Cohort profile: the ECHO prenatal and early childhood pathways to health consortium (ECHO-PATHWAYS)

PURPOSE

Exposures early in life, beginning in utero, have long-term impacts on mental and physical health. The ECHO prenatal and early childhood pathways to health consortium (ECHO-PATHWAYS) was established to examine the independent and combined impact of pregnancy and childhood chemical exposures and psychosocial stressors on child neurodevelopment and airway health, as well as the placental mechanisms underlying these associations.

PARTICIPANTS

The ECHO-PATHWAYS consortium harmonises extant data from 2684 mother-child dyads in three pregnancy cohort studies (CANDLE [Conditions Affecting Neurocognitive Development and Learning in Early Childhood], TIDES [The Infant Development and Environment Study] and GAPPS [Global Alliance to Prevent Prematurity and Stillbirth]) and collects prospective data under a unified protocol. Study participants are socioeconomically diverse and include a large proportion of Black families (38% Black and 51% White), often under-represented in research. Children are currently 5-15 years old. New data collection includes multimodal assessments of primary outcomes (airway health and neurodevelopment) and exposures (air pollution, phthalates and psychosocial stress) as well as rich covariate characterisation. ECHO-PATHWAYS is compiling extant and new biospecimens in a central biorepository and generating the largest placental transcriptomics data set to date (N=1083).

FINDINGS TO DATE

Early analyses demonstrate adverse associations of prenatal exposure to air pollution, phthalates and maternal stress with early childhood airway outcomes and neurodevelopment. Placental transcriptomics work suggests that phthalate exposure alters placental gene expression, pointing to mechanistic pathways for the developmental toxicity of phthalates. We also observe associations between prenatal maternal stress and placental corticotropin releasing hormone, a marker of hormonal activation during pregnancy relevant for child health. Other publications describe novel methods for examining exposure mixtures and the development of a national spatiotemporal model of ambient outdoor air pollution.

FUTURE PLANS

The first wave of data from the unified protocol (child age 8-9) is nearly complete. Future work will leverage these data to examine the combined impact of early life social and chemical exposures on middle childhood health outcomes and underlying placental mechanisms.

Selective imaging of active pharmaceutical ingredients in powdered blends with common excipients utilizing two-photon excited ultraviolet-fluorescence and ultraviolet-second order nonlinear optical imaging of chiral crystals

Second order nonlinear optical imaging of chiral crystals (SONICC) and two-photon excited fluorescence measurements [both autofluorescence and two-photon excited UV-fluorescence (TPE-UVF)] were assessed for the selective detection of APIs relative to common pharmaceutical excipients. Active pharmaceutical ingredients (APIs) compose only a small percentage of most tabulated formulations, yet the API distribution within the tablet can affect drug release and tablet stability. Complementary measurements using either UV-SONICC (266 nm detection) or TPE-UVF were shown to generate signals >50-fold more intense for a model API (griseofulvin) than those produced by common pharmaceutical excipients. The combined product of the measurements produced signals >10(4)-fold greater than the excipients studied. UV-SONICC or TPE-UVF produced greater selectivity than analogous measurements with visible-light detection, attributed to the presence of aromatic moieties within the API exhibiting strong one and two photon absorption at ~266 nm. Complementary SONICC and fluorescence measurements allowed for the sensitive detection of the three-dimensional distribution of tadalafil within a Cialis tablet to a depth of >140 μm.

Interaction of environmental moisture with powdered green tea formulations: effect on catechin chemical stability

Green tea and tea catechins must be stable in finished products to deliver health benefits; however, they may be adversely affected by tea processing/storage conditions and the presence of other components. The objective of this study was to determine the effects of storage relative humidity (RH) and addition of other ingredients on catechin stability in simulated dry beverage mixtures. Samples of green tea powder alone and mixed with sucrose, citric acid, and/or ascorbic acid were prepared and stored in desiccators at 22 degrees C and 0-85% RH for up to 3 months. Epicatechin, epigallocatechin, epicatechin gallate, and epigallocatechin gallate were determined by high-performance liquid chromatography (HPLC). Formulation and the interaction of formulation and RH significantly promoted catechin degradation ( P < 0.0001). The chemical degradation of total and individual catechins in green tea powder formulations was significantly increased ( P < 0.0001) by exposure to increasing RH, and the degradation was exacerbated at > or = 58% RH by the presence of powdered citric acid and at > or = 75% RH by the presence of ascorbic acid. Catechins degraded the most in formulations containing both acids. Although catechin chemical stability was maintained at < or = 43% RH in all samples stored at 22 degrees C for 3 months, caking was observed in samples at these relative humidities. These results are the first to demonstrate that addition of other dry components to tea powders may affect catechin stability in finished dry blends and highlight the importance of considering the complex interplay between a multicomponent system and its environment for developing stable products.

A comparison of alternative polymer excipients and processing methods for making solid dispersions of a poorly water soluble drug

Solid dispersions were prepared with the extremely poorly water soluble drug, probucol and the water soluble polymers, polyvinyl pyrrolidone (PVP), polyacrylic acid (PAA) or polyethylene oxide (PEO) and blends of these polymers. The solid dispersions were prepared either by the solvent evaporation method, or by compression moulding into films. The materials were characterised by a combination of thermal analysis and FT-Raman spectroscopy. The physical state of the drug was observed to be dependent on the carrier, thus the PVP solid dispersions contained amorphous probucol, whilst the PAA and PEO systems contained the crystalline polymorph II. The method of production was not found to greatly influence the state of the drug in the solid dispersion. The greatest extent of release into solution was observed for the binary blend of drug and PEO, and the blending of polymers was not found to have any advantageous effects in this study.

