A multivariate analysis of 416 patients with glioblastoma multiforme: prognosis, extent of resection, and survival

OBJECT

The extent of tumor resection that should be undertaken in patients with glioblastoma multiforme (GBM) remains controversial. The purpose of this study was to identify significant independent predictors of survival in these patients and to determine whether the extent of resection was associated with increased survival time.

METHODS

The authors retrospectively analyzed 416 consecutive patients with histologically proven GBM who underwent tumor resection at the authors' institution between June 1993 and June 1999. Volumetric data and other tumor characteristics identified on magnetic resonance (MR) imaging were collected prospectively.

CONCLUSIONS

Five independent predictors of survival were identified: age, Karnofsky Performance Scale (KPS) score, extent of resection, and the degree of necrosis and enhancement on preoperative MR imaging studies. A significant survival advantage was associated with resection of 98% or more of the tumor volume (median survival 13 months, 95% confidence interval [CI] 11.4-14.6 months), compared with 8.8 months (95% CI 7.4-10.2 months; p < 0.0001) for resections of less than 98%. Using an outcome scale ranging from 0 to 5 based on age, KPS score, and tumor necrosis on MR imaging, we observed significantly longer survival in patients with lower scores (1-3) who underwent aggressive resections, and a trend toward slightly longer survival was found in patients with higher scores (4-5). Gross-total tumor resection is associated with longer survival in patients with GBM, especially when other predictive variables are favorable.

Categories versus dimensions in personality and psychopathology: a quantitative review of taxometric research

Taxometric research methods were developed by Paul Meehl and colleagues to distinguish between categorical and dimensional models of latent variables. We have conducted a comprehensive review of published taxometric research that included 177 articles, 311 distinct findings and a combined sample of 533 377 participants. Multilevel logistic regression analyses have examined the methodological and substantive variables associated with taxonic (categorical) findings. Although 38.9% of findings were taxonic, these findings were much less frequent in more recent and methodologically stronger studies, and in those reporting comparative fit indices based on simulated comparison data. When these and other possible confounds were statistically controlled, the true prevalence of taxonic findings was estimated at 14%. The domains of normal personality, mood disorders, anxiety disorders, eating disorders, externalizing disorders, and personality disorders (PDs) other than schizotypal yielded little persuasive evidence of taxa. Promising but still not definitive evidence of psychological taxa was confined to the domains of schizotypy, substance use disorders and autism. This review indicates that most latent variables of interest to psychiatrists and personality and clinical psychologists are dimensional, and that many influential taxonic findings of early taxometric research are likely to be spurious.

Consistent land- and atmosphere-based U.S. carbon sink estimates

For the period 1980-89, we estimate a carbon sink in the coterminous United States between 0.30 and 0.58 petagrams of carbon per year (petagrams of carbon = 10(15) grams of carbon). The net carbon flux from the atmosphere to the land was higher, 0.37 to 0.71 petagrams of carbon per year, because a net flux of 0.07 to 0.13 petagrams of carbon per year was exported by rivers and commerce and returned to the atmosphere elsewhere. These land-based estimates are larger than those from previous studies (0.08 to 0.35 petagrams of carbon per year) because of the inclusion of additional processes and revised estimates of some component fluxes. Although component estimates are uncertain, about one-half of the total is outside the forest sector. We also estimated the sink using atmospheric models and the atmospheric concentration of carbon dioxide (the tracer-transport inversion method). The range of results from the atmosphere-based inversions contains the land-based estimates. Atmosphere- and land-based estimates are thus consistent, within the large ranges of uncertainty for both methods. Atmosphere-based results for 1980-89 are similar to those for 1985-89 and 1990-94, indicating a relatively stable U.S. sink throughout the period.

Development of a flexible and specific gene delivery system for production of murine tumor models

To develop models of human cancer we have expressed the avian retroviral receptor, TVA, under a variety of mammalian promoters in transgenic mice, thus rendering mice susceptible to infection with avian leukosis virus-derived gene vectors. TVA-based retroviral gene transfer offers advantages over current murine models of human cancer. A single transgenic mouse line can be used to evaluate multiple genetic lesions, individually and in combination. Furthermore, mutant genes are introduced somatically into animals, as occurs in the majority of naturally occurring tumors. Because the avian viral vectors replicate only in avian cells, the viral receptor in infected transgenic mouse cells remains available for multiple rounds of infection with different ASLV vectors. We discuss the theoretical and practical aspects of using recombinant avian retroviruses with TVA transgenic mice to generate cancer models.

