Illuminating gravitational waves: A concordant picture of photons from a neutron star merger

Merging neutron stars offer an excellent laboratory for simultaneously studying strong-field gravity and matter in extreme environments. We establish the physical association of an electromagnetic counterpart (EM170817) with gravitational waves (GW170817) detected from merging neutron stars. By synthesizing a panchromatic data set, we demonstrate that merging neutron stars are a long-sought production site forging heavy elements by r-process nucleosynthesis. The weak gamma rays seen in EM170817 are dissimilar to classical short gamma-ray bursts with ultrarelativistic jets. Instead, we suggest that breakout of a wide-angle, mildly relativistic cocoon engulfing the jet explains the low-luminosity gamma rays, the high-luminosity ultraviolet-optical-infrared, and the delayed radio and x-ray emission. We posit that all neutron star mergers may lead to a wide-angle cocoon breakout, sometimes accompanied by a successful jet and sometimes by a choked jet.

Recombinant antigens based on toxins A and B of Clostridium difficile that evoke a potent toxin-neutralising immune response

Infection with the bacterium Clostridium difficile causes symptoms ranging from mild to severe diarrhoea with life-threatening complications and remains a significant burden to healthcare systems throughout the developed world. Two potent cytotoxins, TcdA and TcdB are the prime mediators of the syndrome and rapid neutralisation of these would afford significant benefits in disease management. In the present study, a broad range of non-toxic, recombinant fragments derived from TcdA and TcdB were designed for soluble expression in E. coli and assessed for their capacity to generate a potent toxin-neutralising immune response as assessed by cell-based assays. Significant differences between the efficacies of isolated TcdA and TcdB regions with respect to inducing a neutralising immune response were observed. While the C-terminal repeat regions played the principal role in generating neutralising antibodies to TcdA, in the case of TcdB, the central region domains dominated the neutralising immune response. For both TcdA and TcdB, fragments which comprised domains from both the central and C-terminal repeat region of the toxins were found to induce the most potent neutralising immune responses. Generated antibodies neutralised toxins produced by a range of C. difficile isolates including ribotype 027 and 078 strains. Passive immunisation of hamsters with a combination of antibodies to TcdA and TcdB fragments afforded complete protection from severe CDI induced by a challenge of bacterial spores. The results of the study are discussed with respect to the development of a cost effective immunotherapeutic approach for the management of C. difficile infection.

Prediction of Optimum Process Conditions for Rotomolded Products

This paper describes analytical and experimental work which has been carried out to identify optimum process conditions for rotomolded products. The mechanical performance of the moldings has been assessed using tensile impact tests. It has been found that changes in the oven temperature or oven time cause a very significant shift in the ductile-brittle transition for the SCLAIR 8504 grade of polyethylene used in the work. Optimum combinations of process variables can be clearly defined and used to establish a processing window for the material.

The ROTOSIM computer simulation for the rotomolding process has been used to establish the best (most economic) combinations of process conditions to obtain the optimum mechanical properties. A single equation is presented to relate pool depletion time to some of the process variables.

Undergraduate pre-registration nursing education in Australia: a longitudinal examination of enrollment and completion numbers with a focus on students from rural and remote campus locations

INTRODUCTION

There is much evidence to indicate a shortage of Registered Nurses (RNs) in Australia and to suggest that the shortage may be more pronounced in rural and remote locations. Attracting RNs to work in rural and remote areas may not be as simple as increasing the intake of students into university undergraduate pre-registration nursing courses. There is some evidence indicating that student nurses may be more likely to enter the nursing workforce in rural and remote locations if they have existing associations with rural and remote areas and/or their undergraduate education provides opportunities to undertake supported placements in rural and remote settings. Two important difficulties have been associated with measuring outcomes in relation to rural and remote pre-registration nursing students. One is defining what constitutes a rural or remote location and the other is suspect data on the number of nursing students enrolled in, and completing, nursing courses. The aims of this study were to provide a longitudinal profile of the number of domestic students studying and completing undergraduate pre-registration nursing courses in Australia, with a particular emphasis on identifying those at rural and remote university campuses, and to compare results across States and Territories.

METHODS

This study presents the combined findings from two investigative reports. Data on undergraduate pre-registration nursing student numbers were collected via electronic survey instruments completed by staff at all Australian educational institutions offering undergraduate pre-registration nursing education programs in 2001 and 2002. Australian domestic students were the focus of this study. Data included the total number of domestic students enrolled in undergraduate pre-registration nursing courses in 2001 and 2002, the number of domestic students who successfully completed courses in 1999, 2000 and 2001, and estimates for the number expected to complete in 2002. Surveys were sent to course coordinators or other staff nominated by heads of divisions of nursing at each institution.

RESULTS

There was a 100% response rate. Twenty-four rural and remote campus locations were identified using an adjusted form of the Rural, Remote and Metropolitan Areas (RRMA) classification system. The Australian Capital Territory and the Northern Territory did not have any rural or remote campus locations. In contrast, undergraduate pre-registration nursing in Tasmania was offered at a rural campus only (for the first 2 years). From 2001 to 2002, there was an increase of just over 5% in the total number of domestic students enrolled in undergraduate pre-registration nursing courses in Australia (2002 total = 22,811 students). Rural and remote location students accounted for slightly more than 25% of these students in 2001, and almost 27% in 2002. The States Victoria, New South Wales and Queensland had the highest percentage of students enrolled at rural and remote campus locations, greater than the Australian average for both years. In contrast, South Australia and Western Australia had less than 11% of students enrolled at rural and remote campus locations for each year. Total undergraduate pre-registration course completions increased by approximately 16% across Australia between 1999 (n = 4868) and 2002 (n = 5667), although for 2002, the figure was projected. Of these total course completions, the percentage of students completing at rural and remote campus locations increased from almost 23% to nearly 28% during the same period. Of the States/Territories with both metropolitan and rural/remote campus locations, only Victoria and Queensland had more than 25% of their total student completions consisting of students enrolled at rural and remote campus locations for each year. In contrast, South Australia and Western Australia had approximately 6% of student completions consisting of students enrolled at rural and remote campus locations in 1999, increasing to approximately 12% projected for 2002.

