g Factor of the ^{99}Zr (7/2^{+}) Isomer: Monopole Evolution in the Shape-Coexisting Region

The gyromagnetic factor of the low-lying E=251.96(9)  keV isomeric state of the nucleus ^{99}Zr was measured using the time-dependent perturbed angular distribution technique. This level is assigned a spin and parity of J^{π}=7/2^{+}, with a half-life of T_{1/2}=336(5)  ns. The isomer was produced and spin aligned via the abrasion-fission of a ^{238}U primary beam at RIKEN RIBF. A magnetic moment |μ|=2.31(14)μ_{N} was deduced showing that this isomer is not single particle in nature. A comparison of the experimental values with interacting boson-fermion model IBFM-1 results shows that this state is strongly mixed with a main νd_{5/2} composition. Furthermore, it was found that monopole single-particle evolution changes significantly with the appearance of collective modes, likely due to type-II shell evolution.

17β-Estradiol modulates UVB-induced cellular responses in estrogen receptors positive human breast cancer cells

Genotoxic agents produce numerous cellular responses that are principally dedicated to maintain or restore DNA integrity. In human cells, nucleotide excision repair (NER) is one of the major pathways for the repair of DNA damage such as ultraviolet (UV) radiation-induced lesions. Endocrine disrupting compounds are environmental contaminants that interfere with the function of the endocrine system. Among them, the natural estrogen 17beta-estradiol (E(2)) exhibits the most potent activity. Some proteins directly or indirectly involved in NER also fulfill other functions such as transcription, DNA damage checkpoints or cell cycle. Moreover, steroids such as E(2) are believed to interact with a large number of proteins including some involved in NER and DNA damage checkpoint control. We therefore investigated the potential modulation of genotoxic stress-cells responses by E(2) treatment. Estrogen receptor (ER)-positive human breast cancer cells were submitted to E(2) before and/or after UVB irradiation and thereafter the repair kinetics of UV-induced DNA damage were evaluated. We report here that the repair rate of UVB-induced DNA damage is enhanced when cells are submitted to an estrogenic stimulation. Moreover, our results suggest that this response could be mediated by cell cycle regulatory proteins in a p53-independent manner.

Phagocyte activation by Trp-Lys-Tyr-Met-Val-Met, acting through FPRL1/LXA4R, is not affected by lipoxin A4

Lipoxin A4 (LXA4) has been shown to bind to the leucocyte formyl peptide receptor (FPR) homologue, FPRL1, without triggering the biological activities induced by other FPRL1 agonists. We investigated the direct effect of LXA4 as well as the effect on agonist-induced biological responses using transfected HL-60 cells expressing FPR, FPRL1 or FPRL2. LXA4 neither induced an intracellular rise in calcium in these transfectants nor affected the response induced by the peptide Trp-Lys-Tyr-Met-Val-Met (WKYMVM), an agonist that activates cells through FPRL1 and -2. Both agonists induced Erk-2 activation; however, the eicosanoid-induced activity was independent of FPRL1 and FPRL2. Moreover, LXA4 was unable to trigger neutrophil upregulation of complement receptor 3 and respiratory burst, and it had no effect on the responses induced by triggering with WKYMVM. We conclude that LXA4 is unable to affect the WKYMVM-induced signalling through FPRL1 and suggest that it acts through a receptor different from FPRL1.

A proinflammatory peptide from Helicobacter pylori activates monocytes to induce lymphocyte dysfunction and apoptosis

Infection with Helicobacter pylori causes chronic gastritis, which is characterized by a dense mucosal infiltration by inflammatory cells such as monocytes/macrophages. H. pylori-induced inflammation is a risk factor for the development of gastric adenocarcinoma, but the mechanisms involved in H. pylori-associated carcinogenesis are poorly understood. A cecropin-like H. pylori peptide, Hp(2-20), was found to be a monocyte chemoattractant and activated the monocyte NADPH-oxidase to produce oxygen radicals. The receptors mediating monocyte activation were identified as FPRL1 and the monocyte-specific orphan receptor FPRL2. Hp(2-20)-activated monocytes inhibited lymphocytes with antitumor properties, such as CD56+ natural killer (NK) cells and CD3epsilon+ T cells. The changes observed in NK cells and T cells--a reduced antitumor cytotoxicity, downregulation of CD3zeta expression, and apoptosis--were mediated by Hp(2-20)-induced oxygen radicals. Histamine, a gastric mucosal constituent, rescued NK cells and T cells from inhibition and apoptosis by suppressing Hp(2-20)-induced oxygen radical formation. We conclude that H. pylori expression of this monocyte-activating peptide contributes to its ability to attract and activate monocytes and reduces the function and viability of antineoplastic lymphocytes. These novel mechanisms may be subject to local, histaminergic regulation in the gastric mucosa.

Proinflammatory activity of a cecropin-like antibacterial peptide from Helicobacter pylori

Helicobacter pylori, the bacterial pathogen associated with gastritis and peptic ulcers, is highly successful in establishing infection in the human gastric mucosa, a process typically associated with massive infiltration of inflammatory cells. Colonization of the mucosa is suggested to be facilitated by H. pylori-produced cecropin-like peptides with antibacterial properties, giving the microbe a competitive advantage over other bacteria. We show that a cecropin-like antibacterial peptide from H. pylori, Hp(2-20), not only has a potent bactericidal effect but also induces proinflammatory activities in human neutrophils, e.g., upregulation of integrins (Mac-1), induction of chemotaxis, and activation of the oxygen radical producing NADPH-oxidase. Furthermore, we show that these effects are mediated through binding of Hp(2-20) to the promiscuous, G-protein-linked lipoxin A(4) receptor-formyl peptide-like receptor 1.

The synthetic peptide Trp-Lys-Tyr-Met-Val-Met-NH2 specifically activates neutrophils through FPRL1/lipoxin A4 receptors and is an agonist for the orphan monocyte-expressed chemoattractant receptor FPRL2

Neutrophils express the G protein-coupled N-formyl peptide receptor (FPR) and its homologue FPRL1, whereas monocytes express FPR, FPRL1, and FPRL2, an orphan receptor sharing 83% amino acid identity with FPRL1. FPRL1 is a promiscuous receptor activated by serum amyloid A and by different synthetic peptides, including the hexapeptide Trp-Lys-Tyr-Met-Val-d-Met-NH(2) (WKYMVm). By measuring calcium flux in HL-60 cells transfected with FPR, FPRL1, or FPRL2, we show that WKYMVm activated all three receptors, whereas the l-conformer WKYMVM activated exclusively FPRL1 and FPRL2. The functionality of FPRL2 was further assessed by the ability of HL-60-FPRL2 cells to migrate toward nanomolar concentrations of hexapeptides. The half-maximal effective concentrations of WKYMVM for calcium mobilization in HL-60-FPRL1 and HL-60-FPRL2 cells were 2 and 80 nm, respectively. Those of WKYMVm were 75 pm and 3 nm. The tritiated peptide WK[3,5-(3)H(2)]YMVM bound to FPRL1 (K(D) approximately 160 nm), but not to FPR. The two conformers similarly inhibited binding of (125)I-labeled WKYMVm to FPRL2-expressing cells (IC(50) approximately 2.5-3 micrometer). Metabolic labeling with orthophosphoric acid revealed that FPRL1 was differentially phosphorylated upon addition of the l- or d-conformer, indicating that it induced different conformational changes. In contrast to FPRL1, FPRL2 was already phosphorylated in the absence of agonist and not evenly distributed in the plasma membrane of unstimulated cells. However, both receptors were internalized upon addition of either of the two conformers. Taken together, the results indicate that neutrophils are activated by WKYMVM through FPRL1 and that FPRL2 is a chemotactic receptor transducing signals in myeloid cells.

