibers in the extracellular matrix of human atherosclerotic plaques. Decorin, a small proteoglycan (PG) carrying chondroitin/dermatan sulfate glycosaminoglycans (GAGs), forms part of the collagen network in human arteries. To explore whether snpPLA(2) may be associated with collagen fibers via interaction with decorin, we performed (1) immunohistochemistry to compare the relative in vivo localization of snpPLA(2) and decorin in human atherosclerotic tissue and (2) in vitro experiments to study the interaction between snpPLA(2) and decorin. In atherosclerotic lesions, decorin was detected within the snpPLA(2)-positive part of the intima close to the media. Electrophoretic mobility shift assay showed that snpPLA(2) binds to decorin synthesized by human fibroblasts. Native and GAG-depleted decorin enhanced the association of snpPLA(2) to collagen types I and VI in a solid-phase binding assay. Furthermore, snpPLA(2) bound efficiently to a recombinant decorin core protein fragment B/E (Asp45-Lys359). This binding was competed with soluble decorin and inhibited at NaCl concentrations >150 mmol/L. The decorin core protein fragment B/E competed better than dermatan sulfate for binding of snpPLA(2) to decorin-coated microtiter wells. The enzymatic activity of snpPLA(2) increased 2- to 3-fold in the presence of decorin or GAG-depleted decorin. The results show that snpPLA(2) binds preferentially to the decorin protein core rather than to the GAG chain and that this interaction enhances snpPLA(2) activity. As a consequence, this active extracellular enzyme may contribute to the pathogenesis of atherosclerosis by modifying lipoproteins and releasing inflammatory lipid mediators at places of lipoprotein retention in the arterial wall.

Expression of cytosolic and secreted forms of phospholipase A(2) and cyclooxygenases in human placenta, fetal membranes, and chorionic cell lines

Lipid mediators play a crucial role in human parturition and phospholipase A(2) (PLA(2)) is a key regulator of the production of these compounds. We have investigated by PCR the expression of different groups of PLA(2) and COX enzymes in human fetal membranes (amnion and chorion), placenta and three chorionic cell lines (JEG-3, Jar, BeWo). Our data show that the cytosolic Group IV PLA(2) and COX-1 are expressed in all of them, whereas the secretory forms of PLA(2), (Groups IIA, and V), have a more restricted expression. Group IIA mRNA is most abundant in placenta and chorion, whereas Group V PLA(2) mRNA is most abundant in placenta and amnion. On the other hand, COX-2 is present in placenta, chorion and amnion, but was not detected in any of the chorionic cell lines. These results suggest that both cytosolic and distinct secreted forms of PLA(2) could be involved in arachidonic acid (AA) release preceding prostaglandin production at the fetal/maternal interface.

MHC-I-induced apoptosis in human B-lymphoma cells is dependent on protein tyrosine and serine/threonine kinases

In addition to providing the framework for peptide presentation, major histocompatibility complex class I (MHC-I) molecules can act as signal transducing molecules in lymphoid cells. Here we show that the mobilization of intracellular calcium, which follows crosslinking of MHC-I molecules on human B lymphoma cells, is dependent on protein tyrosine kinases and the phosphatidylinositol 3 (PI-3) kinase. Functional studies showed that MHC-I crosslinking induced almost complete inhibition of the spontaneous proliferation of the B lymphoma cells as early as 6 h post-crosslinking and apoptosis 24 h post-crosslinking. Preincubation with either protein tyrosine kinase or protein serine/threonine kinase inhibitors reduced the MHC-I-induced apoptosis to background levels, whereas inhibition of PI-3 kinase had no effect. These data demonstrate a pivotal role for protein tyrosine and serine/threonine kinases in MHC-I-mediated apoptosis in human B-cells and suggest the presence of several MHC-I signaling pathways leading to diverse effects in these cells.

