Apoptosis Resistance in Fibroblasts Precedes Progressive Scarring in Pulmonary Fibrosis and Is Partially Mediated by Toll-Like Receptor 4 Activation

Inhalation of environmental toxicants such as cigarette smoke, metal or wood dust, silica, or asbestos is associated with increased risk for idiopathic pulmonary fibrosis (IPF). IPF involves progressive scarring of lung tissue, which interferes with normal respiration and is ultimately fatal; however, the complex cellular mechanisms of IPF pathogenesis remain unclear. Fibroblast apoptosis is essential in normal wound healing but is dysregulated in IPF. Recent studies suggest that Toll-like receptor 4 (TLR4) is key in the onset of IPF. Here, radiation-induced PF was used as a model for IPF because it very closely mimics the progressive and intractable nature of IPF. Female C57BL/6J (C57) and C57BL/6J TLR4-/- mice were exposed to a single dose of 13 Gy whole-thorax ionizing radiation. Although both strains showed similar levels of immediate radiation-induced damage, C57 mice exhibited more extensive fibrosis at 22-week postirradiation (PI) than TLR4-/- mice. Isolated C57 primary 1° MLFs showed decreased apoptosis susceptibility as early as 8-week postirradiation, a phenotype that persisted for the remainder of the radiation response. TLR4-/- 1° mouse lung fibroblasts did not exhibit significant apoptosis resistance at any point. Systemic release of high mobility group box 1, a TLR4 agonist, during the pneumonitis phase of the radiation response may act through TLR4 to contribute to fibroblast apoptosis resistance and thus interfere with wound resolution. These findings demonstrate that apoptosis resistance occurs earlier in pulmonary fibrosis pathogenesis than previously assumed, and that TLR4 signaling is a key mediator in this process.

Rhinovirus-induced modulation of gene expression in bronchial epithelial cells from subjects with asthma

Rhinovirus (RV) infections trigger asthma exacerbations. Genome-wide expression analysis of RV1A-infected primary bronchial epithelial cells from normal and asthmatic donors was performed to determine whether asthma is associated with a unique pattern of RV-induced gene expression. Virus replication rates were similar in cells from normal and asthmatic donors. Overall, RV downregulated 975 and upregulated 69 genes. Comparisons of transcriptional profiles generated from microarrays and confirmed by quantitative reverse transcription PCR and cluster analysis showed some up- and downregulated genes in asthma cells involved in immune responses (IL1B, IL1F9, IL24, and IFI44) and airway remodeling (LOXL2, MMP10, FN1). Notably, most of the asthma-related differences in RV-infected cells were also present in the cells before infection. These findings suggest that differences in RV-induced gene expression profiles of cells from normal and mild asthmatic subjects could affect the acute inflammatory response to RV, and subsequent airway repair and remodeling.

The best interests of the child in assisted human reproduction: the interplay between the state, professionals, and parents

Developments in assisted human reproduction (AHR) have aroused considerable debate and interest around the world, with most governments accepting that they are matters of public policy. This politicization of AHR is explored in the context of a consideration of the oft-used term "the best interests of the child." This "rallying call" is frequently cited as the primary concern in the determination of policy. This article is based on the contention that it is important to examine the interplay between the three main groups directly influencing "best interest" outcomes for AHR offspring. These groups are the professionals, the parents, and the state. It seeks to examine how this high-sounding and well-meaning commitment is addressed, advanced, or ignored in the interplay of these groups.

Background estimation in experimental spectra

A general probabilistic technique for estimating background contributions to measured spectra is presented. A Bayesian model is used to capture the defining characteristics of the problem, namely, that the background is smoother than the signal. The signal is allowed to have positive and/or negative components. The background is represented in terms of a cubic spline basis. A variable degree of smoothness of the background is attained by allowing the number of knots and the knot positions to be adaptively chosen on the basis of the data. The fully Bayesian approach taken provides a natural way to handle knot adaptivity and allows uncertainties in the background to be estimated. Our technique is demonstrated on a particle induced x-ray emission spectrum from a geological sample and an Auger spectrum from iron, which contains signals with both positive and negative components.

