Glucocorticoid augmentation of macrophage capacity for phagocytosis of apoptotic cells is associated with reduced p130Cas expression, loss of paxillin/pyk2 phosphorylation, and high levels of active Rac

Phagocytic clearance of apoptotic granulocytes has a pivotal role in determining an inflammatory outcome, resolution or progression to a chronic state associated with development of fibrotic repair mechanisms, and/or autoimmune responses. In this study, we describe reprogramming of monocyte to macrophage differentiation by glucocorticoids, resulting in a marked augmentation of their capacity for phagocytosis of apoptotic neutrophils. This monocyte/macrophage phenotype was characterized by decreased phosphorylation, and therefore recruitment of paxillin and pyk2 to focal contacts and a down-regulation of p130Cas, a key adaptor molecule in integrin adhesion signaling. Glucocorticoid-treated cells also displayed higher levels of active Rac and cytoskeletal activity, which were mirrored by increases in phagocytic capability for apoptotic neutrophils. We propose that changes in the capacity for reorganization of cytoskeletal elements induced by glucocorticoids are essential for efficient phagocytic uptake of apoptotic cells.

Physical mapping of restriction fragment length polymorphism (RFLP) markers in homoeologous groups 1 and 3 chromosomes of wheat by in situ hybridization

Using wheat ditelosomic lines and in situ hybridization of biotin-labelled DNA probes, 18 restriction fragment length polymorphism (RFLP) markers were physically located on homoeologous groups 1 and 3 chromosomes of wheat. Most of the markers hybridized to chromosome arms in a physical order concordant with the genetic maps. A majority of the markers studied were clustered in non-C-banded, distal euchromatic areas, indicating the presence of recombination hot spots and cold spots in those regions. However, on IBS the markers were well dispersed, which could be due to the abundance of heterochromatin throughout the arm. An inversion between Xpsr653 and Xpsr953 was observed on 1AL. One new Xpsr688 locus, approximately 20-26% from the centromere, was found on 1AS and 1BS. The physical location of Xpsr170 on group 3 chromosomes probably represents an alternative to the loci on the genetic map. Finally, Xpsr313 was mapped to two physical loci on IDL. Five markers were located to bins consistent with the deletion-based physical maps.

Physical mapping of restriction fragment length polymorphism (RFLP) markers in homoeologous groups 1 and 3 chromosomes of wheat by in situ hybridization

Using wheat ditelosomic lines and in situ hybridization of biotin-labelled DNA probes, 18 restriction fragment length polymorphism (RFLP) markers were physically located on homoeologous groups 1 and 3 chromosomes of wheat. Most of the markers hybridized to chromosome arms in a physical order concordant with the genetic maps. A majority of the markers studied were clustered in non-C-banded, distal euchromatic areas, indicating the presence of recombination hot spots and cold spots in those regions. However, on 1BS the markers were well dispersed, which could be due to the abundance of heterochromatin throughout the arm. An inversion between Xpsr653 and Xpsr953 was observed on 1AL. One new Xpsr688 locus, approximately 20–26% from the centromere, was found on 1AS and 1BS. The physical location of Xpsr170 on group 3 chromosomes probably represents an alternative to the loci on the genetic map. Finally, Xpsr313 was mapped to two physical loci on 1DL. Five markers were located to bins consistent with the deletion-based physical maps.Key words: wheat, physical mapping, in situ hybridization.

Uncoupling resistance from cell death in the hypersensitive response of Nicotiana species to cauliflower mosaic virus infection

Cauliflower mosaic virus strain W260 elicits a hypersensitive response (HR) in leaves of Nicotiana edwardsonii, an interspecific hybrid derived from a cross between N. glutinosa and N. clevelandii. Interestingly, we found that N. glutinosa is resistant to W260, but responds with local chlorotic lesions rather than necrotic lesions. In contrast, N. clevelandii responds to W260 with systemic cell death. The reactions of the progenitors of N. edwardsonii to W260 infection indicated that each contributed a factor toward the development of HR. In this study, we present two lines of evidence to show that the resistance and cell death that comprise the HR elicited by W260 can indeed be uncoupled. First, we showed that the non-necrotic resistance response of N. glutinosa could be converted to HR when these plants were crossed with N. clevelandii. Second, we found that cell death and resistance segregated independently in the F2 population of a cross between N. edwardsonii and N. clevelandii. We concluded that the resistance of N. edwardsonii to W260 infection was conditioned by a gene derived from N. glutinosa, whereas cell death was conditioned by a gene derived from N. clevelandii. An analysis of pathogenesis-related (PR) protein expression in response to W260 infection revealed that elicitation of PR proteins was associated with resistance rather than with the onset of cell death.