A dominant role for the Raf-MEK pathway in forskolin, 12-O-tetradecanoyl-phorbol acetate, and platelet-derived growth factor-induced CREB (cAMP-responsive element-binding protein) activation, uncoupled from serine 133 phosphorylation in NIH 3T3 cells

In this study we describe that platelet-derived growth factor (PDGF), 12-O-tetradecanoyl-phorbol-acetate (TPA), and forskolin induced CREB (cAMP-responsive element-binding protein) Ser-133 phosphorylation with comparable magnitude and kinetics in NIH 3T3 cells. While forskolin was the most potent activator of CREB, TPA or PDGF modestly increased CREB activity. The role of protein kinase C, protein kinase A, and the Raf-MEK kinase pathway in the activation and Ser-133 phosphorylation of CREB by these three stimuli was investigated. We found that inhibition of the Raf-MEK kinase pathway efficiently blocks transcriptional activation of CREB by all three stimuli. This dominant involvement of Raf-MEK in CREB transcriptional activation seems to be uncoupled from CREB Ser-133 phosphorylation. We further demonstrate that although inhibition of Raf-MEK represses forskolin-induced CREB activation, forskolin by itself failed to activate ERK1/2 and Elk-1 mediated transcription. These results suggest that a basal level of Raf-MEK activity is necessary for both PDGF- and forskolin-induced CREB activation, independent of CREB Ser-133 phosphorylation.

Concerted expression of BK virus large T- and small t-antigens strongly enhances oestrogen receptor-mediated transcription

Previous studies have shown that the human polyomavirus BK (BKV) genome contains an oestrogen response element (ERE). This isolated element binds its cognate receptor in vitro and can mediate 17beta-oestradiol-induced gene expression when linked to a heterologous promoter. The roles of the ERE- and the AP-1-binding sites in oestrogen receptor-directed transcription from the complete BKV promoter/enhancer (Dunlop strain) have been examined and the effects of the general co-activator CBP and large T- and small t-antigens on oestrogen receptor-mediated transcription have been investigated. A constitutive activated oestrogen receptor stimulated BKV promoter activity in HeLa cells. Mutations in either the ERE- or the AP-1-binding sites did not impair oestrogen receptor-induced activation of the BKV Dunlop promoter, while mutations in both binding motifs almost completely abolished oestrogen receptor-induced transcription. Simultaneous expression of large T- and small t-antigens strongly activated oestrogen receptor-mediated transcription. When expressed separately, only large T-antigen moderately stimulated oestrogen receptor-mediated transcription. The stimulatory effect of large T-antigen on the activity of the oestrogen receptor is probably indirect because no physical interaction between the two proteins was detected in a two-hybrid assay. Large T-antigen abrogated the synergistic effect on transcription between this nuclear receptor and the general co-activator CBP. The findings that the BKV early proteins amplify oestrogen receptor-mediated transcription may have important biological implications in individuals with raised oestrogen concentrations.

Activation of protein kinase A by dibutyryl cAMP treatment of NIH 3T3 cells inhibits proliferation but fails to induce Ser-133 phosphorylation and transcriptional activation of CREB

The cAMP analogue dibutyryl cAMP (dbcAMP) is often used to activate the protein kinase A pathway and to study the expression of cAMP-responsive genes. Here we show that in NIH 3T3 cells dbcAMP is able to activate PKA, but fails to stimulate expression of the cAMP-inducible c-fos gene. Co-expression of A-kinase anchoring protein 75, previously shown to amplify cAMP signalling and to stimulate c-fos expression, could not restore cAMP responsiveness of the c-fos promoter. DbcAMP-induced activation of PKA may result in poor translocation of the catalytic sub-units of PKA to the nucleus, indicated by the lack of both Ser-133 phosphorylation of the cAMP-response element binding factor CREB and stimulation of the transcriptional activity of this factor. DbcAMP treatment, however, inhibited cell proliferation. These results suggest that cAMP-mediated inhibition of proliferation may be independent of translocation of the catalytic sub-units into the nucleus.