Human airway smooth muscle cells secrete vascular endothelial growth factor: up-regulation by bradykinin via a protein kinase C and prostanoid-dependent mechanism

Bronchial vascular remodeling is an important feature of the pathology of chronic asthma, but the responsible mechanisms and main sources of angiogenic factors are unclear. Here we report that human airway smooth muscle cells express vascular endothelial growth factor (VEGF)121, 165, 189, 206 splice variants and secrete VEGF protein constitutively. VEGF protein secretion was increased by the proinflammatory asthma mediator bradykinin through post-transcriptional mechanisms. Bradykinin-induced VEGF secretion was dependent on the B2 bradykinin receptor, activation of protein kinase C, and generation of endogenous prostanoids. This is the first report that bradykinin can increase VEGF secretion in any biological system and the first to show that airway smooth muscle cells produce VEGF. Our results suggest a novel role for human airway smooth muscle in contributing to bronchial mucosal angiogenesis in chronic asthma by secretion of VEGF and suggest a wider role for mesenchymal cell products in mediating angiogenesis in inflammatory and allergic diseases.

TGF-beta1 stimulates IL-8 release, COX-2 expression, and PGE(2) release in human airway smooth muscle cells

We have recently shown that endogenous prostanoids are critical in bradykinin-stimulated interleukin (IL)-8 release from human airway smooth muscle (ASM) cells. In this study, we tested the ability of transforming growth factor (TGF)-beta1 to stimulate IL-8 release, cyclooxygenase (COX)-2 expression and PGE(2) generation in cultured human ASM cells and explored the role of COX products and COX-2 induction on IL-8 release. TGF-beta1 stimulated IL-8 release, COX-2 induction, and PGE(2) generation in a concentration- and time-dependent manner. Maximal IL-8 release was achieved with 10 ng/ml of TGF-beta1 after 16 h of incubation, which was inhibited by the transcription inhibitor actinomycin D and the corticosteroid dexamethasone but was not affected by the nonselective COX inhibitor indomethacin and the selective COX-2 inhibitor NS-398 despite their inhibition on TGF-beta1-induced PGE(2) release. These results show for the first time that TGF-beta1 stimulates IL-8 release, COX-2 induction, and PGE(2) generation in human ASM cells and that PGE(2) generation is not critical for TGF-beta1-induced IL-8 release. These findings suggest that TGF-beta1 may play an important role in the pathophysiology of asthma.

Production of PGE2 by bovine cultured airway smooth muscle cells and its inhibition by cyclo-oxygenase inhibitors

1. Prostaglandin E2 (PGE2) is thought to be an important inhibitory modulator of inflammatory processes in the airway. It inhibits inflammatory cell function and cholinergic neurotransmission in vitro and roles have been postulated in vivo in refractoriness and in the mechanism of action of the diuretic agent, frusemide. 2. The production of PGE2 by bovine cultured airway smooth muscle cells has been studied under a range of conditions. The effects of cyclo-oxygenase inhibitors (flurbiprofen, indomethacin, acetyl salicylic acid) on serum-induced production of PGE2 were assessed over a range of concentrations (10(-7)-10(-4) M). 3. Serum-stimulated production of PGE2 in control wells ranged from 350 to 800 ng PGE2 ml-1 in cells from different animals. All three cyclo-oxygenase inhibitors inhibited PGE2 production with an order of potency, flurbiprofen > indomethacin > acetyl salicylic acid. Log IC50 values were -6.24 for flurbiprofen, -5.23 for indomethacin and -3.50 for acetyl salicylic acid. 4. PGE2 production was stimulated by arachidonic acid (10(-5) M) or addition of the proinflammatory mediator, bradykinin (10(-8)-10(-5) M). 5. Incubation of cells for 24 h with 5 bromo deoxyuridine (BRDU) (10(-4) M) to prevent DNA synthesis did not alter PGE2 production in response to serum, suggesting that it was not a function of proliferation per se. 6. Our study suggests that airway smooth muscle may be an important source of PGE2. Production of PGE2 may be a novel feedback mechanism whereby airway smooth muscle cells can negatively modulate airways inflammation. The differing potencies of the cyclo-oxygenase inhibitors may explain the contrasting effect of these drugs in recent studies in asthma.

