Retinal vascular diameters in relation to physical activity in Danish children - The CHAMPS Eye Study.

Our objective was to determine associations between retinal vascular caliber and physical activity (PA) in a school-based child cohort. In a prospective study, we created a childhood cumulative average PA-index using objectively measured PA (accelerometry) assessed at four periods between 2009 and 2015. Cumulative exposure to PA intensities was estimated. Cross-sectional examinations on biomarkers, anthropometry, and ophthalmological data including retinal fundus photographs were performed in 2015. Semi-automated measurements of retinal vascular diameters were performed and summarized into central retinal arteriolar and venular equivalents (CRAE, CRVE). We included 307 participants. Mean age in 2015 was 15.4 years (0.7). The mean CRAE and CRVE were 156.5 µm (2.8) and 217.6 µm (7.7), respectively. After adjusting for age, gender, and axial length, more time in PA was independently related to thinner retinal venules (ß-coefficient = -1.25 µm/%, 95% confidence interval = -2.20, -0.30, P < .01). Sedentary time was associated with wider venules (P < .01). Furthermore, birthweight (ß-coefficient = 0.56 µm/%, 95% confidence interval = 0.18, 0.95, P < .01) was associated with CRVE. Blood pressure was associated with thinner retinal arterioles (ß-coefficient = -0.19 µm/mmHg, 95% confidence interval = -0.36, -0.01, P = .04). We concluded that children with higher PA in childhood had thinner retinal venular caliber. Our results suggest that PA during childhood positively impacts the retinal microcirculation and that retinal vascular analysis may be a possible assessment to detect microvascular impairments in children with an increased risk of future cardiovascular disease.

C-type Lectin Receptor Expression on Human Basophils and Effects of Allergen-Specific Immunotherapy.

Basophils are emerging as immunoregulatory cells capable of interacting with their environment not only via their characteristic IgE-mediated activation, but also in an IgE-independent manner. Basophils are known to express and respond to stimulation via TLR2, TLR4, DC-SIGN and DCIR, but whether basophils also express other C-type lectin receptors (CLRs) is largely unknown. In this study, we investigate the CLR expression profile of human basophils using multicolour flow cytometry. As FcRs as well as some CLRs are associated with allergen recognition and shown to be involved in subsequent immune responses, the expression of CLRs and FcRs on peripheral blood basophils, as well as their frequency, was monitored for 1 year in subjects undergoing subcutaneous allergen-specific immunotherapy (AIT). Here, we show that human basophils express CLECSF14, DEC205, Dectin-1, Dectin-2 and MRC2. Furthermore, we demonstrate that the frequencies of basophils expressing the allergy-associated CLRs Dectin-1 and Dectin-2 were significantly reduced after 1 year and 8 weeks of AIT, respectively. In contrast, the frequency of basophils positive for FcγRII, as well as the fraction of total basophils, significantly increased after 1 year of AIT. The herein demonstrated expression of various CLRs on basophils, and their altered CLR and FcR expression profile upon AIT, suggest yet unexplored ways by which basophils can interact with antigens and may point to novel immunoregulatory functions targeted through AIT.

Multiple antibody reactivities to citrullinated antigens in sera from patients with rheumatoid arthritis: association with HLA-DRB1 alleles.

BACKGROUND: Autoantibodies to cyclic citrullinated peptides (anti-CCP) are present in most patients with rheumatoid arthritis (RA), and associate with HLA-DRB1 shared epitope (SE) alleles. OBJECTIVE: To investigate reactivities of anti-CCP to various citrullinated proteins/peptides, which represent potential autoantigens in RA, and to examine the relationship between such antibodies, and their association with genetic variants within HLA-DRB1 SE alleles. METHODS: Serum samples from 291 patients with established RA and 100 sex- and age-matched healthy subjects were included in this study. Sera were first analysed for presence of anti-CCP antibodies and further for IgG and IgA antibodies towards candidate autoantigens in both their native and citrullinated form including: fibrinogen, alpha-enolase peptide-1 and the C1-epitope of type II collagen (C1(III)). Antibody specificity was confirmed by cross-reactivity tests. HLA-DR genotyping was performed. RESULTS: 72% of patients with RA were anti-CCP positive. Among the candidate autoantigens examined, IgG antibodies to citrullinated fibrinogen were found in 66% of patients' sera and in 41% for both citrullinated alpha-enolase peptide-1 and citrullinated C1(III). These antibodies were mainly seen in the anti-CCP-positive patient group; they were specific for their respective antigen and displayed limited cross reactivity. IgA responses were also detected, but less frequently than IgG. Anti-CCP and anti-citrullinated protein antibodies were associated with HLA-DRB1*04 rather than with HLA-DRB1*01 alleles. CONCLUSIONS: Antibodies directed against several citrullinated antigens are present in CCP-positive RA, with many patients displaying multireactivity. All specific reactivities were primarily associated with the HLA-DRB1*04 alleles, suggesting common pathways of anti-citrulline immunity.