Seasonal variations in variceal bleeding mortality and hospitalization in France

OBJECTIVES

The circadian variation in portal blood pressure and in the diurnal incidence of variceal bleeding is well known, but the seasonal variation in variceal bleeding is still controversial. This report analyzes the seasonal variations in mortality and hospitalizations due to variceal bleeding in the French population.

METHODS

All the deaths due to variceal bleeding that occurred from 1987 to 1996 (N = 13,514) and all adults discharged from French public hospitals for variceal bleeding from 1995 to 1997 (N = 17,026) were examined retrospectively. Cumulated monthly averages were expressed as the percentage above or below the average monthly value during the entire study period.

RESULTS

Deaths due to variceal bleeding in France occurred with a clear annual periodicity and peaked in winter (December/January), both in the overall population and in subgroups defined by age and sex, except for women. The distribution of cumulative monthly deaths differed by 24%, with a peak (14% above average) in December and a trough (10% below average) in July (Roger's test: p < 0.001). Hospitalizations for variceal bleeding in French public hospitals followed a similar seasonal pattern (p < 0.001) with a winter-spring predominance (4% to 7% from December through April), except in patients aged 15-49 yr. There was a short sharp peak of mortality in early winter in French public hospitals. The seasonality of hospitalization and death increased markedly with age.

CONCLUSIONS

A better understanding of these age- and sex-specific seasonal patterns would allow to improve pharmacological protection measures, disease management, and educational strategies.

Kinase-inactive G-protein-coupled receptor kinases are able to attenuate follicle-stimulating hormone-induced signaling

Homologous desensitization of G-protein-coupled receptors (GPCR) is thought to occur in several steps: binding of G-protein-coupled receptor kinases (GRKs) to receptors, receptor phosphorylation, kinase dissociation, and finally binding of beta-arrestin to phosphorylated receptors and functional uncoupling of the associated Galpha protein. It has recently been reported that GRKs can inhibit Galphaq-mediated signaling in the absence of phosphorylation of some GPCRs. Whether or not comparable phosphorylation-independent effects are also possible with Galphas-coupled receptors remains unclear. In the present study, using the tightly Galphas-coupled FSR receptor (FSH-R) as a model, we observed inhibition of the cAMP-dependent signaling pathway using kinase-inactive mutants of GRK2, 5, and 6. These negative effects occur upstream of adenylyl cyclase activation and are likely independent of GRK interaction with G protein alpha or beta/gamma subunits. Moreover, we demonstrated that, when overexpressed in Cos 7 cells, mutated GRK2 associates with the FSH activated FSH-R. We hypothesize that phosphorylation-independent dampening of the FSH-R-associated signaling could be attributable to physical association between GRKs and the receptor, subsequently inhibiting G protein activation.

Seasonal variation in acute intestinal vasculopathy mortality in France

OBJECTIVES

Seasonal and circadian rhythms are observed in cardiovascular diseases. Seasonal variation in acute intestinal vasculopathy has never been investigated. This report describes the seasonal variation of acute intestinal vasculopathy mortality in the French population.

METHODS

All deaths that occurred among French adults over the period 1987-1996 (N = 20,830) for acute intestinal vasculopathy (International Classification of Diseases, Ninth Revision code 557.0) were examined retrospectively. Cumulated monthly averages were expressed as the percentage above or below the average monthly value during the entire study period.

RESULTS

Deaths for acute intestinal vasculopathy peaked in January (15% above the trend), and were lowest in July (11% below the trend), both in the overall population (Roger's test: p < 0.001) and in subgroups defined by age (>69 yr old) and sex. Compared to other subgroups, the >90 yr old individuals had a higher incidence of acute intestinal vasculopathy with a greater amplitude of seasonal variation (p < 0.001).

CONCLUSIONS

Awareness of higher risk during winter would help to reduce the high mortality from acute intestinal vasculopathy. A better understanding of this seasonal pattern would allow practitioners to improve early diagnosis and treatment.

Seasonal variation in cryptogenic and noncryptogenic hemoptysis hospitalizations in France

STUDY OBJECTIVE

To determine the potential role of seasonality in hospitalizations for cryptogenic and noncryptogenic hemoptysis in the French population.

DESIGN

Retrospective analysis of hospital discharge data from a National Register.

SETTING

All 29 French university hospitals, between July 1, 1994, and June 30, 1997.

PATIENTS

Two thousand six hundred seventy-seven and 3,672 adult hospitalizations for cryptogenic and other hemoptysis, respectively.

MEASUREMENTS

Cumulative monthly averages were determined, expressed as the percentage above or below the average monthly value during the entire study period.

RESULTS

The distribution of cumulative monthly hospitalizations for cryptogenic hemoptysis peaked in March (32% above the average) and was lowest in summer (30% below the average; p < 0.001). Hospitalizations for noncryptogenic hemoptysis followed a similar seasonal pattern (p < 0. 001). In the 16- to 34-year-old individuals, cryptogenic hemoptysis, compared with noncryptogenic hemoptysis, showed a higher incidence with a larger seasonal amplitude (p < 0.001).

CONCLUSIONS

A better understanding of the fundamental pathophysiologic mechanisms underlying this respiratory and hemorrhagic condition may be helpful in developing preventive measures, especially in patients with a risk of recurrence.

The synthetic chemoattractant Trp-Lys-Tyr-Met-Val-DMet activates neutrophils preferentially through the lipoxin A(4) receptor

A D-methionine-containing peptide, Trp-Lys-Tyr-Met-Val-D-Met-NH(2) (WKYMVm), featuring a unique receptor specificity was investigated with respect to its ability to activate neutrophil effector functions. The peptide was found to be more potent than the N-formylated peptide N-formyl-Met-Leu-Phe (fMLF) at inducing neutrophil chemotaxis, mobilization of neutrophil complement receptor 3 (CR3), and activation of the neutrophil NADPH-oxidase. The fact that binding of fML[(3)H]F was inhibited by both fMLF and WKYMVm suggests that N-formyl peptide receptor (FPR) is shared by these peptides. However, the neutrophil response induced by the WKYMVm peptide was insensitive to the fMLF antagonists, cyclosporin H, and Boc-FLFLF that specifically block the function of the FPR. These results suggest that even though WKYMVm may bind FPR the cells are activated preferentially through a receptor distinct from the FPR. Using transfected HL-60 cells expressing either the FPR or its neutrophil homologue FPRL1, also referred to as LXA(4)R because it has been shown to bind lipoxin A(4), we show that WKYMVm is about 300-fold more active at mobilizing intracellular calcium through FPRL1 than through FPR. The WKYMVm activates FPRL1-expressing cells in a cyclosporin H-independent manner with an EC(50 )of around 75 pmol/L, whereas it activates FPR-expressing cells with an EC(50 )of around 25 nmol/L. The observation that exudated cells are primed in their response to WKYMVm suggests that FPRL1/LXA(4)R like FPR is stored in mobilizable organelles. (Blood. 2000;95:1810-1818)