Dynamic quantification of canopy structure to characterize early plant vigour in wheat genotypes

Early vigour is an important physiological trait to improve establishment, water-use efficiency, and grain yield for wheat. Phenotyping large numbers of lines is challenging due to the fast growth and development of wheat seedlings. Here we developed a new photo-based workflow to monitor dynamically the growth and development of the wheat canopy of two wheat lines with a contrasting early vigour trait. Multiview images were taken using a 'vegetation stress' camera at 2 d intervals from emergence to the sixth leaf stage. Point clouds were extracted using the Multi-View Stereo and Structure From Motion (MVS-SFM) algorithm, and segmented into individual organs using the Octree method, with leaf midribs fitted using local polynomial function. Finally, phenotypic parameters were calculated from the reconstructed point cloud including: tiller and leaf number, plant height, Haun index, phyllochron, leaf length, angle, and leaf elongation rate. There was good agreement between the observed and estimated leaf length (RMSE=8.6mm, R (2)=0.98, n=322) across both lines. Significant contrasts of phenotyping parameters were observed between the two lines and were consistent with manual observations. The early vigour line had fewer tillers (2.4±0.6) and larger leaves (308.0±38.4mm and 17.1±2.7mm for leaf length and width, respectively). While the phyllochron of both lines was quite similar, the non-vigorous line had a greater Haun index (more leaves on the main stem) on any date, as the vigorous line had slower development of its first two leaves. The workflow presented in this study provides an efficient method to phenotype individual plants using a low-cost camera (an RGB camera is also suitable) and could be applied in phenotyping for applications in both simulation modelling and breeding. The rapidity and accuracy of this novel method can characterize the results of specific selection criteria (e.g. width of leaf three, number of tillers, rate of leaf appearance) that have been or can now be utilized to breed for early leaf growth and tillering in wheat.

Role of cyclo-oxygenase-2 induction in interleukin-1beta induced attenuation of cultured human airway smooth muscle cell cyclic AMP generation in response to isoprenaline

Airway smooth muscle (ASM) in human asthma shows reduced relaxation and cyclic AMP generation in response to beta-adrenoceptor agonists. IL-beta attenuates cyclic AMP generation but the underlying mechanism is unclear. We have reported that IL-1beta induces cyclo-oxygenase-2 (COX-2) in human ASM cells and results in a marked increase in prostanoid generation with PGE2 and PGI2 as the major products. We investigated the role of COX-2 induction and prostanoid release (measured as PGE2) in IL-1beta induced attenuation of cyclic AMP generation in response to the beta-adrenoceptor agonist isoprenaline (ISO). Pre-treatment of human ASM cells with IL-1beta significantly attenuated cyclic AMP generation in response to high concentrations of ISO (1.0-10.0 microM) in a time- and concentration-dependent manner. The effect was accompanied by a high concentration of PGE2 release. The non-selective COX inhibitor indomethacin (Ind), the selective COX-2 inhibitor NS-398, the protein synthesis inhibitors cycloheximide (CHX) and actinomycin D and the steroid dexamethasone (Dex) all abolished the PGE2 release and prevented the attenuated cyclic AMP generation. COX substrate arachidonic acid time- and concentration-dependently mimicked IL-1beta induced attenuation and the effect was prevented by the non-selective COX inhibitors Ind and flurbiprofen, but not by NS-398, CHX and Dex. In contrast to IL-1beta, TNFalpha and IFNgamma, which are ineffective in inducing COX-2 and releasing PGE2 from human ASM cells, did not affect the cyclic AMP formation. Our study demonstrates that COX-2 induction and the consequent release of prostanoids plays a crucial role in IL-1beta induced attenuation of human ASM cell cyclic AMP response to ISO.

Marquardt's Phi mask: pitfalls of relying on fashion models and the golden ratio to describe a beautiful face

BACKGROUND

Stephen Marquardt has derived a mask from the golden ratio that he claims represents the "ideal" facial archetype. Many have found his mask convincing, including cosmetic surgeons. However, Marquardt's mask is associated with numerous problems. The method used to examine goodness of fit with the proportions in the mask is faulty. The mask is ill-suited for non-European populations, especially sub-Saharan Africans and East Asians. The mask also appears to approximate the face shape of masculinized European women. Given that the general public strongly and overwhelmingly prefers above average facial femininity in women, white women seeking aesthetic facial surgery would be ill-advised to aim toward a better fit with Marquardt's mask. This article aims to show the proper way of assessing goodness of fit with Marquardt's mask, to address the shape of the mask as it pertains to masculinity-femininity, and to discuss the broader issue of an objective assessment of facial attractiveness.

METHODS

Generalized Procrustes analysis is used to show how goodness of fit with Marquardt's mask can be assessed. Thin-plate spline analysis is used to illustrate visually how sample faces, including northwestern European averages, differ from Marquardt's mask.