Arthritogenicity of collagen type II is increased by chlorination.

During inflammation, activated neutrophils, monocytes and macrophages produce and release myeloperoxidase (MPO). MPO converts hydrogen peroxide to hypochlorous acid, a highly reactive and oxidizing agent. Proteins subjected to hypochlorous acid become chlorinated. We analysed how chlorination of the cartilage antigen collagen type II (CII) affects its immunogenic and arthritogenic properties by studying immune responses to chlorinated CII in comparison to immune responses to CII and by studying the development of arthritis in rats immunized with CII-Cl. CII-Cl immunization of LEW.1AV1 rats caused a 100% incidence of arthritis with a mean maximum score of 9.2 (maximal score possible 16). The same dose of non-chlorinated CII did not induce arthritis at all. Rats immunized with CII-Cl developed high anti-CII-Cl IgG titres and also developed IgG antibodies recognizing the non-chlorinated form of CII. Analysis of cytokine mRNA expression in lymph nodes 10 days after immunzation revealed an increased expression of interferon (IFN)-gamma mRNA and interleukin (IL)-1beta mRNA in CII-Cl-immunized rats compared to CII-immunized rats. Thus, chlorination of CII increased its immunogenicity as well as its arthritogenicity. As neutrophils, monocytes and macrophages are abundant cells in arthritic joints of patients with rheumatoid arthritis, chlorination might be a mechanism by which immunoreactivity to CII is induced and by which chronic joint inflammation is supported.

Inhibition by Artocarpus tonkinensis of the development of collagen-induced arthritis in rats.

Extracts of the leaves and roots from the tree Artocarpus tonkinensis A Cheval (family Moraceae) are used in traditional Vietnamese medicine in order to treat backache as well as rheumatic joint diseases. We prepared an ethyl acetate (EtOAc) extract from this plant and tested its anti-inflammatory properties in an experimental arthritis model, collagen-induced arthritis (CIA). CIA was induced in Dark Agouti rats by means of immunization with collagen type II (CII) emulsified in incomplete Freund's adjuvant. Starting at the day of immunization, the rats were treated daily with intraperitoneal injections of Artocarpus extract. Arthritis progression was measured by means of clinical scoring of paws and anti-CII antibody titres were measured by means of ELISA. In vitro, lymph node (LN) cell cultures were treated with Artocarpus extract and the apoptosis-inducing effect was determined with FACS staining by using annexin V and propidium iodide as well as the TUNEL method. Treatment of the rats with Artocarpus extract decreased arthritis incidence and severity and delayed disease onset. When treatment was started after the onset of arthritis, a tendency towards arthritis amelioration was observed. In vitro, Artocarpus extract acted as a T-cell modulator, inhibiting mitogen-induced T-cell proliferation and inducing apoptosis of activated LN-derived lymphocytes. Thus, we have demonstrated that an EtOAc extract of Artocarpus, a plant traditionally used in Vietnamese folk medicine for treating arthritic conditions, has beneficial effects in an experimental arthritis model. This effect is likely to be T cell-dependent and mediated through apoptosis induction in activated cells.

Antigen inhibition of collagen-induced arthritis is associated with up-regulation of IL-4 mRNA and induction of Ox40 on T cells in draining lymph nodes.