CONCLUSIONS

In this study, the authors attempted to improve the accuracy of data collection in relation to the number of domestic undergraduate pre-registration nursing students in Australia, which is representative of the potentially new Australian domestic RN workforce. There was a trend towards an increasing number of students being enrolled in undergraduate pre-registration nursing courses, and also toward an increasing number of course completions. From the perspective of the rural and remote RN workforce, the percentage of students enrolled and completing courses at rural and remote campus locations was found to be increasing. However, there may be some areas of concern for education and workforce planners in States and Territories that are providing a smaller percentage of their undergraduate pre-registration nursing courses in rural and remote areas. Several study limitations are discussed and suggestions made for future research.

PCR-IMS detection and molecular typing of Cryptosporidium parvum recovered from a recreational river source and an associated mussel (Mytilus edulis) bed in Northern Ireland

PCR-IMS was used to detect Cryptosporidium spp. in environmental water samples in Northern Ireland which had previously tested negative by a conventional IFA staining method. Oocysts of C. parvum detected in river water and final treated sewage effluent collected from various sites along the river Lagan were identified as genotype 2 (animal origin) based on polymorphisms observed at the thrombospondin related adhesion protein gene locus. Similarly, genotype 1 (human origin) oocysts of C. parvum were detected in the marine filter feeder mussel, Mytilus edulis, collected from the shores of Belfast Lough. Detection of the human genotype of Cryptosporidium in mussels destined for human consumption identifies the organism's serious potential as a foodborne pathogen. This work highlights the possible value of monitoring filter feeder systems, in conjunction with specific molecular epidemiological tools, as an alternative monitoring system for the parasite within the aquatic environment.

The problem of erectile dysfunction following myocardial infarction

The causes of erection problems after an MI can be physical, psychological, a result of medication or a combination of these factors. This paper examines the causes and considers ways in which nurses can help men experiencing this problem, who may still feel embarrassed to broach this subject even though it is now more publically discussed.

Convergence of cAMP, TGF-beta and retinoic acid signaling pathways in cells of the embryonic palate

We have previously described bi-directional cross-talk between the retinoic acid (RA) and transforming growth factor beta (TGF-beta) signal transduction pathways in primary cultures of murine embryonic palate mesenchymal (MEPM) cells. In this paper we identify interactions between the TGF-beta1, cyclic adenosine 3', 5'-monophosphate (cAMP) and RA signaling systems. TGF-beta1 and forskolin, an activator of the cAMP pathway, inhibited RA-induced expression of RAR-beta mRNA in MEPM cells, though only TGF-beta1 inhibited RA-induced RAR-beta protein expression. Forskolin, but not TGF-beta1, abrogated RA-induced expression of a reporter construct containing 900 base pair (bp) of the RAR-beta gene promoter, transfected into MEPM cells, suggesting that this portion of the promoter contains the forskolin-responsive, but not the TGF-beta-responsive, element. Thus, a putative TGF-beta Inhibitory Element (TIE) adjacent to the retinoic acid response element (RARE) in the RAR-beta promoter is either non-functional, or requires promoter/enhancer elements not present in the promoter construct used in these experiments. These studies further clarify the complex interactions among signal transduction pathways in the regulation of retinoic acid receptor gene expression.

Endometrial evaluation with transvaginal US and hysterosonography in asymptomatic postmenopausal women with breast cancer receiving tamoxifen

PURPOSE

To determine performance characteristics of transvaginal ultrasonography (US) and hysterosonography for diagnosing endometrial abnormality in asymptomatic postmenopausal women with breast cancer receiving tamoxifen.

MATERIALS AND METHODS

The authors prospectively examined 138 women receiving tamoxifen by using transvaginal US, hysterosonography, and office hysteroscopy. The combined hysteroscopic-histopathologic diagnosis was the reference standard. Sensitivity, specificity, positive and negative predictive values, and likelihood ratios of transvaginal US and hysterosonography were calculated.

RESULTS

All 138 women underwent transvaginal US; 104, successful hysterosonography; and 117, successful hysteroscopy. Uterine abnormality was present in 47 (40.2%) of 117 women: 45 with polyps and two with submucosal fibroids. Receiver operating characteristic curve analysis revealed 6 mm to be the optimal endometrial thickness cutoff for diagnosing endometrial abnormalities. When a thickness greater than 6 mm or a focal endometrial finding was considered abnormal, transvaginal US had a sensitivity of 85.1% and a specificity of 55.7%. In 92 women who completed transvaginal US, hysterosonography, and hysteroscopy, hysterosonography was more specific (79.2%; P =.008) but not significantly more sensitive (89.7%; P =.508) than transvaginal US. When women with abnormal transvaginal US findings were further examined with hysterosonography, the sequential combination of transvaginal US and hysterosonography was more specific (77.1%) than transvaginal US alone (P <.001), without a significant decrease in sensitivity (78.7%; P =.25).