Selective inhibitors of cytosolic or secretory phospholipase A2 block TNF-induced activation of transcription factor nuclear factor-kappa B and expression of ICAM-1

TNF signaling mechanisms involved in activation of transcription factor NF-kappaB were studied in the human keratinocyte cell line HaCaT. We show that TNF-induced activation of NF-kappaB was inhibited by the well-known selective inhibitors of cytosolic phospholipase A2 (cPLA2): the trifluoromethyl ketone analogue of arachidonic acid (AACOCF3) and methyl arachidonyl fluorophosphate. The trifluoromethyl ketone analogue of eicosapentaenoic acid (EPACOCF3) also suppressed TNF-induced NF-kappaB activation and inhibited in vitro cPLA2 enzyme activity with a similar potency as AACOCF3. The arachidonyl methyl ketone analogue (AACOCH3) and the eicosapentanoyl analogue (EPACHOHCF3), which both failed to inhibit cPLA2 enzyme activity in vitro, had no effect on TNF-induced NF-kappaB activation. TNF-induced NF-kappaB activation was also strongly reduced in cells stimulated in the presence of the secretory PLA2 (sPLA2) inhibitors 12-epi-scalaradial and LY311727. Addition of excess arachidonic acid suppressed the inhibitory effect of 12-epi-scalaradial and LY311727. Moreover, both methyl arachidonyl fluorophosphate and 12-epi-scalaradial blocked TNF-mediated enhancement of expression of ICAM-1. Activation of NF-kappaB by IL-1beta was markedly less sensitive to both cPLA2 and sPLA2 inhibitors. The results indicate that both cPLA2 and sPLA2 may be involved in the TNF signal transduction pathway leading to nuclear translocation of NF-kappaB and to NF-kappaB-activated gene expression in HaCaT cells.

[High-resolution computer tomography of the lungs]

High-resolution CT (HRCT) is a technique developed over the last decade. It optimises spatial resolution and provides details similar to those obtainable from gross pathologic specimens. HRCT of the lungs provides an accurate assessment of the pattern and distribution of many disease processes that in the conventional chest radiograph are occult or non-specific. HRCT is an established technique and the method of choice for evaluating a variety of pulmonary diseases. In this review we describe the modifications in CT technique that are instrumental in obtaining HRCT, and we also give examples of normal and pathologic findings in general.

Mesocosm study of Mytilus edulis larvae and postlarvae, including the settlement phase, exposed to a gradient of tributyltin

In a mesocosm study, the effects of a gradient of tributylin (TBT) (nominal TBT concentrations of 0.3, 2.3, 18.5, 146, and 1150 ng Sn liter-1) on Mytilus edulis larvae and postlarvae, including the settlement phase, were investigated over 15 days. Effects of TBT on mortality, growth measured as increase in shell length, shell dimensions, and settlement were evaluated. In general, mortality was high in all mesocosms including the control; during the first 24 h of the experiment, mortality was 63% at the highest TBT concentration (26% in the control). An LC50 (24 h) of 254 ng Sn liter-1 was estimated. The mortality rate of larvae/postlarvae increased 40% at 18.5 ng Sn liter-1 (0.41 day-1) compared with the control (0.30 day-1). For postlarvae, the growth rate decreased with increasing TBT concentration. The mean shell length at 2.3 ng Sn liter-1 was significantly reduced in comparison to the control on Day 15. Then EC10 (15 days) for shell growth was estimated to be 5.4 ng Sn liter-1. This is the lowest effect concentration ever reported in the literature. For postlarvae, shell dimensions in terms of shell length-shell width relations were affected by TBT at 1150 ng Sn liter-1, because the reduced growth led to the failure of adult mussels to secret a dissochonch shell. During the first days of exposure, the settlement monitored on polyethylene settling strips was stimulated by TBT, after which the settlement decreased due to the high mortality. Only a small portion of the population survived to the end of the test period. By comparison of the biotic conditions (in terms of larval abundance and particle concentration reflecting larval food) in the control mesocosm with those in the cove where the experiment was conducted, it was concluded that the mesocosm had successfully simulated the field conditions.