RESULTS

Marquardt's mask best describes the facial proportions of masculinized white women as seen in fashion models.

CONCLUSIONS

Marquardt's mask does not appear to describe "ideal" face shape even for white women because its proportions are inconsistent with the optimal preferences of most people, especially with regard to femininity.

Diagnosis of microsporidial keratitis by confocal microscopy and the chromatrope stain

PURPOSE

To illustrate the value of confocal microscopy and chromatrope stain in the diagnosis of microsporidial keratitis.

METHODS

In vivo confocal microscopy was performed on a man with the human immunodeficiency virus who had severe bilateral epithelial keratitis refractory to topical antibacterial medications. The results were compared to conjunctival scrapings stained with the chromatrope-based Weber stain.

RESULTS

Confocal microscopy demonstrated many small, intraepithelial opacities of the corneal epithelium, which were suggestive of Microsporidia. Results of the chromatrope stain of conjunctival scrapings confirmed the diagnosis of microsporidial keratitis.

CONCLUSIONS

Rapid diagnosis allowed prompt initiation of topical fumagillin, which permitted rapid, long-term control of the symptoms of microsporidial keratitis.

Growth and maturation of children with insulin-dependent diabetes mellitus

The purpose of this paper is to define criteria used for classifying patients into varying degrees of diabetic control and to verify that children with diabetes maintained in higher degrees of metabolic control do not have delayed growth and maturation. Growth records of 252 children with insulin-dependent diabetes who have been under continuous observation in our clinic at three- to five-month intervals for at least three years and up to 16 years have been individually reviewed and analyzed. All children received two daily injections of a mixture of two parts of an intermediate to one part of regular insulin and were instructed to eat structured meals of high-quality selected foods. An over-all rating for diabetic control based primarily on the frequency and degree of glycosuria was made for the time period between clinic visits. The over-all diabetic control rating and the size of the subgroups were "good"--20 per cent, "fair to good"--64 per cent, and "fair"--16 per cent. All children maintained in "good" and "fair to good" control (84 per cent), grew and matured at a normal rate regardless of the age at onset or duration of diabetes. All children in lower degrees of control coming under care for greater than 24 months after diagnosis had accelerated growth during the early months after attaining a higher degree of control.

Na+/K+ ATPase in lower airway epithelium from cystic fibrosis and non-cystic-fibrosis lung

The basolateral Na+/K+ ATPase plays a critical role in sodium reabsorption across airway epithelium. Nasal epithelium shows increased Na+/K+ ATPase activity in cystic fibrosis (CF) but Na+/K+ ATPase has not been characterized in human lung epithelium or compared in CF and normal lung. We measured 3[H] ouabain binding and Na+/K+ ATPase activity in human tracheal epithelium and compared Na/K ATPase activity in bronchial epithelium in CF and control subjects. In tracheal epithelium Na+/K+ ATPase pumps were abundant and of high 3[H] ouabain affinity (Kd 4.7 nM, Bmax 38 pmol/mg) and Na+/K+ ATPase activity was 55 +/- 8 nmol/mg protein/min. Bronchial epithelial Na+/K+ ATPase activity was twofold higher in CF patients than in controls. The increased Na+/K+ ATPase activity may contribute to the increased sodium reabsorption seen in cystic fibrosis.

Selectivity of cyclo-oxygenase inhibitors in human pulmonary epithelial and smooth muscle cells

