Destruction of diphenylarsine chloride (CLARK I) with activated ozone

The new technology of Plasmazon uses the extremely strong oxidation of radicals to break up the compounds of organic connections, e.g. chemical warfare agents like Clark I. In making a comparison of oxidation to normal ozone, the factor of the Plasmazon-technology is available up to 10(3). The investigation in an experimental test shows that it is possible to destroy the warfare agent character of Clark I. As the possibility of a large-lot application this technology is the method of choice for other chemical or biological warfare agents.

A rationale for positive selection of peripheral blood stem cells in multiple myeloma: highly purified CD34+ cell fractions of leukapheresis products do not contain malignant cells

In multiple myeloma (MM), the presence of tumor cells in leukapheresis products (LP) has been demonstrated with highly sensitive molecular biological tools in up to 100% of cases. Therefore methods to reduce the tumor load of LP by CD34+ selection are envisaged. However, there is controversy as to whether the CD34+ cell is already involved in the malignant process. We have established a PCR assay with allele-specific oligonucleotide primers (ASO) complementary to the CDR3-hypervariable region of the immunoglobulin heavy chain gene of each patient's myeloma clone. Using this ASO-PCR, 43 LP of 10 patients with MM eligible for high-dose therapy were assessed for malignant cells. Furthermore, in an experimental setting we have examined 10 CD34+ and four CD19+ fractions obtained from PCR-positive LP by sequential preparative magnetic and fluorescence activated cell sorting (purity >96%) for the presence of the tumor-specific CDR3 region. The majority of LP harbored cells of the myeloma clone (93%), while all CD34+ fractions were PCR-negative. In all CD19+ fractions malignant cells were detected. These results confirm that CD34+ selection can be considered for LP in MM. The sensitivity of the ASO-PCR (up to 10[-5]) enables us further to monitor the efficacy of CD34+ enrichment protocols in the clinical setting.

High-dose chemotherapy in multiple myeloma

The median survival of conventionally treated patients with multiple myeloma is 3 years. Modifications of conventional chemotherapy have failed to show an improved survival rate in most randomized trials. Therapy regimens with dose-escalated alkylating agents (ie melphalan) have induced higher remission rates in comparison to conventional treatment modalities. With the support of autologous or allogeneic hematopoietic progenitor cells, it has been possible to reduce the hematoxicity of these dose-escalated treatments. The transplantation of autologous peripheral blood progenitor cells results in faster hematopoietic reconstitution with decreased high-dose therapy-related morbidity compared to autologous bone marrow. The randomized French myeloma trial and the pair-mate analysis of the results of the 'total therapy' including double autografting of the Barlogie group with data from the South Western Oncology Group (SWOG) showed a significant survival advantage for patients following autologous transplantation. Although a graft-versus-myeloma effect was described, the benefit of high-dose treatment with allogeneic transplantation is less clear, mainly due to the high transplantation-related mortality rate. In this paper, results of transplantation trials are summarized. Prognostic factors and future treatment modalities for myeloma are discussed.

Putative control of angiogenesis in hemangioblastomas by the von Hippel-Lindau tumor suppressor gene

The hypoxia-inducible endothelial cell-specific mitogen vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) is expressed in low amounts in adult human brain, but is highly upregulated in the perinecrotic palisading cells of glioblastomas. We observed high VEGF expression in cerebellar hemangioblastomas, which are highly vascular, nonnecrotic and presumably nonhypoxic tumors, and hypothesized that a mechanism other than hypoxia leads to VEGF upregulation. Because hemangioblastomas develop in patients with von Hippel-Lindau disease, and mutations of the von Hippel-Lindau tumor suppressor (VHL) gene have also been reported in sporadic hemangioblastomas, we investigated VHL expression in normal cerebellum and in hemangioblastomas and tested the hypothesis that mutations in the VHL gene lead to upregulation of VEGE We observed constitutive expression of VHL mRNA, but downregulation of VEGF mRNA in the postnatal cerebellum. In the adult cerebellum, VHL is predominantly expressed in neuronal cells. In hemangioblastomas, VHL expression appears to be restricted to stromal cells, suggesting that the neoplastic component is the stromal cell. VHL-deficient renal cell carcinoma cells (786-0) produced significantly higher levels of VEGF mRNA and protein compared with 786-0/ wt10 cells, which were stably transfected with the wild-type VHL gene. Our observations suggest that VHL mutations affect stromal cells in hemangioblastomas and that VEGF is upregulated in stromal cells as a consequence of mutations in the VHL gene.