Fourier transform Raman spectroscopic study of the interaction of water vapor with amorphous polymers

Water associated with amorphous polymers is known to affect their chemical and physical properties. The purpose of this study was to investigate the nature of water-polymer interactions for some polymers of pharmaceutical interest. Using Raman spectroscopy, polymer-water hydrogen bond interactions were probed for two molecular weight grades of poly(vinylpyrrolidone), namely PVP K90 and PVP K12, and also for poly(vinylacetate) and poly(vinyl pyrrolidone-co-vinyl acetate). Water vapor absorption isotherms were obtained for the polymers, and the effect of the absorbed water on the glass transition temperature was determined. A knowledge of the water content and physical state of the polymer was used to aid interpretation of Raman spectral changes. The strength of the hydrogen bond formed with water was found to depend on the chemistry of the polymer, with the pyrrolidone group interacting more strongly than the acetate group. However, minor differences were also observed between the degree of interaction of water and polymer for PVP K12 and PVP K90 at some water contents. This result is attributed to differences in the structural relaxation changes accompanying plasticization by water for the two molecular weight grades. Using principal components analysis of the spectral data, it was also possible to differentiate between samples in the rubbery state and samples in the glassy state. In conclusion, water sorbed into polymers causes changes in the polymer Raman spectra not only because of hydrogen bonding, but also as a result of the plasticizing effect of water on polymer mobility.

Paired inhibitory and activating receptor signals

The immunological literature has become inundated with reports regarding paired inhibitory receptors. Paired inhibitory receptor systems are highly conserved families that contain receptors involved in either cellular inhibition or activation. In most cases the paired putative biochemical antagonists are co-expressed on a given cell and thought to bind similar, if not identical, ligands making their biological role difficult to understand. Examples of these systems include immunoglobulin (Ig)-like receptors (Killer Ig Receptors, Immunoglobulin-like Transcripts/Leukocyte Ig-like Receptors/Monocyte Macrophage Ig Receptors, and Paired Ig-like Receptors), and type II lectin-like receptor systems (NKG2 and Ly49). General characteristics of these inhibitory receptors include a cytoplasmic immunoreceptor tyrosine-based inhibitory motif (ITIM). The ITIM is phosphorylated upon engagement and recruits protein tyrosine phosphatases that dephosphorylate cellular substrates that would otherwise mediate activation. In contrast, the activating receptors of these pairs use charged residues within their transmembrane domains to associate with various signal transduction chains including the gamma chain of the receptor for the Fc portion of IgE, DAP12 or DAP10. Once phosphorylated, these chains direct the signal transduction cascade resulting in cellular activation. Here we review the signaling of several paired systems and present the current models for their signal transduction cascades.

Evaluation of solid-state forms present in tablets by Raman spectroscopy

In this study the potential of Fourier transform (FT)-Raman spectroscopy as a method to probe the solid-state form of active substances present in tablets and capsules is explored. Raman spectra were obtained from intact tablets and capsules containing enalapril maleate, prednisolone, form I and form II polymorphs of ranitidine, anhydrous and monohydrate theophylline, and warfarin sodium clathrate. Spectra were also collected from the corresponding drug substances. These studies show that it is possible to detect the active ingredients in the intact dosage form, even where the substance comprises <1% of the total mass of the tablet. Moreover, it is shown that, in some cases, Raman spectroscopy can also be used to investigate the solid-state form of a drug present in the dosage form and even to determine if a mixture of forms are present.

Myeloid specific human CD33 is an inhibitory receptor with differential ITIM function in recruiting the phosphatases SHP-1 and SHP-2

CD33 is a myeloid specific member of the sialic acid-binding receptor family and is expressed highly on myeloid progenitor cells but at much lower levels in differentiated cells. Human CD33 has two tyrosine residues in its cytoplasmic domain (Y340 and Y358). When phosphorylated, these tyrosines could function as docking sites for the phosphatases, SHP-1 and/or SHP-2, enabling CD33 to function as an inhibitory receptor. Here we demonstrate that CD33 is tyrosine phosphorylated in the presence of the phosphatase inhibitor, pervanadate, and recruits SHP-1 and SHP-2. Co-expression studies suggest that the Src-family kinase Lck is effective at phosphorylating Y340, but not Y358, suggesting that these residues may function in the selective recruitment of adapter molecules and have distinct functions. Further support for overlapping, but nonredundant, roles for Y340 and Y358 comes from peptide-binding studies that revealed the recruitment of both SHP-1 and SHP-2 to Y340 but only SHP-2 to Y358. Analysis using mutants of SHP-1 demonstrated that binding Y340 of CD33 was primarily to the amino Src homology-2 domain of SHP-1. The potential of CD33 to function as an inhibitory receptor was demonstrated by its ability to down-regulate CD64-induced calcium mobilization in U937. The dependence of this inhibition on SHP-1 was demonstrated by blocking CD33-mediated effects with dominant negative SHP-1. This result implies that CD33 is an inhibitory receptor and also that SHP-1 phosphatase has a significant role in mediating CD33 function. Further studies are essential to identify the receptor(s) that CD33 inhibits in vivo and its function in myeloid lineage development. (Blood. 2000;96:483-490)

Three-dimensional sonoelastography: principles and practices

Sonoelastography is an ultrasound imaging technique where low amplitude, low-frequency shear waves (less than 0.1 mm displacement and less than 1 kHz frequency) are propagated through internal organs, while real-time Doppler techniques are used to image the resulting vibration pattern. When a discrete hard inhomogeneity, such as a tumour, is present within a region of soft tissue, a decrease in the vibration amplitude will occur at its location. This forms the basis for tumour detection using sonoelastography. For three-dimensional (3D) imaging the acquisition of sequential tomographic slices using this technique, combined with image segmentation, enables the reconstruction, quantification and visualization of tumour volumes. Sonoelastography and magnetic resonance images (MRI) of a tissue phantom containing a hard isoechoic inclusion are compared to evaluate the accuracy of this method. The tumour delineation from sonoelastography was found to have good agreement with the tumour from MRI except for a bleeding at one of its ends. Although sonoelastography is still in an experimental phase, the principles behind this imaging modality are explained and some practical aspects of acquiring sonoelastography images are described. Results from a 3D sonoelastography reconstruction of a tissue mimicking phantom and an ex vivo whole prostate specimen are presented.