The addition of a foreign antigen to an inoculum completely inhibits the development of collagen-induced arthritis (CIA). However, the mechanism of this phenomenon, antigen -inhibition, is incompletely understood. Previous studies have demonstrated that the inhibition of arthritis is not mediated through suppression of the antibody response to cartilage antigens. In this paper we investigated cytokine mRNA levels in lymph nodes cells recovered 3, 7 or 16 days from animals immunized with either collagen II in IFA or OVA + collagen II in IFA. At day 7, but not at other time-points, IL-4 mRNA was up-regulated in the lymph nodes of OVA-inhibited non-arthritic animals compared to control animals which all developed arthritis. No significant differences between the two groups could be detected when expression of IFN-gamma, IL-2, TNF-alpha, IL-1beta or IL-10 mRNA was analysed. Flow cytometry analysis of draining lymph node cells demonstrated that the T cell marker Ox40 was up-regulated in the OVA-inhibited group. Our results indicate that the complete inhibition of CIA caused by addition of OVA to the collagen II inoculum is due to the presence of a TH2 environment resulting from an increased production of IL-4 mRNA and a parallel increase in Ox40+ T cells.

Single vs weekly courses of antenatal corticosteroids for women at risk of preterm delivery: A randomized controlled trial.

CONTEXT: The practice of administering weekly courses of antenatal corticosteroids to pregnant women at risk of preterm delivery is widespread, but no randomized trial has established the efficacy or safety of this practice. OBJECTIVES: To evaluate the efficacy of weekly administration of antenatal corticosteroids compared with a single course in reducing the incidence of neonatal morbidity and to evaluate potential complications of weekly treatment. DESIGN AND SETTING: Randomized, double-blind, placebo-controlled intention-to-treat trial conducted in 13 academic centers in the United States from February 1996 through April 2000. PARTICIPANTS: A total of 502 pregnant women between 24 and 32 completed weeks' gestation who were at high risk of preterm delivery. INTERVENTION: All patients received a complete single course of antenatal corticosteroids (either betamethasone, 12 mg intramuscularly repeated once in 24 hours for 2 doses, or dexamethasone, 6 mg intramuscularly repeated every 12 hours for 4 doses). Participants who had not delivered 1 week after receipt of the single course were randomly assigned to receive either betamethasone, 12 mg intramuscularly repeated once in 24 hours for 2 doses every week until 34 weeks' gestation or delivery, whichever came first (n = 256), or a similarly administered placebo (n = 246). MAIN OUTCOME MEASURE: Composite neonatal morbidity (including severe respiratory distress syndrome, bronchopulmonary dysplasia, severe intraventricular hemorrhage, periventricular leukomalacia, proven sepsis, necrotizing enterocolitis, or perinatal death). RESULTS: Composite morbidity occurred in 22.5% of the weekly-course group vs 28.0% of the single-course group (unadjusted relative risk, 0.80; 95% confidence interval, 0.59-1.10). Neither group assignment nor the number of treatment courses was associated with a reduction in composite morbidity. CONCLUSIONS: Weekly courses of antenatal corticosteroids did not reduce composite neonatal morbidity compared with a single course of treatment. Weekly courses of antenatal corticosteroids should not be routinely prescribed for women at risk of preterm delivery.

Immune-specific up-regulation of adseverin gene expression by 2,3,7,8-tetrachlorodibenzo-p-dioxin.

To identify genes that are regulated by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and possibly involved in TCDD-induced immunotoxicity, we used the differential display technique to screen for differentially expressed genes in the mouse thymus. Here we show that TCDD increased the expression of adseverin, a Ca(2+)-dependent, actin-severing protein. The induction of adseverin is dose- and time-dependent in parallel with the induction of CYP1A1, which is currently the most frequently used marker for TCDD exposure. A comparison between mouse strains with different TCDD responsiveness indicated that the induction of adseverin is dependent on the aryl hydrocarbon receptor, a transcription factor known to mediate most of TCDD's biological effects. Examination of additional organs revealed that the up-regulation of the adseverin gene expression is immune-specific. Using an anti-adseverin antibody, we confirmed the induction of adseverin by TCDD at the protein level and it was confined to the thymic cortex, which harbors immature thymocytes that are known target cells of TCDD. Considering adseverin's role in actin cytoskeletal reorganization, our observations reveal new mechanistic aspects of how TCDD might exert some of its immunotoxic effects.

Oxidative modification and inactivation of the proteasome during coronary occlusion/reperfusion.

