Which agonist properties are important for the activation of 5-HT3A receptors?

PURPOSE: Why do anesthetics not activate excitatory ligand-gated ion channels such as 5-HT3 receptors in contrast to inhibitory ligand-gated ion channels? This study examines the actions of structural closely-related 5-HT derivatives and 5-HT constituent parts on 5-HT3A receptors with the aim of finding simpler if not minimal agonists and thus determining requirements for successful agonist action. EXPERIMENTAL APPROACH: Responses to 5-HT derivatives of human 5-HT3A receptors stably expressed in HEK 293 cells have been examined with the patch-clamp technique in the outside-out configuration combined with a fast solution exchange system. RESULTS: Phenol, pyrrole and alkyl amines, constituents of 5-HT, even at high concentrations, cannot activate 5-HT3A receptors but they can inhibit them. To date, tyramines are the smallest known agonists. However, an aromatic ring is not required for activation as acetylcholine is also an agonist of similar strength. CONCLUSION: Simultaneous interactions of adequate strength at two separate subsites within the 5-HT binding domain appear to be essential for successful agonist function. Anesthetics either fail to achieve this or the activation they produce is so weak that it is masked by a comparatively very strong inhibition.

Shifting priorities in the aftermath of a Q fever epidemic in 2007 to 2009 in The Netherlands: from acute to chronic infection.

From 2007 to 2009, the Netherlands faced large seasonal outbreaks of Q fever, in which infected dairy goat farms were identified as the primary sources. Veterinary measures including vaccination of goats and sheep and culling of pregnant animals on infected farms seem to have brought the Q fever problem under control. However, the epidemic is expected to result in more cases of chronic Q fever among risk groups in the coming years. In the most affected area, in the south of the country, more than 12% of the population now have antibodies against Coxiella burnetii. Questions remain about the follow-up of acute Q fever patients, screening of groups at risk for chronic Q fever, screening of donors of blood and tissue, and human vaccination. There is a considerable ongoing research effort as well as enhanced veterinary and human surveillance.

Cytogenetic clonality analysis in myelodysplastic syndrome: monosomy 7 can be demonstrated in the myeloid and in the lymphoid lineage.

Bone marrow and blood from three patients with myelodysplastic syndrome (MDS) and monosomy 7 were studied for cell lineage involvement of the chromosomal abnormality. Cytogenetic involvement of the myeloid and erythroid cell lineages in MDS with monosomy 7 has been shown before. Lymphoid subpopulations have also been investigated but generally with negative results. A combined technique of May-Grünwald-Giemsa (MGG) for cell cytology and interphase fluorescence in situ hybridization (FISH) using a chromosome 7 specific DNA probe was applied. Further, immunophenotype and genotype of the cells were simultaneously examined with alkaline phosphatase anti-alkaline phosphatase (APAAP) immunostaining and FISH. The monosomy 7 was found in the blasts and in all or in subpopulations of myeloid and erythroid cells. T cells (CD3+, CD5+) did not appear to be involved. B cells (CD19+, CD22+) showed a normal distribution of FISH spots in two patients. In one patient however the loss of a chromosome 7 was found in approximately 70% of the cells positive for B cell markers including CD79a. The results of this study show that in some cases MDS is a disease arising in a progenitor cell with repopulative abilities restricted to myelopoiesis and erythropoiesis. In other cases, the pluripotent progenitor cells in MDS may show the capacities to differentiate into B lineage lymphoid cells, as well as suggesting that in those instances MDS represents a condition of more primitive transformed hematopoietic ancestor cells.

Four aged siblings with B cell chronic lymphocytic leukemia.

