Monitoring mRNA expression by polymerase chain reaction: the "primer-dropping" method

We have developed a method to monitor mRNA expression that is based upon the reverse transcriptase-polymerase chain reaction (RT-PCR) and includes multiple sets of primer pairs in coamplification reactions. To observe relative changes in mRNA steady-state levels, each target in a multiplex reaction was amplified to within a predetermined range by using PCR cycle numbers specific for each target. Optimal PCR cycle numbers for target templates were determined by preliminary titration experiments performed using the "primer-dropping" method. By employing this method, the overall amplification reaction was limited, permitting the PCR products to remain within the exponential range of the amplification curve and yet be detectable on ethidium bromide-stained gels. We demonstrated the utility of this method by monitoring the expression kinetics of cyclins A, B1, D1, and E, and of the immediate-early genes c-fos, c-myc, and beta-actin. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was included in the multiplex reactions as an endogenous internal standard to control for variations in product abundances due to differences in individual RT and PCR reaction efficiencies. Changes in gene expression of less than twofold to greater than 75-fold were readily distinguished.

Cellular and biochemical analysis of induced sputum from asthmatic and from healthy subjects

To determine the feasibility of cellular and biochemical analysis of sputum induced after inhalation of hypertonic (3%) saline, we analyzed sputum induced in 10 healthy and in 18 asthmatic subjects. We also analyzed saliva samples from all subjects. The entire sputum sample and the saliva sample were reduced using dithiothreitol, and cell counts and differentials were determined. Biochemical analysis was performed on sputum and saliva supernatants obtained after centrifugation. We found that induced sputum from asthmatic subjects had a higher percentage of eosinophils [8.1 +/- 3.43 (mean +/- SEM) versus 0.03 +/- 0.02%, p < 0.009] (after excluding squamous cells) and also had higher levels of albumin (232.3 +/- 54.8 versus 79.5 +/- 9.7 micrograms/ml, p < 0.02), fibrinogen (44.2 +/- 11.6 versus 11.9 +/- 2.5 micrograms/ml, p < 0.008) and eosinophil cationic protein (ECP) (142.6 +/- 34.2 versus 26.1 +/- 4.7 ng/ml, p < 0.006) but not of histamine or tryptase. In saliva, squamous cells made up more than 99% of the cells in both groups, and protein concentrations were not significantly different. We conclude that cellular and biochemical analysis of induced sputum is feasible in healthy and in asthmatic subjects and that it reveals differences similar to those reported from analyses of bronchial lavage fluid.

Dose-dependent cigarette smoking-related inflammatory responses in healthy adults

The aim of this study was to determine the dose-response relationship between cigarette smoke exposure and pulmonary cell and cytokine concentrations in bronchoalveolar lavage (BAL). BAL cells and BAL supernatant concentrations of tumour necrosis factor-alpha (TNF alpha), interleukin (IL)-1 beta, IL-6, IL-8, and monocyte chemoattractant protein (MCP)-1 from 14 healthy smokers and 16 healthy nonsmokers were quantified. Statistically greater concentrations of neutrophils, macrophages, IL-1 beta, IL-6, IL-8 and MCP-1 were observed among smokers compared with nonsmokers (p < or = 0.0007 in all cases). Cigarette smoking, categorized ordinally as: less than one pack, one pack, or greater than one pack per day, was predictive of BAL macrophages (p < 0.0001), neutrophils (p = 0.015), IL-1 beta (p < 0.001) and IL-8 (p = 0.02). We conclude that concentrations of macrophages, neutrophils, IL-1 beta and IL-8 are elevated in the pulmonary microenvironment of smokers in a cigarette dose-dependent manner. Based on the present findings, we would caution against simple analyses that treat current smokers as a homogeneous group and which do not account for smoking intensity.