Restoration of blood flow to ischemic myocardial tissue results in an increase in the production of oxygen radicals. Highly reactive, free radical species have the potential to damage cellular components. Clearly, maintenance of cellular viability is dependent, in part, on the removal of altered protein. The proteasome is a major intracellular proteolytic system which degrades oxidized and ubiquitinated forms of protein. Utilizing an in vivo rat model, we demonstrate that coronary occlusion/reperfusion resulted in declines in chymotrypsin-like, peptidylglutamyl-peptide hydrolase, and trypsin-like activities of the proteasome as assayed in cytosolic extracts. Analysis of purified 20 S proteasome revealed that declines in peptidase activities were accompanied by oxidative modification of the protein. We provide conclusive evidence that, upon coronary occlusion/reperfusion, the lipid peroxidation product 4-hydroxy-2-nonenal selectively modifies 20 S proteasome alpha-like subunits iota, C3, and an isoform of XAPC7. Occlusion/reperfusion-induced declines in trypsin-like activity were largely preserved upon proteasome purification. In contrast, loss in chymotrypsin-like and peptidylglutamyl-peptide hydrolase activities observed in cytosolic extracts were not evident upon purification. Thus, decreases in proteasome activity are likely due to both direct oxidative modification of the enzyme and inhibition of fluorogenic peptide hydrolysis by endogenous cytosolic inhibitory protein(s) and/or substrate(s). Along with inhibition of the proteasome, increases in cytosolic levels of oxidized and ubiquitinated protein(s) were observed. Taken together, our findings provide insight into potential mechanisms of coronary occlusion/reperfusion-induced proteasome inactivation and cellular consequences of these events.

Clinical results of phacoemulsification with the use of Healon5 or Viscoat.

PURPOSE: To compare the ophthalmic viscosurgical devices Healon5 (viscoadaptive) and Viscoat (dispersive) regarding their overall clinical performance during phacoemulsification and posterior chamber intraocular lens (IOL) implantation as well as their influence on intraocular pressure (IOP). SETTING: Department of Ophthalmology, Ruprecht-Karls-University Heidelberg, Heidelberg, Germany. METHODS: In this prospective randomized patient- and observer-masked clinical study, the performance of Healon5 (sodium hyaluronate 2.3%) and Viscoat (sodium hyaluronate 3.0%-chondroitin sulfate 4.0%) was assessed by 3 surgeons during cataract surgery in 90 patients. Surgeons used a 5-point scale for the subjective assessment of the ease of injection, maintenance capacity during continuous curvilinear capsulorhexis, remaining capacity during phacoemulsification, facilitation of IOL implantation, removal from the eye, transparency, and overall performance throughout surgery. Intraocular pressure was measured preoperatively and 24 hours and 7 days postoperatively. Best corrected visual acuity was assessed preoperatively and 7 days postoperatively. RESULTS: Overall intraoperative product performance was assessed as good or very good in 34 of 44 patients (77%) in the Healon5 group and in 16 of 46 patients (35%) in the Viscoat group (P <.001). Retention in the anterior chamber was graded good or very good in 36 patients (82%) in the Healon5 group and in 23 (50%) in the Viscoat group (P =.001). There were no statistically significant between-group differences in mean IOP preoperatively and 24 hours postoperatively. CONCLUSIONS: Surgeons graded Healon5 better than Viscoat in overall surgical performance and retention in the anterior chamber during phacoemulsification. These data support that Healon5 adapts to each step during surgery.

Association of ABO incompatibility with elevation of nucleated red blood cell counts in term neonates.