All four aged siblings (>80 years) of one family presented with B cell chronic lymphocytic leukemia (B-CLL). In an attempt to find common characteristics in the four patients, we performed detailed immunological marker analysis, Southern blot analysis of immunoglobulin (Ig) genes, and cytogenetic studies. In three patients clonality of the B-cells could be proven by single Ig light chain expression, but in the fourth patient no Ig light chain expression was detected and clonality of the B cells could only be demonstrated by Southern blot analysis of the Ig genes. Interestingly, in two patients, the Ig gene rearrangement patterns were compatible with the presence of two independent B cell clones, whereas in the two other siblings a monoclonal rearrangement pattern was found. All four patients showed clonal chromosome aberrations, which were different in each patient. In the two patients with biclonal Ig gene rearrangement patterns, two unrelated clones could also be demonstrated by the cytogenetic studies. These combined Ig gene and cytogenetic data indicate the presence of two different B-CLL in two of the four patients. Remarkably, the B-CLL cells of the two oldest patients expressed the CD8 antigen, which is rarely observed. Our finding of six different B-CLL in the four living siblings indicates that the members of this family are highly susceptible to the development of B-CLL. However we could not identify a common factor to explain this susceptibility further. In contrast to the literature, the occurrence of two B-CLL in one patient and the expression of CD8 were not associated with clinically aggressive disease in this family.

Induction of clinical remission in T-large granular lymphocyte leukemia with cyclosporin A, monitored by use of immunophenotyping with Vbeta antibodies.

A 54-year-old woman presented with a severe autoimmune anemia, thrombocytopenia, neutropenia (Evans' syndrome), and CD8+ lymphocytosis, without signs of lymphadenopathy or splenomegaly. A diagnosis of T cell large granular lymphocyte (T-LGL) leukemia was made, based on cytomorphology, the typical CD3+/CD4-/CD8+/CD16+/CD56-/CD57-/HLA-DR(+/-) immunophenotype of the lymphocytosis (9 x 10(9)/l), and biallelic clonally rearranged T cell receptor beta (TCR beta) genes. Clonality of the TCR alphabeta+ T-LGL was also demonstrated with a panel of antibodies against variable domains of TCR beta chains, which showed single Vbeta7.1 expression on the CD3+ T-lymphocytes. After treatment failure with corticosteroids, splenectomy, and cyclophosphamide, respectively, a complete clinical remission was induced and sustained with cyclosporin A. Vbeta7.1/CD8/CD3 triple immunofluorescence stainings appeared to be valuable for titrating the cyclosporin A dosage by monitoring the T-LGL cells during treatment.

Flow cytometric detection of intracellular antigens for immunophenotyping of normal and malignant leukocytes.

Intracellular antigens are of major importance for immunophenotyping of normal leukocytes as well as leukemias and malignant lymphomas. Immunofluorescence microscopic evaluation of cytocentrifuge preparations has remained the preferred technique for detection of intracellular antigens for a long time. Recently, flow cytometric detection of intracellular antigens has been improved by the development of new permeabilization/fixation solutions. We compared four commercially available solutions: FACS Brand Lysing Solution (FACS Brand; Becton Dickinson, San Jose, CA, USA), Fix & Perm cell permeabilization kit (Fix & Perm; An der Grub, Vienna, Austria), OptiLyse B lysing solution (OptiLyse B; Immunotech, Marseille, France), and ORTHO PermeaFix(PermeaFix; Ortho Diagnostic Systems, Raritan, NJ, USA). These solutions were evaluated for the complexity and duration of the intracellular staining procedure, the effects on light scatter patterns, and the staining results for the intracellular antigens terminal deoxynucleotidyl transferase (TdT), cytoplasmic CD3 (CyCD3), myeloperoxidase (MPO), and cytoplasmic immunoglobulin light chains (CylgL). The four methods could easily be introduced in our laboratory and had only minor effect on the light scatter patterns of the tested cell samples. Each of the four tested antigens was detectable with at least one of the four methods. Only the Fix & Perm cell permeabilization kit could be used for reliable detection of all four intracellular antigens. In a large series of 450 BM and PB samples containing various percentages of TdT+ cells, the results of flow cytometric TdT staining with FACS Brand Lysing Solution were highly comparable to the results obtained by immunofluorescence microscopy (P = <0.00001). Our comparative study shows that flow cytometric detection of the intracellular antigens TdT, CyCD3, MPO, and CylgL can now reliably be performed on a routine basis.