Does the definition of ADHD affect heritability?

OBJECTIVE

A twin study design was used to examine the genetic validity of attention-deficit hyperactivity disorder (ADHD)-related phenotypes.

METHOD

Questionnaires covering ADHD symptoms were sent to the families of 2,846 school-age twins. Parent-rated symptoms were obtained for 2,082 twin pairs and teacher-rated symptoms were available for 1,470 twin pairs.

RESULTS

Broadly defined parent-rated, teacher-rated, and "pervasive" (both parent- and teacher-rated) ADHD categories were found to be highly heritable. Significant shared environmental effects were also detected for teacher-rated ADHD. A common genetic factor was found to have a modest influence on both parent- and teacher-rated symptom scores and categories, but additional genetic and environmental influences were also found forteacher-rated ADHD. Consistent with previous findings, ADHD symptom scores were again found to be highly heritable. Maternal contrast effects were found for the Rutter A scale items but could not be detected for the DuPaul ADHD rating scale.

CONCLUSIONS

Broadly defined pervasive ADHD appears to be as heritable as ADHD behaviors defined by maternal reports alone. A common genetic factor influences maternally rated and teacher-rated ADHD but does not account for all of the genetic variance for teacher-rated ADHD. ADHD symptom scores are highly heritable, and maternal contrast effects appear to vary for different measures.

Physical location of homoeologous groups 5 and 6 molecular markers mapped in Triticum aestivum L

In situ hybridization was used to map 21 restriction fragment length polymorphism (RFLP) probes to linkage groups 5 and 6 of hexaploid wheat (Triticum aestivum L. em Thell.) in order to compare physical distances and genetic distances between adjacent markers. All 21 probes hybridized to the corresponding homoeologous chromosome arms. The linear order and linkage relationships among the DNA probes on the in situ-based physical maps were generally the same as those on the RFLP-based genetic maps. However, significant differences were observed between the centiMorgan distances on a linkage map and the physical distances of the probes using in situ-based techniques. The results indicated a clustering of polymorphic RFLP markers in the middle of all of the homoeologous group 5 and 6 chromosome arms. This suggests that the available linkage maps do not completely cover the physical length of the chromosomes. As with the genetic maps, the physical map clearly showed the presence of nonhomoeologous rearrangements in the terminal regions of chromosome arms 5AL and 6BS. However, the physical mapping gave an indication of the physical size of the rearrangements as well as their arm location.

When to suspect fungal infection in neonates: A clinical comparison of Candida albicans and Candida parapsilosis fungemia with coagulase-negative staphylococcal bacteremia

OBJECTIVES

To determine the epidemiology of candidemia in our neonatal intensive care unit; to compare risk factors, clinical presentation, and outcomes for neonates infected with Candida albicans, Candida parapsilosis, and coagulase-negative staphylococcus (CoNS); and to suggest a rational approach to empiric antifungal therapy of neonates at risk for nosocomial infection.

DESIGN

Retrospective chart review of all neonatal intensive care unit patients with systemic candidiasis or CoNS infection between January 1, 1995 and July 31, 1998 at Duke University Medical Center.