Pathogen-specific loss of host resistance in mice lacking the IFN-gamma-inducible gene IGTP

Interferon-gamma (IFN-gamma) is critical for defense against pathogens, but the molecules that mediate its antimicrobial responses are largely unknown. IGTP is the prototype for a family of IFN-gamma-regulated genes that encode 48-kDa GTP-binding proteins that localize to the endoplasmic reticulum. We have generated IGTP-deficient mice and found that, despite normal immune cell development and normal clearance of Listeria monocytogenes and cytomegalovirus infections, the mice displayed a profound loss of host resistance to acute infections of the protozoan parasite Toxoplasma gondii. By contrast, IFN-gamma receptor-deficient mice have increased susceptibility to all three pathogens. Thus, IGTP defines an IFN-gamma-regulated pathway with a specialized role in antimicrobial resistance.

Cloning and characterization of a novel activating Ly49 closely related to Ly49A

The majority of the known Ly49 family members have been isolated from either C57BL/6 (B6) or BALB/c mice. Interestingly, the anti-Ly49 Ab reactivities observed in 129/J mice are different from those of B6 mice. Furthermore, immunoprecipitation of 129/J NK cell lysates with YE1/32 and YE1/48, Abs specific for the inhibitory Ly49A in B6, resulted in detection of the activation-associated DAP12 molecule. These results indicated a need for a more detailed study of this strain. Therefore, a cloning strategy was devised to isolate Ly49 cDNAs from 129/J mice. An immunoreceptor tyrosine-based inhibitory motif-containing, Ly49D-related clone was discovered that we have named Ly49O, and one immunoreceptor tyrosine-based inhibitory motif-lacking, Ly49A-related clone was discovered that we have named Ly49P. No anti-Ly49 mAb reacted with Ly49O, whereas the molecule encoded by the Ly49P cDNA was found to react with YE1/32 and YE1/48. Ly49P was found to associate with mouse DAP12, and Ab-mediated cross-linking of Ly49P resulted in mouse DAP12 phosphorylation and Ca2+ mobilization, indicating that Ly49P is a competent activation receptor. Ly49P, therefore, represents a novel member of the Ly49 activating receptor subfamily.

Experiences of ethnic minority primary care physicians with managed care: a national survey

OBJECTIVES

To determine if ethnic minority physicians experience more barriers in acquiring and maintaining managed care contracts than white physicians, and to determine if the physician's perceptions of his or her ability to provide appropriate care to patients varies with physician ethnicity.

STUDY DESIGN

Using a national sample, we identified 4 research areas germane to this topic and analyzed them by physician ethnic group.

METHODS

Analysis involved a pre-existing data set from a national survey that employed a random sampling approach to achieve reasonably accurate national population estimates with acceptable margins of error (95% CI = +/- 2).

RESULTS

A total of 1032 primary care physicians completed the survey (response rate of 48%). After controlling for confounding variables, we found that Asian physicians have the most difficulty keeping managed care contracts. Type of practice varies with physician ethnicity, and solo practitioners have more problems securing contracts than physicians in other types of practices. Board-certified physicians are more likely to have managed care contracts than those who are not. Latino physicians have significantly fewer managed care patients than primary care physicians who are white, African American, or Asian. The perceptions of the physicians of their ability to deliver appropriate care overall did not vary by ethnicity, but 2 major subcategories of this item did vary by physician ethnicity: quality of care, and limitations to providing care.

CONCLUSIONS

Although we did not find overwhelming evidence of discrimination against ethnic minority physicians, differences in rates of termination, type of practice, board certification rates, and managed care affiliation were related to physician ethnicity.

Functional association of FcepsilonRIgamma with arginine(632) of paired immunoglobulin-like receptor (PIR)-A3 in murine macrophages

Paired immunoglobulin-like receptors (PIR) are expressed on B cells and macrophages and include inhibitory and putative activating receptors referred to as PIR-B and PIR-A, respectively. Although PIR-B's inhibitory pathway has been described, it is unknown whether PIR-A receptors can deliver activation signals to macrophages, and if so, through what mechanism. Here we use chimeric receptors to address the mechanisms of PIR-A signaling. Cotransfection of chimeric receptors comprised of the extracellular region of human CD4 and the transmembrane and cytoplasmic domains of murine PIR-A3 showed the ability of PIR-A3 to physically interact with the FcepsilonRIgamma chain in 293T cells. This interaction is dependent on Arg(632) within the PIR-A3 transmembrane domain. We also demonstrate PIR-A3 interaction with the endogenous FcepsilonRIgamma of the ANA-1 macrophage cell line, again in an Arg(632)-dependent manner. Furthermore, we show that crosslinking of these chimeric receptors synergizes with IFN-gamma in the production of nitric oxide. Our data are the first to show the potential of PIR-A3 to deliver activation signals to macrophages and establish its dependence on Arg(632). These findings suggest that further study of the PIR-A receptors should be aggressively pursued toward a complete understanding of the intricate regulation of macrophage biology.

DAP12-mediated signal transduction in natural killer cells. A dominant role for the Syk protein-tyrosine kinase

The murine Ly49 family contains nine genes in two subgroups: the inhibitory receptors (Ly49A, B, C, E, F, G2, and I) and the noninhibitory receptors (Ly49D and H). Unlike their inhibitory counterparts, Ly49D and H do not contain immunoreceptor tyrosine-based inhibitory motifs but associate with a recently described co-receptor, DAP12, to transmit positive signals to natural killer (NK) cells. DAP12 is also expressed in myeloid cells, but the receptors coupled to it there are unknown. Here we document the signaling pathways of the Ly49D/DAP12 complex in NK cells. We show that ligation of Ly49D results in 1) tyrosine phosphorylation of several substrates, including phospholipase Cgamma1, Cbl, and p44/p42 mitogen-activated protein kinase, and 2) calcium mobilization. Moreover, we demonstrate that although human DAP12 reportedly binds the SH2 domains of both Syk and Zap-70, ligation of Ly49D leads to activation of Syk but not Zap-70. Consistent with this observation, Ly49D/DAP12-mediated calcium mobilization is blocked by dominant negative Syk but not by catalytically inactive Zap-70. These data demonstrate the dependence of DAP12-coupled receptors on Syk and suggest that the outcome of Ly49D/DAP12 engagement will be regulated by Cbl and culminate in the activation of transcription factors.