Successful collection of peripheral blood progenitor cells in patients with acute myeloid leukaemia following early consolidation therapy with granulocyte colony-stimulating factor-supported high-dose cytarabine and mitoxantrone

We evaluated the feasibility of collecting peripheral blood progenitor cells (PBPC) in patients with acute myeloid leukaemia (AML) following two cycles of induction chemotherapy with idarubicin, cytarabine and etoposide (ICE), and one cycle of consolidation therapy with high-dose cytarabine and mitoxantrone (HAM). Thirty-six patients of the multicentre treatment trial AML HD93 were enrolled in this study, and a sufficient number of PBPC was harvested in 30 (83%). Individual peak concentrations of CD34+ cells in the blood varied (range 13.1-291.5/microl; median 20.0/microl). To reach the target quantity of 2.5 x 10(6) CD34+ cells/kg, between one and six (median two) leukaphereses (LP) were performed. The LP products contained between 0.2 x 10(6) and 18.9 x 10(6) CD34+ cells/kg (median 1.2 x 10(6)/kg). Multivariate analysis showed that the white blood cell count prior to HAM and the time interval from the start of HAM therapy to reach an unsupported platelet count > 20 x 10(9)/l were predictive for the peak value of CD34+ cells in the blood during the G-CSF stimulated haematological recovery. In 16 patients an intraindividual comparison was made between bone marrow (BM) and PBPC grafts. Compared to BM grafts, PBPC grafts contained 14-fold more MNC, 5-fold more CD34+ cells and 36-fold more CFU-GM. A CD34+ subset analysis showed that blood-derived CD34+ cells had a more immature phenotype as indicated by a lower mean fluorescence intensity for HLA-DR and CD38. In addition, the proportion of CD34+/Thy-1+ cells tended to be greater in the PBPC grafts. The data indicate that sufficient PBPC can be collected in the majority of patients with AML following intensive double induction and first consolidation therapy with high-dose cytarabine and mitoxantrone.

Cloning and functional characterization of the genes encoding 3-dehydroquinate synthase (aroB) and tRNA-guanine transglycosylase (tgt) from Helicobacter pylori

The aroB gene from Helicobacter pylori strain P1 was cloned and further characterized by sequence analysis and by functional complementation of the aroB mutation in Escherichia coli. The aroB gene encodes the enzyme 3-dehydroquinate synthase which catalyzes one of the early steps in the shikimate pathway. This pathway, which creates aromatic molecules from sugar precursors, is present in prokaryotes, fungi and plants but is absent from mammalian cells. The predicted amino acid sequence of the H. pylori aroB gene product showed significant homology (30-40% identity and 50-60% similarity) to 3-dehydroquinate synthases from various other prokaryotes and eukaryotes. The single gene on a plasmid was biologically active in E. coli. It suppressed the specific phenotype of aroB mutants by restoring the shikimate pathway-dependent synthesis of aromatic amino acids and the production of the siderophore enterobactin. Two other reading frames were found adjacent to the aroB gene. The first, designated as orf1, had no significant homology to proteins and genes present in databases, whereas the second was found to share a significant degree of homology with the tgt gene encoding tRNA-guanine transglycosylase from a variety of other bacteria (40-50% identity and 60-70% similarity). The function of the tgt gene was confirmed by heterologous complementation. The gene on a plasmid was shown to complement the queuosine biosynthesis defect in a genetically defined tgt- strain of E. coli. The presence of the aroB gene and the putative tgt homologue in unrelated H. pylori strains was confirmed by Southern blot hybridization and by polymerase chain reaction with specific primers.