Cyclo-oxygenase (COX) inhibitors may have a role in reducing inflammation in asthma and other pulmonary diseases. COX inhibitors have different selectivities for the two COX isoenzymes (COX 1 and COX 2) which vary between purified enzyme and intact cell preparations. The relative selectivity of COX inhibitors has not been studied in human airway cells. A number of COX inhibitors in cultured human airway cells were compared which exclusively express either COX 1 (primary degree cultured human airway smooth muscle (HASM) cells) or COX 2 (A549 pulmonary epithelial cell-line) as measured by Western blotting. COX activity was assayed by prostaglandin (PG)E2 production following 30 min incubation with 5 mM arachidonic acid. COX activity in both cell types was similar; HASM cells 92.2+/-12.1 ng PGE2 x mg-1 protein, A549 cells 87.7+/-24.4 ng PGE2 mg-1 protein. In HASM cells the median inhibitory concentration (IC50) was >10-5 M for nimesulide, 3.2 x 10-6 M for N-(2-cyclohexyloxy-4-nitrophenyl)-methanesulphonamide (NS398), 1.8 x 10-8 M for flurbiprofen, 6.7 x 10-9 M for indomethacin and >10-5 M for aspirin. In A549 cells the IC50 was 1.8 x 10-9M for nimesulide, 4.1 x 10-9 M for NS398,6.2 x 10-10 M for flurbiprofen, 1.3 x 10-8 M for indomethacin and >10-5 M for aspirin. Sodium valerate had no effect in either HASM or A549 cells. The COX 2:COX 1 selectivity ratio (COX 2 IC50/COX I IC50) was <0.0001 for nimesulide, 0.001 for NS398, 0.03 for flurbiprofen and 1.9 for indomethacin. In conclusion the present study has shown that cyclo-oxygenase inhibitors have a range of selectivities for cyclo-oxygenase 1 and cyclo-oxygenase 2 in intact human airway cells. The relative cyclo-oxygenase 2 selectivity of N-(2-cyclohexyloxy-4-nitrophenyl)-methanesulphonamide and nimesulide may have implications for the treatment of asthma and other inflammatory pulmonary diseases.

Obesity paradox in group 1 pulmonary hypertension: analysis of the NIH-Pulmonary Hypertension registry

BACKGROUND

The 'obesity paradox' refers to the fact that obese patients have better outcomes than normal weight patients. This has been observed in multiple cardiovascular conditions, but evidence for obesity paradox in pulmonary hypertension (PH) remains sparse.

METHODS

We categorized 267 patients from the National Institute of Health-PH registry into five groups based on body mass index (BMI): underweight, normal weight, overweight, obese and morbidly obese. Mortality was compared in BMI groups using the χ² statistic. Five-year probability of death using the PH connection (PHC) risk equation was calculated, and the model was compared with BMI groups using Cox proportional hazards regression and Kaplan-Meier (KM) survival curves.

RESULTS

Patients had a median age of 39 years (interquartile range 30-50 years), a median BMI of 23.4 kg m^-2 (21.0-26.8 kg m^-2) and an overall mortality at 5 years of 50.2%. We found a U-shaped relationship between survival and 1-year mortality with the best 1-year survival in overweight patients. KM curves showed the best survival in the overweight, followed by obese and morbidly obese patients, and the worst survival in normal weight and underweight patients (log-rank P=0.0008). In a Cox proportional hazards analysis, increasing BMI was a highly significant predictor of improved survival even after adjustment for the PHC risk equation with a hazard ratio for death of 0.921 per kg m^-2 (95% confidence interval: 0.886-0.954) (P<0.0001).

CONCLUSION

We observed that the best survival was in the overweight patients, making this more of an 'overweight paradox' than an 'obesity paradox'. This has implications for risk stratification and prognosis in group 1 PH patients.

Eye banking and screening for Creutzfeldt-Jakob disease

OBJECTIVES

To quantify the risk of Creutzfeldt-Jakob disease (CJD) among cornea donors, evaluate supplemental screening strategies, and address concerns about the adequacy of current methods of screening tissue donors in the United States.

METHODS

Reported data on deaths due to CJD and from all causes were used to estimate the rate of CJD among cornea donors. The impact of increased screening on risk of CJD and donor supply was evaluated.

RESULTS

Only 1.3 of the approximately 45 000 cornea donors in the United States each year might be expected to have CJD. Most of the estimated risk (91%) is due to preclinical (asymptomatic) disease and therefore could not be eliminated by screening for signs or symptoms. If only the highest-risk age group (60 to 69 years) were screened and specificity were 90%, more than 21 000 otherwise acceptable donors would incorrectly be excluded over a period of 17.5 years to correctly exclude a single donor with symptomatic CJD.

CONCLUSIONS

Currently, the risk of CJD transmission following cornea transplantation is remarkably low. Screening for symptoms of CJD would have minimal impact on safety, but would reduce donor supply and likely result in many patients not receiving needed treatment.

