Differential modulation of Bordetella pertussis virulence genes as evidenced by DNA microarray analysis

The production of most factors involved in Bordetella pertussis virulence is controlled by a two-component regulatory system termed BvgA/S. In the Bvg+ phase virulence-activated genes (vags) are expressed, and virulence-repressed genes (vrgs) are down-regulated. The expression of these genes can also be modulated by MgSO(4) or nicotinic acid. In this study we used microarrays to analyse the influence of BvgA/S or modulation on the expression of nearly 200 selected genes. With the exception of one vrg, all previously known vags and vrgs were correctly assigned as such, and the microarray analyses identified several new vags and vrgs, including genes coding for putative autotransporters, two-component systems, extracellular sigma factors, the adenylate cyclase accessory genes cyaBDE, and two genes coding for components of a type III secretion system. For most of the new vrgs and vags the results of the microarray analyses were confirmed by RT-PCR analysis and/or lacZfusions. The degree of regulation and modulation varied between genes, and showed a continuum from strongly BvgA/S-activated genes to strongly BvgA/S-repressed genes. The microarray analyses also led to the identification of a subset of vags and vrgs that are differentially regulated and modulated by MgSO(4) or nicotinic acid, indicating that these genes may be targets for multiple regulatory circuits. For example, the expression of bilA, a gene predicted to encode an intimin-like protein, was found to be activated by BvgA/S and up-modulated by nicotinic acid. Furthermore, surprisingly, in the strain analysed here, which produces only type 2 fimbriae, the fim3 gene was identified as a vrg, while fim2 was confirmed to be a vag.

GABA-ergic innervation of thyrotropin-releasing hormone-synthesizing neurons in the hypothalamic paraventricular nucleus of the rat

To determine whether GABA-ergic axons are anatomically situated to directly influence TRH neurons in the PVN, double-labeling light- and electronmicroscopic immunocytochemistry was performed using antisera against glutamic acid decarboxylase (GAD) and prothyrotropin-releasing hormone (proTRH). In the anterior, periventricular and medial parvocellular subdivisions of the PVN, GAD-immunoreactive (IR) axon varicosities were closely apposed to all proTRH containing cell bodies and proximal dendrites. Ultrastucturally, GAD-IR nerve terminals established symmetric type synapses with both perikarya and dendrites of proTRH-IR neurons, indicating the inhibitory nature of the contacts. Since a subpopulation of neuropeptide Y (NPY) neurons in the hypothalamic arcuate nucleus co-synthesize GABA, and NPY-containing neurons of arcuate nucleus origin densely innervate TRH neurons in the PVN, we performed triple labeling immunocytochemistry to elucidate the origin of the GAD-IR innervation of hypophysiotropic TRH neurons. While axons co-containing GAD and NPY were observed throughout the PVN, only approximately 10% of GAD-IR terminals in contact with TRH neurons were found to contain NPY-immunoreactivity. We conclude that GABA-ergic neurons are in position to act directly on hypophysiotropic TRH neurons and while this innervation arises partly from neurons in the arcuate nucleus that co-synthesize NPY, the majority of the GABA-ergic input arises from other neuronal groups.

Medullary adrenergic neurons contribute to the neuropeptide Y-ergic innervation of hypophysiotropic thyrotropin-releasing hormone-synthesizing neurons in the rat

The arcuate nucleus gives rise to approximately 80% of the neuropeptide Y (NPY)-immunoreactive (IR) innervation to thyrotropin-releasing hormone (TRH) neurons in the hypothalamic paraventricular nucleus (PVN). However, the source of the remaining 20% is unknown. Since medullary adrenergic neurons synthesize NPY and also innervate the hypophysiotropic TRH neurons, we raised the possibility that adrenergic neurons contribute to the NPY-ergic innervation of TRH neurons in the PVN. Triple-labeling immunofluorescence was performed to study the colocalization of NPY and phenylethanolamine N-methyltransferase (PNMT)--the key enzyme of adrenaline synthesis--in axons in association with hypophysiotropic TRH neurons. NPY-immunoreactivity was observed in 74% of PNMT-IR axon varicosities apposed to proTRH-IR neurons, comprising 26% of all NPY-IR axons in contact with proTRH perikarya and dendrites in the PVN. We conclude that at least two distinct populations of NPY neurons innervate hypophysiotropic TRH neurons, the NPY neurons of the hypothalamic arcuate nucleus and the medullary adrenergic neurons that co-contain NPY.