Subtypes Y1 and Y2 of the neuropeptide Y receptor are respectively expressed in pro-opiomelanocortin- and neuropeptide-Y-containing neurons of the rat hypothalamic arcuate nucleus

The arcuate nucleus of the hypothalamus houses a number of neurochemically different cell populations. Among these, a dense cluster of small neuropeptide-Y (NPY)-expressing neurons is located in its ventromedial subdivision and a pro-opiomelanocortin (POMC)-expressing neuron population in its ventrolateral part. Furthermore, both neuropeptide Y Y1 and Y2 receptors (Y1-Rs and Y2-Rs) are expressed in the arcuate nucleus. Here we analyse the co-expression of NPY and POMC/adrenocorticotropic hormone with the Y1-R and Y2-R in arcuate neurons using immunohistochemistry and in situ hybridization. Many, but not all, POMC neurons expressed Y1-R mRNA and protein. Conversely, several Y1-R-positive, POMC-negative neurons were found. NPY-positive nerve terminals were found in close apposition to Y1-R-like immunoreactivity localized close to the dendritic and somatic cell membranes. Y2-R mRNA was found in almost all NPY mRNA-expressing neurons, but also in a group of NPY mRNA-negative cells. These results show that the POMC neurons are targets for NPY, which is presumably present in, and released from, fibres originating in the ventromedial arcuate nucleus and which may play a role in NPY-induced feeding. Release of NPY, and possible coexisting messengers, may be controlled by presynaptic Y2-R expressed in NPY neurons. Taken together, the findings support the division of Y1-Rs and Y2-Rs into post- and presynaptic receptors, respectively.

Increased activity of p53 in senescing fibroblasts

The p53 tumor-suppressor protein binds DNA and activates the expression of a 21-kDa protein that inhibits both the activity of cyclin-dependent kinases and the function of proliferating cell nuclear antigen. Since p21 expression has been reported to increase 10- to 20-fold as human diploid fibroblasts lose the ability to replicate, we examined the expression and activity of p53 during replicative aging. Similar levels of total p53 mRNA and protein were expressed in low-passage (young) and high-passage (old) cells but both DNA binding activity in vitro and transcriptional activity of p53 in vivo were increased severalfold in high-passage cells. While the basis of increased p53 activity is presently unclear, it is not correlated with differential phosphorylation or changes in p53-mouse double minute 2 gene product interactions. These results provide evidence for the activation of a protein involved in the control of cell cycle checkpoints during cellular aging, in the absence of increased expression.

Glycation impairs high-density lipoprotein function

AIMS/HYPOTHESIS

To examine the effects of incubation of high-density lipoprotein (HDL) under hyperglycaemic conditions on several functions of HDL in vitro.

METHODS

Human HDL (5 mg protein) was incubated for 1 week at 37 degrees C in the presence or absence of 25 mmol/l glucose. Additional samples of human HDL were incubated in butylated hydroxytoluene to control for oxidation.

RESULTS

High-density lipoprotein incubated for 1 week in 25 mmol/l glucose had significant increases in the glycation product, fructoselysine and in the advanced glycation end product, N epsilon-(carboxymethyl)-lysine. High-density lipoprotein apolipoprotein AI and AII concentrations were not altered but glycated HDL had a 65% reduction in paraoxonase enzymatic activity. Glycated HDL did not inhibit monocyte adhesion to human aortic endothelial cells in response to oxidised low-density lipoprotein in vitro (43 +/- 4 monocytes bound vs 21 +/- 2 monocytes for control HDL, p < 0.0001). Hepatic lipase-mediated non-esterified fatty acid release from HDL lipids was enhanced in glycated HDL compared with control HDL (25 +/- 1 vs 16 +/- 1 nmol non-esterified fatty acid hydrolysed/min, respectively, p < 0.0001). Direct glycation of purified paraoxonase protein by incubation in 25 mmol/l glucose caused a 40% reduction in enzymatic activity. This glycated paraoxonase did not inhibit monocyte adhesion to human aortic endothelial cells in vitro (68 +/- 3 monocytes vs 49 +/- 2 monocytes bound for control paraoxonase, respectively, p < 0.001). We also measured a 40% reduction in paraoxonase activity in patients with Type II (non-insulin-dependent) diabetes mellitus and documented coronary artery disease compared with non-diabetic subjects, p < 0.0001.

CONCLUSIONS/INTERPRETATION

Alterations in function of HDL caused by exposure to hyperglycaemic conditions could contribute to the accelerated atherosclerosis observed in Type II diabetes.