Gradient-based iterative image reconstruction scheme for time-resolved optical tomography

Currently available tomographic image reconstruction schemes for optical tomography (OT) are mostly based on the limiting assumptions of small perturbations and a priori knowledge of the optical properties of a reference medium. Furthermore, these algorithms usually require the inversion of large, full, ill-conditioned Jacobian matrixes. In this work a gradient-based iterative image reconstruction (GIIR) method is presented that promises to overcome current limitations. The code consists of three major parts: 1) A finite-difference, time-resolved, diffusion forward model is used to predict detector readings based on the spatial distribution of optical properties; 2) An objective function that describes the difference between predicted and measured data; 3) An updating method that uses the gradient of the objective function in a line minimization scheme to provide subsequent guesses of the spatial distribution of the optical properties for the forward model. The reconstruction of these properties is completed, once a minimum of this objective function is found. After a presentation of the mathematical background, two- and three-dimensional reconstruction of simple heterogeneous media as well as the clinically relevant example of ventricular bleeding in the brain are discussed. Numerical studies suggest that intraventricular hemorrhages can be detected using the GIIR technique, even in the presence of a heterogeneous background.

Epidermal trans-urocanic acid and the UV-A-induced photoaging of the skin

The premature photoaging of the skin is mediated by the sensitization of reactive oxygen species after absorption of ultraviolet radiation by endogenous chromophores. Yet identification of UV-A-absorbing chromophores in the skin that quantitatively account for the action spectra of the physiological responses of photoaging has remained elusive. This paper reports that the in vitro action spectrum for singlet oxygen generation after excitation of trans-urocanic acid mimics the in vivo UV-A action spectrum for the photosagging of mouse skin. The data presented provide evidence suggesting that the UV-A excitation of trans-urocanic acid initiates chemical processes that result in the photoaging of skin.

Risk factors associated with Corynebacterium pseudotuberculosis infection in California horses

A case-control study was designed using equine medical records from the UC Davis Veterinary Medical Teaching Hospital (VMTH) and data derived through a mailed survey. The objective was to evaluate the associations between horse demographics, horse-management factors, and equine Corynebacterium pseudotuberculosis infection in California. Horses admitted to the VMTH between July 1 1992 and June 30 1994 served as the study base for case identification and simple random sampling of 800 controls. A questionnaire was mailed to the owners of all horses enrolled in the study to collect data on demographics, management and health-related questions. A logistic-regression model containing age, outdoor activity level, other locations in California, insect-control measures, contact with other horses, and summer pasture was developed. The final model was adjusted for the suspected confounding variables admission type, regular teaching hospital patient and breed. Horses of age between 1 and 2 yrs and between 3 and 5 yrs, and horses in contact with other horses or horses on summer pasture had significantly increased odds (p < 0.05) of being diagnosed with C. pseudotuberculosis infection. The results support the hypotheses that the disease predominantly affects young-adult horses of all breeds and both sexes, and that management factors play an important role in occurrence of the disease. Since the existing serological test system is not reliable and destruction of infected animals is not feasible, the most-logical approach for disease prevention is the early identification and isolation of clinical cases and the implementation of management changes like improvement of stable hygiene and insect control and change of pasture practices.

The origin of the wavelength-dependent photoreactivity of trans-urocanic acid

Two-color, pulsed-laser photoacoustic calorimetry is used to distinguish between multiple rotamer or electronic state contributions to the absorption spectrum of the epidermal chromophore trans-urocanic acid. The data definitively show that the wavelength-dependent photochemistry of trans-urocanic acid results from the presence of two distinct, weakly coupled electronic states absorbing between 264 nm and 310 nm.

Tomographic reconstruction using 3D deformable models

We address the issue of reconstructing the shape of an object with uniform interior activity from a set of projections. We estimate directly from projection data the position of a triangulated surface describing the boundary of the object while incorporating prior knowledge about the unknown shape. This inverse problem is addressed in a Bayesian framework using the maximum a posteriori (MAP) estimate for the reconstruction. The derivatives needed for the gradient-based optimization of the model parameters are obtained using the adjoint differentiation technique. We present results from a numerical simulation of a dynamic cardiac imaging study. A first-pass exam is simulated with a numerical phantom of the right ventricle using the measured system response of the University of Arizona FASTSPECT imager, which consists of 24 detectors. We demonstrate the usefulness of our approach by reconstructing the shape of the ventricle from 10,000 counts. The comparison with an ML-EM result shows the usefulness of the deformable model approach.