Human complement 5a (C5a) anaphylatoxin receptor (CD88) phosphorylation sites and their specific role in receptor phosphorylation and attenuation of G protein-mediated responses. Desensitization of C5a receptor controls superoxide production but not receptor sequestration in HL-60 cells

Upon agonist binding, the anaphylatoxin human complement 5a receptor (C5aR) has previously been found to be phosphorylated on the six serine residues of its carboxyl-terminal tail (Giannini, E., Brouchon, L., and Boulay, F. (1995) J. Biol. Chem. 270, 19166-19172). To evaluate the precise roles that specific phosphorylation sites may play in receptor signaling, a series of mutants were expressed transiently in COS-7 cells and stably in the physiologically relevant myeloid HL-60 cells. Ser(334) was found to be a key residue that controls receptor phosphorylation. Phosphorylation of either of two serine pairs, namely Ser(332) and Ser(334) or Ser(334) and Ser(338), was critical for the phosphorylation of C5aR and its subsequent desensitization. Full phosphorylation and desensitization of C5aR were obtained when these serines were replaced by aspartic acid residues. The mutation S338A had no marked effect on the agonist-mediated phosphorylation of C5aR, but it allowed a sustained C5a-evoked calcium mobilization in HL-60 cells. These findings and the ability of the S314A/S317A/S327A/S332A mutant receptor to undergo desensitization indicate that the phosphorylation of Ser(334) and Ser(338) is critical and sufficient for C5aR desensitization. The lack of phosphorylation was found to result not only in a sustained calcium mobilization and extracellular signal-regulated kinase 2 activity but also in the enhancement of the C5a-mediated respiratory burst in neutrophil-like HL-60 cells. For instance, the nonphosphorylatable S332A/S334A mutant receptor triggered a 1.8-2-fold higher production of superoxide as compared with the wild-type receptor. Interestingly, although the desensitization of this mutant was defective, it was sequestered with the same time course and the same efficiency as the wild-type receptor. Thus, in myeloid HL-60 cells, desensitization and sequestration of C5aR appear to occur through divergent molecular mechanisms.

Seasonal variation in chronic heart failure hospitalizations and mortality in France

BACKGROUND

Circannual variation in blood pressure and in the incidence of acute myocardial infarction is well known but has not been investigated in chronic heart failure. This report describes and compares the seasonal variation of chronic heart failure hospitalizations and mortality in the French population.

METHODS AND RESULTS

All deaths that occurred among French adults over the period 1992 to 1996 (n=138 602) and all discharges by adults in French public hospitals for chronic heart failure over the period 1995 to 1997 (n=324 013) were examined retrospectively. First, chronic heart failure deaths in France occurred with a striking annual periodicity and peaked in winter (December through January), both in the overall population and in subgroups defined by age (>44 years old) and sex. The distribution of cumulative monthly deaths differed by nearly 35%, ranging from a peak of 20% above average in January to 15% below average in August (Roger's test: P<0.001). Second, hospitalizations for chronic heart failure in French public hospitals followed a similar seasonal pattern (P<0.001), with a winter-spring predominance (+7% to +10% from December through April). Third, for persons >/=85 years old, excess hospitalizations occurred earlier in the year, with marked synchronized peaks in January for both mortality and hospitalizations (P<0.001).

CONCLUSIONS

Clear seasonal variations in adult chronic heart failure hospitalizations and deaths were identified. The considerable economic impact on health care services warrants further epidemiological investigations and a more comprehensive approach to disease management.

Selection of a C5a receptor antagonist from phage libraries attenuating the inflammatory response in immune complex disease and ischemia/reperfusion injury

A C5a-receptor antagonist was selected from human C5a phage display libraries in which the C terminus of des-Arg74-hC5a was mutated. The selected molecule is a competitive C5a receptor antagonist in vitro and in vivo. Signal transduction is interrupted at the level of G-protein activation. In addition, the antagonist does not cause any C5a receptor phosphorylation. Proinflammatory properties such as chemotaxis or lysosomal enzyme release of differentiated U937 cells, as well as C5a-induced changes in intracellular Ca2+ concentration of murine peritoneal macrophages, are inhibited. The in vivo efficacy was evaluated in three different animal models of immune complex diseases in mice, i.e., the reverse passive Arthus reaction in the peritoneum, skin, and lung. The i.v. application of the C5a receptor antagonist abrogated polymorphonuclear neutrophil accumulation in peritoneum and markedly attenuated polymorphonuclear neutrophil migration into the skin and the lung. In a model of intestinal ischemia/reperfusion injury, i.v. administration of the C5a receptor antagonist decreased local and remote tissue injury: bowel wall edema and hemorrhage as well as pulmonary microvascular dysfunction. These data give evidence that C5a is an important mediator triggering the inflammatory sequelae seen in immune complex diseases and ischemia/reperfusion injury. The selected C5a receptor antagonist may prove useful to attenuate the inflammatory response in these disorders.

Overexpression of wild-type and catalytically inactive forms of GRK2 and GRK6 fails to alter the agonist-induced phosphorylation of the C5a receptor (CD88): evidence that GRK6 is autophosphorylated in COS-7 cells

The G protein-coupled receptor kinase family comprises six members (GRK1 to GRK6) that phosphorylate and desensitize a number of agonist-occupied G protein-coupled receptors. Overexpression of the dominant negative mutant GRK2-K220R is often accompanied by an inhibition of the agonist-mediated phosphorylation of G protein-coupled receptors. In the case of the C5a receptor (C5aR), the overexpression of wild-type GRK2 or GRK6 as well as of catalytically inactive forms of these kinases (GRK2-K220R and GRK6-K215R) failed to increase or to inhibit the agonist-mediated phosphorylation of C5aR, respectively. Replacement of Lys215 by an arginine residue in GRK6 yielded a protein with a relative molecular mass of 63 kDa, whereas wild-type GRK6 had a relative molecular mass of 66 kDa on polyacrylamide gel. The mutations S484D and T485D in the catalytically inactive mutant GRK6-K215R resulted in a protein (GRK6-RDD) with the same electrophoretic mobility as wild-type GRK6. Furthermore, in the absence of phosphatase inhibitors, GRK6 was rapidly converted into the 63 kDa species, whereas GRK6-RDD was not. Overepression of GRK6-RDD failed to alter the agonist-mediated phosphorylation of C5aR. Taken together, the results suggest that C5aR is not a substrate for either GRK2 or GRK6 and that GRK6 is very likely autophosphorylated on Ser484 and Thr485 in vivo.