OBJECTIVE: Nucleated red blood cells in the circulation in term neonates have been associated with a wide range of pathologic conditions. We sought to examine the relationship between nucleated red blood cells in the circulation of term neonates and maternal-neonatal blood type compatibility. STUDY DESIGN: We prospectively collected umbilical blood from all live-born neonates delivered at our institution. Venous blood was analyzed for nucleated red blood cells and is reported as the number of nucleated red blood cells per 100 white blood cells. We reviewed maternal and neonatal records for neonates born at > or =37 weeks' gestation for correlative clinical data. Statistical analysis was performed with the SAS statistical software package (version 6.12; SAS Institute, Inc, Cary, NC). Kruskal-Wallis analysis was used as a nonparametric test. RESULTS: We evaluated 1661 neonates delivered during the study period and found a mean (+/-SD) of 9.29 +/- 18.56 nucleated red blood cells per 100 white blood cells (range, 0-327 nucleated red blood cells per 100 white blood cells). Nucleated red blood cell counts were lower in ABO-compatible maternal-fetal dyads (mean +/- SD, 8.29 +/- 12.84 nucleated red blood cells per 100 white blood cells; range, 0-216 nucleated red blood cells per 100 white blood cells) than in ABO-incompatible dyads (mean +/- SD, 13.16 +/- 13.16 nucleated red blood cells per 100 white blood cells; range, 0-327 nucleated red blood cells/100 white blood cells; P =.006). Neonates of mothers with blood groups A and B had significantly lower nucleated red blood cell counts (P <.05). Dyads with maternal type O and neonate type B had significantly higher nucleated red blood cell counts (P <.002). Nonparametric testing determined that type O mother and type B neonate combinations had significantly higher umbilical cord nucleated red blood cell counts (P <.001). CONCLUSION: Maternal-fetal ABO incompatibility is associated with elevation of nucleated red blood cell count in term neonates. Nucleated red blood cell elevation does not always connote a serious pathologic process, however, because ABO incompatibility usually does not adversely affect neonatal outcome. The clinical significance of an elevated nucleated red blood cell count thus is limited.

Umbilical vein white blood cell count as a marker of acidemia in term neonates.

OBJECTIVE: White blood cells are mobilized under both hypoxic and infectious conditions. Intrauterine hypoxia is linked to increased risk of cerebral palsy and is potentiated by the presence of infection. We hypothesized that umbilical vein white blood cell elevation in term neonates is associated with intrauterine acidemia. METHODS: We prospectively evaluated all liveborn neonates delivered at our institution for a 6-month period. Umbilical arterial blood was analyzed for pH and blood gas and venous blood for hematologic indices. Medical records of cases greater than or equal to 37 weeks' gestation were reviewed for correlative data. Student's t-test was used to determine difference of means and Chi-square test for goodness of fit. Pearson coefficients of correlation were applied where appropriate. RESULTS: A total of 1,948 liveborn, term neonates were delivered during the study period; 1,561 cases had white blood cell analysis and arterial blood gas data available. Acidemic cases had higher white blood cell (15.0 vs. 12.4 cells x 10(3)/mm3, P < 0.001), lymphocyte (4.43 vs. 3.59 cells X 10(3)/mm3, P < 0.0001), and neutrophil counts (9.08 vs. 7.71 cells x 10(3)/mm3, P < 0.01). As umbilical artery pH decreased, white blood cells became more prevalent. Likewise, as base deficit deepened, white blood cell counts increased. CONCLUSIONS: This study demonstrates an association between deepening acidemia and increasing white blood cell, lymphocyte, and neutrophil counts. Although statistically different, mean white blood cell counts for acidemic and nonacidemic cases are fairly close, limiting the clinical applicability in determining whether pathology is present in an individual case.

Nucleated red blood cells as a marker of acidemia in term neonates.

OBJECTIVES: Nucleated red blood cells are produced in increased numbers under hypoxic conditions. We sought to examine the relationship between nucleated red blood cell count in the circulations of term neonates and other possible markers of fetal hypoxia. STUDY DESIGN: We prospectively collected umbilical blood from all live-born neonates delivered at our institution. Arterial blood was analyzed for pH and blood gas values. Venous blood was analyzed for nucleated red blood cell count. We reviewed the medical records for maternal data and neonatal outcomes of gestations of >/=37 weeks' duration. RESULTS: We evaluated 1561 cases. The mean nucleated red blood cell count per 100 white blood cells was 9.2 +/- 18.1 (range, 0-327). Nucleated red blood cell counts were higher in infants with pH <7.20 (P =.001). Both patients with respiratory acidemia and patients with uncompensated metabolic acidemia had elevated nucleated red blood cell counts (P =.013 and P =.014, respectively). As umbilical artery pH and base excess decreased, nucleated red blood cells became more prevalent. Elevated nucleated red blood cell counts were associated with presence of meconium (P =. 020) and neonatal intensive care unit admission (P =.024). CONCLUSIONS: We found that nucleated red blood cell counts vary widely in the circulation of term neonates. Elevated nucleated red blood cell counts are associated with fetal acidemia, meconium, and neonatal intensive care unit admission.

Specificity and function of "natural" antibodies in immunodeficient subjects: clues to B cell lineage and development.