Gelatinase-A (MMP-2), gelatinase-B (MMP-9) and membrane type matrix metalloproteinase-1 (MT1-MMP) are involved in different aspects of the pathophysiology of malignant gliomas

Matrix metalloproteinases (MMPs) have been implicated as important factors in gliomas since they may both facilitate invasion into the surrounding brain and participate in neovascularization. We have tested the hypothesis that deregulated expression of gelatinase-A or B, or an activator of gelatinase-A, MT1-MMP, may contribute directly to human gliomas by quantifying the expression of these MMPs in 46 brain tumour specimens and seven control tissues. Quantitative RT-PCR and gelatin zymography showed that gelatinase-A in glioma specimens was higher than in normal tissue; these were significantly elevated in low grade gliomas and remained elevated in GBMs. Gelatinase-B transcript and activity levels were also higher than in normal brain and more strongly correlated with tumour grade. We did not see a close relationship between the levels of expression of MT1-MMP mRNA and amounts of activated gelatinase-A. In situ hybridization localized gelatinase-A and MT1-MMP transcripts to normal neuronal and glia, malignant glioma cells and blood vessels. In contrast, gelatinase-B showed a more restricted pattern of expression; it was strongly expressed in blood vessels at proliferating margins, as well as tumour cells in some cases. These data suggest that gelatinase-A, -B and MT1-MMP are important in the pathophysiology of human gliomas. The primary role of gelatinase-B may lie in remodelling associated with neovascularization, whereas gelatinase-A and MT1-MMP may be involved in both glial invasion and angiogenesis. © 1999 Cancer Research Campaign

Gelatinase-A (MMP-2), gelatinase-B (MMP-9) and membrane type matrix metalloproteinase-1 (MT1-MMP) are involved in different aspects of the pathophysiology of malignant gliomas

Matrix metalloproteinases (MMPs) have been implicated as important factors in gliomas since they may both facilitate invasion into the surrounding brain and participate in neovascularization. We have tested the hypothesis that deregulated expression of gelatinase-A or B, or an activator of gelatinase-A, MT1-MMP, may contribute directly to human gliomas by quantifying the expression of these MMPs in 46 brain tumour specimens and seven control tissues. Quantitative RT-PCR and gelatin zymography showed that gelatinase-A in glioma specimens was higher than in normal tissue; these were significantly elevated in low grade gliomas and remained elevated in GBMs. Gelatinase-B transcript and activity levels were also higher than in normal brain and more strongly correlated with tumour grade. We did not see a close relationship between the levels of expression of MT1-MMP mRNA and amounts of activated gelatinase-A. In situ hybridization localized gelatinase-A and MT1-MMP transcripts to normal neuronal and glia, malignant glioma cells and blood vessels. In contrast, gelatinase-B showed a more restricted pattern of expression; it was strongly expressed in blood vessels at proliferating margins, as well as tumour cells in some cases. These data suggest that gelatinase-A, -B and MT1-MMP are important in the pathophysiology of human gliomas. The primary role of gelatinase-B may lie in remodelling associated with neovascularization, whereas gelatinase-A and MT1-MMP may be involved in both glial invasion and angiogenesis.

Comparison of samples collected by sputum induction and bronchoscopy from asthmatic and healthy subjects

To compare markers of inflammation in secretions obtained by sputum induction (SI), bronchial wash (50 ml instillate [BW]), and bronchoalveolar lavage (4 x 60 ml instillates [BAL]), we analyzed markers of inflammation in samples obtained by these methods in 10 healthy and 10 asthmatic subjects. Of the asthmatic subjects 8 had mild disease (FEV1, % of predicted > 75%). Within subjects from both groups, we found that sputum, compared with either BW or BAL, had higher numbers of nonsquamous cells (p = 0.0001) and higher levels of eosinophil cationic protein (ECP) (p = 0.0001), albumin (p = 0.0001), and mucin-like glycoprotein (p = 0.0001). The eosinophil percentages and the ECP levels in sputum correlated more closely with those in BW (r = 0.67, p = 0.005; r = 0.69, p = 0.0008, respectively) than in BAL (r = 0.5, p = 0.03; r = 0.37, p = 0.11). Comparing the asthmatic and healthy subgroups, we found that eosinophil percentages were higher in sputum (p = 0.0003) and BW (p = 0.006) from asthmatic subjects and that ECP levels were higher in BW (p = 0.001) and BAL (p = 0.0005) from asthmatic subjects. We conclude that analysis of induced sputum reveals information qualitatively similar to that obtained by analysis of BW and BAL and that sputum induction is not only noninvasive and easily repeated but also yields samples more concentrated and richer in airway secretions than those obtained by bronchoscopy.