CONCLUSION

In asymptomatic postmenopausal women receiving tamoxifen, 6 mm is the optimal endometrial thickness cutoff for diagnosing endometrial abnormalities with transvaginal US. Further examination with hysterosonography can improve specificity by reducing the high false-positive rate of transvaginal US.

Structure-function studies of an IGF-I analogue that can be chemically cleaved to a two-chain mini-IGF-I

The structure and biological activities of two disulphide isomers of a C-region deletion mutant of insulin-like growth factor-I (IGF-I) which has an Asn--Gly link engineered at the junction of the A- and B-regions were studied before and after chemical cleavage. Circular dichroism (CD) spectra and binding affinity to IGF binding protein 3 (IGFBP3) indicated that the treatment with hydroxylamine did not disrupt the overall tertiary fold of the hormones. Cleavage restored some binding affinity for the IGF-I receptor in both isomers and weakly restored the ability to stimulate incorporation of tritiated thymidine into DNA in NIH 3T3 fibroblasts transfected with the human IGF-I receptor. Cleavage also restored metabolic capacity, as measured by the ability of the isomers to promote lipogenesis in isolated rat adipocytes through the insulin receptor. These results are consistent with the theory that binding of IGF-I to the IGF-I receptor requires a conformational change similar to that involved in insulin binding the insulin receptor. The weak affinity for the IGF-I receptor after cleavage is consistent with the belief that residues in the C-region interact with the IGF-I receptor. This structural difference between insulin and IGF-I gives each a higher binding affinity for its own receptor.

Expression of the E2F family of transcription factors during murine development

The E2F family of transcription factors plays a crucial role in the control of cell cycle progression and regulation of cellular proliferation, both processes fundamental to mammalian development. In the present study, we have examined the levels of expression of the six currently identified E2F proteins in murine embryos/fetuses as a function of gestational age, compared the expression of these six proteins in selected developing and adult tissues, and examined E2F expression in the embryonic murine palate, a tissue in which perturbation of proliferation is associated with induction of cleft palate. Our results indicate that: 1) multiple forms of individual E2F family members are present in embryonic, fetal and adult cells/tissues; 2) each of the six E2Fs is expressed in a tissue specific manner in both adult and embryonic/fetal organs; 3) certain forms of individual E2F family members are preferentially detected in adult tissues, whereas others are preferentially expressed in embryonic/fetal tissues; 4) expression of the various E2Fs and their isoforms follows distinct temporal patterns during murine gestation; and 5) individual E2F family members also exhibit differential patterns of temporal expression during murine palatogenesis.

The role of RXR-alpha in retinoic acid-induced cleft palate as assessed with the RXR-alpha knockout mouse

Treatment of pregnant mice with retinoic acid (RA) in mid-gestation produces cleft palate and limb defects in the fetuses. RXR-alpha has been previously shown to mediate the teratogenic effects of RA in the limb. In this study, we show that RXR-alpha is also involved in retinoid-induced palatal clefting. Treatment of RXR-alpha knockout mice with a teratogenic dose of RA on gestation day 11 or 12 induces cleft palate at a lower frequency than that seen in wild-type animals.

Fluorescent excitation transfer immunoassay for the determination of spinosyn A in water

A fluorescent excitation transfer immunoassay for spinosyn A, a fermentation derived insect control agent, has been developed and applied to the analysis of tap water and wastewater effluent from manufacturing plants. Fluorescein (F) and tetramethylrhodamine (TMR) were chosen as donor and quencher, respectively, for the excitation transfer. Fluorescence quenching was observed from the binding of F-labeled antigen to TMR-labeled antibody. By employing nonlabeled antigen in a competitive immunoassay format, we reversed fluorescence quenching. The assay provides a limit of detection of 0. 01 ppb and a working range of 0.05-1 ppb and allows for the rapid determination of spinosyn A in water with recovery values ranging from 96% to 120%. With the exploitation of the small size of optical fibers, fluorescence from an assay volume of 24 microL could be measured without special vessels.

Differential display identification of plunc, a novel gene expressed in embryonic palate, nasal epithelium, and adult lung

We have identified a novel gene transcript of approximately 1.1 kilobases in length that is expressed in the presumptive nasal epithelium of the mouse embryo. In situ hybridization analysis shows discrete regions of expression associated with the palate, nasal septum, and nasal conchae. This transcript is also expressed strongly in the trachea and bronchi of the adult lung. Screening of a mouse heart cDNA library yielded several overlapping clones to give a continuous sequence of 1113 bases, containing an open reading frame of 278 codons comprising the complete mRNA. No significant homologies with known genes were observed at the nucleotide level; limited amino acid homology with two salivary gland-specific proteins was noted. A search for functionally significant protein motifs revealed consensus sequences for N-glycosylation, protein kinase C and casein kinase phosphorylation, and a leucine zipper. Additionally, we observed a unique amino acid sequence pattern, consisting of the residues Gly-(Leu/Pro/Gln)-(Pro/Leu)-Leu-Pro-Leu, repeated four times near the amino-terminal portion of the protein with two amino acid residues separating the repeats. Based on these observations, we propose that we have identified a new gene, which we call plunc (for palate, lung, and nasal epithelium clone; GenBankTM accession number U69172).