RESULTS

Fifty-one patients were reviewed. Nine of 19 patients infected with C parapsilosis and 5 of 15 patients infected with C albicans died of fungemia. Seventeen neonates had >2 positive cultures for CoNS obtained within 96 hours and 1 died. There was no statistically significant difference in birth weight, gestational age, or age at diagnosis between patient groups; however, candidemic patients had a sevenfold higher mortality rate. Before diagnosis, candidemic patients had greater exposure to systemic steroids, antibiotics, and catecholamine infusions. Of the 51 patients, 32 received third-generation cephalosporins in the 2 weeks before diagnosis and 19 did not. Twenty-nine of the 32 who were treated with third-generation cephalosporins subsequently developed candidemia, while candidemia occurred in only 5 of 19 patients who were not treated with cephalosporins. At the time of diagnosis, candidemic patients were more likely to have required mechanical ventilation and were less likely to be tolerating enteral feeding. Multivariate clustered logistic regression analysis revealed that candidemic patients had more exposure to third-generation cephalosporins. Once the clinician was notified of a positive blood culture for Candida, patients infected with C parapsilosis retained their central catheters longer than patients infected with C albicans.

CONCLUSIONS

In this retrospective review, we were able to identify aspects of the clinical presentation and medication history that may be helpful in differentiating between candidemia and CoNS bacteremia. Those key features may be used by clinicians to initiate empiric amphotericin B therapy in premature neonates at risk for nosocomial infections. Prolonged use of third-generation cephalosporins was strongly associated with candidemia. There was no statistically significant difference in the morbidity and mortality between patients infected with C parapsilosis and those infected with C albicans. Observed delays in removal of the central venous catheter may have contributed to finding a mortality rate from C parapsilosis that was higher than was previously reported.

Prevalence of Alzheimer's disease and other dementing disorders in an urban community of Beijing, China

A door-to-door two-phase study was used to investigate the prevalence of senile dementia in an urban community of Beijing. In the study population, 5,003 individuals aged 60 years and older (>/=65 years, n = 3,728) were screened at home with the Chinese version of the MMSE. Persons who screened positive for dementia, using different cutoff scores based on degree of literacy, were further evaluated using the criteria of DSM-III-R and ICD-10. Among subjects who screened positive in phase I, 134 were diagnosed as having dementia in phase II. The prevalence ratios of dementia were 2.68% in the population aged 60 years and older, and 3.49% in the population aged 65 years and older. The prevalence rates among those aged 65 years and older were 1.85% for Alzheimer's disease, 1.37% for vascular dementia and 0.27% for other dementia (including mixed dementia). The prevalence of all dementia and AD increased steeply with advancing age and was consistently higher in women, but it was not obviously higher for VaD in women. Alzheimer's disease was the commonest type of dementia. Our prevalence figures for dementia and AD are similar to those previously reported for China.

Molecular characterization of the surface of apoptotic neutrophils: implications for functional downregulation and recognition by phagocytes

We have used a panel of monoclonal antibodies and lectins to examine the profile of surface molecule expression on human neutrophils that have undergone spontaneous apoptosis during in vitro culture. Neutrophil apoptosis was found to be accompanied by down-regulation of the immunoglobulin superfamily members PECAM-1 (CD31), ICAM-3 (CD50), CD66acde, and CD66b and the integrin-associated proteins CD63 and urokinase plasminogen activator receptor (CD87) that may alter the potential for adhesive interactions. Cellular interactions may be further influenced by the reduction of the expression of surface carbohydrate moieties, including sialic acid. Reduced expression of FcgammaRII (CD32), complement receptor type 1 (CD35) and receptors for pro-inflammatory mediators C5a (CD88) and TNFalpha (CD120b) associated with apoptosis might limit neutrophil responsiveness to stimuli that trigger degranulation responses. Although many of the receptors we have examined are expressed at reduced levels on apoptotic neutrophils, we found that there was differential loss of certain receptors (e.g. CD16, CD15 and CD120b) and increased expression of aminopeptidase-N (CD13). Together with our previous data showing that expression of certain molecules e.g. LFA-3 (CD58) is not altered during neutrophil apoptosis, these data are suggestive of specific changes in receptor mobilisation and shedding associated with apoptosis. Although reduced expression of CD63 (azurophilic granules) and CR1 (specific granules) indicates that granule mobilisation does not accompany apoptosis, a monoclonal antibody (BOB78), that recognises a 90 kDa antigen localised in intracellular granules, defines a subpopulation of apoptotic neutrophils that exhibit nuclear degradation yet retain intact plasma membranes. BOB78 positive neutrophils were found to bind biotinylated thrombospondin, suggesting that this mAb defines surface molecular changes associated with exposure of thrombospondin binding moieties.