Isolation and characterization of a variant HL60 cell line defective in the activation of the NADPH oxidase by phorbol myristate acetate

Promyelocytic human leukemia HL60 cells can be differentiated into neutrophil-like cells that exhibit an NADPH oxidase activity through direct stimulation of protein kinase C (PKC) with PMA or through formyl peptide receptor activation. We have isolated a variant HL60 clone that exhibited a conditional PMA-induced oxidative response depending on the agent used for the differentiation. While cells differentiated with DMSO responded to either PMA or N-formyl peptide (N-formyl-Met-Leu-Phe-Lys or fMLFK), cells differentiated with dibutyryl-cAMP (Bt2cAMP) responded to fMLFK but very poorly to PMA. However, in Bt2cAMP-differentiated cells, the expression of the different PKC isoforms was similar to that observed in DMSO-differentiated cells. Moreover, PMA was able to induce a normal phosphorylation of the cytosolic factor p47phox and to fully activate extracellular signal-regulated kinases (Erk1/2). Interestingly, Bt2cAMP-differentiated cells exhibited a strong and sustained O2- production when costimulated with PMA and suboptimal concentrations of fMLFK which were, per se, ineffective. This sustained response was only slightly reduced by the conjunction of the mitogen-activated protein (MAP) kinase kinase (MEK) inhibitor PD98059 and wortmannin, a phosphatidylinositol-3 kinase (PI3K) inhibitor. Variant HL60 cells that were stably transfected with a constitutively active form of Rac1 were able, when differentiated with Bt2cAMP, to secrete oxidant following PMA stimulation. Altogether, the results suggest that, in addition to the phosphorylation of p47phox, the activation of NADPH oxidase requires the activation of a Rac protein through a pathway that diverges at a point upstream of MEK and that is independent of the activation of wortmannin sensitive PI3K.

[Data interchange in blood transfusion: the impact of a new standard on the evolution of health electronic data exchange in France]

The sanitary and social data interchange within care establishments or networks is today the subject of many national or international considerations. Electronic data interchange in the health field has characteristics linked to ethical and deontological principles of care staff. Used daily, this tool contributes to the quality of care, to the optimization of patient treatment and to the organization of the system care. In the transfusion field, the standardization of messages related to the traceability of blood products in now required by the No. 2 instruction of French Blood Agency, which rules the using of national norms elaborated by the French Agency of Normalization. If the technicality is the greater part of these regulated and formalized messages, this standardization systematizes and justifies the nominative and ciphered data interchange in an open environment, opening a new dimension in the interoperability of data system between care establishments. This article analyzes the characteristics and the potential impact of this normalization on the evolution of the electronic data interchange in the health field.

[Should occupational medicine physicians be linked to future computerized medical record networks?]

Upcoming reforms of the health care system place high expectations on computerized medical file networks to control medical expenditures. In France, information flow from the care delivery sector to the occupational medicine sector is often slow or incomplete. Company and social security expenditures or dysfunctions as well as patient incomfort may result. An analysis of occupational medicine practices and the needs of physicians working in this sector leads to several perspective proposals for improvement including access to future computerized medical file networks and the health data card Sesame.

Broad immunocytochemical localization of the formylpeptide receptor in human organs, tissues, and cells

The formylpeptide receptor (FPR), previously found only on polymorphonuclear leukocytes and monocytes/macrophages, responds to both synthetic N-formyl oligopeptides and those produced by bacteria. The cDNA for human FPR has been cloned and a rabbit polyclonal antiserum directed against a synthetic 11-amino-acid peptide corresponding to the deduced carboxy-terminus has been produced. We have now extensively characterized and used the antibody to detect FPR on normal human tissues and cell types. The receptor antigen is present on some epithelial cells, especially those with a secretory function, and on some endocrine cells, e.g., follicular cells of the thyroid and cortical cells of the adrenal. Liver hepatocytes and Kupffer cells are positive. Smooth muscle and endothelial cells are also generally positive. In the brain and spinal cord, the neurons of the motor, sensory, and cerebellar systems, and those of the parasympathetic and sympathetic systems stain positively. These data suggest that the putative endogenous agonist for FPR or an antigenically similar receptor reacts with cellular targets in the neuromuscular, vascular, endocrine, and immune systems.

[A method for auditing medical records quality: audit of 467 medical records within the framework of the medical information systems project quality control]

Future hospital accreditation could take into account the quality of medical files. The objectives of this study is to test a method for auditing and evaluating the quality of the handing of medical files. We conducted a retrospective regional audit based on the frame of reference the National Agency for Medical Development and Evaluation, by using a sample of cases, stratified by establishment. In our region, the global budgets of 47 public and private hospitals participating in the public hospital service, are adjusted while keeping in mind the medicalised activity data (PMSI). This audit was proposed to the doctors of the Department of Medical Information on the occasion of the regulatory PMSI quality control. A total of 467 questionnaires were given by 39 of the 47 sollicited hospitals (83%). The methodological aspects (questionnaire, cooperative approach...) are discussed. The make-up of medical files can alos be improved by raising the percentage of the presence of important data or documents such as the reason for admission (74.1%), the surgery report (83.2%), and the hospitalisation report (66.6%). A system for classifying the paraclinical results is shared and systematic throughout the service or hospital in only 73.2% of cases. The quality of the handing of medical files seems problematic in our hospitals and actions for improving the quality should be undertaken as a priority.

[Can medical files be used to audit hospital health care? Results of a regional audit of hospital file quality]

OBJECTIVES

The clinical audit method based on a retrospective analysis of medical files can be used to assess hospital health care. The reliability of the results obtained depends on the validity of the data in the file and its completeness. The aim of this work was to assess the quality of this information source.

METHODS

The simplified ANDEM/ANAES from was proposed to 47 medical information departments of public and private hospitals participating in the public health care service in the Provence-Alples-Côte d'Azur region. The audit was conducted on a sample of hospital stays during a regular 6-month quality control assessment of hospital health care activity.

RESULTS

Analysis of the 467 forms returned by 39 hospitals, showed that the quality of medical file recordings should be improved as a large amount of data or important documents were missing: reason for hospitalization (recorded on 74.1% of files), operation report (found in 83.2% of files) and discharge summary (found in 66.6% of files).

CONCLUSION

Clinical audits would be compromised in certain hospitals by the use of medical files. Efforts to improve the quality of hospital medical files should be a priority.

Phagocyte chemoattractant receptors

Myeloid cells are attracted and activated by a variety of chemoattractants that bind to G protein-coupled receptors. In the past few years, the receptors for the classical chemoattractants (fMLF, C5a, PAF) and the chemotactic cytokines, known as C-X-C and C-C chemokines, have been cloned from myeloid cells. This review briefly describes recent advances in structure-function relationships of chemotactic receptors in human leukocytes as well as activation of signaling pathways and regulation of receptor function. In neutrophils, the binding of chemoattractants mainly activates the Gi2 protein inducing PIP2 hydrolysis and activation of the MAP kinase pathway. The C-C chemokine receptor, CC CKR5, and a chemokine receptor homologue, named fusin, have been shown to be the major cofactors for HIV-1 entry in macrophages and T cells. Recent studies suggest that the phosphorylation of chemoattractant receptors is a key event that regulates their biological function.