MSX-1 gene expression and regulation in embryonic palatal tissue

The palatal cleft seen in Msx-1 knock-out mice suggests a role for this gene in normal palate development. The cleft is presumed secondary to tooth and jaw malformations, since in situ hybridization suggests that Msx-1 mRNA is not highly expressed in developing palatal tissue. In this study we demonstrate, by Northern blot analysis, the expression of Msx-1, but not Msx-2, in the developing palate and in primary cultures of murine embryonic palate mesenchymal cells. Furthermore, we propose a role for Msx-1 in retinoic acid-induced cleft palate, since retinoic acid inhibits Msx-1 mRNA expression in palate mesenchymal cells. We also demonstrate that transforming growth factor beta inhibits Msx-1 mRNA expression in palate mesenchymal cells, with retinoic acid and transforming growth factor beta acting synergistically when added simultaneously to these cells. These data suggest a mechanistic interaction between retinoic acid, transforming growth factor beta, and Msx-1 in the etiology of retinoic acid-induced cleft palate.

Differential expression and biological activity of retinoic acid-induced TGFbeta isoforms in embryonic palate mesenchymal cells

The effect of retinoic acid (RA) on TGF-beta mRNA expression and protein production in murine embryonic palate mesenchymal (MEPM) cells was examined by Northern blotting and TGF-beta bioassay in association with TGF-beta isoform-specific neutralizing antibodies. Heat or acid activation was used to distinguish between latent and active TGF-beta protein released into the culture medium. RA had little or no effect on TGF-beta1 mRNA expression and protein production. In contrast, RA increased TGF-beta2 and beta3 protein released into the culture medium, the protein being mostly in an inactive or latent form. The amount of active TGF-beta released was increased relative to the total increase in TGF-beta released, suggesting that RA treatment stimulated activation of latent TGF-beta. RA also increased TGF-beta2 mRNA expression; we have previously shown that RA upregulates TGF-beta3 mRNA in these cells. RA and TGF-beta individually inhibited 3H-thymidine incorporation into MEPM cell DNA, while, when administered simultaneously, they inhibited proliferative activity to a greater extent. Heat- or acid-activated conditioned medium (CM) from MEPM cells treated with RA was able to inhibit 3H-thymidine incorporation into MEPM cell DNA to an extent greater than seen with RA treatment alone. Coincubation of heat-activated CM from RA-treated MEPM cells with pan-specific or TGF-beta2 or beta3-specific neutralizing antibodies partially relieved the inhibitory effect on 3H-thymidine incorporation, suggesting that this proliferative response was due to RA-induced TGF-beta. Simultaneous treatment with RA and TGF-beta also stimulated gycosaminoglycan (GAG) synthesis to an extent greater than that seen with TGF-beta treatment alone, this despite the ability of RA to inhibit GAG synthesis. These data demonstrate a role for RA and RA-induced TGF-beta in the regulation of palate cell proliferation and GAG synthesis and suggest a role for TGF-beta in retinoid-induced cleft palate.

A 2.3 A resolution structure of chymosin complexed with a reduced bond inhibitor shows that the active site beta-hairpin flap is rearranged when compared with the native crystal structure

In the crystal structure of uncomplexed native chymosin, the beta-hairpin at the active site, known as 'the flap', adopts a different conformation from that of other aspartic proteinases. This conformation would prevent the mode of binding of substrates/inhibitors generally found in other aspartic proteinase complexes. We now report the X-ray analysis of chymosin complexed with a reduced bond inhibitor CP-113972 ¿(2R,3S)-isopropyl 3-[(L-prolyl-p-iodo-L-phenylalanyl-S-methyl-cysteinyl)amino-4]-cyclohexy l-2-hydroxybutanoate¿ at 2.3 A resolution in a novel crystal form of spacegroup R32. The structure has been refined by restrained least-squares methods to a final R-factor of 0.19 for a total of 11 988 independent reflections in the resolution range 10 to 2.3 A. The extended beta-strand conformation of the inhibitor allows hydrogen bonds within the active site, while its sidechains make both electrostatic and hydrophobic interactions with residues lining the specificity pockets S4-->S1. The flap closes over the active site cleft in a way that closely resembles that of other previously determined aspartic proteinase inhibitor complexes. We conclude that the usual position and conformation of the flap found in other aspartic proteinases is available to native chymosin. The conformation observed in the native crystal form may result from intermolecular interactions between symmetry-related molecules in the crystal lattice.

Mutagenesis, biochemical characterization and X-ray structural analysis of point mutants of bovine chymosin

Chymosin B point mutants, A115T and G243D (chymosin A), were expressed in Escherichia coli and Trichoderma reesei respectively, characterized biochemically, crystallized and studied by X-ray analysis at 2.3 and 2.8 angstroms resolutions respectively. The three-dimensional structures showed that the mutations gave rise to local conformational changes only when compared with that of chymosin B. Kinetic analysis of the A115T mutant with a six residue synthetic peptide revealed a reduction in Km with respect to the wild type, possibly caused by the small local changes in the vicinity of S1 and S3. Although, kinetic analyses of the G243D mutant using the short substrate showed reduced catalytic activity, use of a 15 residue substrate based on residues 98-112 of kappa-casein, the natural substrate, revealed an increase in the kcat compared with chymosin B, probably a consequence of the charge introduced that may interact with the substrate between P4 and P8.