Time course and pattern of pulmonary flow distribution following unilateral airway occlusion in sheep

1. Unilateral bronchial occlusion causes ipsilateral hypoxic pulmonary vasoconstriction, which shifts blood flow towards the other lung. We studied the time course of flow diversion following acute bronchial occlusion, and the temporal effect of the latter on blood gases and vertical distribution of blood flow within the two lungs. 2. Serial infusion of radioactive or fluorescent microspheres were given to each of seven adult standing sheep before, during occlusion of the left mainstem bronchus for up to 6 min, and after release of occlusion. Pulmonary and systemic arterial pressures were recorded continuously and arterial and mixed venous blood gases were determined intermittently. Post-mortem, the lungs were inflated, dried and cut into slices. Relative blood flow at the time of infusion was expressed as the weight-normalized intensity of each tracer in each slice or lung divided by the weight-normalized intensity in the two lungs. 3. Within 30 s, 1 min and 2 min after onset of occlusion, flow in the occluded lung had decreased to 68-84% (range), 51-78% and 43-79% respectively, of the initial value. In the contralateral lung, flow increased by 10-24%, 14-37% and 23-39% respectively. The distribution of flow along the gravitational axis within each lung varied widely between animals, both before and during occlusion. The during-occlusion profiles in the occluded lung differed from those in the non-occluded lung. In either lung, during-occlusion profiles could not be predicted with certainty from the pre-occlusion profiles. Two minutes post-occlusion, inter- and intra-lung flow distribution were nearly the same as before occlusion. Arterial oxygen tension fell in the first minute of occlusion, but never below 7.5 kPa, and increased slowly thereafter. Arterial carbon dioxide tension increased slightly throughout the occlusion period. No appreciable changes in systemic or pulmonary artery pressure were observed. Post-occlusion, arterial oxygen tension was still sub-normal, while carbon dioxide tension continued to increase. 4. We conclude that acute unilateral bronchial occlusion diverts blood flow within 30 s towards the contralateral lung. This rapidly occurring flow diversion prevents the development of severe arterial hypoxaemia. The variable and largely unpredictable distribution of blood flow in the hyperfused non-occluded lung might explain some of the gas-exchange abnormalities observed in physiologically hyperfused lungs and in patients with one hyperfused lung.

Synergistic increase in c-fos expression by simultaneous activation of the ras/raf/map kinase- and protein kinase A signaling pathways is mediated by the c-fos AP-1 and SRE sites

Expression of the c-fos proto-oncogene is induced by numerous stimuli some of which are transmitted through the Ras/Raf/MAP kinase or the cAMP-dependent protein kinase (PKA) pathways. The effect of cell-specific interactions between these pathways on c-fos expression was investigated by exposing quiescent NIH3T3 cells to serum, forskolin, or a combination. Co-stimulation with serum and forskolin resulted in a more than additive increase in c-fos transcription. Synergistic increase in c-fos promoter activity was also observed in transient transfection studies after co-stimulation with serum plus forskolin or co-transfection with c-Raf and PKA expression plasmids. Analysis of the cAMP signaling pathway revealed that the synergy was neither due to an increase in PKA activity nor to Ser-133 phosphorylation/activation of CREB. The activation status of the MAP kinases ERK1 and ERK2 in co-treated cells was comparable to that in serum-treated cells. Co-stimulation with forskolin did not alter the phosphorylation state of Elk-1 compared to serum-induced phosphorylation of Elk-1. Deletion of c-fos promoter elements previously shown to be important for regulation of c-fos expression in response to mitogens indicates a role for SRE and FAP-1 elements.