Internalization and recycling of the C5a anaphylatoxin receptor: evidence that the agonist-mediated internalization is modulated by phosphorylation of the C-terminal domain

The C5a anaphylatoxin receptor is a member of the G protein-coupled receptor family involved in chemoattraction and activation of myeloid cells, as well as in host defence against infection by Pseudomonas aeruginosa. Upon challenge by C5a, the C5a receptor undergoes a rapid phosphorylation on serine residues in the carboxyl-terminal region. In this study, we used cells stably transfected with either the wild-type C5a receptor, or mutants affected in their capacity to be phosphorylated, to examine the role played by phosphorylation in the intracellular trafficking of the C5a receptor. Upon agonist binding, the wild-type receptor was rapidly internalized into endosomes that cluster near the nucleus after 10 minutes. Internalization of a non-phosphorylable mutant was severely impaired relative to wild-type receptor, whereas a mutant phos-phorylated on serine 327 and/or serine 338, showed a rate of internalization intermediate between that of wild-type receptor and that of the non-phosphorylable mutant. Under continuous exposure to C5a and in the absence of protein synthesis, the C5a receptor was maintained in a highly phosphorylated state but was not degraded. Confocal microscopy and ligand-binding studies indicated that internalized receptors were recycled to the plasma membrane. During this process, receptors were dephosphorylated with kinetics that correlated with the kinetics of receptor recovery on the cell surface. Altogether, our data suggest that phosphorylation plays a key role in the intracellular trafficking of the C5a receptor. Phosphoryl-ated receptors might be recognized by an adaptor protein that interacts with the endocytic machinery.

[Public health education integrated in hospital. An internship proposal, "Medical information and pharmacology"]

According to a recent circular reforming french medical studies, we propose a teaching of medical information and pharmacology in situ within hospital instructions. Students could acquire an investigation methodology on the medicine economy. It will cover in four sessions the succeeding stages of medical information processing and be subject to an assessment: case studies and appreciation on student's, instruction record. By combining public health teaching with clinical practice, our project promotes its development in contact with other learnings and activities such as clinical research.

Direct or C5a-induced activation of heterotrimeric Gi2 proteins in human neutrophils is associated with interaction between formyl peptide receptors and the cytoskeleton

The binding of ligands to N-formyl peptide chemoattractant receptors in human neutrophils results in a rapid association of these receptors with a cytoskeletal fraction and a specific activation and release of Gi2 alpha-subunits from this fraction. In the present study we could show that pretreating neutrophils with GDPbetaS prevented the fMet-Leu-Phe-induced association of its receptor with a cytoskeletal fraction and also blocked the release of Gi2 alpha-subunits from the same cytoskeletal fraction. In contrast, direct activation of Gi2 proteins by addition of GTPgammaS or AlF4- not only caused a release of Gi2 alpha-subunits from the cytoskeleton but also an association of formyl peptide receptors with the cytoskeleton. The receptor for complement fragment 5a, which transduces its signaling through the same Gi2 protein, triggers both a release of Gi2 alpha-subunits from the cytoskeleton fraction and, of even greater interest, an association between formyl peptide receptors and the cytoskeleton. The close relationship between the activation and release of Gi2 alpha-subunits from the cytoskeleton and the association of formyl peptide receptors with the cytoskeleton might, however, not be a matter of protein-protein exchange, since the increased binding of formyl peptide receptors to the cytoskeleton occurs more rapidly than the release of Gi2 alpha-subunits from the cytoskeleton. The present findings suggest a possible mechanism for the initiation of formyl peptide receptor desensitization during neutrophil locomotion.

Site-directed mutagenesis of conserved charged residues in the helical region of the human C5a receptor. Arg2O6 determines high-affinity binding sites of C5a receptor

The human C5a receptor (C5aR) belongs to the family of G-protein-coupled receptors with seven transmembrane helices. This part of the molecule is thought to contain part of the ligand-binding pocket, specifically to bind the C-terminal Arg of human C5a. Guided by sequence similarity and molecular modelling studies, several residues including polar (Asn119, Thr168, Gln259) as well as all conserved charged amino acids in the upper transmembrane region of the C5aR (Asp37, Asp82, Arg175, Arg2O6, Asp282) were exchanged by site-directed mutagenesis. Receptor mutants were transiently expressed in COS cells and analyzed for altered binding behaviour and/or localization at the cell surface by immunofluorescence. For all residues, suitable mutants could be found that exhibited wild-type affinity towards the ligand, providing evidence against a major contribution of these residues to high-affinity ligand binding. Some mutants, however, exhibited a complete (Asp282-->Ala) or partial loss of ligand-binding capacity (Arg175-->Ala, Arg2O6-->Gln) despite adequate expression levels on the cell surface. This phenotype was further analyzed in the [Gln2O6]C5aR mutant: quantitative flow cytometric analysis of epitope-tagged receptor derivatives in 293 cells confirmed an equal level of wild-type and mutant C5aR on the cell surface. Competitive binding curves revealed the presence of only a small population (<10%) of high-affinity sites (Kd approximately 2 nM), which was functionally active at 20 nM in the heterologous Xenopus oocyte expression system after coexpression of G alpha-16. The number of high-affinity sites of wild-type and [Gln2O6]C5aR in 293 cells could be up-regulated by coexpression of Gi alpha-2 and down-regulated by GTP[gamma S]-mediated uncoupling of the G-protein receptor interaction in membrane preparations. These findings are compatible with a model in which the Arg2O6 residue located in the upper third of transmembrane helix V determines high-affinity binding in the human C5aR by affecting the intracellular G-protein coupling.

Identification of the major phosphorylation sites in human C5a anaphylatoxin receptor in vivo

Interaction of human C5a anaphylatoxin with cell surface receptors mediates cell activation and receptor desensitization. Treatment of differentiated HL60 cells or transiently transfected COS-7 cells with C5a or phorbol 12-myristate 12-acetate (PMA) results in rapid hyperphosphorylation of the C5aR. In an attempt to gain more insight into the function of phosphorylation in the desensitization of C5aR, we have initiated experiments to identify phosphoacceptor sites at the amino acid level after stimulation of cells with either C5a or PMA. In this report we show that C5aR is phosphorylated exclusively on serine residues in both differentiated HL60 and transfected COS-7 cells irrespective of the stimulus used. Peptide mapping after cyanogen bromide cleavage of phosphorylated C5aR indicates that despite the presence of a protein kinase C consensus motif the third cytoplasmic loop is not phosphorylated when cells are challenged with either C5a or PMA. Thus, whether the cells are stimulated with C5a or PMA, the phosphorylation sites appear to be restricted to serine residues in the carboxyl tail. Phosphoamino acid analysis of a series of mutants in which an individual serine residue was replaced by a threonine residue indicates that the C5aR undergoes C5a-dependent phosphorylation to the maximal stoichiometry of 6 mol of PO4/mol of receptor at Ser314, Ser317, Ser327, Ser332, Ser334, and Ser338. Simultaneous substitution of serine residues by alanine at positions 332, 334, and 338 affected neither the binding of C5a nor the cell surface expression of the mutant, but resulted in a dramatic reduction (more than 80%) of both C5a- and PMA-mediated phosphorylation as compared to the wild type receptor. This result suggests that phosphorylation on the segment extending from Ser332 to Ser338 is required for the subsequent phosphorylation of the carboxyl-terminal tail of C5aR.