Use of antiviral agents and other measures in an influenza pandemic.

The Dutch Ministry of Health asked the Health Council for advice on how to prepare for a possible influenza pandemic. In two advisory reports the Committee responsible indicated the measures that it believes would need to be taken if such a pandemic were to reach the Netherlands. During a pandemic, the Committee recommends that every resident of the Netherlands with influenza-like illness should be treated with neuraminidase inhibitors such as antiviral agents. This approach serves to mitigate the course of the disease, to reduce infectivity and to allow patients to build up immunity to the virus. Since up to 30% of the population could become ill, the Committee anticipates that a stock of five million courses of the neuraminidase inhibitor oseltamivir is sufficient. If a pandemic were to occur at a time that the stock does not exceed the present 225,000 courses, the committee advises restricting treatment to three specified groups of patients. If the first few patients are traced shortly after they fall ill, the Committee recommends treatment of the patient and postexposure prophylaxis for his/her close contacts. The Committee does not advocate prophylaxis in general, but it can envisage prophylaxis for particular groups of patients or under particular circumstances. The Committee believes that in order to reduce rapid spread of the virus, schools should be closed and events where large numbers of people gather in a confined space should be cancelled. Because this recommendation would have major social and economic consequences, the Committee understands that its implication will depend on the anticipated severity and extent of the pandemic. The Committee regards vaccination against influenza as the best means of protecting the population. The development of a vaccine should be the absolute priority.

Altered specificity of alloreactive cardiac graft-infiltrating cells by prophylactic treatment with OKT3 or horse antilymphocyte globulin.

Graft-infiltrating lymphocytes from patients who were prophylactically treated with OKT3 or horse antilymphocyte globulin (H-ALG) were found to have different specificity patterns from those in the control group that received cyclosporine from the day of transplantation. This prophylactic treatment led to a significant decrease of the HLA-DR-directed cytotoxicity, while the cytolytic response against HLA-class I mismatches was hardly affected. In H-ALG patients without rejection, the percentages of class I-reactive cultures were found to be lower than in the other treatment groups, which was mainly due to a lower percentage of HLA-B--reactive cultures. In CsA and OKT3 patients, cytotoxic T cells were rather directed to HLA-B mismatches than to HLA-A antigens, while in H-ALG patients no difference in HLA-A and B-directed cytotoxicity was found. Our data suggest that OKT3 and H-ALG influence the specificity of the T cell allorepertoire, resulting in a decreased frequency of class II-specific cytotoxic T cells after transplantation. H-ALG also has a downregulating influence on the CTL response against HLA class I (HLA-B) antigens. In some patients a fast regeneration of these cells occurs, which results in a higher rejection incidence during the first posttransplant year.

Comparison of two nonculture techniques for detection of Hemophilus influenzae in sputum. In situ hybridization and immunoperoxidase staining with monoclonal antibodies.

Two nonculture methods, in situ hybridization and immunoperoxidase staining with monoclonal antibodies, were compared for the detection of Hemophilus influenzae in 184 sputa. For in situ hybridization, a biotin-labeled probe of total genomic DNA of H influenzae type b was prepared that hybridizes specifically with H influenzae, H parainfluenzae, H hemolyticus, and H parahemolyticus DNA. Immunoperoxidase staining was done with monoclonal antibody 8BD9 directed against outer membrane protein P6 of H influenzae. Both techniques detected Hemophilus in sputum equally well and were superior to culture: all 30 sputum samples culture-positive for H influenzae were positive on both nonculture tests, and 13 additional positive sputum samples were detected from which Hemophilus was not cultured. The higher sensitivity of the nonculture tests was mainly attributed to culture failure because of overgrowth of H influenzae by other bacteria, especially in patients with cystic fibrosis. The immunoperoxidase staining technique appeared slightly easier and quicker to perform than the in situ hybridization test. For the in situ DNA hybridization probe, DNA can be prepared from any strain of H influenzae. The immunoperoxidase test requires monoclonal antibody 8BD9 but has a higher specificity than the hybridization technique. Both techniques can be reliably applied, especially for the detection of Hemophilus in sputum of patients with cystic fibrosis.