Mild dyslipidemia in mice following targeted inactivation of the hepatic lipase gene

In order to gain better understanding of the function of hepatic lipase (HL) in vivo, we have generated mice that lack HL using gene targeting in embryonic stem cells. No mRNA for HL was detected in the liver of homozygous mutants, and no HL activity was detected in their plasma. Total cholesterol levels in plasma of mutant mice were increased by about 30% compared with wild type animals. Plasma phospholipids and high density lipoprotein (HDL) cholesterol were also increased, but plasma levels of triglycerides were not altered. Analysis of density fractions of plasma lipoproteins revealed that HDL1 (d = 1.02-1.04) was increased in homozygous mutants fed regular chow. In response to a diet containing high fat and high cholesterol, HDL cholesterol was doubled in the mutants, but was slightly decreased in the wild type mice. These results clearly demonstrate the importance of HL in HDL remodeling and metabolism in vivo. Various earlier studies suggested a role of HL in metabolism of triglyceride-rich particles, but the mutant mice appear to have no impairment in clearing them; the mutants clear exogenously introduced chylomicrons from plasma at a normal rate, and they tolerate acute fat loading as well as normal animals unless the loading is extreme. These differences may reflect species differences. However, it is also possible that the consequence of absence of HL as in our mutants is different from the consequence when nonfunctional HL protein is present as in the human HL-deficient patients and in rats treated with HL antibodies. We hypothesize that absence of HL in mutant mice allows other lipases to bind to the sites in the liver normally occupied by HL and facilitate the clearance of triglyceride-rich particles in these mice.

Expression of the neuropeptide Y Y1 receptor in the CNS of rat and of wild-type and Y1 receptor knock-out mice. Focus on immunohistochemical localization

The distribution of neuropeptide Y (NPY) Y1 receptor-like immunoreactivity (Y1R-LI) has been studied in detail in the CNS of rat using a rabbit polyclonal antibody against the C-terminal 13 amino acids of the rat receptor protein. The indirect immunofluorescence technique with tyramide signal amplification has been employed. For specificity and comparative reasons Y1 knock-out mice and wild-type controls were analyzed. The distribution of Y1R mRNA was also studied using in situ hybridization. A limited comparison between Y1R-LI and NPY-LI was carried out.A widespread and abundant distribution of Y1R-LI, predominantly in processes but also in cell bodies, was observed. In fact, Y1R-LI was found in most regions of the CNS with a similar distribution pattern between rat and wild-type mouse. This staining was specific in the sense that it was absent in adjacent sections following preadsorption of the antibody with 10(-5) M of the antigenic peptide, and that it could not be observed in sections of the Y1 KO mouse. In contrast, the staining obtained with an N-terminally directed Y1R antiserum did not disappear, strongly suggesting unspecificity. In brief, very high levels of Y1R-LI were seen in the islands of Calleja, the anterior olfactory nucleus, the molecular layer of the dentate gyrus, parts of the habenula, the interpeduncular nucleus, the mammillary body, the spinal nucleus of the trigeminal, caudal part, the paratrigeminal nucleus, and superficial layers of the dorsal horn. High levels were found in most cortical areas, many thalamic nuclei, some subnuclei of the amygdaloid complex, the hypothalamus and the nucleus of the stria terminalis, the nucleus of the solitary tract, the parabrachial nucleus, and the inferior olive. Moderate levels of Y1R-LI were detected in the cornu Ammonis and the subicular complex, many septal, some thalamic and many brainstem regions. Y1R staining of processes, often fiber and/or dot-like, and occasional cell bodies was also seen in tracts, such as the lateral lemniscus, the rubrospinal tract and the spinal tract of the trigeminal. There was in general a good overlap between Y1R-LI and NPY-LI, but some exceptions were found. Thus, some areas had NPY innervation but apparently lacked Y1Rs, whereas in other regions Y1R-LI, but no or only few NPY-positive nerve endings could be detected. Our results demonstrate that NPY signalling through the Y1R is common in the rat (and mouse) CNS. Mostly the Y1R is postsynaptic but there are also presynaptic Y1Rs. Mostly there is a good match between NPY-releasing nerve endings and Y1Rs, but 'volume transmission' may be 'needed' in some regions. Finally, the importance of using proper control experiments for immunohistochemical studies on seven-transmembrane receptors is stressed.