The origin of natural antibodies has long been a subject of controversy. Polyreactive natural antibodies recognize multiple ligands and are thought to arise from B1 B cells. Natural antibodies against carbohydrate antigens such as Gal alpha 1-3Gal or against blood groups A and B are thought to be "elicited" by gut bacteria, but their origin is uncertain. To explore the origin of naturally occurring anticarbohydrate antibodies, the specificity and function of the xenoreactive antibodies and isohemagglutinins were investigated in immunodeficient subjects. Subjects with defects in T cell-dependent antibody synthesis had normal levels of xenoreactive natural antibodies, most of which, like xenoreactive antibodies from normal individuals, were specific for Gal alpha 1-3Gal. On the other hand, some subjects with hyper-IgM syndrome who were able to synthesize abundant quantities of xenoreactive antibodies and polyreactive antibodies were devoid of anti-Gal alpha 1-3Gal antibodies. These results suggest that the lineages of B cells giving rise to anti-Gal alpha 1-3Gal antibodies and isohemagglutinins are distinct from B1 B cells or at least exist at a more "advanced" stage of development than those B1 B cells that give rise to polyreactive antibodies. The findings also suggest that B cells which synthesize anti-Gal alpha 1-3Gal antibodies and isohemagglutinins may be distinct from B2 B cells or exist at a more "primitive" stage of development than B2 B cells that synthesize elicited antibodies in normal individuals.

Nucleated red blood cells in cord blood of singleton term neonates.

OBJECTIVE: This study aims to establish normal values for nucleated red blood cells in term singletons and factors associated with their elevation. STUDY DESIGN: Cord blood was prospectively collected from term singleton gestations from Feb. 1 to July 31, 1995. Umbilical vein white blood cells and nucleated red blood cells were counted and umbilical arterial pH was determined. Medical records provided maternal and neonatal information. RESULTS: Cord blood from 1112 cases was obtained and evaluated for nucleated red blood cells per 100 white blood cells. Nine outliers were censored (nucleated red blood cells per 100 white blood cells = 126 to 830); five cases were excluded because of missing data. The mean value of nucleated red blood cells per 100 white blood cells was 8.55, the SD was 10.27, and the range was 0 to 89. The value did not very by maternal tobacco or drug use, anemia, fetal presentation, or mode of delivery. Both maternal diabetes and meconium were associated with elevated values, p < 0.01. Apgar scores and cord pHs showed trends toward inverse proportionality to the number of nucleated red blood cells per 100 white blood cells. CONCLUSION: The mean number of nucleated red blood cells per 100 white blood cells was 8.55, with a wide range and SD. Elevated values may be associated with markers of intrauterine hypoxia such as meconium, lower Apgar scores, and lower pH values.

Kinetics and mechanism of amyloid formation by the prion protein H1 peptide as determined by time-dependent ESR.

BACKGROUND: Peptides derived from three of four putative alpha-helical regions of the prion protein (PrP) form amyloid in solution. These peptides serve as models for amyloidogenesis and for understanding the alpha helix -->beta strand conformational change that is responsible for the development of disease. Kinetic studies of amyloid formation usually rely on the detection of fibrils. No study has yet explored the rate of monomer peptide uptake or the presence of nonfibrillar intermediate species. We present a new electron spin resonance (ESR) method for probing the kinetics of amyloid formation. A spin label was covalently attached to a highly amyloidogenic peptide and kinetic trials were monitored by ESR. RESULTS: Electron microscopy shows that the spin-labeled peptide forms amyloid, and ESR reveals the kinetic decay of free peptide monomer during amyloid formation. The combination of electron microscopy and ESR suggests that there are three kinetically relevant species: monomer peptide, amyloid and amorphous aggregate (peptide aggregates devoid of fibrils or other structures with long-range order). A rather surprising result is that amyloid formation requires the presence of this amorphous aggregate. This is particularly interesting because PrPSc, the form of PrP associated with scrapie, is often found as an aggregate and amyloid formation is not a necessary component of prion replication or pathogenesis. CONCLUSIONS: Kinetic analysis of the time-dependent data suggests a model whereby the amorphous aggregate has a previously unsuspected dual role: it releases monomer into solution and also provides initiation sites for fibril growth. These findings suggest that the beta-sheet-rich PrPSc may be stabilized by aggregation.

Effect of diclofenac on prostaglandin liberation in the rabbit after photorefractive keratectomy.