Mechanisms of transcriptional regulation of cellular genes by SV40 large T- and small T-antigens

During the past decade a number of virus-encoded transcriptional trans-activators that regulate the expression of viral genes have been reported. These trans-activators may also affect the expression or activity of several cellular genes or gene products to create an optimal cellular environment that favors viral replication. Among the better-studied viral trans-activating proteins are the Simian virus 40 large T- and small t-antigens. During the last few years, mechanisms by which these two viral proteins influence cellular gene expression start to emerge. They are grouped provisionally and reflect the methods used to determine the effects of large T-antigen. Large T-antigen may influence cellular gene expression by: i. altering mRNA levels of cellular transcription factors; ii. interacting with and regulating the DNA-binding or transcriptional activity of specific transcription factors; iii. functionally substitution of eukaryotic transcription factors; iv. direct binding to DNA; or v. regulating components of signaling transduction pathways. Small t-ag seems to exert its effect mainly through inhibiting a cellular phosphatase, protein phosphatase 2A, thereby modulating components of signal transduction pathways and preventing dephosphorylation of several transcription factors. However, small t-ag may also control cellular gene expression by regulating mRNA levels of transcription factors or by interacting with other transcription factors.

A simple method for the preparation and purification of C1 complement cleaved beta 2-microglobulin from human serum

A simple method is described for the preparation of proteolytically processed forms of beta 2-microglobulin suitable for structural and biological studies. PEG 6000 was added to the serum of healthy individuals to precipitate the C1 complement complex from C1 esterase inhibitor (C1-inh). After dissolving the precipitate containing the C1 complement in Tris-HCl buffer, pH 7.6, efficient conversion of added beta 2-microglobulin to desLys58 beta 2-microglobulin was observed. Addition of a specific carboxypeptidase B inhibitor (Plummers inhibitor) could partly prevent the deletion of Lys-58 from cleaved beta 2-microglobulin, whereby Lys58-cleaved beta 2-microglobulin was obtained. The proteolytically processed forms were subsequently purified by G-75 Sephadex gel filtration followed by chromatofocusing. A yield of 10-40% of proteolytically processed beta 2-microglobulin was obtained. Only one component was seen by SDS-PAGE stained with Coomassie Brilliant Blue.

Localization of nonpancreatic secretory phospholipase A2 in normal and atherosclerotic arteries. Activity of the isolated enzyme on low-density lipoproteins

Secretory nonpancreatic type II phospholipase A2 (snpPLA2) hydrolyzes fatty acids at the sn-2 position in phospholipids releasing free fatty acids (FFAs) and lysophospholipids. These products may act as intracellular second messengers or can be further metabolized into proinflammatory lipid mediators. The presence of snpPLA2 in extracellular fluids and serum during inflammation has suggested a role of the enzyme in this process. However, the presence of snpPLA2 in a variety of normal tissues suggests that snpPLA2 may also have physiological functions. Atherosclerosis appears to have an inflammatory component. Here we report on the snpPLA2 localization in normal and atherosclerotic lesions and on the properties of the isolated enzyme. A strong snpPLA2 immunoreactivity was observed in the arterial media that was colocalized with alpha-actin-positive vascular smooth muscle cells (SMCs) in both normal and atherosclerotic vessels. In aortic atherosclerotic lesions, snpPLA2 was observed colocalized with CD68-positive macrophages and HHF-35-positive SMCs and extracellularly in the lipid core. snpPLA2 was isolated from human normal arteries and from aorta with lesions. The enzyme was isolated by acid extraction of normal arterial tissues followed by immunoaffinity chromatography. The purified snpPLA2 had an expected molecular weight of 14 kD by polyacrylamide gel electrophoresis and appeared as a single band in immunoblotting. The enzymatic activity was followed by measuring release of fatty acids from phospholipid liposomes or LDL as substrates. The enzymatic activity was inhibited with two specific inhibitors for human snpPLA2: (1) monoclonal antibody 187 and (2) LY311727, a synthetic selective inhibitor. The mRNA for snpPLA2 was detected with reverse transcriptase polymerase chain reaction. These results indicate that snpPLA2 is present in human arteries and that it is able to hydrolyze phospholipids in LDL. The results support the hypothesis that snpPLA2 can release proinflammatory lipids at places of LDL deposition in the arterial wall.