Isobaric tagging-based quantification by mass spectrometry of differentially regulated proteins in synaptosomes of HIV/gp120 transgenic mice: implications for HIV-associated neurodegeneration

HIV/gp120 transgenic mice manifest neuropathological features similar to HIV-associated neurocognitive disorders (HAND) in humans, including astrogliosis, microglia activation, and decreased neuronal synapses. Here, proteomic screening of synaptosomes from HIV/gp120 transgenic mice was conducted to determine potential neuronal markers and drug targets associated with HAND. Synaptosomes from 13 month-old wild-type (wt) and HIV/gp120 transgenic mouse cortex were subjected to tandem mass tag (TMT) labeling and subsequent analysis using an LTQ-Orbitrap mass spectrometer in pulsed-Q dissociation (PQD) mode for tandem mass spectrometry (MS/MS). A total of 1301 proteins were identified in both wt and HIV/gp120 transgenic mice. Three of the most differentially-regulated proteins were validated by immunoblotting. To elucidate putative pathways associated with the proteomic profile, 107 proteins manifesting a ≥1.5 fold change in expression were analyzed using a bioinformatics pathway analysis tool. This analysis revealed direct or indirect involvement of the phosphotidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway, a well-known neuronal survival pathway. Immunoblots confirmed a lower phospho (p)Akt/Akt ratio in synaptosomes from HIV/gp120 transgenic animals compared to wt, suggesting that this neuroprotective pathway was inactivated in the HIV/gp120 transgenic brain. Based on this information, we then compared immunoblots of pAkt/Akt in the forebrains of these mice as well as in human postmortem brain. We observed a significant decrease in the pAkt/Akt ratio in synaptosomes and forebrain of HIV/gp120 transgenic compared to wt mice, and a similar decrease in human forebrain from HAND patients compared to neurologically unimpaired HIV+ and HIV- controls. Moreover, mechanistic insight into an additional pathway for decreased Akt activity in HIV/gp120 mouse brains and human HAND brains was shown to occur via S-nitrosylation of Akt protein, a posttranslational modification known to inhibit Akt activity and contribute to neuronal cell injury and death. Thus, MS proteomic profiling in the HIV/gp120 transgenic mouse predicted dysregulation of the PI3K/Akt pathway observed in human brains with HAND, providing evidence that this mouse is a useful disease model and that the Akt pathway may provide multiple drug targets for the treatment of HIV-related dementias.

Production of PGE2 by bovine cultured airway smooth muscle cells: regulation by cAMP

Prostaglandin E2 (PGE2) is thought to be an important inhibitory modulator of inflammatory processes in the airway. Previous studies have shown that it is produced by bovine cultured airway smooth muscle (ASM) cells in large quantities, but its regulation by second messengers has not been studied in this tissue. To determine whether PGE2 production by ASM might be an important action of beta-adrenoceptor agonists in asthma, the regulation of PGE2 production by adenosine 3',5'-cyclic monophosphate (cAMP) was assessed using dibutyryl cAMP (DBcAMP), forskolin, and albuterol. DBcAMP increased PGE2 production over a 24-h time course. Forskolin and albuterol both increased PGE2 production over control cells to similar levels after 24 h. Incubation of albuterol-treated cells with propranolol significantly (70%) reduced the stimulatory effect of albuterol on PGE2 production. Incubation of forskolin-treated cells with Rp-cAMP, a cAMP antagonist, inhibited the PGE2 response evoked by forskolin by 80%. Ro-20-1724, a selective inhibitor of type IV phosphodiesterase, stimulated PGE2 production (P = 0.02). Cycloheximide, a protein-synthesis inhibitor, did not inhibit the response to DBcAMP. The effects of DBcAMP were additive with the effects of bradykinin, a proinflammatory mediator known to increase PGE2 production (P < 0.05). These studies suggest that cAMP may play an important regulatory role in stimulating PGE2 production by ASM. This may be a novel beneficial action of beta-adrenoceptor agonists in asthma.

Immunocytochemical localization of cyclo-oxygenase isoforms in cultured human airway structural cells

BACKGROUND

Cyclo-oxygenase (COX) exists as two isoforms, COX-1, the constitutive isoform, and COX-2, which is inducible by cytokines or inflammatory stimuli and may participate in airway inflammation.

OBJECTIVE

To determine the basal distribution of COX isoforms, and their regulation by interleukin-1 beta (IL-1beta), bradykinin (BK) and dexamethasone (Dex) in cultured airway structural cells.

METHODS

We measured COX-1 and COX-2 in cultured human airway smooth muscle (HASM) cells, MRC5 fibroblasts and normal human epithelial cells (NHBE) using immunocytochemical analysis.

RESULTS

The majority of all types of untreated cultured cells expressed COX-1 (75% of HASM, 75% of MRC5 fibroblasts and 72% of NHBE cells). Fibroblasts and smooth muscle cells showed low constitutive COX-2 expression (2 and 8%, respectively) but this was higher in NHBE cells (28%). IL-1beta (24 h incubation) or BK (4 h incubation) had no effect on COX-1 expression in any of the cells studied. In contrast, there was a two- and 1.5-fold rise in the percentage of NHBE cells expressing COX-2; a 7.5- and sixfold rise in the percentage of HASM cells expressing COX-2 and a 33.5- and 20.5-fold increase in the percentage of fibroblasts expressing COX-2 after IL-1beta or BK treatment, respectively. Pretreatment with dexamethasone abolished IL-1beta- and BK-stimulated COX-2 induction in all cells studied.