Blood products and parvovirus B19.

A Committee of the Health Council of The Netherlands has expressed its opinion on introducing testing of blood products for parvovirus B19 (B19). Although infections with B19 generally run their course without any serious health problems, for some groups, such as pregnant women, patients with underlying haematological problems and patients with immunodeficiency, infections with B19 can result in serious complications. For cellular blood products, which are derived either from a single donor or a limited number of donors and are administered either to a single patient or to a limited number of patients, the Committee recommends that a risk-group approach be adopted and that 'Big-virus safe' blood products be administered to the risk groups mentioned above. The Committee defines as 'Big-virus safe' cellular blood products from a donor in which IgG antibodies against B19 have been detected in two separate blood samples, one taken at least six months after the other. Patients other than those in the risk groups should continue to receive cellular blood products that have been produced in accordance with current safety criteria. For plasma products, which are prepared from plasma pools and are administered to large numbers of patients, the measures must be aimed at cutting down the levels of B19 infectivity in such pools. For plasma pools, the Committee proposes a maximum permissible limit of 104 genome copies of Bl9 per ml.

Isolated blunt chest injury leads to transient activation of circulating neutrophils.

INTRODUCTION: The acute respiratory distress syndrome (ARDS) is a severe and frequently seen complication in multi-trauma patients. ARDS is caused by an excessive innate immune response with a clear role for neutrophils. As ARDS is more frequently seen in trauma patients with chest injury, we investigated the influence of chest injury on the systemic neutrophil response and the development of ARDS. MATERIALS AND METHODS: Thirteen patients with isolated blunt chest injury [abbreviated injury score (AIS) 2-5] were included. To avoid systemic inflammation caused by tissue damage outside the thorax, injuries to other regions than the chest did not exceed an AIS of 2. At 3, 9 and 24 h after injury, the expression of circulating activating molecules on neutrophils and levels of circulating interleukine (IL)-6 were determined. Blood samples from eight healthy volunteers were used as control. RESULTS: Blunt chest injury resulted in the activation of circulating neutrophils, as characterized by a decreased expression of l-selectin (CD62L), CXCR2 (CD182b) and C5aR (CD88) compared to control (p < 0.05). Expression of l-selectin, CXCR2 and C5aR was partially restored at 24 h after injury. In addition, the mean expression of FcγRIII (CD16) dropped (p < 0.001), indicating the recruitment of young neutrophils into the circulation. IL-6 levels increased to a maximum mean concentration of 86 ± 31 pg/ml at 24 h postinjury. None of the patients developed ARDS. CONCLUSION: Blunt chest trauma caused a systemic inflammatory reaction with transient activation of neutrophils and mobilization of young neutrophils into the circulation. Isolated chest injury, however, was not abundant enough to cause ARDS, so a second hit appears crucial.

Changes in the activities of key enzymes of glycolysis during the cell cycle in yeast: a rectification.

Activities of glycolytic enzymes were determined in elutriation fractionated cultures of Saccharomyces cerevisiae grown on different carbon sources. Almost pure fractions of single cells at the G1 state of cell division were obtained for some of the growth conditions tested, whereas other stages were enriched in particular fractions. Specific activities of glucose-6-phosphate dehydrogenase and alcohol dehydrogenase were found to be constant during the cell cycle, as reported by van Doorn et al. (1988a), Journal of Bacteriology 170, 4808-4815, and (1988b), Journal of General Microbiology 134, 785-790. In contrast to the earlier reports, the activities of hexokinase, phosphofructokinase, pyruvate kinase and trehalase were also constant in different states of the cell cycle. For hexokinase and phosphofructokinase it was shown that the apparent specific activity in a cell-free extract strongly diminished when extracts contained less that 0.5-1 mg protein ml-1. In the experiments of van Doorn et al. (1988a) the protein content of the outer fractions was up to 20 times lower than that of the central fractions, suggesting an alternative explanation for the observed changes in enzyme activities during the cell cycle. Therefore, we want to rectify the observations presented by van Doorn et al. (1988a), and conclude that the activities of the glycolytic enzymes do not vary greatly during the cell cycle of S. cervisiae.