Binding of human phospholipase A2 type II to proteoglycans. Differential effect of glycosaminoglycans on enzyme activity

Phospholipase A2 acting on low density lipoproteins in the extracellular arterial intima may form proinflammatory lipid mediators. Human nonpancreatic secretory phospholipase A2 has three regions that may associate with sulfated glycosaminoglycans. The apoB-100 molecule in low density lipoproteins also has glycosaminoglycan binding regions that could mediate its retention in the arterial intima. Here we report that human nonpancreatic phospholipase A2 isolated from a transfected cell line binds to glycosaminoglycans secreted by cultured human arterial smooth muscle cells. A gel mobility shift assay showed that the affinity of phospholipase A2 for glycosaminoglycans from a heparan sulfate/chondroitin sulfate proteoglycan was higher than for chondroitin sulfate glycosaminoglycans from a larger versican-like proteoglycan. Affinity chromatography confirmed these results. All glycosaminoglycans tested, at concentrations up to 100 microM, increased the activity of phospholipase A2 toward phosphatidylcholine liposomes. Above this concentration, heparan sulfate and heparin inhibited the enzyme. Heparin and chondroitin 6-sulfate increased phospholipase A2 activity on low density lipoproteins up to 4-fold at 100 microM, whereas heparan sulfate had no effect. The results indicate that human nonpancreatic secretory phospholipase A2 interacts with proteoglycans via their glycosaminoglycan moiety and that the enzyme activity may be modulated by the association of the enzyme and its substrate to the sulfated polysaccharides.

Single lung transplantation for chronic obstructive pulmonary disease: pulmonary function and impact of bronchiolitis obliterans syndrome

Chronic obstructive pulmonary disease (COPD) is now the most common indication for single lung transplantation. In long-term follow-up, obliterative bronchiolitis is a major problem. The aim of the present study was to perform a long-term follow-up of the pulmonary function and to examine the effect of development of bronchiolitis obliterans syndrome (BOS). Nineteen patients with end-stage COPD underwent single lung transplantation and were followed regularly with pulmonary function tests, and ventilation and perfusion scintigraphy (mean observation time 29 months). They were divided into two categories, with and without BOS, using the definition recommended by the International Society for Heart and Lung Transplantation working group. A mixed model analysis of variance with BOS as co-variate was used to evaluate its effect on pulmonary function. Spirometry, lung transfer factor for carbon monoxide (TLCO), arterial blood gases and 6-min walk test improved significantly (P < 0.001) from before transplantation to 3 months after transplantation. Nine patients developed BOS. Implied by the definition of the syndrome, forced expiratory volume in 1 s (FEV1) was significantly (P < 0.001) lower for patients with BOS while there was no significant effect of BOS category on TLCO corrected for alveolar volume (VA) or perfusion to transplant. Patients without BOS maintained their pulmonary function, and ventilation and perfusion to transplant for more than 3 yr after transplantation. The present results suggest that decreasing FEV1 accompanied by an unchanged TLCO/VA and pulmonary perfusion support the diagnosis of BOS after single lung transplantation for COPD.

When to suspect and how to diagnose pulmonary lymphangioleiomyomatosis

The objective of this study was to present clinical and radiological data of eight women with histologically proven lymphangioleiomyomatosis (LAM) diagnosed between 1984 and 1994, and to suggest a diagnostic strategy when LAM is suspected. A review of case reports, including results of biopsies, lung function and radiological procedures was undertaken. The mean age of the women at start of symptoms was 36 years, and the mean age at time of diagnosis 42 years. The most frequent presenting complaint was dyspnea, either in conjunction with pneumothorax (3), chylothorax (2) or on exertion (2). All patients had airflow limitation and markedly reduced gas transfer. Five patients had 16 episodes of pneumothorax. In seven patients multiple cysts were observed on the surface of the lung during thoracotomy while computerized tomography (CT) scans revealed numerous cysts evenly distributed throughout the lung parenchyma. The procedures that confirmed the diagnosis included transbronchial lung biopsy (4), open lung biopsy (2), thoracoscopy (1), thoracotomy (3) and autopsy (1). Three specimens had to be revised before the histological diagnosis was confirmed. It was concluded that the important clues to a diagnosis of LAM are recurrent episodes of pneumothoraces in fertile women, progressive air-flow limitation, markedly reduced gas transfer and characteristic findings on thoracic CT scans. A specific request to the pathologist to stain lung tissue specimens for smooth muscle cells is mandatory.