CONCLUSION

COX-1 is expressed constitutively in human airway fibroblasts, smooth muscle and epithelial cells but epithelial cells also show constitutive expression of COX-2. Both IL-1beta and BK induced COX-2 expression in all cells studied and this induction was blocked by dexamethasone. Immunocytochemical techniques can be successfully used to detect the distribution of COX isoforms in cell cultures.

Regulation of cGMP by soluble and particulate guanylyl cyclases in cultured human airway smooth muscle

Although guanosine 3',5'-cyclic monophosphate (cGMP) acts as a relaxant second messenger, the regulation of intracellular cGMP has not been comprehensively studied in human airway smooth muscle. We studied the production of cGMP by cultured human airway smooth muscle cells (HASMC) after stimulation with activators of soluble guanylyl cyclase [sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine (SNAP)] and particulate guanylyl cyclase [atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), C-type natriuretic peptide (CNP), and Escherichia coli heat stable enterotoxin (STa)]. cGMP was measured by enzyme-linked immunosorbent assay. Both SNP (10(-6) to 10(-3) M) and SNAP (10(-6) to 10(-3) M) caused concentration-dependent elevation of cGMP in the presence of the nonselective phosphodiesterase (PDE) inhibitor 3-isobutyl-1-methylxanthine (10(-3) M), with cGMP increasing 6- and 15-fold in response to SNP and SNAP, respectively, at the highest concentration tested (10(-3) M). The increases in cGMP in response to SNP (5 x 10(-5) M) and SNAP (10(-5) M) were inhibited by hemoglobin (Hb; 5 x 10(-5) M), a nitric oxide scavenger, and methylene blue (MB; 5 x 10(-4) M), an inhibitor of guanylyl cyclase. cGMP accumulation after SNAP was abolished by both Hb and MB. The response to SNP was inhibited by 79% with Hb and was abolished with MB. ANP, BNP, and CNP (10(-9) to 10(-5) M) + phosphoramidon (10(-6) M) caused a concentration-dependent elevation in cGMP with an order of potency ANP > BNP > CNP. cGMP formation in the presence of the highest concentration of the most potent natriuretic peptide (10(-5) M ANP) was two- to threefold greater than with the highest concentration of SNAP. The increase in cGMP seen with natriuretic peptides was similar in the presence or absence of phosphoramidon, a neutral endopeptidase (NEP) inhibitor, suggesting that NEP is not playing a role in modulating the effect of natriuretic peptides in HASMC. STa (400 IU/ml) had no effect on cGMP levels. SNAP- and ANP-induced cGMP accumulation was increased by the selective type V PDE inhibitors SKF-96231 and zaprinast, suggesting that type V PDE is responsible for cGMP breakdown in HASMC. These results suggest that cultured HASMC contain both soluble and particulate guanylyl cyclases. The order of potency of the natriuretic peptides ANP > BNP > CNP suggests that type A particulate membrane-bound guanylate cyclase predominates.

TEL Induces Aggregation in Transformed Cells and Induces Tube Formation in NIH3T3-UCLA Cells

TEL/ETV6 is the frequent target of translocations associated with lymphoid and myeloid leukemias and solid tumors. We show that TEL induces aggregation of immortalized and transformed fibroblasts, endothelial cells and astrocytes. These aggregates form cellular cords in NIH3T3-UCLA by a cell autonomous process, which occurs when the monolayer is made up of over 75% of cells expressing exogenous TEL. Cords with a diameter of 15-25 microm contain a lumen and occur as tube structures. The possible relevance for vasculogenic mimicry is discussed. By contrast TEL did not induce aggregation of regular NIH3T3 cells, an effect that could only be induced by co-expression of oncogenic RAS/Lys12. Also transduction of TEL and RAS retroviral vectors into the endothelial MS1 cell line and TEL alone in the highly transformed glioblastoma cell lines EH-A and EH-B resulted in extensive aggregation. Thus, the induction of cellular aggregation by TEL correlates with transformation.