Regional methylation of the 5' end CpG island of BRCA1 is associated with reduced gene expression in human somatic cells

In mammalians, demethylation of specific promoter regions often correlates with gene activation; inversely, dense methylation of CpG islands leads to gene silencing, probably mediated by methyl-CpG binding proteins. In cell lines and cancers, inhibition of tissue-specific genes and tumor suppressor genes expression seems to be related to such hypermethylation. The 5' end of the breast cancer predisposition gene BRCA1 is embedded in a large CpG island of approximately 2.7 kb in length. In human sporadic breast cancers, the down-regulation of BRCA1 does not seem to be related to BRCA1 gene alterations. Southern blot analysis and the bisulfite sequencing method indicate that the BRCA1 CpG island is regionally methylated in all human tissues analyzed and unmethylated in the gametes, suggesting a role for DNA methylation in the control of gene expression. We have therefore investigated the potential role of methyl-CpG binding proteins in the regulation of BRCA1 gene expression. In vitro, partial methylation of constructs containing this region strongly inhibits gene expression in the presence of MeCP2 protein. Moreover, in the five human cell lines analyzed, chemically induced hypomethylation is associated with BRCA1 gene activation. These data suggest that methyl-CpG binding proteins might be associated with the control of BRCA1 gene expression and that methyl-DNA binding proteins may participate in the regulation of gene expression in mammalian cells.

Preparation of autologous bone marrow grafts for cryopreservation using the AS104 cell separator

We evaluated the AS104 cell separator (Fresenius AG, Bad Homburg, Germany) for ex vivo processing of bone marrow (BM) grafts of 43 patients suffering from germ cell cancer (GCC, n = 22), acute lymphocytic leukemia (ALL, n = 13) and malignant lymphoma (ML, n = 8). Recoveries of total nucleated cells (TNC), mononuclear cells (MNC) and colony-forming units granulocyte-macrophage (CFU-GM) were determined in the BM concentrates prepared for cryopreservation. Hematopoietic reconstitution was analyzed in patients who underwent autologous transplantation following high-dose radio-/chemotherapy (HDRCT). Processing of the BM suspension with a median volume of 1,013 ml (range: 422-1,574) resulted in 156 ml (80-186) within 50-120 min (median: 90). In the BM concentrates, medians of 28.6% TNC (10.6-69.6), 37.9% MNC (22.3-86.4), and 52.4% CFU-GM (20.8-96.4) were recovered. Twenty-six patients underwent HDRCT with reinfusion of autologous BM and were evaluable for engraftment. They received a median of 0.8 x 10(8) MNC/kg (0.3-1.6 x 10(8)) and 2.2 x 10(4) CFU-GM/kg (0.6-12.8 x 10(4) for hematopoietic rescue. Engraftment with neutrophils > 500/microliter occurred in a median time of 12 days (8-33) in all patients. We conclude that ex vivo processing of autologous BM with median recovery rates of 37.9% for MNC, and 52.4% for CFU-GM, results in a cell population that can rescue patients from HDRCT. The described technique is convenient, time-efficient, and provides reliable results in preparing BM autografts for cryopreservation.

Arthroscopic synovectomy of the knee joint in early cases of rheumatoid arthritis: follow-up results of a multicenter study

A retrospective multicenter study on a total of 93 knee joints in 81 patients with early forms of rheumatoid arthritis treated by arthroscopic synovectomy was carried out. During the average follow-up period of 33 months, the patients' clinical state showed appreciable improvement. The Lysholm score modified by Klein and Jensen increased from 43.2 points preoperatively to 78.1 points at follow-up. Also, the Insall score (knee score and functional score) showed a highly significant increase of 25.7 and 25.2 points to 71.2 and 80.2 points, respectively. Patients receiving additional radiation synovectomy showed a highly significantly better result than those receiving synovectomy alone. Among the individual variables investigated, pain, swelling, and walking distance in particular were improved. Only radiologically was a mild worsening observed (from Larsen stage 1.57 preoperatively to 1.95 at follow-up). The follow-up examination revealed no synovitis in 80.6% of the patients. Subjectively, 76.4% of the patients assessed the results to be good or very good, with only 7.5% remaining unsatisfied. 90.3% of the patients declared themselves in retrospect willing to undergo the operation again.

[Gel agglutination test--a new test system for semiquantitative detection of feto-maternal transfusion in Rhesus incompatibility]

BACKGROUND

The postpartum administration of an adequate amount of anti-D immunoglobulin to the mother in cases of Rhesus incompatibility requires the exact quantification of the amount of Rh-positive fetal cells that may be present in the Rh-negative maternal circulation. The classical methods to detect an intrapartum fetomaternal hemorrhage are either time-intensive (such as the Kleihauer-Betke test), of low specificity (such as the indirect Coombs test), or technically cumbersome (such as flow cytometry). The goals of our study were to develop a simple screening test that may be used routinely to quantify fetomaternal hemorrhage in cases of Rhesus incompatability and to evaluate this test in clinical practice.