Phosphorylation, dephosphorylation, and recycling of the C5a receptor in differentiated HL60 cells

Binding of activation peptide from the fifth component of C (C5a) to its receptor triggers events leading to both stimulation of cellular responses and receptor desensitization in myeloid cells. However, although transmission of a signal to pertussis toxin-sensitive G proteins is a prerequisite to neutrophil activation, we show that the process of receptor phosphorylation is mainly independent from activation of this pathway. Treatment of cells with pertussis toxin did not modify the incorporation of phosphate mediated by a saturating concentration of C5a, indicating that agonist-occupied C5aR can be fully phosphorylated, presumably by a specific G protein-coupled receptor kinase, in the absence of activation of the Gi protein. Receptor phosphorylation was transient, with a half-life of 30 to 40 min, which suggested a role for protein phosphatases in the regulation of the state of phosphorylation of C5aR in dHL60 cells. Pretreatment of cells with okadaic acid, an inhibitor of protein phosphatases 1 and 2A, increased the basal phosphorylation of unoccupied receptor and extended the phosphorylation mediated by C5a binding. Okadaic acid delayed, but did not suppress, the dephosphorylation process, which suggests either the involvement of additional phosphatase(s) or the degradation of nondephosphorylated receptors in the endocytic pathway. The data strongly suggest that internalized C5aR are recycled to the plasma membrane with a time course consistent with the kinetics of dephosphorylation. Dephosphorylation of C5aR might be essential to receptor recycling and resensitization during chemotaxis.

Phosphorylation, dephosphorylation, and recycling of the C5a receptor in differentiated HL60 cells

Binding of activation peptide from the fifth component of C (C5a) to its receptor triggers events leading to both stimulation of cellular responses and receptor desensitization in myeloid cells. However, although transmission of a signal to pertussis toxin-sensitive G proteins is a prerequisite to neutrophil activation, we show that the process of receptor phosphorylation is mainly independent from activation of this pathway. Treatment of cells with pertussis toxin did not modify the incorporation of phosphate mediated by a saturating concentration of C5a, indicating that agonist-occupied C5aR can be fully phosphorylated, presumably by a specific G protein-coupled receptor kinase, in the absence of activation of the Gi protein. Receptor phosphorylation was transient, with a half-life of 30 to 40 min, which suggested a role for protein phosphatases in the regulation of the state of phosphorylation of C5aR in dHL60 cells. Pretreatment of cells with okadaic acid, an inhibitor of protein phosphatases 1 and 2A, increased the basal phosphorylation of unoccupied receptor and extended the phosphorylation mediated by C5a binding. Okadaic acid delayed, but did not suppress, the dephosphorylation process, which suggests either the involvement of additional phosphatase(s) or the degradation of nondephosphorylated receptors in the endocytic pathway. The data strongly suggest that internalized C5aR are recycled to the plasma membrane with a time course consistent with the kinetics of dephosphorylation. Dephosphorylation of C5aR might be essential to receptor recycling and resensitization during chemotaxis.

Regulation of cytosolic calcium and insulin secretion by galanin and ATP receptors: interactions of pertussis-toxin-sensitive and -insensitive signalling pathways

In a previous study it was found that the expression of the exogenous fMet-Leu-Phe-receptor (NFPR) in the insulin-secreting cell line RINm5F mediates inhibition of hormone release and additionally raises cytosolic calcium concentration ([Ca2+]i) by activating phospholipase C (PLC) in a pertussis-toxin (PTX)-sensitive manner. We investigated whether an endogenous receptor could elicit similar effects and examined the interaction with PTX-insensitive signalling pathways. The hormone galanin inhibited insulin release at subnanomolar concentrations and increased [Ca2+]i, mainly by a PTX-sensitive mechanism with an EC50 (50 nM) comparable with that for hyperpolarization of membrane potential. The effect of galanin or fMet-Leu-Phe on [Ca2+]i was inhibited by pre-activation of the P2-receptor by ATP, which mobilizes calcium in a PTX-insensitive fashion. Simultaneous activation of the P2- and peptide receptors caused additive increases in [Ca2+]i saturating at a calcium concentration corresponding to the optimal ATP response. This suggests a specific convergence of PTX-sensitive and -insensitive pathways. In contrast, galanin and FMLP inhibited the insulin secretion induced by ATP (1-100 microM), but only when added prior to the nucleotide. In permeabilized cells, FMLP added after the calcium stimulus still inhibited secretion, indicating that the inefficacy observed in intact cells was not due to the rapid ATP-evoked rise in [Ca2+]i. Thus, (i) insulin-secreting cells possess an endogenous PTX-sensitive pathway mobilizing [Ca2+]i, (ii) inhibitory hormones preferentially activate different effectors depending on the agonist concentration and (iii) activation of NFPR or galanin receptor reveals an unusual dissociation between [Ca2+]i rises and insulin secretion, pointing towards an overriding inhibitory control of exocytosis.

Subcellular localization and translocation of the receptor for N-formylmethionyl-leucyl-phenylalanine in human neutrophils

The subcellular localization of N-formylmethionyl-leucyl-phenylalanine (fMLP) receptors in human neutrophils was investigated. The fMLP receptor was detected with a high-affinity, photoactivatable, radioiodinated derivative of N-formyl-methionyl-leucyl-phenylalanyl-lysine (fMLFK). Neutrophils were disrupted by nitrogen cavitation and fractionated on Percoll density gradients. fMLP receptors were located in the beta-band containing gelatinase and specific granules, and in the gamma-band containing plasma membrane and secretory vesicles. Plasma membranes and secretory vesicles were separated by high-voltage free-flow electrophoresis, and secretory vesicles were demonstrated to be highly enriched in fMLP receptors. The receptors found in secretory vesicles translocated fully to the plasma membrane upon stimulation with inflammatory mediators. The receptor translocation from the beta-band indicated that the receptor present there was mainly located in gelatinase granules. A 25 kDa fMLP-binding protein was found in the beta-band. Immunoprecipitation revealed that this protein was identical with NGAL (neutrophil gelatinase-associated lipocalin), a novel protein found in specific granules. In summary, we demonstrate that the compartment in human neutrophils that is mobilized most easily and fastest, the secretory vesicle, is a major reservoir of fMLP receptors. This explains the prompt and extensive upregulation of fMLP receptors on the neutrophil surface in response to inflammatory stimuli.