Impaired cAMP production in human airway smooth muscle cells by bradykinin: role of cyclooxygenase products

Interleukin (IL)-1beta impairs human airway smooth muscle (ASM) cell cAMP responses to isoproterenol (Iso). We investigated if bradykinin (BK) could cause a similar effect and the role of cyclooxygenase (COX) products in this event, since we have recently reported that BK, like IL-1beta, also causes COX-2 induction and prostanoid release in human ASM cells. BK pretreatment significantly attenuated Iso-induced cAMP generation in a time- and concentration-dependent manner. cAMP generation by prostaglandin (PG) E2 but not by forskolin was also impaired. The COX inhibitor indomethacin completely prevented the impairment, whereas the selective COX-2 inhibitors NS-398 and nimesulide, protein synthesis inhibitors cycloheximide and actinomycin D, and steroid dexamethasone were all partially effective. The impairment was mimicked by the B2 agonist [Tyr(Me)8]BK, the Ca2+ ionophore A-23187, and PGE2 and prevented by the B2 antagonist HOE-140, but anti-IL-1beta serum was ineffective. The results indicate that BK impairs human ASM cell responses to Iso, and the effect is largely mediated by B2 receptor-related COX product release via both COX isoforms and is independent of IL-1beta.

Effect of diuretics on allergen-induced contractions of passively sensitized human bronchi in vitro

Inhaled furosemide has been shown to protect subjects with asthma from bronchoconstriction induced by a wide variety of stimuli, including allergen, but the mechanism of action is controversial. We have used an in vitro model of allergen-induced bronchoconstriction to examine the effects of furosemide and other ion transport inhibitors. Human bronchial rings were passively sensitized by incubation with serum from an atopic donor and were challenged with Dermatophagoides pteronyssinus. Allergen-challenged bronchial rings developed bronchoconstriction which was effectively inhibited by the cysteinyl-leukotriene antagonist ICI 198,615 (10(-7) M) and to a lesser extent by terfenadine (10(-5) M). Assessed over 60 min furosemide 10(-6), 10(-5), and 10(-4) M inhibited contractions by a mean (95% confidence interval [CI]) 7.9% (-23.5, 39.3%, p > 0.05), 44.2% (12.9, 75.2%, p < 0.01), and 86.9% (55.5, 118.3%, p < 0.001) respectively (n = 5). The same concentrations of bumetanide inhibited contractions by 21.5% (-8.4, 51.4%, p > 0.05), 13.6% (-16.3, 43.4%, p > 0.05) and 51.6% (21.7, 81.4%, p < 0.01) respectively (n = 5). The sodium transport inhibitor amiloride and the anion transport inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) were without effect (both 10(-4) M; n = 4). Furosemide increased PGE2 production by the bronchial rings by 134% (95% CI 53, 259%). Indomethacin (3 x 10(-6) M) blocked the furosemide-induced increase in PGE2 production and reduced the protection afforded by 10(-4) M furosemide against allergen-induced contractions from 67.9% to 34.7% (mean difference 33.2%; 95% CI 9.7, 56.6%; p < 0.01; n = 8).(ABSTRACT TRUNCATED AT 250 WORDS)

Desensitization of guanylyl cyclases in cultured human airway smooth-muscle cells

We previously showed that cultured human airway smooth-muscle cells (HASMC) contain soluble and particulate guanylyl cyclases (GCs). We studied the desensitization of soluble and particulate GCs in HASMC. Homologous desensitization of soluble GC occurred after incubation with S-nitroso-N-acetyl pencillamine (SNAP). SNAP-dependent desensitization was blocked by hemoglobin, a nitric oxide (NO) scavenger, suggesting that it was due to NO release. Cross-desensitization between SNAP and sodium nitroprusside (SNP) and the lack of thiol reduction after SNAP or SNP treatment suggested that thiol depletion was not involved. Assays for soluble GC activity and experiments using protein synthesis inhibitors suggested that SNAP-dependent desensitization was due to reduced soluble GC. Homologous desensitization of particulate GC occurred after pretreatment with atrial natriuretic peptide (ANP) accompanied by reduced particulate GC activity. Recovery required protein synthesis, suggesting that it was due to reduction in particulate GC. Homologous desensitization to either SNAP or ANP was not altered by phosphodiesterase (PDE) inhibitors, suggesting that increased PDE activity was not involved. Cross-desensitization experiments using SNAP and ANP and experiments using zaprinast to elevate cyclic guanosine monophosphate showed no evidence of heterologous desensitization. Our results suggest that pretreatment of HASMC with SNAP or ANP causes homologous, but not heterologous, desensitization of soluble and particulate GCs, respectively.