Socioeconomic and demographic factors are associated with worldwide patterns of stunting and wasting of children

We estimated the variability among nations in the prevalence of stunting and wasting, evaluated which national factors are associated with stunting and wasting and examined the relationship of stunting with wasting. The World Health Organization Global Database on Child Growth, a comprehensive conceptual model and a database of national factors were used with variance components and regression analyses. There was substantial variability among nations and among provinces within nations. Most national variability for stunting (76%) and wasting (66%) was explained by national factors and geographic region. Higher energy availability, female literacy and gross product were the most important factors associated with lower prevalence of stunting. The association of health expenditures and stunting differed by region. Higher immunization rate and, for Asia only, energy availability were the most important factors associated with lower prevalence of wasting. Regional differences in the relationship between stunting and wasting were accounted for by national factors. Some factors associated with stunting and wasting differ at the national level. Child malnutrition within a household is greatly influenced by issues at national and provincial levels, and intervention should be considered at all three levels.

Determinants of variability among nations in child growth

This cross-national study aimed at understanding variability in growth among nations and its determinants. It examined the variability of growth among nations, the factors most important for explaining this variability, how these factors jointly determine growth, and the consistency of the patterns and relationships. A conceptual model was adapted from U. Jonsson. National data on height and weight of children, sex, ethnicity, and 15 social, economic, health, education, and political factors were combined from three secondary sources. A sequence of multiple linear regression models was used with three age groups: 1-2, 3-5, and 6-10 years. Substantial variability in growth among nations was seen in comparison to that within nations. Regression models with sex, ethnicity, food security, maternal and child care, and health services and environment explained a large percentage of this variability. Institutions, politics/ideology, economic structure, and potential resources contributed little additionally to the models. Ethnic differences among nations were observed and persisted even when models controlled for other factors, but should not necessarily be interpreted as genetic differences. Determinants for height, weight, and weight adjusted for height were somewhat different. Adjustment for only previous growth and sex explained about 90% of variability in growth, supporting the assumption that growth patterns are generally established early in life. As policy decisions and programmes addressing mild-to-moderate malnutrition are increasingly considered, the implications of cross-national variability in growth may assume greater importance. Future work should examine simultaneously the effects of national, community, family, and individual characteristics on growth using data from individuals in a number of nations.

Enzyme inhibitors: new and known polybrominated phenols and diphenyl ethers from four Indo-Pacific Dysidea sponges

Extracts and pure compounds isolated from four samples of Dysidea sp. sponges collected from two geographically distinct regions of the Indo-Pacific (Chuuk Atoll and Fiji) were assayed against five different enzyme assays, four of which are relevant to anticancer drug discovery and one of which (15-lipoxygenase) may detect compounds significant in modulating the development of atherosclerotic plaque. The pure compounds that inhibited various enzymes were polybrominated phenols and polybrominated phenoxyphenols. Fourteen of these phenols were isolated, six of which were new compounds. A variety of the phenols inhibited inosine monophosphate dehydrogenase (IMPDH), guanosine monophosphate synthetase, and 15-lipoxygenase. No activity was observed with protein tyrosine kinase pp60v-src or matrix metalloprotease.

Solvent and temperature effects on the excited singlet state absorption of diphenylbutadiene

Nanosecond excited state absorption spectra of all-trans-1,4-diphenyl-1,3-butadiene (DPB) and a rigid s-cis DPB analog, 1,4-diphenyl-1,3-cyclopentadiene, were obtained in several hydrocarbon solvents at room temperature and low temperatures. Analysis of the excited state absorption spectra of these two molecules suggests the presence of excited state s-cis rotamers in DPB at room temperature.

Radiographic screen-film noise power spectrum: calibration and intercomparison

The magnitude of a measurement of the noise power spectrum (NPS) of a radiographic screen-film system is affected by the light-scattering properties of the film studied and the optical characteristics of the micro-densitometer used to sample the image. To facilitate absolute NPS intercomparisons among laboratories, NPS in terms of instrument density must be converted to diffuse density. Conversion in terms of a Callier Q factor was found to be inadequate due to nonlinearity of the density response of the microdensitometer. By establishing instrument-to-diffuse density characteristic curves for the microdensitometers at two laboratories and correcting the NPS by the square of the slopes of these curves at the density of the image, good agreement was achieved for independent NPS measurements of a given film sample.

On the optimality of the filtered backprojection algorithm

It is shown that under certain conditions the filtered backprojection algorithm produces a computed tomographic reconstruction for which the statistical accuracy attainable in the amplitude estimation of large-area objects meets the general lower bound derived by Tretiak. In this sense, filtered backprojection is an optimum algorithm.