Effects of dexamethasone on the expression of transforming growth factor-beta in mouse embryonic palatal mesenchymal cells

The central role of TGF-beta in the development of the embryonic palate has been well characterized. TGF-beta inhibits mesenchymal cell proliferation, induces medial edge epithelial cell differentiation, and modulates the expression of extracellular matrix proteins as well as the proteases that act upon them. Mechanisms by which TGF-beta expression itself is regulated are less well understood. Glucocorticoids are recognized in several cellular systems as able to regulate the expression of TGF-beta. This study was therefore designed to examine whether glucocorticoids affect the expression of TGF-beta isoforms in embryonic palatal cells. Based on flow cytometric analysis and viability determination, confluent primary cultures of mouse embryonic palate mesenchymal (MEPM) cells exposed to up to 10(-6) M dexamethasone (dex) exhibited no signs of cytotoxicity after 24 hours of exposure. Northern blot analyses revealed that dexamethasone reduced steady-state mRNA levels of TGF-beta 3 in a dose-dependent manner as early as 4 hours after treatment but had little effect on TGF-beta 1 and TGF-beta 2 expression up to 24 hours of dex exposure. Dex also reduced the synthesis of both latent and mature forms of TGF-beta protein by approximately four-fold as determined by the mink lung epithelial cell growth inhibition bioassay. Assessment of the ratio of mature to latent protein found in conditioned medium of control compared to dex-treated cultures indicated that dexamethasone may reduce the activation of latent TGF-beta to mature biologically active TGF-beta. Dexamethasone inhibited the proliferation of MEPM cells despite the down-regulation of TGF-beta suggesting that dex-induced growth inhibition of MEPM cells is not mediated by TGF-beta. These data suggest that dex modulates TGF-beta signaling pathways directly by down-regulating TGF-beta expression and possibly indirectly by altering the availability of mature TGF-beta necessary to exert its biological effects in the developing palate.

TGF-beta modulates the expression of retinoic acid-induced RAR-beta in primary cultures of embryonic palate cells

We have previously shown that both transforming growth factor-beta (TGF-beta) and retinoic acid (RA) regulate the expression of cellular retinoic acid binding proteins (CRABP) I and II and TGF-beta 3 mRNAs in primary cultures of murine embryonic palate mesenchymal (MEPM) cells. We now describe additional cross-talk between the RA and TGF-beta signal transduction pathways--the ability of TGF-beta, including the endogenous form(s), to modulate the expression of the nuclear retinoic acid receptor-beta (RAR-beta). Northern blot hybridization revealed that RA induced the expression of RAR-beta mRNA, there being little or no detectable expression in untreated MEPM cells. Induction by 3.3 microM RA was abrogated by simultaneous treatment with TGF-beta 1 (5 ng/ml). TGF-beta 1 alone had no effect on RAR-beta mRNA expression. Determination of RAR-beta mRNA half-life by treatment with actinomycin D indicated that TGF-beta 1 did not alter the stability of RAR-beta mRNA. Conditioned medium (CM) from MEPM cells contained little active TGF-beta protein; heat treatment of the CM dramatically increased the amount of active TGF-beta as assessed by the mink lung epithelial cell bioassay. Furthermore, heat- or acid-activated CM also inhibited CRABP-I and RA-induced RAR-beta expression. The effect of heat-activated conditioned medium could be abrogated with panspecific neutralizing antibodies to TGF-beta, confirming that endogenous TGF-beta is the biologically active factor in heat-activated CM. These results provide evidence for complex interactions between TGF-beta and RA in the regulation of gene expression in embryonic palatal cells and suggest a role for endogenous TGF-beta in the regulation of expression of genes encoding elements of the RA signal transduction pathway.

Antisense oligonucleotides to CRABP I and II alter the expression of TGF-beta 3, RAR-beta, and tenascin in primary cultures of embryonic palate cells

The cellular retinoic acid-binding proteins (CRABPs) are thought to modulate the responsiveness of cells to retinoic acid (RA). We have previously shown that primary cultures of murine embryonic palate mesenchymal (MEPM) cells express both CRABP-I and CRABP-II genes and that this expression is regulated by RA and transforming growth factor beta (TGF-beta). These cells also express high levels of TGF-beta 3, which is also regulated by RA and TGF-beta. We have used an antisense strategy to investigate the role of the CRABPs in retinoid-induced gene expression. Subconfluent cultures of MEPM cells were treated for several days with phosphorothioate modified 18-mer oligonucleotides antisense to CRABP-I or CRABP-II and then with all-trans-retinoic acid at a concentration of 3.3 microM or 0.33 microM for 5 or 22 h. Total RNA was then extracted and the expression of TGF-beta 3, retinoic acid receptor beta (RAR-beta), and tenascin was assessed by northern blot analysis. Antisense oligonucleotides to CRABP-I partially inhibited the RA-induced TGF-beta 3, RAR-beta, and tenascin mRNA expression. The corresponding mis-sense oligonucleotides were without effect. Antisense oligonucleotides to CRABP-II also partially inhibited RA-induced expression of these genes. As with the CRABP-I antisense, mis-sense oligonucleotides to CRABP-II had no effect. These data suggest that both CRABPs modulate the responsiveness of MEPM cells to retinoic acid. Inhibition of endogenous CRABP expression renders MEPM cells less responsive to RA with respect to induction of TGF-beta 3, RAR-beta, and tenascin gene expression.(ABSTRACT TRUNCATED AT 250 WORDS)

Patterns of cyclic AMP-dependent protein kinase gene expression during ontogeny of the murine palate