The NH2-terminal region of C5aR but not that of FPR is critical for both protein transport and ligand binding

The N-formylated tripeptide, formylmethionylleucyl-phenylalanine (fMLP), and the 74-amino-acid long human C5a anaphylatoxin activate phagocytic cells via two structurally related G protein-coupled receptors (FPR and C5aR), which are 34% identical in amino acid sequence. C5aR chimeras were constructed in which the entire NH2-terminal extracellular sequence or part of it was replaced by the counterparts from FPR or FPRH. Although the NH2-terminal region of C5aR presents an extremely high interspecies variability, substitution of the entire NH2-terminal sequence of C5aR by that of FPR or FPRH surprisingly resulted in chimeras that were apparently retained in the endoplasmic reticulum. In contrast, when the NH2-terminal domain of FPR was replaced by the corresponding region from C5aR or FPRH normal expression to the plasma membrane and high affinity binding of N-formylated peptides were observed. Thus, the NH2-terminal region of C5aR, in contradistinction to that of FPR, seems to be required either for the translocation of C5aR through the ER membrane or for correct folding and sorting of C5aR to the plasma membrane. Replacement of the first 8 residues of C5aR by the corresponding region of FPR did not alter the cellular transport and the C5a binding capacity, whereas the exchange of the first 13 residues resulted in a chimera that was readily transported to the plasma membrane but showed no capability to bind C5a. Mutations of Asp into Asn in the NH2-terminal segment of C5aR further indicated that negative charges are required to endow the receptor with a C5a binding capacity. The residues critical for binding are either involved directly by interacting with cationic residues of C5a, or indirectly by influencing the overall structure of the ligand-binding site.

Evidence that the extracellular N-terminal domain of C5aR contains amino-acid residues crucial for C5a binding

The human C5a anaphylatoxin is a cationic 74 amino-acid long glycopeptide which derives from proteolysis of the fifth component of complement. It interacts with high affinity with a receptor that belongs to the G protein-coupled receptor superfamily. Several studies have previously suggested that multiple contact points between C5a and the receptor are required to achieve high-affinity interaction. However, at the receptor level little is known about the sites of interaction with C5a. We have investigated by in vitro mutagenesis whether the N-terminal extracellular sequence of the C5a receptor, which is rich in aspartic acid residues, could play some role in C5a binding. Conversion of Asp10 into asparagine did not impair the level of expression at the plasma membrane, nor did it alter the affinity for C5a. However, we consistently observed a discrepancy between an apparent high level of surface expression and a weak capacity to bind C5a with high affinity, suggesting that many receptor molecules, although present on the cell surface, might be misfolded and unable to bind C5a. Replacement of Pro9 by an isoleucine had little effect, if any, on either the affinity or the C5a-binding capacity, whereas the conversion of Pro36 into leucine dramatically reduced the expression of high-affinity receptor at the cell surface. N-glycosylation of human C5a receptor was found to be dispensable for the function of the receptor.

Expression of transcripts for two interleukin 8 receptors in human phagocytes, lymphocytes and melanoma cells

Two cDNAs coding for distinct interleukin 8 (IL-8) receptors, IL-8R1 [Murphy and Tiffany (1991) Science 253, 1280-1283] and IL-8R2 [Holmes, Lee, Kuang, Rice and Wood (1991) Science 253, 1278-1280] have been reported, and biochemical studies on human neutrophils have revealed two proteins (p70 and p44) that bind IL-8 with high affinity [Moser, Schumacher, von Tscharner, Clark-Lewis and Baggiolini (1991), J. Biol. Chem. 266, 10666-10671]. We have cloned the cDNA coding for IL-8R1 from a library of differentiated HL-60 cells. Transfection of this cDNA into Jurkat cells resulted in the expression of high-affinity binding for IL-8 and two related cytokines, GRO alpha and neutrophil-activating peptide 2 (Kd 0.5-1.0 nM). Northern-blot analysis with the IL-8R1 cDNA as probe revealed abundant expression of transcripts of different size in human neutrophils and low-level expression of a single RNA species in HL-60 cells differentiated with dimethyl sulphoxide and retinoic acid. Because of the extensive nucleotide sequence similarity of the cDNAs for IL-8R1 and IL-8R2, the reverse-transcription PCR method was used for analysis of RNA expression in myeloid and lymphoid cells, 19 cell lines established from human primary melanomas or metastases, two melanocyte and one fibroblast cell lines. IL-8R1 mRNA transcripts were expressed at high levels in neutrophils, and to a lesser extent in blood monocytes and the myeloid cell lines, HL-60 and AML 193, but were not found in THP-1 cells, lymphocytes and Jurkat cells. IL-8R2 mRNA transcripts, by contrast, were found in all blood cells and related cell lines, as well as in all melanoma, melanocyte and fibroblast cell lines tested. As for IL-8R1, IL-8R2 mRNA expression was highest in neutrophils. These results suggest that IL-8R1 and IL-8R2 may both be involved in neutrophil activation by IL-8 and related cytokines, and presumably correspond to p70 and p44, the receptors that were identified biochemically. Possible IL-8 functions on lymphocytes and melanoma cells, e.g. chemotaxis and proliferation, must be independent of IL-8R1 and may be mediated by IL-8R2.

Activation of neutrophil leukocytes: chemoattractant receptors and respiratory burst

The human organism survives the constant attack by bacteria and other pathogens thanks to the surveillance function of the neutrophil leukocytes. At sites of infection, several messenger molecules are generated that attract neutrophils from the blood and direct their migration toward the microbes, a process termed chemotaxis. Neutrophils sense chemotactic agonists through a group of closely related, GTP-binding protein-coupled receptors. Several of these have been recently cloned and shown to belong to the superfamily of rhodopsin-like, seven-transmembrane-domain receptors. At the site of infection, the neutrophils engulf and kill the invading microbes. This critical function depends on the production of superoxide and related radicals by a tightly regulated, membrane-bound NADPH oxidase that is activated by chemotactic agonists and other inflammatory stimuli. The characteristics of the receptors as well as new insights into the mechanism of activation of the superoxide-forming oxidase as presented at a recent FASEB meeting symposium are reviewed.

Conserved transducer coupling but different effector linkage upon expression of the myeloid fMet-Leu-Phe receptor in insulin secreting cells

In neutrophils fMet-Leu-Phe activates phospholipase C via a pertussis toxin sensitive G-protein and induces granule secretion. We have transfected a human cDNA sequence encoding the fMet-Leu-Phe receptor into the insulin secreting cell line RINm5F to study receptor-effector coupling with special regard to secretion. Stable overexpression resulted in membrane hyperpolarization, reduction of cAMP accumulation and inhibition of insulin secretion upon exposure of cells to fMet-Leu-Phe with EC50 values in the pmol range. As in the neutrophil, nanomolar concentrations of ligand induced membrane depolarization and activation of phospholipase C, with subsequent mobilization and influx of calcium. In permeabilized cells the inhibitory effect of fMet-Leu-Phe on secretion was partially retained indicating a direct action of the fMet-Leu-Phe receptor on exocytosis. Pertussis toxin abolished the effects of fMet-Leu-Phe. Our results suggest conserved coupling from fMet-Leu-Phe receptor to pertussis toxin sensitive transducers analogous to the mechanism in neutrophils. However, the net biological effect of receptor activation is determined by additional factors intrinsic to the host cell.