Disinfection of cell-associated and extracellular HIV-1 by PUVA treatment

To inactivate cell-associated and extracellular HIV-1 while preserving cellular surface antigens, a procedure was used based on PUVA treatment, i.e. addition of psoralen to cell suspensions followed by irradiation with UVA light. T-lymphoid MT-4 cells were infected with HIV-1 strain NL4-3, 4'-aminomethyl-4,5',8-trimethylpsoralen was added, and the cell suspension was irradiated with 20 mW/cm2 UVA light for 3, 4 and 5 min. To evaluate virus inactivation, cells and supernatants were diluted serially and cocultured with uninfected MT-4 cells. Infectious HIV-1 was detected by cytopathic effects, immunofluorescence and p24 antigen ELISA. UVA irradiation at 3.6 J/cm2 (3 min 20 mW/cm2) reduced the amounts of both cell-associated and extracellular infectious HIV-1 by more than five orders of magnitude. Even at more stringent conditions of PUVA treatment (10 min 20 mW/cm2 UVA irradiation), conformational cellular surface epitopes remained detectable by flow cytometry.

Peripheral blood progenitor cell transplantation in multiple myeloma following high-dose melphalan-based therapy

The objective of our study was to evaluate the efficacy and toxicity of a high-dose melphalan-based therapy with or without total body irradiation (TBI) followed by peripheral blood progenitor cell (PBPC) transplantation in patients with multiple myeloma. Between June 1992 and June 1996, 104 patients (71 male, 33 female) with a median age of 51 years (range 30-65 years) underwent transplantation at our center. PBPC were mobilized using high-dose chemotherapy followed by treatment with G-CSF. Fifty patients were treated with TBI+melphalan 140 mg/m2 while 54 patients received melphalan 200 mg/m2. Following PBPC autografting, the median time to attainment of platelets > or = 20 x 10(9)/l and neutrophils > or = 0.5 x 10(9)/l was 11 and 14 days, with no difference between the treatment groups. In the TBI group significantly longer periods of total parenteral nutrition were required due to the occurrence of severe mucositis. Two patients from the TBI group died of transplantation-related complications. Following high-dose treatment, remission state improved in 43 out of 102 patients. No statistically significant advantage in reaching complete or partial remission was observed with TBI+high-dose melphalan compared to the treatment with high-dose melphalan alone. The optimal high-dose treatment, with particular reference to the inclusion or omission of TBI, should be prospectively investigated.

Protection of hematopoietic stem cells from chemotherapy-induced toxicity by multidrug-resistance 1 gene transfer

An increased chemotherapeutic dose intensity is believed to translate into higher survival rates among cancer patients. Pancytopenia is the dose-limiting toxic result of most anticancer agents. Overexpression of the human multidrug resistance 1 (MDR1) gene in transgenic animals resulted in complete myeloprotection against high doses of cytostatic drugs. Stem cell research, vector development, and experimental pharmacology are uniting their efforts in an attempt to achieve a similar effect in human hematopoietic stem cells. This article gives an overview of the crucial steps involved, from retroviral vector design and optimization of viral titers to vector uptake, gene integration, and expression. The authors' own results are presented with special regard in vitro and in vivo assays for the detection of hematopoietic stem cell transduction.

Factors influencing collection of peripheral blood progenitor cells following high-dose cyclophosphamide and granulocyte colony-stimulating factor in patients with multiple myeloma