Sugar-polymer hydrogen bond interactions in lyophilized amorphous mixtures

The objective of this work was to investigate hydrogen bonding interactions between a variety of glass-forming sugars and a model polymer, poly(vinylpyrrolidone) (PVP), in binary amorphous solid solutions, produced by lyophilization. The glass transition temperatures of the sugars and sugar-PVP colyophilized mixtures were assessed using differential scanning calorimetry. The hydrogen bonding interactions between each sugar and PVP were monitored using FT-Raman spectroscopy. Sucrose was found to hydrogen bond to a greater extent with PVP at a particular sugar:polymer ratio than the other disaccharides studied including trehalose and the trisaccharide raffinose. Maltodextrins showed a decreased tendency to hydrogen bond with the polymer compared to the lower molecular weight sugars. The extent of hydrogen bonding was found to correlate inversely with the glass transition temperature of the sugar, with the tendency to hydrogen bond decreasing as the Tg increased. The importance of hydrogen bonding interactions to the thermodynamics of mixing in amorphous solids is discussed.

Particle size dependent molecular rearrangements during the dehydration of trehalose dihydrate in situ FT-Raman spectroscopy

PURPOSE

(1) To characterise the different phases of trehalose using FT-Raman spectroscopy. (2) To monitor the changes in the structure of trehalose dihydrate on isothermal heating at 80 degrees C.

METHODS

Different phases of trehalose were prepared and FT-Raman spectra obtained. Trehalose dihydrate was sieved to < 45 microns and > 425 microns particle size fractions and FT-Raman spectra were obtained at various time intervals during heating at 80 degrees C.

RESULTS

During heating at this temperature, the spectra of a < 45 microns particle size fraction showed a loss of peak resolution with time and after 210 minutes resembled the spectrum of amorphous trehalose prepared by lyophilisation, indicating that the material was rendered amorphous by heating. In contrast, spectra obtained from a > 425 micron particle size fraction altered with time and became characteristic of the crystalline anhydrate. The approximate kinetics of this transformation to the anhydrate were monitored by analysis of peak intensity ratios with time. A two state rearrangement was indicated; some functional groups appeared to manoeuvre into the spatial arrangement found in the anhydrate initially before the rest of the ring structure relaxed into this conformation. This may be due to some parts of the molecule being immediately affected by the loss of the water molecules on dehydration prior to the subsequent reorientation of the entire molecule into the anhydrate crystal lattice.

CONCLUSIONS

The < 45 micron particle size fraction becomes disordered on dehydration induced by heating at 80 degrees C whilst the > 425 micron particle size fraction crystallises to the anhydrate under the same conditions.

Mixing behavior of colyophilized binary systems

The purpose of this study was to investigate the factors which govern the mixing of amorphous sucrose with trehalose, poly(vinylpyrrolidone) (PVP), dextran, and poly(vinylpyrrolidone-co-vinyl acetate) (PVP/VA). These materials were chosen as model systems to represent multicomponent freeze-dried pharmaceutical preparations. Mixtures were prepared by colyophilization of the components from aqueous solutions. The glass transition temperatures (Tg) of these mixtures were measured using differential scanning calorimetry (DSC) and were compared to predictions based on simple mixing rules. FT-Raman spectroscopy was used to probe selected mixtures for evidence of molecular interactions between components. Colyophilized mixtures were confirmed to be amorphous by X-ray powder diffraction. The Tg values of the various mixtures generally were lower than values predicted from free volume and thermodynamic models, indicating that mixing is not ideal. The FT-Raman spectra of colyophilized sucrose-PVP and sucrose-PVP/VA mixtures provided evidence for interaction between the components through hydrogen bonding. Hydrogen bonds formed between components in colyophilized sucrose-additive mixtures are formed at the expense of hydrogen bonds within sucrose and in some cases within the additive. A thermodynamic analysis of these mixtures indicates that mixing is endothermic, which is consistent with a net loss in the degree of hydrogen bonding on mixing. There is also a positive excess entropy of mixing which accompanies the net loss in hydrogen bonds. Despite this gain in excess entropy, the excess free energy of mixing is positive, consistent with the observed deviations in Tg from values predicted using models which assume ideal mixing.

The quantitative analysis of crystallinity using FT-Raman spectroscopy

PURPOSE

To establish if FT-Raman spectroscopy can be used to quantitate the degree of crystallinity in a model compound.

METHODS

Mixtures containing different proportions of amorphous and crystalline indomethacin were prepared. Using the peak intensity ratio 1698 cm(-1) (crystalline) to 1680 cm(-1) (amorphous), a correlation curve was prepared. This correlation curve was validated by testing further samples of known composition. Partially crystalline indomethacin was prepared by milling crystalline indomethacin.

RESULTS

A linear correlation curve was obtained across the entire range of 0-100% crystallinity. Using this method, it was possible to detect down to either 1% amorphous or crystalline content. The largest errors were found to result from inhomogeneities in the mixing of the calibration and validation samples. The spectra of the mechanically processed samples were similar to the spectra of the calibration samples, and the degree of crystallinity could be estimated in these samples.

CONCLUSIONS

FT-Raman spectroscopy is a potentially useful method to complement existing techniques for the quantitative determination of crystallinity.

Characterization of the phase transitions of trehalose dihydrate on heating and subsequent dehydration

Many pharmaceutical compounds of interest form hydrates. The phase behavior of different particle size fractions of trehalose dihydrate was studied as the sugar was dehydrated by heating. Hot-stage microscopy, X-ray powder diffraction, thermogravimetric analysis, and differential scanning calorimetry were used to characterize the phase changes. Small particles (<45 microm) formed an amorphous phase on dehydration and subsequently liquefied at temperatures above the glass transition temperature of amorphous trehalose. Crystallization to the anhydrate was observed from this supercooled liquid. Large particles (>425 microm) underwent a solid-solid conversion from the dihydrate to the anhydrate at temperatures as low as 80 degrees C. This solid-solid conversion was explained by a catalytic effect of the liberated dihydrate water on the rearrangement of the dehydrated phase to the anhydrate. The large surface area-to-volume ratio of the small particles resulted in dehydration prior to attaining the threshold temperature for rearrangement, explaining why solid-solid conversion was absent for these particles.