Altered mTOR signaling and enhanced CYFIP2 expression levels in subjects with fragile X syndrome

Fragile X syndrome (FXS) is the most common form of inherited intellectual disability and autism. The protein (FMRP) encoded by the fragile X mental retardation gene (FMR1), is an RNA-binding protein linked to translational control. Recently, in the Fmr1 knockout mouse model of FXS, dysregulated translation initiation signaling was observed. To investigate whether an altered signaling was also a feature of subjects with FXS compared to typical developing controls, we isolated total RNA and translational control proteins from lymphocytes of subjects from both groups (38 FXS and 14 TD). Although we did not observe any difference in the expression level of messenger RNAs (mRNAs) for translational initiation control proteins isolated from participant with FXS, we found increased phosphorylation of the mammalian target of rapamycin (mTOR) substrate, p70 ribosomal subunit 6 kinase1 (S6K1) and of the mTOR regulator, the serine/threonine protein kinase (Akt), in their protein lysates. In addition, we observed increased phosphorylation of the cap binding protein eukaryotic initiation factor 4E (eIF4E) suggesting that protein synthesis is upregulated in FXS. Similar to the findings in lymphocytes, we observed increased phosphorylation of S6K1 in brain tissue from patients with FXS (n = 4) compared to normal age-matched controls (n = 4). Finally, we detected increased expression of the cytoplasmic FMR1-interacting protein 2 (CYFIP2), a known FMRP interactor. This data verify and extend previous findings using lymphocytes for studies of neuropsychiatric disorders and provide evidence that misregulation of mTOR signaling observed in the FXS mouse model also occurs in human FXS and may provide useful biomarkers for designing targeted treatments in FXS.

Role of growth factors in inflammation and repair

Mononuclear cells generate a variety of hormone-like proteins termed growth factors that are instrumental in the evolution and resolution of inflammatory reactions. Many of these growth regulatory molecules have multifunctional properties. For example, the mononuclear cell-derived growth factors, platelet-derived growth factor (PDGF), and transforming growth factor beta (TGF-beta), are potent leukocyte chemoattractants. In addition, TGF-beta, a product of platelets, T lymphocytes, and monocytes, appears to induce the transcription of other monocyte-derived growth hormone genes. In this regard, picomolar concentrations of TGF-beta stimulate peripheral blood monocytes to transcribe the genes for PDGF (c-sis), basic fibroblast growth factor (FGF), interleukin 1 (IL-1), and tumor necrosis factor (TNF). Furthermore, levels of mRNA for TGF-beta, which is constitutively expressed in resting monocytes, are also increased by exogenous TGF-beta. Each of these monocyte products exhibits a plethora of biological activities on other cell types. T lymphocytes, in response to antigen, contribute to this network by secreting growth factors and lymphokines that regulate monocyte growth factor production.

Trafficking of proteinase-activated receptor-2 and beta-arrestin-1 tagged with green fluorescent protein. beta-Arrestin-dependent endocytosis of a proteinase receptor

Proteases cleave proteinase-activated receptors (PARs) to expose N-terminal tethered ligands that bind and activate the cleaved receptors. The tethered ligand, once exposed, is always available to interact with its binding site. Thus, efficient mechanisms must prevent continuous activation, including receptor phosphorylation and uncoupling from G-proteins, receptor endocytosis, and lysosomal degradation. beta-Arrestins mediate uncoupling and endocytosis of certain neurotransmitter receptors, which are activated in a reversible manner. However, the role of beta-arrestins in trafficking of PARs, which are irreversibly activated, and the effects of proteases on the subcellular distribution of beta-arrestins have not been examined. We studied trafficking of PAR2 and beta-arrestin1 coupled to green fluorescent protein. Trypsin induced the following: (a) redistribution of beta-arrestin1 from the cytosol to the plasma membrane, where it co-localized with PAR2; (b) internalization of beta-arrestin1 and PAR2 into the same early endosomes; (c) redistribution of beta-arrestin1 to the cytosol concurrent with PAR2 translocation to lysosomes; and (d) mobilization of PAR2 from the Golgi apparatus to the plasma membrane. Overexpression of a C-terminal fragment of beta-arrestin-319-418, which interacts constitutively with clathrin but does not bind receptors, inhibited agonist-induced endocytosis of PAR2. Our results show that beta-arrestins mediate endocytosis of PAR2 and support a role for beta-arrestins in uncoupling of PARs.