Normal growth and differentiation of embryonic palatal tissue depends on regulated levels of intracellular cAMP. Cyclic AMP-dependent protein kinases (PKA) act to mediate the biological activities of cAMP. PKA isozyme protein profiles demonstrate a clear pattern of temporal alterations in embryonic palatal tissue during its development. In order to ascertain the molecular basis for changing PKA isozyme profiles during palatal ontogeny, the spatial and temporal expression of mRNAs for regulatory (RI alpha, RII alpha, and RII beta) and catalytic (C alpha) subunits of PKA was examined. RNA extracted from murine embryonic palatal tissue (days 12-14 of gestation) was examined by Northern blot analysis. Significant levels of constitutively expressed RI alpha and C alpha mRNA were seen on all days of gestation examined. RI alpha transcripts were substantially less abundant in palate mesenchymal cells in vitro than in palatal tissue in vivo. Levels of RII alpha and RII beta mRNA were highest on gestational day (GD) 12, a period characterized by pronounced palatal tissue growth. In addition, patterns of tissue distribution of RII beta, not previously described, were examined in the developing embryonic palate. A dramatic developmental shift in tissue distribution of RII beta was seen. The isozyme was evenly distributed between palatal epithelial and mesenchymal cells on GD 12 but by GD 14, RII beta was predominantly localized to palatal epithelial cells. Direct activation of adenylate cyclase with forskolin in murine embryonic palate mesenchymal (MEPM) cells resulted in an increase in RII alpha mRNA levels but had no effect on steady state levels of RII beta or C alpha mRNA. In addition, elevation of intracellular levels of cAMP resulted in a shift in the transcriptional profile of RI alpha mRNAs. Results of this study document specific patterns of expression for the genes encoding the various cAMP-dependent protein kinase regulatory and C alpha subunits in murine embryonic palatal tissue. In addition, we have demonstrated adaptational changes of this kinase in MEPM cells in response to conditions of increased intracellular levels of cAMP.

Student Selection and Predictors of Success for a New Course of Study in Critical Care Nursing

Nursing education in Australia is undergoing many changes. In line with these changes, a new innovative collaborative course in critical care nursing has been developed and offered at Deakin University, Melbourne. The process and rationale for student selection for this new course is outlined in this paper and in particular, a model for selection that defines aspects related to potential for success.

Inhibition of retinoic-acid-induced gene expression by 2,3,7,8-tetrachlorodibenzo-p-dioxin

The polychlorinated aromatic hydrocarbon 2,3,7,8-tetrachlorodibenzo-p-dioxin, commonly referred to as dioxin or TCDD, has been shown to cause cleft palate in mice. TCDD displays an interesting interaction with another cleft palate teratogen, retinoic acid (RA): when mice are treated with TCDD and RA simultaneously, palatal clefts can be observed in 100% of offspring of mothers at dose levels far below those required for either agent to produce clefting if given singly. This synergy strongly suggests that the pathways controlled by these agents converge at one or more points in cells of the developing palate. In this study, we examined the effects of TCDD on induction of the type II cellular retinoic acid binding protein (CRABP-II) and the retinoic acid receptor beta (RAR beta) by RA in murine embryonic palate mesenchyme (MEPM) cells. While TCDD alone had no effect on basal levels of expression of either gene, the induction of both genes by RA was strongly inhibited by TCDD. These results represent the first evidence for a direct molecular interaction between the RA and TCDD-mediated signaling pathways.

Interactions between the transforming growth factor beta (TGF beta) and retinoic acid signal transduction pathways in murine embryonic palatal cells

Regulation of expression of transforming growth factor-beta 3 (TGF-beta 3) and the cellular retinoic acid-binding proteins-I and II (CRABP-I, -II) by retinoic acid (RA) and TGF-beta was examined in primary cultures of murine embryonic palate mesenchymal (MEPM) cells. Northern blot hybridization revealed that RA and TGF-beta 1, beta 2 and beta 3 stimulated the expression of TGF-beta 3 mRNA within 24 hours of treatment. RA down-regulated the expression of CRABP-I mRNA and up-regulated the expression of CRABP-II mRNA in a time- and dose-dependent fashion. TGF-beta 1, beta 2 and beta 3 also down-regulated the expression of CRABP-I mRNA, while epidermal growth factor (EGF) and transforming growth factor alpha (TGF-alpha) were without effect. TGF-beta 1 also stimulated a dose-dependent increase in the expression of CRABP-II mRNA. Again EGF and TGF-alpha were without effect. Basic fibroblast growth factor (bFGF) elicited a slight inhibitory effect on CRABP-II and a slight stimulatory effect on CRABP-I mRNA expression. Thus, cells derived from the mammalian developing palate express CRABP-I and CRABP-II mRNAs, both of which may be regulated by RA and TGF-beta. These data constitute the first demonstration of an effect of TGF-beta on the expression of CRABP-I and CRABP-II and provide further evidence for cross-talk between RA and TGF-beta signal transduction pathways.

Regulation of TGF beta 3 gene expression in embryonic palatal tissue

The TGF beta family of genes has been shown to play an important role in regulating various aspects of development, although the mechanisms by which TGF beta exerts its effects have not yet been clarified. Growth and differentiation of both murine embryonic palate mesenchymal (MEPM) cells and palatal epithelium can be regulated by the TGF beta s. We therefore examined the expression of mRNAs encoding TGF beta 1, TGF beta 2, and TGF beta 3 in developing embryonic palatal tissue as well as factors that modulate their levels of expression. Northern blot analysis of RNA isolated from murine embryonic palatal tissue on gestational days (GD) 12, 13, and 14 demonstrated the presence of one mRNA transcript for TGF beta 1 (2.5 kb), two transcripts for TGF beta 2 (4.4 kb, 6.0 kb), and one transcript for TGF beta 3 (3.5 kb). Although steady-state levels of TGF beta 1 mRNA showed no changes during development of the palate, TGF beta 2 mRNA levels were maximal on both GD13 and GD14 and TGF beta 3 mRNA levels transiently increased on GD 13. In addition, levels of TGF beta 3 mRNA seemed much higher than either TGF beta 1 or TGF beta 2. both TGF beta 1 and TGF beta 2 were able to increase, in a dose-related manner, the expression of TGF beta 3 mRNA in murine embryonic palate mesenchymal cells in vitro. In contrast, epidermal growth factor (EGF) down-regulated the expression of TGF beta 3 mRNA even in the presence of TGF beta 1 or TGF beta 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Milk-alkali syndrome. A consequence of chronic antacid abuse