Spectroscopic characterization of interactions between PVP and indomethacin in amorphous molecular dispersions

PURPOSE

To study the molecular structure of indomethacin-PVP amorphous solid dispersions and identify any specific interactions between the components using vibrational spectroscopy.

METHODS

Solid dispersions of PVP and indomethacin were prepared using a solvent evaporation technique and IR and FT-Raman spectra were obtained.

RESULTS

A comparison of the carbonyl stretching region of gamma indomethacin, known to form carboxylic acid dimers, with that of amorphous indomethacin indicated that the amorphous phase exists predominantly as dimers. The hydrogen bonding of alpha indomethacin is not as dimers. Addition of PVP to amorphous indomethacin increased the intensity of the infrared band assigned to non-hydrogen bonded carbonyl. Concomitantly, the PVP carbonyl stretch appeared at a lower wavenumber indicating hydrogen bonding. Model solvent systems aided spectral interpretation. The magnitude of the spectral changes were comparable for an indomethacin-PVP solid dispersion and a solution of indomethacin in methylpyrrolidone at the same weight percent.

CONCLUSIONS

Indomethacin interacts with PVP in solid dispersions through hydrogen bonds formed between the drug hydroxyl and polymer carbonyl resulting in disruption of indomethacin dimers. PVP may influence the crystallisation kinetics by preventing the self association of indomethacin molecules. The similarity of results for solid dispersions and solutions emphasises the "solution" nature of this binary amorphous state.

Mean intensity patterns of mirror telescopes with random tilt errors

The mean intensity of an illuminated mirror with random tilt errors (jitter) is expressed as the transform of the convolution of the pupil function times the tilt-error characteristic function. The result is applied to a mirror with a centered hole.

Characterization of frozen glucose solutions

Reducing sugars may be used as additives in freeze-dried formulations. The purpose of this study is to examine the effect of freezing on nonequilibrated glucose solutions using FT-Raman spectroscopy. The methods used solutions freshly prepared from either alpha- or beta-crystalline glucose, frozen at different time intervals after dissolution. Solutions frozen immediately after dissolution showed peaks in the anomeric region of the spectrum characteristic of those observed for the parent crystalline form. No change occurred in these spectra after 24 hr in the frozen state. Solutions prepared from either alpha- or beta-crystalline glucose and left for 24 hr at room temperature before freezing showed the presence of both anomers. The glass transition temperature of maximally freeze-concentrated solutions of beta-glucose, frozen immediately after dissolution, was found to be approximately 3 degrees C lower than for solutions prepared from alpha-glucose. Freezing appears to halt the interconversion of glucose anomers, enabling the formation of predominantly alpha- or beta-frozen solutions which exhibit different properties. Freezing of nonequilibrated solutions of reducing sugars may lead to variation in the properties of freeze-dried formulations.

Bryostatin-1 and IFN-gamma synergize for the expression of the inducible nitric oxide synthase gene and for nitric oxide production in murine macrophages

Bryostatin-1 (Bryo) is a nontumor-promoting protein kinase C modulator that has been shown to have both in vitro and in vivo activity against several murine and human tumors. In this study, we investigated the effects of Bryo on nitric oxide production, measured as accumulated nitrite (NO2-) in culture supernatant, and inducible nitric oxide synthase (iNOS) gene expression in the murine macrophage cell line ANA-1. ANA-1 macrophages did not produce NO2- or iNOS mRNA constitutively, and very little or no NO2- or iNOS mRNA were detectable upon exposure to IFN-gamma. Bryo, although ineffective alone, and IFN-gamma synergized to produce high levels of NO2- and iNOS mRNA. The activity of Bryo was evident at a concentration of 0.1 ng/ml and reached its maximum at 1 ng/ml. The effects of Bryo were time dependent because expression of iNOS mRNA was detectable as early as 6 h and increased through 24 h. Analyses of the molecular mechanisms involved indicate that Bryo and IFN-gamma mainly regulate iNOS gene expression posttranscriptionally through stabilization of iNOS mRNA. Experiments designed to investigate the role of tumor necrosis factor alpha (TNF-alpha) in NO2- production by Bryo- and IFN-gamma-activated macrophages revealed that ANA-1 macrophages expressed low levels of TNF-alpha mRNA constitutively that were not augmented in the presence of IFN-gamma. However, Bryo alone augmented the TNF-alpha mRNA expression, which was only slightly increased with the addition of IFN-gamma. A polyclonal antibody to TNF-alpha was able to completely neutralize TNF-alpha secreted in either medium or Bryo plus IFN-gamma-treated cultures. Neutralizing concentrations of anti-TNF-alpha antibody suppressed the Bryo plus IFN-gamma-induced NO2- production approximately by 50%, suggesting that NO2- produced by Bryo plus IFN-gamma-treated ANA-1 macrophages may involve both TNF-alpha-dependent and TNF-alpha-independent mechanisms. Overall, these findings provide the first evidence that Bryo and IFN-gamma can synergize for the induction of NO2- production as well as iNOS gene expression and show the involvement of posttranscriptional mechanisms in the induction of iNOS mRNA.