TGF-beta regulates production of growth factors and TGF-beta by human peripheral blood monocytes

Transforming growth factor beta 1 (TGF-beta 1) and its closely related homologue, TGF-beta 2, rapidly induce growth factor gene expression by freshly isolated human peripheral blood monocytes. Within 3 h of exposure to TGF-beta, mRNA species specific for interleukin-1 (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), platelet-derived growth factor (PDGF), and basic fibroblast growth factor (bFGF) were observed. By 14-18 h, cytokine bioactivity and protein were detected in the culture supernatants. Furthermore, not only TGF-beta 1, but also TGF-beta 2 mRNA are expressed constitutively in unstimulated monocytes. However, in response to exogenous TGF-beta (beta 1 or beta 2), only TGF-beta 1 gene expression is upregulated, and the expression of TGF-beta 2 mRNA is unchanged. This selective autoinduction of TGF-beta 1 appears to be controlled at both transcriptional and post-transcriptional levels. These paracrine and autocrine activities of TGF-beta suggest potential mechanisms through which an inflammatory response can be initiated and amplified. In addition, the TGF-beta enhancement of growth factor generation may promote fibrosis and angiogenesis relevant to physiological tissue repair as well as pathological fibrotic sequelae.

Avian influenza in Hong Kong 1997-2002

In 1997, a high-pathogenicity H5N1 avian influenza virus caused serious disease in both man and poultry in Hong Kong, China. Eighteen human cases of disease were recorded, six of which were fatal. This unique virus was eliminated through total depopulation of all poultry markets and chicken farms in December 1997. Other outbreaks of high-pathogenicity avian influenza (HPAI) caused by H5N1 viruses occurred in poultry in 2001 and 2002. These H5N1 viruses isolated had different internal gene constellations to those isolated in 1997. No new cases of infection or disease in man due to these or other H5N1 viruses have been reported. This paper provides an overview and chronology of the events in Hong Kong relating to avian influenza, covering the period from March 1997 to March 2002.

The solution structure and activity of caerin 1.1, an antimicrobial peptide from the Australian green tree frog, Litoria splendida

Caerin 1.1 is one of the major antimicrobial peptides isolated from the skin of the Australian green tree frog, Litoria splendida. Two-dimensional 1H-1H and 1H-13C NMR spectroscopy in trifluoroethanol/H2O (50:50, by vol.) have been used to assign the 1H and 13C-NMR spectra of this 25-amino-acid peptide. From an examination of these data, and using distance geometry and molecular dynamics calculations, the solution conformation of caerin 1.1 has been determined. The peptide adopts two well-defined helices from Leu2 to Lys11 and from Val17 to His24 separated by a region of less-defined helicity and greater flexibility. Overall, the peptide has a distinct amphipathic charge distribution. The solution structure of caerin 1.1 is compared with activity data against a variety of micro-organisms for the parent peptide and some naturally occurring and synthetic variants of caerin 1.1. The structural and activity data are consistent with caerin 1.1 interacting with membranes in a similar manner to other antimicrobial peptides, i.e. via a carpet-like mechanism whereby the individual peptides aggregate in a helical manner and orient themselves parallel to the membrane in a sheet-like arrangement [Shai, Y. (1995) Trends Biochem. Sci. 20, 460-464].

Activated N-ras gene induces neuronal differentiation of PC12 rat pheochromocytoma cells

Activated mouse N-ras gene transfected into PC12 rat pheochromocytoma cells suppressed proliferation and promoted neuronal differentiation. Normal mouse N-ras in a LTR-containing vector caused differentiation with a reduced efficiency, but normal N-ras in a vector lacking LTR sequences failed to alter the PC12 phenotype. Cultures of NGF-resistant PC12 variant subline U7 also showed outgrowth of neurites and cessation of cell division following transfection with the mutated ras gene. The present findings suggest that ras genes can, in certain cells, play a role in promoting differentiation and suppressing proliferation, in contrast to their established oncogenic neoplasia-promoting activity in other cells.