We treated 103 multiple myeloma (MM) patients with 7 g/m2 cyclophosphamide (Cy) followed by 300 micrograms G-CSF/d to harvest peripheral blood progenitor cells (PBPC). PBPC autografts containing > 2.0 x 10(6) CD34+ cells per kg body weight were obtained at the first attempt from 90/100 evaluable patients. The most significant factor predicting impairment of PBPC collection was the duration of previous melphalan treatment (P < 0.0001). In multivariate discriminate analysis, treatment with melphalan during the most recent chemotherapy cycles prior to mobilization (P = 0.0727) and previous radiotherapy (P = 0.0628) had a marginally significant negative influence on the efficacy of PBPC collection. We found no reduced functional capacity of CD34+ cells to restore haemopoiesis after myeloablative treatment related to the duration of melphalan exposure. At the time of best response to conventional treatment, a median paraprotein reduction of 21% was achieved following high-dose cyclophosphamide (HD-Cy). Two heavily pretreated patients died and one patient developed pulmonary toxicity W.H.O. grade IV following HD-Cy. Potential transplant candidates should undergo mobilization and harvesting of PBPC before melphalan-containing treatment. Combinations of haemopoietic growth factors and their dose-modifications should be investigated to improve PBPC collection, to allow a dosage reduction of the mobilization chemotherapy.

Elimination of bacteria on different implant surfaces through photosensitization and soft laser. An in vitro study

Microbiologic examinations of implants have shown that certain microorganisms described as periodontal pathogens may have an influence on the development and the progression of peri-implant disease. This experimental study aimed to examine the bactericidal effect of irradiation with a soft laser on bacteria associated with peri-implantitis following exposure to a photosensitizing substance. Platelets made of commercially pure titanium, either with a machined surface or with a hydroxyapatite or plasma-flame-sprayed surface or with a corundum-blasted and etched surface, were incubated with a pure suspension of Actinobacillus actinomycetemcomitans or Porphyromonas gingivalis or Prevotella intermedia. The surfaces were then treated with a toluidine blue solution and irradiated with a diode soft laser with a wave length of 905 nm for 1 min. None of the smears obtained from the thus treated surfaces showed bacterial growth, whereas the smears obtained from surfaces that had been subjected to only one type of treatment showed unchanged growth of every target organism tested (P < 0.0006). Electron microscopic inspection of the thus treated platelets revealed that combined dye/laser treatment resulted in the destruction of bacterial cells. The present in vitro results indicate that lethal photosensitization may be of use for treatment of peri-implantitis.

Expression and purification of recombinant human apolipoprotein A-I in Chinese hamster ovary cells

The expression of apolipoprotein A-I (apoA-I) has been shown to be very difficult due to its amphiphilic character, autoaggregation, and degradation. We have expressed apoA-I using CHO cells, Baculovirus, and Escherichia coli [Schmidt et al., J. Biol. Chem. (1995) 270, 469-475]. Here we report about optimized conditions for the expression of proapoA-I in CHO cells, testing various serum-free media. We were able to yield apoA-I expression up to 80 micrograms/ml, by far the highest ever reported. However, immunoblot analysis revealed degraded apoA-I. The best apoA-I expression testing various conditions was about 20-30 micrograms/ml without any evidence of degradation. Interestingly, the apoA-I expression resulted in reproducible apoA-I fragments of 26 and 14 kDa. These fragments are consistent with already reported in vivo findings, in which carboxy-terminal proteolysis was suggested. The use of the protease inhibitors pepstatin and chymostatin, both carboxy-peptidase inhibitors, did result in contrast to other studied protease inhibitors in increased apoA-I yield. Therefore, limited carboxy-terminal proteolysis contributes to the degradation of CHO cell-secreted apoA-I. In addition, we evaluated various purification methods for the preparative isolation of recombinant apoA-I. In our hands we obtained the best recovery and no degradation with reversed-phase chromatography using a FPLC system.