Agonist-dependent phosphorylation of N-formylpeptide and activation peptide from the fifth component of C (C5a) chemoattractant receptors in differentiated HL60 cells

Attenuation of signaling is a key step in controlling the cytotoxic potential of leukocyte responses to chemotactic factors. Antipeptide antibodies, directed against the N-formyl chemotactic peptide receptor (FPR) and the activation peptide from the fifth component of C (C5a) anaphylatoxin receptor (C5aR) of human neutrophils, were used to analyze the ability of these receptors to be phosphorylated. Our data show that, in granulocyte-like differentiated HL-60 cells, both FPR and C5aR undergo an agonist dose-dependent phosphorylation that reaches completion in less than 2 to 3 min, consistent with the rate and the dose-dependent attenuation of signaling in phagocytes. Therefore, phosphorylation might be one of the possible mechanisms involved in the desensitization process of FPR and C5aR. Addition of either C5a or the protein kinase C activator (PMA) did not appear to induce the phosphorylation of FPR in the absence of FMLP or to modulate the phosphorylation of the latter at low concentrations of agonist. In contrast, although FMLP at a saturating concentration barely stimulated the phosphorylation of unoccupied C5aR, it markedly potentiated C5aR phosphorylation in cells exposed to low concentrations of C5a. Moreover, PMA was able to induce C5aR phosphorylation in the absence of agonist, indicating that protein kinase C or protein kinase C-activated kinase(s) could be involved in the phosphorylation of C5aR. Pretreatment of cells with staurosporine, a potent but nonspecific inhibitor of protein kinase C, resulted in the partial inhibition of both FPR and C5aR phosphorylation induced by saturating concentrations of agonist, suggesting that a kinase different from protein kinase C might be mainly responsible for the phosphorylation of these chemotactic receptors.

Agonist-dependent phosphorylation of N-formylpeptide and activation peptide from the fifth component of C (C5a) chemoattractant receptors in differentiated HL60 cells

Attenuation of signaling is a key step in controlling the cytotoxic potential of leukocyte responses to chemotactic factors. Antipeptide antibodies, directed against the N-formyl chemotactic peptide receptor (FPR) and the activation peptide from the fifth component of C (C5a) anaphylatoxin receptor (C5aR) of human neutrophils, were used to analyze the ability of these receptors to be phosphorylated. Our data show that, in granulocyte-like differentiated HL-60 cells, both FPR and C5aR undergo an agonist dose-dependent phosphorylation that reaches completion in less than 2 to 3 min, consistent with the rate and the dose-dependent attenuation of signaling in phagocytes. Therefore, phosphorylation might be one of the possible mechanisms involved in the desensitization process of FPR and C5aR. Addition of either C5a or the protein kinase C activator (PMA) did not appear to induce the phosphorylation of FPR in the absence of FMLP or to modulate the phosphorylation of the latter at low concentrations of agonist. In contrast, although FMLP at a saturating concentration barely stimulated the phosphorylation of unoccupied C5aR, it markedly potentiated C5aR phosphorylation in cells exposed to low concentrations of C5a. Moreover, PMA was able to induce C5aR phosphorylation in the absence of agonist, indicating that protein kinase C or protein kinase C-activated kinase(s) could be involved in the phosphorylation of C5aR. Pretreatment of cells with staurosporine, a potent but nonspecific inhibitor of protein kinase C, resulted in the partial inhibition of both FPR and C5aR phosphorylation induced by saturating concentrations of agonist, suggesting that a kinase different from protein kinase C might be mainly responsible for the phosphorylation of these chemotactic receptors.

Modulation of human neutrophil function by fibronectin degradation products isolated from cryoglobulins

The proteolytic fragments of native fibronectin (cryopeptides) complexed to pathological immunoglobulins in cryoglobulins were isolated from the serum of six different patients. Two peptides of 117,000 daltons and 70,000 daltons were purified and characterized by N-terminal amino acid sequencing. The priming effect of the mixture of these two peptides, referred to as cryopeptides, on neutrophil functions, namely the respiratory burst, exocytosis, and Ca2+ release, was investigated. Cryopeptides and cryoglobulins assayed separately did not increase neutrophil respiration or cytosol free calcium concentration; however, both of them induced granule enzyme secretion. Sequential exposure of neutrophils to either cryopeptides or the respective cryoglobulins, and then to N-formyl-methionyl-leucyl-phenylalanine or serum opsonized zymosan, resulted in a synergistic stimulation of O2 uptake compared to the effect of N-formyl-peptides or opsonized zymosan tested separately; Ca2+ release was significantly enhanced by the pretreatment of neutrophils with cryopeptides. These data suggest that cryopeptides and cryoglobulins may play a role in host defense against bacterial infections through neutrophil activation.

European strategies for training in health information systems

The Committee of Ministers of the Council of Europe recently adopted a recommendation on training strategies for health information systems. The main elements were: specific adaptation of training both to the wider health care setting and to the individual work situation; training provided on a multidisciplinary basis; involvement of local health care, educational, research and commercial establishments; setting up of a network of reference centres to facilitate rapid exchange and harmonisation at national and European levels.

Expression cloning of a receptor for C5a anaphylatoxin on differentiated HL-60 cells

A cDNA clone encoding the human C5a anaphylatoxin receptor has been isolated by expression cloning from a CDM8 expression library prepared from mRNA of human myeloid HL-60 cells differentiated to the granulocyte phenotype with dibutyryladenosine cyclic monophosphate. The cDNA clone was able to transfer to COS-7 cells the capacity to specifically bind iodinated human recombinant C5a. The cDNA was 2.3 kb long, with an open reading frame encoding a 350-residue polypeptide. Cross-linking of iodinated C5a to the plasma membrane of transfected COS cells revealed a complex with an apparent molecular mass of 52-55 kDa, similar to that observed for the constitutively expressed receptor in differentiated HL-60 cells or human neutrophils. Although differentiated HL-60 cells display a single class of binding sites, with a dissociation constant of approximately 800-900 pM, the C5a-R cDNA, expressed in COS cells, generates both high-affinity (1.7 nM) and low-affinity (20-25 nM) receptors. Sequence comparison established that the degree of sequence identity between the C5a receptor and the N-formylpeptide receptor is 34%.

The human N-formylpeptide receptor. Characterization of two cDNA isolates and evidence for a new subfamily of G-protein-coupled receptors

Two variants of the human N-formylpeptide chemoattractant receptor have been isolated from a CDM8 expression library prepared from mRNA of human myeloid HL-60 cells differentiated to the granulocyte phenotype with Bt2cAMP. Both recombinant receptors, fMLP-R26 and fMLP-R98, are 350 amino acids long (Mr 38,420); they differ from each other by two residue changes at positions 101 and 346 and by significant differences in the 5' and 3' untranslated regions. Both clones were able to transfer to COS-7 cells the capacity to specifically bind a new and highly efficient hydrophilic derivative of N-formyl-Met-Leu-Phe-Lys, referred to as fMLPK-Pep12. Photolabeling experiments revealed that the glycosylated form of the fMLP receptor in COS cells has a molecular weight (Mr 50,000-70,000) similar to that observed for the native receptor in differentiated HL-60 cells. Northern blot analysis revealed a major transcript of 1.6-1.7 kb and two minor hybridization signals of 2.3 and 3.1 kb, suggesting a related family of receptors. The complex hybridization pattern obtained with restricted genomic DNA was consistent with either two genes encoding fMLP receptor isoforms or a single gene with at least one intron in the coding sequence. Sequence comparison established that the fMLP receptor belongs to the G-protein-coupled receptor superfamily. The structural similarities observed with RDC1, a receptor isolated from a dog thyroid cDNA library, which shares weak homologies with other members of the family, suggests that the fMLP receptor is representative of a new subfamily.