Analysis of induced sputum to examine the effects of prednisone on airway inflammation in asthmatic subjects

To determine whether induced sputum samples might provide a useful means for evaluating the effects of therapy on airway mucosal inflammation, we examined induced sputum samples obtained before and after 6 days of treatment with prednisone (0.5 mg/kg/day) or placebo in a randomized, double-blind study of 24 asthmatic subjects. Induced sputum was analyzed for total and differential cell counts and for concentrations of eosinophil cationic protein, albumin, and mucin-like glycoprotein. We found that the mean (+/- SEM) percentage of eosinophils in sputum samples from the prednisone-treated group fell from 14.1% +/- 5.0% at baseline to 1.8% +/- 0.8% after treatment, a decrease significantly greater than in the placebo-treated group (from 10.3% +/- 4.9% to 11.1% +/- 4.0%; p = 0.002). The absolute number of eosinophils also decreased significantly more in the prednisone-treated group than in the placebo-treated group (p = 0.04). In addition, eosinophil cationic protein levels in induced sputum fell more in the prednisone-treated group than in the placebo-treated group (from 324 +/- 131 ng/ml to 144 +/- 84 ng/ml vs 173 +/- 50 ng/ml to 188 +/- 47 ng/ml; p = 0.002). Furthermore, prednisone treatment was associated with a significant increase in peak expiratory flow, an effect that was significantly correlated with the decrease in eosinophil percentage in induced sputum (rs = 0.64, p = 0.04). Prednisone treatment was not associated with any significant change in the concentrations of albumin or mucin-like glycoprotein. We conclude that analysis of induced sputum is a useful noninvasive method for studying the effects of asthma therapy on airway eosinophilic inflammation.

Genetic aspects of antibiotic induced deafness: mitochondrial inheritance

Analysis of 36 pedigrees with a positive family history of aminoglycoside antibiotic induced deafness, ascertained in a population of 483,611 in Zhabei District in Shanghai, showed that the susceptibility to antibiotic ototoxicity was transmitted by females exclusively, indicating mitochondrial inheritance. Reanalysis of 18 other published pedigrees confirmed this conclusion.

Rhinovirus-16 colds in healthy and in asthmatic subjects: similar changes in upper and lower airways

Rhinovirus (RV) infections appear to precipitate most asthma exacerbations. To investigate whether RV-16 induces different inflammatory changes in upper and lower airways of asthmatic and healthy subjects, we inoculated 10 nonatopic healthy and 11 atopic asthmatic adults with 2,000 TCID50 RV-16. Subjects recorded symptoms and peak flow daily; and they underwent spirometry, methacholine challenge (PC20), nasal lavage, and sputum induction at baseline and on Days 2, 4, 15, and 29 d after inoculation. One asthmatic subject developed an exacerbation requiring prednisone treatment 5 d after inoculation. The cold symptom severity (Jackson score) did not differ between groups. During the cold, asthma symptoms increased slightly from baseline in the asthmatic group; and PC20 decreased in the healthy group. However, peak flow, bronchodilator use, and spirometry did not change in either group. At baseline, asthmatics had higher neutrophils, eosinophils, and interleukin (IL)-6 in nasal lavage. After inoculation, both groups developed significant increases in nasal neutrophils, IL-6 and IL-8, and modest increases in sputum neutrophils and IL-6, but not IL-8. However, these changes did not differ between groups. IL-5, interferon-gamma, and RANTES were detected only in nasal lavages from two asthmatic subjects, who had the most severe colds. IL-11 was not detected in any sample. We conclude that inflammatory responses of upper and lower airways during RV-16 colds are similar in asthmatic and healthy subjects, and that RV-16 infection is not by itself sufficient to provoke clinical worsening of asthma.

Fat-induced ileal brake in the dog depends on peptide YY

BACKGROUND & AIMS

Fat in the distal gut inhibits transit through the proximal small intestine as the ileal brake. Although the mediator of this response is not established, peptide YY (PYY) has been considered the most likely peptide candidate because inhibition of intestinal motility by fat in the distal gut correlated with the release of PYY but not other distal gut peptides such as enteroglucagon or neurotensin. Although intravenous administration of PYY inhibits intestinal transit, the role of this peptide remains to be confirmed because systemic PYY may not exert its effect by the same regulatory pathway as fat-induced ileal brake. The aim of this study was to definitively test the hypothesis that PYY mediates fat-induced ileal brake using the technique of peptide immunoneutralization.