Growth of lungs after transplantation in infants and in children younger than 3 years of age

We report serial measurements of lung volume and airflow in small children after lung transplantation. We expected that immature lungs could grow and develop normal volumes after transplantation, despite denervation and immunosuppression. At predetermined intervals, functional residual capacity (FRC) and forced expiratory flow were measured 86 times in 23 recipients younger than 3 yr of age (age at transplant, 13.2 +/- 8.4 mo; range, 2 to 30 mo). FRC was measured using open-circuit N2 washout. Maximal flow at FRC by rapid thoracoabdominal compression was used to distinguish between infants with and those without airflow obstruction. The slope of FRC (in milliliters) versus body length (in centimeters) for all 23 recipients studied was 8.63. For those children without obstruction (flow at FRC >/= 0.9 FRC/s, n = 16), the slope of FRC versus length was 6.61. The coefficient of variation for FRC measurements for all infants was 3.90 +/- 2.80% (range, 0.3 to 16.9%). We conclude that in the absence of significant airflow obstruction the volume of transplanted immature lungs increases at a rate similar to that reported in normal infants.

Dysbaric osteonecrosis of the shoulder in a sport scuba diver

The previously unreported occurrence of dysbaric osteonecrosis in an amateur sport scuba diver who had no other identified cause of avascular bone necrosis is described.

Regulation of macrophage phagocytosis of apoptotic neutrophils by adhesion to fibronectin

The potential for leukocyte-mediated host tissue damage during resolution of inflammatory responses is influenced by the rate at which extravasated apoptotic leukocytes are cleared from inflammatory sites. Regulation of macrophage capacity for clearance of apoptotic granulocytes is likely to be an important factor determining whether inflammation ultimately resolves or progresses to a chronic state. In this study we have investigated the molecular basis for rapid augmentation of macrophage phagocytosis of apoptotic neutrophils, which was observed following macrophage adhesion to fibronectin. We used a combination of monoclonal antibodies, blocking peptides, and recombinant fibronectin fragments to investigate the role of beta1 integrins in mediating the fibronectin effects. Blockade of alpha5beta1 or alpha4beta1 alone did not attenuate fibronectin-augmentation of phagocytosis. In addition, adhesion of macrophages to recombinant fibronectins lacking alpha4beta1 recognition motifs failed to promote phagocytosis of apoptotic neutrophils. Our results would be consistent with a model in which multiple fibronectin receptors, including beta1 integrins, act co-operatively to augment macrophage phagocytic responses. Together, these data suggest that the extracellular matrix environment of macrophages may provide regulatory signals that act indirectly to rapidly alter the potential for removal of apoptotic cells and influence the process of resolution of inflammation.

Binary interactions of the SNARE proteins syntaxin-4, SNAP23, and VAMP-2 and their regulation by phosphorylation

The SNARE hypothesis proposes that synaptic vesicles dock at presynaptic membranes via interactions among the vesicular, integral membrane proteins VAMP (vesicle-associated membrane protein) and synaptotagmin and the target membrane proteins SNAP25 (synaptosome-associated protein with an Mr of 25 kDa) and syntaxin-1. Non-neuronal cells express isoforms of these proteins, believed to mediate secretory vesicle docking and/or fusion. Secretion in neuronal and non-neuronal systems differs in time course, Ca2+ dependence, and regulatory input. It is not known whether the non-neuronal protein isoforms form complexes akin to those of their neuronal counterparts. In this study, we defined the binding characteristics of three SNARE proteins: SNAP23, VAMP-2, and syntaxin-4. Binary, saturable interactions among all three partners (VAMP-2-syntaxin-4, VAMP-2-SNAP23, and SNAP23-syntaxin-4) were measured in vitro. Unlike its neuronal counterpart, SNAP23 did not potentiate VAMP-2 binding to its putative t-SNARE partner, syntaxin-4. The susceptibility of SNARE proteins to phosphorylation by exogenous kinases and their impact on binary interactions were explored. Syntaxin-4 was efficiently phosphorylated by casein kinase II (CKII) and cAMP-dependent protein kinase (PKA) (incorporating 0.8 and 3.9 mol of phosphate/mol of syntaxin-4, respectively), while syntaxin-1 was only strongly phosphorylated by CKII. Each of the syntaxin isoforms was weakly phosphorylated by protein kinase C (PKC) (<0.05 mol of phosphate/mol of syntaxin-4). Importantly, PKA but not casein kinase II phosphorylation of syntaxin-4 disrupted its binding to SNAP23. We hypothesize that PKA may modulate syntaxin-4-dependent SNARE complex formation to regulate exocytosis in non-neuronal cells.