Changes in outer membrane proteins of nontypable Haemophilus influenzae in patients with chronic obstructive pulmonary disease.

Five individual colonies of Haemophilus influenzae were isolated from each of one to three cultures of sputum collected from 18 patients with chronic obstructive pulmonary disease (COPD). The isolates were studied to investigate whether the major outer membrane proteins (MOMPs) changed during persistence. The relationship between isolates was analyzed by fingerprinting their chromosomal DNA. The fingerprints of eight strains (isolated from eight patients) with various MOMP compositions were different, whereas fingerprints of isolates with identical MOMP compositions were indistinguishable. In 12 patients, two or more strains with different MOMP compositions were found; one strain was isolated from the sputum samples of each of the six remaining patients. In seven of the 12 patients, strains with different MOMPs but with indistinguishable fingerprints were found. The differences were found in proteins b,c (five patients) and d (five patients). In patients with COPD, the MOMPs of H. influenzae are subject to changes that may enable this bacterium to escape immunological defense mechanisms.

Haemophilus influenzae infections in patients with chronic obstructive pulmonary disease despite specific antibodies in serum and sputum.

The titer and specificity of antibodies to the infecting Haemophilus influenzae was determined in sera and sputa from 27 patients with chronic obstructive pulmonary disease (COPD) to analyze the specific immune response. COPD patients had significantly higher serum IgG and IgA antibody titers than 13 healthy controls (mean IgG titers 12,302 and 5,623, respectively; mean IgA titers, 2,398 and 912; p less than 0.001). The mean IgM titers were comparable: 501 and 447, respectively. Specific IgA antibodies were also detectable in the sputum of the COPD patients (mean IgA antibody titer, 776). The local antibody production was determined by calculating the relative coefficient of excretion (RCE) to albumin. The mean RCE of 89.1 for IgA indicated statistically significant local production (p less than 0.02), in contrast to a nonsignificant increase for IgG (mean RCE of 3.6). Specific IgM was below the detection level. Immunoblotting experiments showed that the antibodies in sera from COPD patients and controls were directed against most of the outer membrane proteins of H. influenzae, with individual differences between IgG, IgA, and IgM. The IgA and IgG antibodies in serum had a similar specificity as those in sputum. The appearance or persistence of H. influenzae coincided with minor changes in antibody titer and specificity. From these results we conclude that COPD patients are infected with H. influenzae despite the presence of at least as many antibodies in sputum and serum as in controls and that these antibodies are directed against a variety of antigenic determinants of the infecting strain.

Human tonsil B lymphocyte function. I. The proliferative response to Staphylococcus aureus and pokeweed mitogen in relation to surface heavy chains mu and delta.

Human tonsil non-T cells were separated into surface IgD positive (sIgD+), surface IgD negative (sIgD-), sIgM+ and sIgM- fractions by rosetting and gradient centrifugation with ox red blood cells, coated with immunosorbent purified goat anti-human heavy chain antibodies. No activation or suppression was found as a result of the separation technique. The sIg patterns of the isolated B cell fractions showed the effectiveness of the separations; sIgD+ and sIgM+ fractions were to a great extent overlapping populations, but there was a definite population of s mu + delta- cells (about 20% of the sIgD- fraction). The isolated fractions were tested for proliferative responses to Staphylococcus aureus (Sta) and pokeweed mitogen (PWM). The sIgM+ fraction showed the best response to Sta, eight times better than the sIgM- fraction, while the sIgD+ and sIgD- fraction showed equal responses to Sta. The sIgM- fraction responded best to PWM but all fractions responded quite well. Our results indicate that PWM is a mitogen to a whole variety of rather mature B cells while the Sta target B cell is restricted to the relatively immature sIgM+D- and sIgM+D+ cells.