METHODS

In a fistulated dog model, intestinal transit during perfusion of the distal gut with 60 mmol/L oleate (ileal brake) was examined after intravenous administration of 0.5 mg/kg of PYY antibody (anti-PYY), nonspecific immunoglobulin G (control), or 0.15 mol/L NaCl. Intestinal transit result (cumulative percent recovery of 99mTc) was normalized within each animal against the transit result of the 0.15 mol/L NaCl experiment.

RESULTS

Intestinal transit accelerated with PYY immunoneutralization, increasing cumulative percent recovery from 25.9 +/- 6.2 (control) to 81.2 +/- 6.3 (anti-PYY).

CONCLUSIONS

Fat-induced ileal brake depends on PYY.

Neurokinin-1 receptor expression in inflammatory bowel disease: molecular quantitation and localisation

BACKGROUND

Substantial evidence implicates the neuropeptide substance P (SP) in mucosal immunoinflammatory responses. Autoradiographic studies have suggested a disturbance in SP receptor expression in inflammatory bowel disease (IBD).

AIMS

Because of technical limitations such as poor cellular resolution with autoradiography, we used molecular methods to specifically localise the cellular expression of the neurokinin-1 receptor (NK-1R) in IBD colon, and to quantitate NK-1R mRNA expression levels therein.

METHODS

In situ hybridisation and immunohistochemistry were used to localise NK-1R mRNA and protein, respectively, in normal, ulcerative colitis (UC), and Crohn's disease (CD) colonic resections. NK-1R mRNA expression levels of normal, UC, and CD mucosal biopsies were quantitated by competitive reverse transcription-polymerase chain reaction.

RESULTS

NK-1R expression was localised to lamina propria mononuclear cells, epithelium, submucosal vasculature, smooth muscle, and myenteric plexus of normal and IBD colon. No ectopic NK-1R expression was observed in IBD. However, we found increased numbers of NK-1R expressing lymphoid cells in IBD tissue, aberrant negative epithelial expression of NK-1R in UC, and increased expression of NK-1R in CD myenteric plexus. Quantitation of NK-1R mRNA expression in IBD colonic mucosal biopsies revealed marked upregulation of NK-1R mRNA levels compared with non-inflamed mucosal expression levels (p<0.01).

CONCLUSIONS

This report demonstrates the strategic localisation and upregulation of NK-1R expression in IBD colon, and thereby suggests the involvement of substance P in the pathophysiological symptoms of IBD.

Cytokines in metal fume fever

Metal fume fever is a flulike illness caused by zinc oxide inhalation and accompanied by an impressive pulmonary cellular response. We hypothesized that the syndrome is mediated by cytokines released in the lung after exposure to zinc oxide fume. We carried out 26 experimental welding exposures in 23 volunteer subjects, performing postexposure bronchoalveolar lavage (BAL) 3 h (n = 6), 8 h (n = 11), or 22 h (n = 9) after exposure. We detected tumor necrosis factor (TNF), interleukin-6 (IL-6), and interleukin-8 (IL-8) varying in a time- and exposure-related manner. The concentration of TNF in the BAL fluid supernatant was significantly greater at 3 h than at 8 h or 22 h after exposure (p < 0.05), exhibiting a statistically significant exposure-response relationship to airborne zinc at each follow-up time period (p < 0.05). TNF concentrations were statistically correlated with those of IL-6 in BAL supernatant obtained at 22 h (r = 0.78, p = 0.01) and with concentrations of IL-8 in BAL 8 h after exposure (r = 0.85, p = 0.001). IL-6 displayed a significant exposure-response relationship to zinc (p < 0.05) at 22 h. IL-8 exhibited a significant exposure-response relationship to zinc (p < 0.05) at 8 h after exposure, a time at which IL-8 correlated with marked increases in BAL fluid polymorphonuclear leukocytes (PMN) (r = 0.7, p = 0.01). Although we also detected interleukin-1 (IL-1) in BAL samples, this cytokine did not demonstrate a statistically significant exposure response. TNF, IL-6, and IL-8 in BAL fluid supernatant concentrations increased in a time and exposure-dependent fashion after zinc oxide welding fume exposure. The time course of increased cytokines, their correlations with one another and with PMN in the BAL fluid, and the consistency of our findings with the known kinetics and actions of these cytokines support the hypothesis that a network of cytokines is involved in the pathogenesis of metal fume fever.