BACKGROUND: An analyses of the concentration of arachidonic acid metabolites and the infiltration of leukocytes in the aqueous humour of rabbits after excimer laser keratectomy was performed. The ability of topical diclofenac to block prostaglandin E2 liberation into the aqueous humour was also investigated. METHODS: Photorefractive keratectomy was performed on both eyes of 60 New Zealand rabbits. Prostaglandin E2, 6-keto prostaglandin F1 alpha and thromboxane B2 were detected by radioimmunoassay and leukocytes were counted in the aqueous humour for 120 hours postoperatively. Topical diclofenac was instilled (1 drop/4h) in six animals and prostaglandin E2 was analyzed in the aqueous humour 16 hours postoperatively. RESULTS: The prostaglandin E2 concentration in the aqueous humour increased from 13 in control animals, to 251 pg/100 microliters at 16 hours after treatment (p < 0.05). A statistically significant elevation in the aqueous concentration of 6-keto prostaglandin F1 alpha could not be demonstrated. Thromboxane B2 and leukocytes could not be detected at any time point. Topical diclofenac (1 drop/4h) reduced the levels of prostaglandin E2 in the aqueous humour below 10 pg/100 microliters, 16 hours postoperatively. CONCLUSION: Topical diclofenac (1 drop/4h) inhibited prostaglandin E2 release into the aqueous humour.

Accelerated fetal lung maturity profiles and maternal cocaine exposure.

OBJECTIVE: To determine the effect of maternal cocaine exposure on fetal lung maturity as measured by surfactant-albumin ratios determined by the TDx-FLM test. METHODS: A case-control study design was used to compare fetal lung maturity as assessed by a surfactant-albumin ratio assay (TDx-FLM) in amniotic fluid (AF) obtained from women who were known to use cocaine and those who were not known to use cocaine during the study pregnancy. Multiple logistic regression procedures were used to control for gestational age and possible confounders, such as obstetric and nonobstetric complications, other substance abuse, race, infant sex, and payer status. RESULTS: Maternal cocaine use during pregnancy was associated with an accelerated fetal lung maturity profile (adjusted odds ratio [OR] 2.04, 95% confidence interval [CI] 1.04-4.00) as determined by the TDx-FLM test. Other variables found to be statistically significant predictors of a mature fetal lung profile were cigarette smoking during the current pregnancy (OR 1.61, 95% CI 1.02-2.56). Preterm labor, preterm rupture of membranes, nonobstetric illness during pregnancy, and exposure to other abused substances were not associated with accelerated fetal lung maturity. CONCLUSION: Maternal cocaine use during pregnancy is associated with a doubling of the probability of a mature fetal lung profile as determined by TDx-FLM analysis of AF. Tobacco use is also a predictor of accelerated fetal lung maturity profiles.

Intermediate steps in thymic positive selection. Generation of CD4-8+ T cells in culture from CD4+8+, CD4int8+, and CD4+8int thymocytes with up-regulated levels of TCR-CD3.

Minor thymus subpopulations representing possible intermediates in thymic positive selection were isolated by cell sorting from bcl-2 transgenic mice, and cultured 1 to 4 days in simple medium to assess their ability to spontaneously develop the surface phenotype of mature T cells. Recovery of cells was in the 60 to 80% range, and no cell proliferation occurred. Only cells originally expressing high, near mature T cell levels of CD3 developed further in culture by down-regulation of CD4 or CD8. The main mature cell product was CD4-8+, regardless of whether the starting phenotype of the CD3high intermediates was CD4+8+, CD4int8+, or CD4+8int; only an intermediate subpopulation expressing the highest levels of CD4 (CD4high8int) produced a dominance of CD4+8- mature progeny. Partial down-regulation of CD8 was therefore not a good indicator of CD4+ T lineage commitment. These and previous results indicate that maturation to the CD8+ T lineage involves a rapid up-regulation of the TCR-CD3 complex, but a relatively slow down-regulation of CD4; it may also involve a partial, transient reduction in surface CD8. In contrast, maturation to the CD4+ T lineage involves a relatively rapid down-regulation of CD8, with maintenance of high levels of CD4. There appears to be a marked asymmetry in the developmental steps leading from CD4+8+ thymocytes to the CD8+ or to the CD4+ T cell lineage.