Evaluation of edge-induced streaking artifacts in CT scanners

A phantom is presented which permits the evaluation of streaking artifacts produced in CT reconstructions by abrupt edges. Its application is demonstrated by results obtained from nine CT scanners. It is observed that even in regions where streaking is not readily apparent, edge-induced artifacts can significantly increase the variance in the reconstruction.

Alpha-adrenergic blocking agents and the cardiovascular response to pharmacological doses of vasopressin

The effects of alpha-adrenergic blockade with phentolamine or dibenamine on the cardiovascular response to pharmacological doses of vasopressin were studied in anesthetized dogs. Some observations were also made on the combined effects of vasopressin and norepinephrine. Changes in mean systemic arterial pressure, portal pressure, and resistance in the prehepatic splanchnic vasculature during vasopressin infusion were noted. A total of 97 dogs were used. alpha-Blockade appeared to enhance the response of arterial pressure to vasopressin, possibly because of loss of baroreceptor-mediated buffering action which normally attenuates its pressor action. Effects of vasopressin on mesenteric vascular resistance and portal pressure were unchanged or somewhat less after alpha-blockade, hence no evidence that its therapeutic effect would be improved by this combination. Vasopressin and norepinephrine when given together result in an additive pressor response with little or no evidence of potentiation.

Detectability in computed tomographic images

The detection limitations inherent in statistically limited computed tomographic (CT) images are described through the application of signal detection theory. The detectability of large-area, low-contrast objects is shown to be chiefly dependent upon the low-frequency content of the noise power spectral density. For projection data containg uncorrelated noise, the resulting ramplike, low-frequency behavior of the noise power spectrum of CT reconstructions may be conveniently characterized by the number of noise-equivalent x-ray quanta (NEQ) detected in the projection measurements. The NEQ for a given image may be determined either from a measurement of the noise power spectrum or from the noise granularity computed with an appropriate weighting function. A measure of the efficiency of scanner dose utilization is proposed which compares the average dose to that required by an ideal scanner to obtain the same NEQ.

Treatment of severe drug overdosage with charcoal hemoperfusion

Mortality from severe poisoning remains excessively high in patients managed conservatively. In this report, charcoal hemoperfusion was used as a therapeutic aid to active drug removal in 10 patients (9 of whom were in Grade IV coma) intoxicated with a variety of drugs and a further 3 patients poisoned with the highly lethal herbicide, paraquat. All 10 patients who ingested drugs recovered. One of the 3 patients ingesting paraquat survived. The hemoperfusion treatments were associated with demonstrated drug removal. Complications associated with hemoperfusion were minor. Decreases in platelet levels were observed but were not accompanied by clinically important bleeding. The technique of hemoperfusion is simple and provides a therapeutic aid in the care of the severely poisoned patient.

Species specificity and other aspects of chymotrypsin inhibition by plasma

The inhibition of chymotrypsin activity by pig, dog, human and rat blood plasma was studied. N-Benzoyl-L-tyrosyl-p-amino-benzoate (PABA-peptide) was used as the substrate. Crystalline bovine chymotrypsin as well as activated lyophilized human, pig, rat and chicken pancreatic secretions were used as enzyme sources. Certain species differences were noted. Swine plasma had no effect on bovine or human chymotrypsin while it inhibited that of the chicken by 67%. Dog plasma was a potent inhibitor of chymotrypsin activity from all sources tested. An acute pancreatitis model using the rat was also developed in which pancreatic juice flow was blocked without interference with biliary flow. After 24 h, these animals had increased plasma amylase activity, decreased plasma protease inhibitor and decreased hematocrit. By 72 h, amylase, trypsin inhibitor and hematocrit had nearly recovered while chymotrypsin inhibitor had actually increased above control levels. In rats subjected to hepatectomy or to hepatectomy plus pancreatic blockage, plasma protease inhibitor was even more severely depressed and remained so.

A new substrate for the rapid evaluation of enteric microbial overgrowth

The possibility of a new approach to diagnosis of intestinal bacterial overgrowth has been evaluated in laboratory animals. The diagnostic test involves oral administration of an enzyme-labile substrate consisting of para-aminobenzoic acid (PABA) conjugated to a bile acid. In the presence of enteric bacteria, PABA is split from the bile acid and is rapidly absorbed and excreted in the urine. The amount of PABA recovered during the 6 hr following the administered dose of the conjugate may be used as an index of bacterial overgrowth in the upper-gastrointestinal tract. The procedure has been shown to be a reliable index of this condition in laboratory animal models.