PCR and sequencing from a single pollen grain

In order to eliminate the laborious step of DNA extraction preceding all studies within the field of plant molecular biology we attempted to do PCR amplifications directly on pollen grains. Successful PCR amplification was obtained in reactions including a single pollen grain from Hordeum vulgare or Secale strictum. Both the plastid gene encoding ribulose-1,5-biphosphate carboxylase/oxygenase (rbcL) and the nuclear-encoded internal transcribed spacer regions (ITS) and the 5.8S rDNA region were amplified and sequenced to verify PCR amplification.

Extracellular phospholipase A2 expression in sarcoidosis

This study was conducted in order to focus upon the Ca2- dependent secretory non-pancreatic phospholipase A2 (npPLA2) enzyme and its possible role in the pathophysiology of sarcoidosis. Serum samples were taken from 24 patients with sarcoidosis to determine the levels of npPLA2. Moreover, in another group of patients with active chest x-ray stage II and III sarcoidosis, bronchoscopy with bronchoalveolar lavage (BAL) and transbronchial lung biopsies (TBL) were taken. Highly significant increase of npPLA2 in serum was found in patients compared to controls (p < 0.001). Furthermore, those patients with stable and inactive disease and those who were under treatment with corticosteroids, tended to have lower values than those with active disease and those who were untreated. An intense accumulation of npPLA2 was found in smooth muscle tissue in lung biopsy specimens, in close connection with fibroblast accumulation and deposition of collagen. These cells also stained positive for alpha-smooth muscle actin (alpha-SMA). In addition, when using the technique of in situ hybridization, expression of npPLA2-mRNA was found in the fibroblast layer surrounding the epitheloid cell granulomas. These fibroblasts did not stain positive for alpha-SMA. Our data suggest that npPLA2 is actively involved, and has an important role, in the pathophysiology of sarcoidosis.

Acid-base status and cardiovascular function in mink (Mustela vison) anaesthetized with ketamine/midazolam

Heart rate, arterial blood pressure and blood acid-base status were determined in 18 adult female mink (mean (+/- SEM) body weight 1052 +/- 34 g) during long-term anaesthesia with either controlled ventilation (n=12) or spontaneous respiration (n=6). Surgical anaesthesia was induced by intramuscular injection of ketamine hydrochloride (Ketaminol Vet, 40.0 +/- 1.7 mg/kg) and midazolam hydrochloride (Dormicum 2.8 +/- 0.1 mg/kg) and maintained for at least 5 h by continuous intravenous infusion of this drug combination in 0.9% saline. For all animals, the mean rates of infusion of ketamine and midazolam were 48.4 +/- 1.6 and 1.61 +/- 0.12 mg/h, respectively. Following continuous infusion of the anaesthetics in isotonic saline, at a rate of 20 ml/h, a moderate 'dilution acidosis' developed, which could be corrected by replacement of part of the saline with sodium bicarbonate to a final concentration of approximately 25 mmol NaHCO3 per litre. However, when the animals were allowed to breathe spontaneously, an increase in heart rate and a combined respiratory and metabolic acidosis occurred, due to severe respiratory depression. Apart from these effects and a few cases of increased salivation, no adverse effects over time were observed on the arterial blood acid-base status and cardiovascular function of the animals during ketamine/midazolam anaesthesia. It is concluded that the procedure described for long-term anaesthesia in mink is convenient and safe for acute physiological experiments in this species, provided normal body temperature and pulmonary gas exchange is sufficiently maintained. Thus, the need for an adequately controlled artificial ventilation is strongly emphasized. Finally, a proposal for the composition of an intravenous solution, containing ketamine and midazolam hydrochloride, and sodium bicarbonate in saline, suitable for long-term anaesthesia in adult mink is presented.