STUDY DESIGN AND METHODS

In cases of Rhesus-negative mothers of Rhesus-positive neonates, 2.5 ml of maternal Rhesus negative blood was sampled in an EDTA tubes immediately postpartum and was incubated with anti-D antibodies. Thereafter, a semiquantitative determination was made of the amount of antibody that remained unbound in the serum via a gel agglutination test (GAT) (DiaMed., Switzerland) after mixing with test red blood cells. The amount of anti-D consumed (bound to fetal cells in the first phase) is the semi-quantitatively indicated by the degree of positivity in the second phase the weaker reaction--the more anti-D absorbed in the first phase--the more Rhesus-positive fetal cells present in the maternal sample--the larger the fetomaternal hemorrhage. Following the development of a discrimination zone using this GAT which could ascertain an Rhesus-positive erythrocyte concentration of over 0.2%, the test was applied in a clinical setting. Between September 1995 and April 1998 in unselected postpartum blood samples from 603 Rhesus negative parturients, the GAT was used to test the same blood samples as those requiring evaluation for HbF concentration using the traditional Kleihauer-Betke test.

RESULTS

In 585 of the 603 cases (97%) there was no evidence of a fetomaternal transfusion following testing using both methods. Furthermore, both tests showed significant evidence for a fetomaternal transfusion in five cases. The Kleihauer-Betke test was false-positive in three cases of mothers who had a hereditary elevation of the HbF concentration. The GAT showed three false-positive reaction due to a Dweak maternal varient. In two cases, the disparity between the GAT and the Kleihauer-Betke test could be attributed to an antecedant dose of anti-D antibody. In the two cases, the Kleihauer-Betke test results were 0.3% while the GAT was only 0.2%.

CONCLUSION

The GAT may be used as a screening method in routine clinical practice. This is a quick test that allows for the specific determination and semiquantitative evaluation of the Rh-positive erythrocyte concentration in clinically relevant concentrations. Thus, following a positive GAT screening test, a further specific test such as the Kleihauer-Betke test may be utilized to absolutely quantify the amount of blood transfused from fetus to mother. It is also possible to perform such a quantification test with the GAT by eventually using a diluted maternal blood sample.

Antibodies to private and public HLA class I epitopes in platelet recipients

BACKGROUND

Transfusions or pregnancies can cause immunization against private HLA determinants and public epitopes shared by more than one private HLA antigen. HLA antibodies are correlated with febrile transfusion reactions, lower platelet response following platelet transfusion, and an increased rate of renal transplant rejection. Until now, antibody specificities in alloantisera from platelet recipients have been poorly characterized.

STUDY DESIGN AND METHODS

Consecutive serum screens from platelet recipients were analyzed for antibodies against private HLA class I antigens and public HLA epitopes using a serum analysis program based on the 2 x 2 table analysis of correlations. Serum screens of highly immunized patients and of patients with new alloimmunization events were reviewed separately.

RESULTS

Of the serum screens from 566 platelet recipients, 1577 indicated alloimmunization (panel-reactive antibodies >5%). The program assigned a specificity in 1024 of these screens (64.9%) and at least once in 522 of 566 patients (92.2%). In 267 patients, antibodies detecting public epitopes in the combined A- or B-locus cross-reacting groups were found; other public markers were detected in 39 patients. Patterns of reactivity were remarkably less stable than in patient groups previously studied. In many patients, antibodies with apparent private epitope specificity preceded the identification of antibodies against a shared marker of the same cross-reactive group. However, the disappearance of antibodies (whether or not this was followed by a new antibody against a private or public marker belonging to another cross-reacting group) was also observed.

CONCLUSION

The computerized analysis of microlymphocytotoxicity tests enhances the rate of antibody specification in sera from platelet recipients with lymphocytotoxic antibodies. The identified antibodies should be taken into account in the selection of platelet donors. The data confirm and extend previous observations on HLA class I antibodies and elucidate new alloimmunization events.