Long-term survival of heart grafts in the presence of donor-specific cytotoxic T-cell precursors (CTLp) in the peripheral blood.

To monitor their immunological status we determined donor and third-party-specific cytotoxic T-cell precursor frequencies (CTLpf) in the peripheral blood of 15 heart transplant recipients. PBL samples were obtained at different time points before and after transplantation. Donor-specific CTLpf and third-party-specific CTLpf were within the same range for all samples (1-1489/10(6) cells). The donor-specific CTLpf were not different between patients who had never had an acute rejection (AR) and patients who had an acute rejection as diagnosed by endomyocardial biopsy (EMB). No difference was observed between donor-specific CTLpf of samples taken on the day of transplantation and those obtained between 3 months and 3 years after transplantation. There was also no relationship between the donor-specific CTLpf in the PBL and the culturing success of lymphocytes from EMB taken at the same time. CTLpf were in the same range both when cultures could be propagated from the graft and when no cells grew out. We conclude that long-term graft survival is possible in the presence of CTLpf in peripheral blood.

Endogenous and exogenous reinfections by Haemophilus influenzae in patients with chronic obstructive pulmonary disease: the effect of antibiotic treatment on persistence.

To analyze whether exacerbations in chronic obstructive pulmonary disease (COPD) coincide with reinfection by Haemophilus influenzae, 16 COPD patients were studied longitudinally for 3 years. Exacerbations coincided with reinfection by H. influenzae, either endogenous, by a strain with a DNA fingerprint indistinguishable from the strain previously present but with another major outer membrane protein (MOMP) pattern (2 patients), or exogenous, by a strain with a different DNA fingerprint and MOMP pattern (3 patients). The other patients, remaining in an infectious state without clear exacerbations for longer periods, were persistently infected by a particular H. influenzae strain (median persistence time, 5.5 months; range, 2-23 months). Of 8 antibiotic-treated patients, 7 remained infected by H. influenzae with the same DNA fingerprint, although all strains were sensitive to the antibiotics prescribed. Results of the study suggested that exacerbations in COPD patients coincide with endogenous or exogenous reinfection by H. influenzae, persistently infected patients keep the same H. influenzae strain for longer periods, and antibiotic treatment was not effective in eradicating H. influenzae.

Antigenic drift of Haemophilus influenzae in patients with chronic obstructive pulmonary disease.

Differences in the major outer membrane protein b,c (molecular weight, 39,000 to 41,000) of related Haemophilus influenzae strains isolated from the sputum of patients with chronic obstructive pulmonary disease were analyzed biochemically and immunologically. Protein b,c was isolated from a total of six related H. influenzae strains from two chronic obstructive pulmonary disease patients. After CNBr digestion of the proteins, the differences in size appeared in the larger of the two fragments. Trypsin and chymotrypsin digests of proteins from related H. influenzae strains showed that proteins differed by only a few peptides or were very similar, in contrast to the peptide maps of proteins from nonrelated strains. Peptide analysis of b,c proteins from related H. influenzae strains by high-performance liquid chromatography after Staphylococcus aureus V8 protease digestion and amino acid analysis of corresponding fractions revealed highly comparable patterns, indicating only minor differences in the amino acid sequences of these proteins. Immunization of rabbits with intact bacteria of four related H. influenzae strains resulted in a strong anti-protein b,c antibody response in all animals. In three of four rabbits, antibodies specific for the b,c protein of the strain used for immunization were elicited, indicating that the changed proteins contained specific immunodominant epitopes. Anti-protein b,c antibodies promoted strain-specific, complement-dependent, bactericidal activity. From these results, we conclude that H. influenzae shows antigenic drift in immunodominant epitopes, caused by small changes in amino acid composition of the b,c protein. Antibodies to these epitopes promote complement-dependent bactericidal activity.