The case described here illustrates the need to consider milk-alkali syndrome in the differential diagnosis of hypercalcemia, even in this age of histamine2 blockers and mucosal protectors. Thorough history taking and gastrointestinal workup help rule out alternative causes of hypercalcemia, such as cancer, hyperparathyroidism, and other metabolic and endocrine diseases. Milk-alkali syndrome is managed by administration of saline solution and loop diuretics and avoidance of thiazide diuretics. Patient education regarding the hazards of abusing calcium-containing antacids is essential.

Use of an antisense oligonucleotide to inhibit expression of a mutated human procollagen gene (COL1A1) in transfected mouse 3T3 cells

A series of antisense oligonucleotides were developed to inhibit specifically expression of a mutated exogenous gene for collagen without inhibiting expression of an endogenous gene for the same protein. The test system consisted of mouse NIH 3T3 cells that were stably transfected with an internally deleted construct of the human gene for the pro alpha 1(I) chain of type I procollagen [Olsen et al. (1991) J. Biol. Chem. 266, 1117]. The target site was a region at the 3' end of exon 1 and the first few nucleotides of intron 1 of the exogenous human gene that differed in sequence by nine nucleotides from the sequence of the endogenous mouse gene. Expression of the two genes was assayed by Western blot with cross-reacting antibodies and by steady-state levels of mRNAs. None of the oligonucleotides were effective in concentrations up to 25 microM when administered without any carrier. However, when administered with 5 or 10 micrograms/mL lipofectin, one of the oligonucleotides in concentrations of 0.1-0.2 microM inhibited expression of the exogenous gene from 50% to 80% without significant inhibition of expression of the endogenous gene. Also, a missense version of the same oligonucleotide had no significant effect, and the inhibition observed with the most effective oligonucleotide was abolished by a single base change. Time course experiments indicated that, after a 4-h treatment, inhibition appeared at 8 h and persisted for at least 22 h.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of the IGF1 receptor in the regulation of cdc2 mRNA levels in fibroblasts

The levels of cdc2 mRNA increase when quiescent cells are stimulated by growth factors. In BALB/c 3T3, both platelet-derived growth factor and insulin-like growth factor 1 (IGF-1) are required to increase cdc2 mRNA levels. In p6 cells, which constitutively overexpress the IGF-1 receptor, IGF-1 is sufficient. The importance of the IGF-1/IGF-1 receptor interaction in regulating the levels of cdc2 mRNA was further confirmed by showing that an antisense oligodeoxynucleotide to the IGF-1 receptor RNA inhibited the IGF-1-mediated increase.

Venous thrombosis in patients who have undergone major hip or knee surgery: detection with compression US and impedance plethysmography

To compare the sensitivity, specificity, and predictive values of compression ultrasonography (US) in postoperative orthopedic patients with those of (a) impedance plethysmography in postoperative patients and (b) compression US in symptomatic outpatients, the authors performed an investigator-blinded cohort study. One hundred thirty-four consecutive inpatients who had undergone elective knee-replacement surgery or surgery for a fractured hip and 65 consecutive outpatients with clinically suspected venous thrombosis who had undergone venography were evaluated. Compression US allowed detection of 11 of 21 (52.4%) proximal-vein thrombi but was insensitive to calf-vein thrombi in the orthopedic patients. Compression US had a significantly greater specificity and positive predictive value than impedance plethysmography for all thrombi in orthopedic patients; compression US also had greater sensitivity. The sensitivity of compression US for proximal-vein thrombi was significantly higher (92.1%) in symptomatic outpatients than in orthopedic patients. The authors conclude that compression US has significant advantages over impedance plethysmography in the detection of proximal-vein thrombi in patients who have undergone hip- or knee-replacement surgery.

Effect of the SV40 T antigen on the posttranscriptional regulation of the proliferating cell nuclear antigen and DNA polymerase-alpha genes

tk-ts13 cells are G1-specific temperature-sensitive mutants of the cell cycle that arrest in G1 at the restrictive temperature. In these cells the mRNAs for early growth-regulated genes (for instance, c-myc) are inducible by serum at both permissive and restrictive temperatures. In contrast, the mRNAs for late growth-regulated genes [such as histones, proliferating cell nuclear antigen (PCNA), and DNA polymerase-alpha] are not detectable at the restrictive temperature, although they are normally induced by serum at the permissive temperature. Despite the absence of their mRNAs at the restrictive temperature, transcription rates for DNA polymerase-alpha, PCNA, and histone H3 are the same in serum-deprived cells and in cells that are serum stimulated at either the permissive or the restrictive temperature. Since the half-lives of the mRNAs are not substantially different at the two temperatures, the conclusion is that in tk-ts13 cells the mRNA levels of these late growth-regulated genes are regulated at a posttranscriptional level, presumably during hnRNA processing. When serum-deprived tk-ts13 cells carrying a stably integrated SV40 T antigen-coding gene (T-neo cells) are stimulated with serum, they are capable of one additional round of DNA replication at the restrictive temperature. At 20 h after stimulation of T-neo cells, the mRNAs for the late growth-regulated genes are detectable at the restrictive temperature in amounts not substantially different than those at the permissive temperature. Transcription rates in T-neo cells are increased for histone H3 (in comparison to tk-ts13 cells) but not for PCNA and DNA polymerase-alpha. The presence of the T antigen does not seem to seriously affect the half-lives of the mature mRNAs. The conclusion is that the presence of the SV40 T antigen in tk-ts13 cells promotes the appearance of mature mRNAs for DNA polymerase-alpha and PCNA. These experiments suggest that T antigen, in this instance, may intervene either directly or indirectly at a posttranscriptional level in the regulation of the steady state mRNA levels of certain cellular genes.