Tandem and triple high-dose chemotherapy with autologous stem cell rescue in metastatic breast cancer

The purpose of this phase II study was to evaluate the therapeutic efficacy and toxicity of a tandem or triple high-dose chemotherapy (HDC) with autologous peripheral blood stem cell transplantation (PBSCT) in patients with metastatic breast cancer (MBC) as first line chemotherapy. Conventional chemotherapy consisted of two cycles of epirubicin 120 mg/m2 and ifosfamide 7500 mg/m2 in the case of tandem HDC and one cycle of paclitaxel 135 mg/m2, epirubicin 90 mg/m2 and ifosfamide 6000 mg/m2 in the case of triple HDC. Tandem HDC was composed of two cycles of epirubicin 180 mg/m2, ifosfamide 12000 mg/m2 and carboplatin 900 mg/m2. In the case of triple HDC, paclitaxel 180 mg/m2, etoposide 1500 mg/m2 and thiotepa 600 mg/m2 was added as the third cycle. Patients with tandem HDC (n = 20) were evaluable for both survival and toxicity, and patients with triple HDC (n = 21) only for toxicity because of short-term follow-up. Both tandem and triple HDC were well tolerated and could be safely administered. Non-hematological WHO grade 3 or 4 toxicities were mucositis (8), temporary renal insufficiency (1), myocardial infarction (1), and neuropathy (1). No toxic death occurred. The Kaplan-Meier estimates for 44-months without progression and the overall survival were 12% and 38% respectively. The median survival was 22 months (95% CI: 7.4-51.7 months) and the median progression-free interval 14 months (95% CI: 5.1-43.7 months). In a population with an unfavorable prognosis, tandem HDC showed similar efficacy as to that described in other phase II studies. Triple HDC seems not to improve patient outcome compared to tandem HDC, but a long-term follow up is required.

Changes in platelet membrane glycoproteins before bone marrow transplantation and after engraftment--a pilot study

Thrombotic complications are observed in patients undergoing bone marrow transplantation despite thrombocytopenia and impaired coagulation due to liver function disturbances. Endothelial cell damage which is involved in the pathogenesis of major transplant related complications like graft-versus-host disease, veno-occlusive disease, sepsis or microangiopathy may be a contributing factor. Little is known about platelet function in bone marrow transplant recipients. In order to study functional alterations in circulating platelets we investigated unstimulated and ADP-stimulated platelets of 10 bone marrow transplant recipients ex vivo by flow cytometry in a pilot study using a panel of monoclonal antibodies to characterize changes in membrane glycoproteins. Samples were collected before and during conditioning and at three timepoints after engraftment. 10 healthy volunteers served as controls. Platelets of bone marrow transplant recipients showed partly a significant, higher expression of surface bound fibrinogen, activated fibrinogen receptor, and glycoprotein Ib as compared to controls. P-selectin, a marker of platelet degranulation was significantly elevated after ADP-induced stimulation at all timepoints compared to controls. Only marginal differences were found for GP IIb/IIIa surface expression. The data point to an increased platelet activation state in bone marrow transplant recipients which might contribute to the thrombotic phenomena observed in these patients.

[MLC reactivity demonstrates transfusion-induced immunosuppression]

The improved graft survival in preoperatively transfused renal transplant recipients led to the hypothesis that blood transfusions have an immunosuppressive effect. We examined 12 patients undergoing cardiac surgery, who received autologous red cells and one homologous HLA class-I-matched platelet concentrate. None of these patients produced red cell or lymphocytotoxic antibodies. Using the mixed lymphocyte culture (MLC) we observed a reduced lymphocyte responce to cells of the platelet donor during the first 4 days after transfusion. The MLC reactivity recovered on days 4-5 to the initial strength and reached over 200% of the initial strength from day 6 on. It must be assumed that these changes in MLC reactivity represent the early signs of the transfusion-induced immunosuppression. As intraoperative transfusions might correlate with cancer relapse, further studies must show whether this immunosuppressive effect can be avoided by the application of filtered leucocyte-depleted red cell transfusions.

[Effect of various rabbit complement batches of HLA class I antigen determination in lymphocytotoxicity testing]

HLA class I lymphocytotoxicity testing is strongly complement-dependent. We tested 13 commercially available rabbit complement batches (7 distributors) using a panel of 14 donors with decisive patterns of HLA antigens. We defined a scoring system that weights the different possible faulty reactions. The rating score ranged from 12.45 to 46.55 (median 16.09). Comparing the reactions in batches with low and high rating scores gave statistically significant differences (chi 2 test, p < 0.05). Our complement reaction score may be helpful to find the optimal complement batch for HLA class I lymphocytotoxicity testing.

Use of the gel agglutination technique for determination of fetomaternal hemorrhage

BACKGROUND

Adequate administration of Rh immune globulin requires an accurate determination of the number of D-positive cells in the circulation of D-negative women. Although several tests have been described for the detection of fetomaternal hemorrhage, there is still a need for a rapid, simple, and clinically relevant screening test.