Functional requirement of the hypoxia-responsive element in the activation of the inducible nitric oxide synthase promoter by the iron chelator desferrioxamine

We have previously reported that a 19-base pair element of the 5'-flanking region of the inducible nitric oxide synthase (iNOS) gene containing a sequence homology to a hypoxia-responsive enhancer (iNOS-HRE) mediates picolinic acid (PA)- or hypoxia-induced activation of the iNOS promoter in interferon-gamma (IFN-gamma)-treated murine macrophages. The iron chelator desferrioxamine (DFX) induces the activity of the human erythropoietin enhancer in Hep3B cells. We have investigated the influence of DFX on the activation of the iNOS promoter and iNOS gene expression in ANA-1 macrophages. We have found that DFX induced DNA-binding activity to the hypoxia-inducible factor 1 (HIF-1) consensus sequence of the iNOS promoter and activated the iNOS-HRE in murine macrophages. These activities of DFX were associated with a synergistic induction of iNOS mRNA expression and iNOS transcription in IFN-gamma-treated ANA-1 macrophages. Functional analysis of the 5'-flanking region of the iNOS gene demonstrated that IFN-gamma plus DFX activated the full-length iNOS promoter and that the iNOS-HRE was required for DFX-induced iNOS transcriptional activity. We also investigated the role of iron metabolism in the DFX- or PA-dependent induction of HIF-1 activity and iNOS expression. We demonstrate that addition of iron sulfate completely abolished DFX or PA induction of HIF-1 binding and iNOS-HRE activation and abrogated IFN-gamma plus either DFX- or PA-induced iNOS expression. These data establish that DFX is a co-stimulus for the transcriptional activation of the iNOS gene in IFN-gamma-treated macrophages, and they provide evidence that the iNOS-HRE is required for the DFX-dependent activation of the iNOS promoter. Furthermore, our results indicate that the iNOS-HRE is a regulatory element of the iNOS promoter responsive to iron chelation.

The antineoplastic agent bryostatin-1 induces proinflammatory cytokine production in human monocytes: synergy with interleukin-2 and modulation of interleukin-2Rgamma chain expression

The antineoplastic agent bryostatin-1 (bryo-1) possesses powerful immunomodulatory properties and can function as a biological response modifier in vivo. However, there is currently little information regarding the effects of bryo-1 on cells of the monocytic lineage. In this study, we demonstrate that bryo-1 can potently induce the production of pro-inflammatory cytokines from human peripheral blood monocytes. Stimulation of monocytes with subnanomolar concentrations of bryo-1 significantly upregulated the constitutive levels of interleukin-8 (IL-8) mRNA and induced the expression of IL-1beta, tumor necrosis factor-alpha (TNF-alpha), and IL-6 mRNA in a time and dose-dependent manner. Accordingly, secretion of all four proinflammatory cytokines was induced after monocyte exposure to bryo-1. Furthermore, we showed that bryo-1 selectively synergized with IL-2 in triggering monocyte activation, and this effect seemed to be dependent, at least in part, on the ability of bryo-1 to upregulate IL-2Rgamma chain expression. Finally, we demonstrated that the responses of monocytes to bryo-1 could be blocked by the protein kinase C (PKC) inhibitors staurosporine and UCN-01, indicating a role for PKC in monocyte activation by bryo-1. These results show for the first time that bryo-1 is a powerful activator of human monocytes and suggest that stimulation of monokine secretion by bryo-1 may represent at least one of the mechanisms responsible for the in vivo antitumor activity of this drug.

Molecular cloning and characterization of a novel mouse macrophage gene that encodes a nuclear protein comprising polyglutamine repeats and interspersing histidines

Simple tandem repeats of the trinucleotide sequence CAG encode homopolymeric stretches of glutamine. Although polyglutamine has been identified in diverse proteins, it is present predominantly in transcription factors. We observed that oncogene-immortalized mouse macrophages express several genes that contain a CAG repeat motif. Therefore, we attempted to clone a novel gene that contains a CAG repeat and is associated with cytokine activation of macrophages. Screening of a mouse macrophage cDNA library with a probe comprising 12 consecutive CAG triplets identified at least one unique clone. The cDNA encodes a protein (named GRP-1 or glutamine repeat protein-1) with 171 amino acids, a calculated molecular mass of 21.6 kDa, and a predicted pI of 10.67. Greater than two-thirds of GRP-1 are only two amino acids, namely glutamine (50%) and histidine (18%). There are four polyglutamine motifs interspersed with histidine-rich regions. There is also a putative nuclear localization signal flanked by sites for possible serine phosphorylation. GRP-1 mRNA was expressed constitutively in some macrophage cell lines and B and T cell lines. Interferon-gamma or lipopolysaccharide augmented GRP-1 mRNA expression in the mouse macrophage cell line ANA-1. Western blot analyses using an antipeptide serum revealed that GRP-1 was localized in the nucleus of ANA-1 macrophages and transfected 3T3 fibroblasts. Overexpression of GRP-1 decreased Sp1-driven chloramphenicol acetyltransferase gene expression in transient cotransfection experiments. Because polyglutamine motifs can cause protein oligomerization and can function as transcriptional activation domains, we suggest that GRP-1 may be a transcription factor associated with interferon-gamma- or lipopolysaccharide-induced activation of macrophages.

Regulation of inducible nitric oxide synthase expression in IFN-gamma-treated murine macrophages cultured under hypoxic conditions

We recently reported that a hypoxia-responsive element mediates a novel pathway of transcriptional activation of the inducible nitric oxide synthase (iNOS) promoter in murine macrophages treated with IFN-gamma plus hypoxia (1% O2). In this study, we investigated the expression of NOS activity and the regulation of NOS induction in IFN-gamma treated ANA-1 murine macrophages or thioglycollate-elicited peritoneal macrophages cultured under hypoxic conditions. We found that murine macrophages stimulated with IFN-gamma plus hypoxia, despite a significant accumulation of iNOS mRNA, did not release nitrite into culture supernatant. However, cytosol from macrophages treated with IFN-gamma plus hypoxia contained significant levels of iNOS protein and enzymatic activity. Experiments in which cells were treated with IFN-gamma plus hypoxia and then cultured in normoxic conditions (20% O2) demonstrated that reoxygenation was required to achieve detectable accumulation of nitrite in the culture supernatant. Furthermore, we demonstrated that IL-4 inhibited IFN-gamma plus hypoxia-dependent induction of iNOS mRNA expression, iNOS protein, and enzymatic activity. Experiments in which ANA-1 macrophages were transfected transiently with the full-length iNOS promoter linked to a chloramphenicol acetyltransferase reporter gene demonstrated that IL-4 also down-regulated the IFN-gamma plus hypoxia-induced activation of the iNOS promoter. These data establish that hypoxia is a costimulus with IFN-gamma for the induction of iNOS activity in ANA-1 macrophages as well as in murine peritoneal macrophages, and they provide the first evidence that IL-4 inhibits hypoxia-inducible gene expression. In addition, our results suggest that hypoxia, which occurs in many pathologic conditions, may play an important role in the activation of murine macrophages.