Splanchnic vascular responses to the infusion of prostaglandins A1, A2 and B1

The effects of PGA1, PGA2 and PGB1 on the vasculature of the liver and small intestine were studied in 73 dogs. Infusions were made into a branch of the superior mesenteric artery, the hepatic artery, portal vein or femoral vein. They decreased systemic arterial pressure and dilated the hepatic arterial and prehepatic splanchnic (small intestinal) vascular beds, PGA being most active. Dilator response was not decreased by beta-adrenergic blockade. Compounds appear to be inactivated by liver and decreased systemic pressure less when infused directly into liver circulation. Dilator response was transient, particulary in small intestine, and abated or even converted to constriction when infusion was continued for a period of time. Intrahepatic portal venous vasculature appeared to be constricted by PGA.

Hepatic, vascular and biliary responses to infusion of gastrointestinal hormones and bile salts

The effects of secretin, cholecystokinin, synthetic pentagastrin, sodium dehydrocholate and sodium taurocholate on hemodynamics of the canine liver were studied in a total of 57 dogs. Bile flow was also measured. Dehydrocholate and cholecystokinin significantly decreased systemic arterial pressure while the other substances did not. Hepatic arterial vessels were dilated by pentagastrin and the bile salts; however, flow was not increased in the latter case. Intraheptic portal venous resistance was decreased by pentagastrin and increased by the bile salts. Portal flow was decreased by the bile salts and increased by pentagastrin. Apart from this, mean changes in portal venous flow and portal pressure were not statistically significant. All were potent choleretic agents except pentagastrin which produced only a relatively small transient increase in bile flow.

Response of intrahepatic vasculature to isoproterenol and epinephrine influsions

Response of hepatic arterial and intrahepatic portal venous vasculature to 10-min infusions of either isoproterenol or epinephrine was studied in 37 <i>in situ</i> dog liver preparations. Isoproterenol infusions at various dose rates (3.06–24.45 µg/min) were given by way of hepatic artery or portal vein. Hepatic arterial vasodilation, which was abolished by propranolol, was clearly evident while response of intrahepatic portal venous bed was incon sistent and not indicative of significant vasodilation. Arterial dilator response was attenuated later in the infusion period when isoproterenol was given at high dose rates. Femoral venous infusions of epinephrine (9.55 µg/min) resulted in a variable and slight hepatic arterial response while portal resistance was consistently increased. Following sotalol, epinephrine produced a marked increase in hepatic artery resistance in every case while intrahepatic portal venous resistance was increased to the same extent as before. It was concluded that both α-receptors (constrictors) and β-receptors (dilators) are present in canine hepatic arterial and mesenteric vessels while intrahepatic portal venous vasculature appears to possess few, if any, β-receptors.

Dilator responses of the canine hepatic vasculature

Experiments were performed on 70 isolated, <i>in situ</i>, autoperfused canine liver preparations. Hepatic artery and portal venous flows were measured by means of an electromagnetic blood flowmeter. Effects of papaverine, dibenzyline, dibenamine and propranolol on hepatic artery and intra-hepatic portal venous vascular resistance were observed. Also the effects of these drugs on certain local vasomotor responses of the hepatic arterial bed (reactive hyperemia, autoregulation and reciprocity response to shunting of portal inflow) were also studied. Inhibition of vasodilator responses by these drugs was largely related to the amount of reduction in basal vascular tone which they produced.

Capillary filtration in the small intestine of the dog

The purpose of these studies was to determine the capillary filtration coefficient of the small intestine of anesthetized dogs by the gravimetric technique. Capillary filtration was produced by elevating venous pressure. Filtration rate increased as venous pressure was increased but the relation between the two was not proportional. At venous pressures greater than 10 mm Hg, filtration rate tended to reach a limit. As a consequence, the filtration coefficient decreased at higher pressures. Mean capillary pressure was estimated by the isogravimetric technique. When capillary pressure was 10 mm Hg, the filtration coefficient averaged 0.37 ml/min per 100 g and decreased to 0.11 when capillary pressure was elevated to 20 mm Hg. The reduction in filtration coefficient at high capillary pressures was apparently due to closure of precapillary sphincters.