Fibrin glue sealing of polytetrafluoroethylene vascular graft anastomoses: comparison with oxidized cellulose

To evaluate potential clinical applications of nonautologous fibrin glue (FG) as a hemostatic agent in vascular surgery, we compared its efficacy to oxidized regenerated cellulose (OC) in hemostatically sealing polytetrafluoroethylene (PTFE) vascular graft anastomoses. PTFE grafts (4 mm wide and 4 to 6 cm in length) were placed to each femoral artery in a heparinized canine model, in end-to-end fashion in half of the dogs and in end-to-side fashion in the remaining dogs. Each set of graft-arterial anastomoses was then sealed with either FG or OC, determined randomly, followed by simultaneous measurement of blood loss through the graft anastomoses and needle holes. There was significantly less bleeding from anastomoses sealed with FG compared with those sealed with OC, regardless of whether the anastomoses sealed with FG compared with those sealed with OC, regardless of whether the anastomosis was constructed in end-to-end (p less than 0.03) or end-to-side (p less than 0.004) fashion; overall, the operative blood loss for grafts sealed with FG was 14 +/- 6 (mean +/- standard error of the mean) vs 99 +/- 27 ml/min for those sealed with OC (p less than 0.001). In the early postoperative period, significant groin hematomas occurred more frequently in grafts sealed with OC compared with those sealed with FG. Microscopic examination of graft-arterial specimens harvested at postoperative intervals ranging from 1 day to 3 months revealed no significant inflammatory reaction with either hemostatic agent; after 2 to 3 weeks, paired specimens appeared histologically similar despite previous treatment with either FG or OC.(ABSTRACT TRUNCATED AT 250 WORDS)

The surgeon's role in treating acquired immunodeficiency syndrome

The ever-increasing number of patients with acquired immunodeficiency syndrome (AIDS) will involve more surgeons in their diagnosis and treatment. The surgeon should be aware of the cause of AIDS, mode of transmission, method of diagnosis, usual cutaneous and abdominal manifestations, complications needing operative procedures, and precautions needed during surgery and the postoperative period. The gravity of AIDS requires the surgeon to be aware of the potential risks to other surgical patients by contaminated blood transfusions. From 110 cases of AIDS, we analyzed the indications, types of surgical procedures, and effect on final outcome in patients with AIDS.

Large extra-abdominal cyst as a postpartum complication of peritoneal shunt. Case report

An extra-abdominal cyst filled with cerebrospinal fluid was found postpartum in a patient with a ventriculoperitoneal (VP) shunt. No similar complication of VP shunting has been reported before.

Breast cancer and pregnancy

Previous studies have found a poor prognosis for breast cancer occurring during pregnancy due to the intense hormonal stimulation produced by the pregnancy. In our study of 176 patients, pregnancy did not seem directly to affect the prognosis of breast cancer. Rather, poor survival was related to the patients' youth (less than 40 years old) and to the large number of estrogen receptor-negative tumors. Of the pregnant patients, 71% had estrogen receptor-negative tumors, implying hormonal insensitivity. Terminating the pregnancy on this basis does not seem warranted. Subsequent pregnancies in young patients did not seem to affect survival adversely. Future pregnancy in patients with stage I tumors can be considered after two years. Survival is so poor in patients with stage II or III tumors that subsequent pregnancies should be discouraged for socioethical reasons.

Heterogeneity of very-low-density lipoprotein metabolism in hyperlipidemic subjects

Very-low-density lipoproteins (VLDL) are triglyceride-rich lipoproteins that have been shown, by physicochemical means, to comprise more than one group of particles. Because of the potential atherogenicity of catabolized VLDL, we used the technique of heparin-affinity chromatography to separate VLDL into two classes of particles, one of which appears to contain partly catabolized VLDL. This observation is based on the higher cholesterol/triglyceride and higher apoprotein E/apoprotein C ratios in VLDL particles that are bound to heparin, resembling in this way intermediate-density lipoproteins (IDL), which are certainly derived in the main through VLDL catabolism. Further studies showed separate metabolic characteristics for the unbound and heparin-bound VLDL particles. Radiolabeled whole VLDL or unbound particles were reinjected into seven hypertriglyceridemic subjects and the kinetics studied in serial samples of plasma over the next 18-48 hours. The specific radioactivity-time curves of apoprotein B in the unbound and bound particles showed that the bound particles were derived wholly or partly from the unbound particles and in turn, were the precursors of IDL. This confirmed that heparin-bound VLDL particles represented VLDL undergoing catabolism, although in one subject about one-half of the bound particles appeared to have an origin other than through VLDL catabolism. These studies show that VLDL metabolism is heterogeneous, that the kinetics of total VLDL must be interpreted accordingly, and that the technique of heparin-affinity chromatography can be used for more detailed studies of VLDL.