Regulation of inducible nitric oxide synthase expression in IFN-gamma-treated murine macrophages cultured under hypoxic conditions

We recently reported that a hypoxia-responsive element mediates a novel pathway of transcriptional activation of the inducible nitric oxide synthase (iNOS) promoter in murine macrophages treated with IFN-gamma plus hypoxia (1% O2). In this study, we investigated the expression of NOS activity and the regulation of NOS induction in IFN-gamma treated ANA-1 murine macrophages or thioglycollate-elicited peritoneal macrophages cultured under hypoxic conditions. We found that murine macrophages stimulated with IFN-gamma plus hypoxia, despite a significant accumulation of iNOS mRNA, did not release nitrite into culture supernatant. However, cytosol from macrophages treated with IFN-gamma plus hypoxia contained significant levels of iNOS protein and enzymatic activity. Experiments in which cells were treated with IFN-gamma plus hypoxia and then cultured in normoxic conditions (20% O2) demonstrated that reoxygenation was required to achieve detectable accumulation of nitrite in the culture supernatant. Furthermore, we demonstrated that IL-4 inhibited IFN-gamma plus hypoxia-dependent induction of iNOS mRNA expression, iNOS protein, and enzymatic activity. Experiments in which ANA-1 macrophages were transfected transiently with the full-length iNOS promoter linked to a chloramphenicol acetyltransferase reporter gene demonstrated that IL-4 also down-regulated the IFN-gamma plus hypoxia-induced activation of the iNOS promoter. These data establish that hypoxia is a costimulus with IFN-gamma for the induction of iNOS activity in ANA-1 macrophages as well as in murine peritoneal macrophages, and they provide the first evidence that IL-4 inhibits hypoxia-inducible gene expression. In addition, our results suggest that hypoxia, which occurs in many pathologic conditions, may play an important role in the activation of murine macrophages.

The imperative of outcomes analysis: an integration of traditional and nontraditional outcomes measures

The health care industry is compelled to reduce costs while providing high-quality patient care. Outcomes analysis enables monitoring and maintenance of quality of care in our rapidly changing practice environment. Comprehensive outcomes research cannot occur, however, without a database incorporating practice-related data, interventions and components of care, and outcomes of care. The article reports the design and proposed implementation of an outcomes assessment infrastructure in a multifacility health maintenance organization in Northern California. The infrastructure integrates traditionally measured outcomes and cost data with nontraditional, nurse-influenced, health-related outcomes.

A hypoxia-responsive element mediates a novel pathway of activation of the inducible nitric oxide synthase promoter

Picolinic acid, a catabolite of L-tryptophan, activates the transcription of the inducible nitric oxide synthase gene (iNOS) in IFN-gamma-treated murine macrophages. We performed functional studies on the 5' flanking region of the iNOS gene linked to a CAT reporter gene to identify the cis-acting element(s) responsible for the activation of iNOS transcription by picolinic acid. Transient transfection assays showed that the full-length iNOS promoter in the murine macrophage cell line ANA-1 was activated by the synergistic interaction between IFN-gamma and picolinic acid. Deletion or mutation of the iNOS promoter region from -227 to -209, containing a sequence homology to a hypoxia-responsive enhancer (iNOS-HRE), decreased picolinic acid- but not LPS-induced CAT activity by more than 70%. Functional studies using a tk promoter-CAT reporter gene plasmid demonstrated that the iNOS-HRE was sufficient to confer inducibility by picolinic acid but not by IFN-gamma or LPS. Electrophoretic mobility shift assays confirmed that picolinic acid alone induced a specific binding activity to the iNOS-HRE. Furthermore, we found that the iNOS-HRE activity was inducible by hypoxia and that hypoxia in combination with IFN-gamma activated the iNOS promoter in transient transfection assays and induced iNOS transcription and mRNA expression. These data establish that the iNOS-HRE is a novel regulatory element of the iNOS promoter activity in murine macrophages and provide the first evidence that iNOS is a hypoxia-inducible gene.

Sucrose reduces the efficiency of protein denaturation by a chaotropic agent

Sugars and polyols are used to stabilize proteins. The degree of stabilization conferred on a model protein by sucrose was calculated in terms of the free energy of folding. Phosphoglycerate kinase (PGK) was denatured by guanidine hydrochloride (GuHCl) in different sucrose concentrations. The linear extrapolation method [1,2] was used to calculate the free energy of folding in the absence of denaturant. Although sucrose increased the concentration of GuHCl required to unfold the protein, the free energy of folding in water was unchanged. In order to probe the nature of the stabilizing effect of sucrose, an FT-Raman spectroscopic study of denaturant-polyol systems was undertaken. Investigations of interactions between GuHCl, urea or formamide and polyhydric compounds, revealed no evidence for hydrogen bonding or dipole-dipole associations. Polyhydric compounds caused minor changes in denaturant spectra although the converse was not observed. The structure of deuterated water changed on addition of denaturants. For non-ionic denaturants, addition of polyhydric solutes countered this change in water structure. Thus polyhydric compounds oppose the effect of denaturants on water structure. The observed increase in GuHCl concentration required to unfold PGK in the presence of sucrose may be attributed to this property of sucrose.