Neoral: the new cyclosporine

Neoral is an improved formulation of cyclosporine which, through microemulsion technology, provides a more consistent rate of absorption and exposure. If patients are able to take less Neoral and still maintain the same cyclosporine level, there will also be a cost savings involved. A dose reduction of 30% yields pharmacoeconomic savings. With a more consistent rate of absorption, the risks of nephrotoxicity may be reduced.

Project to develop an autonomous practitioner programme

The early 1990s has seen a rapid expansion in the nature of clinical roles in health care in response to a number of changes. Throughout 1996, The Oxford Radcliffe Hospital National Health Service (NHS) Trust, in partnership with Oxford Brookes University, School of Health Care, and the Royal College of Nursing (UK) have been collaborating to develop an educational programme at degree and masters level, to support new and evolving clinical roles in acute and primary care, across most professional health registration areas and clinical specialities. To ensure the proposed programme was 'fit for purpose'the Trust commissioned a Training Needs Analysis by the University of Birmingham and a Role Analysis by The Royal College of Nursing. Nurses and Midwives with expertise in practice, management, education and research, have collaborated to develop an innovative educational programme which enables a wide range of public and private health care professionals across acute and community settings to develop their autonomous practice. The programme is fully supported by development of policies which are appropriate to service delivery, support professional practice, multi-professional relationships, risk management and patient safety. The issue of contractual and professional responsibilities related to career development have been debated and a proactive strategy agreed. To ensure there is thorough evaluation of the area of practice, research projects to evaluate outcomes for patients as well as practitioners have been designed. This will additionally promote a culture of evidence-based practice.

Serotonin levels, pain threshold, and fibromyalgia symptoms in the general population

OBJECTIVE

To investigate the association of serum serotonin with fibromyalgia (FM), and to study the relationship of serotonin to clinical variables associated with FM.

METHODS

Serum samples (n = 292) were obtained on subjects without pain, with regional pain, and with widespread pain during a population survey. The tender point examination was made according to American College of Rheumatology examination criteria by an examiner blind to the subjects' complaints. Serotonin was determined by high performance liquid chromatography coupled to an electrochemical detector.

RESULTS

No associations between clinical variables and serotonin levels were found in the group as a whole. Subjects with FM had lower serotonin levels unadjusted (p = 0.019) and adjusted for age and sex (p = 0.059) than those without FM. Within the FM group, associations between serotonin and tender point count (r = 0.563) and depression (r = 0.549) were noted, but the direction of association was opposite to previous reports and expectations.

CONCLUSION

Serum serotonin levels are significantly lower in persons with FM compared to those without FM, but the range of values is wide. Difficult to explain correlations with reversed directions are noted for tender point count, dolorimetry, depression, and anxiety among those with FM. Serotonin is not correlated with any clinical variables in the general population, and separate pain groups cannot be distinguished.

Location, catalytic activity, and subunit composition of NAD-reducing hydrogenases of some Alcaligenes strains and Rhodococcus opacus MR22

Six new strains of Alcaligenes enriched for and isolated as nickel-resistant bacteria resemble Alcaligenes eutrophus H16 and contain both an NAD-reducing, tetrameric soluble hydrogenase and a membrane-bound hydrogenase. None of the soluble hydrogenases share with the Rhodococcus opacus MR11 enzyme tetramer the property of being cleaved easily into two dimeric moieties [a hydrogenase (betadelta) and an NADH:acceptor oxidoreductase (alphagamma)], in the absence of nickel or at low ionic strength. The soluble hydrogenase of the newly isolated strain MR22 of R. opacus equalled that of strain MR11. The absence of a membrane-bound hydrogenase in Alcaligenes denitrificans strain 4a-2 and in Alcaligenes ruhlandii was confirmed.