STUDY DESIGN AND METHODS

Serial dilutions of a monoclonal anti-D were incubated with stock solutions (0.2 mL) of adult D-negative red cells in the absence or presence of various amounts of fetal D-positive cells (0.1, 0.2, 0.3, 0.4, and 0.5%). After incubation, the supernatants were tested against D-positive red cells by using the new, gel agglutination technique (GAT). After the GAT was adapted to detect D-positive cells at concentrations of > or = 0.2 percent, unselected postpartum samples from D-negative women (n = 420) who delivered D-positive infants were analyzed by both the new test and the Kleihauer-Betke test (KBT).

RESULTS

Three of a total of 420 postpartum samples were positive (> or = 0.4% fetal cells), and 406 were negative in both tests. One had 0.5-percent fetal cells in the KBT and gave negative results in the GAT. The latter test was, however, performed after administration of Rh immune globulin. The KBT gave false-positive results in two cases, because of hereditary persistence of hemoglobin F, and the GAT gave a false-positive reaction in one case because of a maternal weak D variant. In the remaining seven cases, the KBT results were only weakly positive (0.2%) and could not be attributed solely to D positive red cells.

CONCLUSION

The GAT is suited for routine screening. It provides rapid and specific detection of D-positive red cells at clinically relevant concentrations. The test may (rarely) yield false-negative results due to insufficient administration of Rh immune globulin before testing.

Intensity dependence and white-light gating of two-color photorefractive gratings in LiNbO(3)

Photorefractive gratings have been written in Pr:LiNbO(3) by use of a diode laser for writing and of filtered white light (390-520nm) as a gating source. The gating light increases the writing efficiency by more than 3 orders of magnitude, and the two-step writing process provides nondestructive readout. The material sensitivity for two-color writing rises strongly for gating wavelengths near the bandgap and approaches that of Fe-doped lithium niobate at power densities of a few watts per square centimeter. In addition, we show that the dynamic range of the recording process is strongly dependent on the writing intensity.

Living epithelial-mesenchymal compounds formed in vitro suitable for autografting

Three different, human epithelial-mesenchymal compounds (EMC) were generated in vitro for prospective grafting in epithelial defects. All compounds consisted of a fibroblast-populated collagen lattice as a mesenchymal component seeded with different types of cultured epithelial cells isolated from biopsies of healthy skin, oral mucosa and respiratory mucosa. Maturation of the epithelial cells was enabled by the presence of a high calcium concentration (1.8 mM) when cultures were lifted to the air-liquid interface. Light and electron microscopy revealed moderate differentiation of the multilayered epithelium in all compounds as well as basement membrane development at the epithelial-mesenchymal junction after 2-3 weeks. A coherent, tissue-like consistency of the collagen lattice and the presence of a basement membrane preventing detachment of the epithelium permitted easy handling and even loose suturing of the compounds produced.

Diclofenac-induced immune haemolytic anaemia: simultaneous occurrence of red blood cell autoantibodies and drug-dependent antibodies

During the last 5 years we have identified a total of 17 patients (nine females and eight males aged between 53 and 85 years) with immune haemolytic anaemia related to diclofenac (a nonsteroidal anti-inflammatory drug). All patients developed acute intravascular haemolysis. Two patients died, and eight patients developed temporary renal failure that required haemodialysis. The direct antiglobulin test was positive with anti-IgG and anti-C3d in all cases, with anti-IgA in 4/10 cases tested, and negative with anti-IgM. The indirect antiglobulin test was moderately or weakly positive in 11 cases, and IgG autoantibodies could be eluted from the red blood cells (RBCs) of all patients. Initially, the diagnosis of autoimmune haemolytic anaemia of warm type was suggested in all cases. All patients had simultaneously developed autoantibodies and drug-dependent antibodies. The majority of drug-dependent antibodies (n = 13) reacted with urine containing the drug and its metabolites (ex vivo antigen), the native drug, and diclofenac-treated RBCs. The antibodies in the remaining four cases were detectable only in the presence of ex vivo antigen. Diclofenac appears to bind only weakly to RBCs in the absence of the drug-dependent antibodies. We conclude that diclofenac forms neoantigens with RBCs that may stimulate the production of autoantibodies and drug-dependent antibodies. The resulting haemolytic syndrome is very similar to autoimmune haemolytic anaemia of warm type.

Photon-gated spectral hole burning in Pr(3+):YAG

We observed photon-gated spectral hole burning in Pr:YAG and assigned the hole-burning mechanism to selective photoionization of trivalent praseodymium. Gated holes were observed in absorption lines to the two lowest components of the (1)D(2) manifold. At 1.4 K the gating ratio is in excess of 1.5 x 10(4). Strong competition from the transient mechanism of optical pumping of hyperfine levels occurs below 6 K.