Hypertension management: a comparison of urban versus rural general practitioners in Western Australia

1. We have conducted a survey of 75 rural and 75 urban randomly selected general practioners (GPs) in Western Australia to ascertain how closely current practice mirrors published Australian guidelines for the management of hypertension. 2. Fifty-one rural and 49 urban GPs completed the 19 item questionnaire. The two groups were well matched in terms of age and years in general practice. An assessment of the criteria utilized to diagnose hypertension revealed a tendency for much greater scatter in the cut points used to define systolic compared to diastolic hypertension, but no systematic difference between urban and rural GPs. 3. After an initial finding of mild hypertension the follow-up time to the next check-up was significantly longer for rural patients compared to urban patients (72 +/- 13 and 36 +/- 5 days respectively, P < 0.01). Urban GPs reviewed established hypertensive patients more commonly at 1-3 monthly intervals (89%) while rural GPs reviewed more commonly at 3-6 monthly intervals (86%). 4. In terms of target blood pressure (BP) for BP reduction, 67% rural compared to 83% urban GPs aimed for a systolic BP of < 140 mmHg (P = 0.06), while 95% of both groups aimed for diastolic BP < 90 mmHg. 5. The profile of first line antihypertensive agents most commonly used was also similar in both groups with 46% preferring angiotensin converting enzyme inhibitors, 18.5% diuretics, 18.5% beta blockers, 16% calcium entry blockers and 1% prazosin. 6. This study demonstrates a clear preference for the newer anti-hypertensive agents.(ABSTRACT TRUNCATED AT 250 WORDS)

Flanged coaxial microwave probes for measuring thin moisture layers

We obtain an analytical, closed-form expression for the input admittance of a flanged, open-ended coaxial line radiating into a layered lossy material. The effect of higher modes as well as the dominant mode have been taken into consideration. The results obtained in the experimental measurement of the microwave reflection coefficient of the probe radiating into very thin water layers are described and compared with the results obtained from numerical calculations based on a theoretical model. The measurements were made in the 5.0-7.0 GHz range. The results demonstrate, for example, the usefulness of this type of device in measuring thin moisture layers in the outer layer of the human skin.

Screening for cancer and coronary risk factors through a nurse practitioner-staffed preventive health clinic

The Preventive Health Examination (PHE) program was designed to screen for cancer of the lung, colon, skin, and prostate (or breast) and to detect the risk factors for coronary artery disease, i.e., arterial hypertension, hypercholesterolemia, cigarette smoking, and obesity. To investigate the cost-effectiveness of PHE performed by nurse practitioners, the first 176 subjects enrolled in the PHE program at a northeastern, suburban VA Medical Center were evaluated prospectively. The subjects were recruited through random mailing. The direct cost of PHEs was $80 per patient. PHEs were performed on 171 men and 5 women, mean age 57.2 years, divided into groups according to the date of evaluation. Nine percent of patients had findings highly suspicious of cancer (lung nodules in 7, skin lesions in 9). As a consequence, one patient underwent lobectomy for squamous carcinoma of the lung and another underwent prostatectomy for adenocarcinoma of the prostate. Fifty-five percent of patients had high cholesterol levels, 53% were obese, 30% were heavy cigarette smokers, and 19% were hypertensive. Nineteen percent of the patients had three or more coronary artery disease risk factors. We conclude that low cost PHEs performed by nurse practitioners have a high yield in detecting risk factors for coronary artery disease, and for detecting potentially treatable malignancies.

Radio-Telemetry Transmitters for Use in Studies of the Thermoregulation of Unrestrained Common Wombats, Vombatus ursinus

The designs of radio-telemetry transmitters used in a study of thermoregulation in the common wombat, Vombatus ursinus, are described. A single-channel implantable transmitter, weighing 25 g and with a range of 100 m, was designed to monitor deep body temperature. Two versions are described of an externally mounted transmitter used to monitor heart rate and physical activity. In the first, each heartbeat was transmitted as a single radio-frequency pulse of short duration; this technique conserved power but was found to be unreliable for monitoring very low heart rates. In the second version, the electrocardiogram waveform was transmitted as a frequency-modulated signal. The multichannel transmitters weighed 300 g with batteries, and had a range of up to 400 m. A transducer consisting of a multiposition mercury switch was used to monitor activity. Changes in orientation of the transducer were transmitted as different audio-frequency tones.

Optimal dietary conditions for hemoccult testing

Preliminary rehydration of Hemoccult II slides increases slide sensitivity for blood and lowers the false-negative rate for colorectal cancer. To test the effect of this modification on the false-positive rate due to peroxidase-containing foods, 156 healthy young subjects crossed between diets of differing peroxidase content. Hemoccult II slides were prepared in duplicate for testing with and without rehydration. When developed without rehydration, only seven (0.4%) of 1856 slides were positive, the positive results occurring with challenge diets containing 250 g rare red meat. With preliminary rehydration, 53 (5.7%) of 926 slides were positive, in 26 (17%) of the 156 subjects on a challenge diet that included rare red meat and uncooked fruit and vegetables. Well-cooked red meat also gave positive tests, Diets excluding red meat but with large quantities of uncooked fruit and vegetables produced only five positive results in 314 rehydrated tests, in 3 of 53 subjects. On a strict low-peroxidase diet, two of 310 tests, in 2 of 52 subjects, were positive. Rehydration of Hemoccult slides and exclusion of red meat and certain other high-peroxidase foods should give optimal sensitivity and specificity for colorectal cancer detection. The effect of these conditions on yield of lesions and false-positive rates should be tested in screening programs.

The mechanisms of athermal microwave biological effects

A brief survey of current ideas about the physical mechanisms of low-level millimeter/microwave-biological effects is given, and the experimental evidence supporting these ideas is reviewed. The conjectural models do not yet represent a complete physical theory, but they do counter the idea that low-level effects are physically impossible and suggest experiments.

Infrared noise caused by turbulent flows

Formulas are derived for the rms noise power and power spectrum observed by an ir detector adjacent to a turbulent flow layer. The power spectrum seen by a finite aperture is conveniently expressed in terms of the power spectrum observed by a point detector. Using a simple idealization of experimental results for the latter, the spectrum observed by a finite circular aperture is calculated. Aperture averaging appears to be surprisingly ineffective in limiting the noise spectrum unless wide apertures can be employed.