Immunomagnetic selection of CD34+ peripheral blood stem cells for autografting in patients with breast cancer

Contamination of transplants with tumour cells may contribute to relapse after peripheral blood stem cell transplantation (PBSCT). We studied the feasibility of CD34+ cell selection from blood-derived autografts obtained following G-CSF-supported cytotoxic chemotherapy in a group of 25 patients with breast cancer (10 with high-risk stage II/III and 15 with stage IV without bone or bone marrow involvement). Using immunomagnetic beads (Isolex 300 SA. Baxter) CD34+ cells were enriched and released by chymopapain resulting in a median purity of 95% (range 82-99%) and a median recovery of 80% (range 27-132%). The enrichment procedure did not change the proportion of CD34+ subsets coexpressing HLA-DR, CD38 and Thy-1, while L-selectin was removed from the cell surface following selection. Using a sensitive immunocytological technique with a cocktail of epithelial-specific antibodies (anti-cytokeratin 8, 18 and 19; HEA125; BM7 and BM8), five leukaphereses products contained epithelial cells, whereas the selected CD34+ cell fraction was free of tumour cells. A neutrophil count of 0.5 x 10(9)/l and a platelet count of 20 x 10(9)/l was reached after a median time of 14 and 10d following 40 high-dose chemotherapy (HDC) cycles. Our results indicate that immunomagnetic selection of CD34+ cells yields highly purified autografts devoid of tumour cells whereas the engraftment ability of the progenitor and stem cells is fully retained.

Lack of t(14;18) polymerase chain reaction-positive cells in highly purified CD34+ cells and their CD19 subsets in patients with follicular lymphoma

Follicular lymphoma (FL) is characterized in a significant proportion of cases by the t(14;18) chromosomal translocation, which results in the juxtaposition of the oncogene bcl-2 to the joining region of the immunoglobulin heavy chain (IgH) gene. Molecular sequence analysis indicates that the t(14;18) rearrangement occurs in a B-lymphoid progenitor cell at the time of IgH rearrangement. We were interested whether hematopoietic stem and progenitor cells as characterized by CD34 expression bear the translocation. Bone marrow (BM)-CD34+ cells were enriched from 14 patients with FL whose BM was known to be positive for bcl-2/IgH (major breakpoint region [MBR]). Six patients were in complete remission (CR), two patients were in partial remission (PR), and six patients had active disease. Six patients had histological BM involvement when the samples were obtained. Using an immunomagnetic selection device (MINI-MACS), a mean purity of 88.7% +/- 4% CD34+ cells was achieved. The CD34+ cells were further enriched by fluorescence activated cell sorting (FACS) using CD34 fluorescein isothiocyanate (FITC)- and CD19 phycoerythrin (PE)-conjugated antibodies. The IgH gene was rearranged in the CD34+/CD19+ cell subset of all patients assessed by polymerase chain reaction (PCR). This population is thought to represent the progenitor stage at which the bcl-2/IgH translocation occurs. The unseparated BM mononuclear cell fraction from all 14 patients was positive for bcl-2/IgH using a nested PCR, but the BM-CD34+ cell fraction and the respective CD34+/CD19+ subset were negative in 13 of these 14 patients. The one patient with a positive PCR signal in the CD34+ cell subset had a relapse with BM involvement. We conclude that CD34+ progenitor cells including CD34+/CD19+ B-cell progenitors are not involved in the malignant cell clone. These data are in agreement with a transgenic mouse model, which indicates that the malignant phenotype in FL is sustained by mature B cells.

Expression of the human immunodeficiency virus type-1 coreceptors CXCR-4 (fusin, LESTR) and CKR-5 in CD34+ hematopoietic progenitor cells

CD34+ hematopoietic progenitor cells were assessed for mRNA expression of the human immunodeficiency virus type-1 (HIV-1) coreceptors CXCR-4, also termed fusin or LESTR, and CKR-5, also called CC-CKR-5 or CCR-5. The CD34+ cells were obtained from leukapheresis products of 17 patients after granulocyte colony-stimulating factor-supported cytotoxic chemotherapy. Using a two-step enrichment procedure including immunomagnetic bead separation and fluorescence-activated cell sorting, the CD34+ cells had a median purity of 99.8%. Assessing 9 CD34+ cell samples by polymerase chain reaction after reverse transcription (RT-PCR), CXCR-4 mRNA was found in all samples, whereas CKR-5 mRNA was only present in 3 samples, even though a nested PCR was used. Eight additional CD34+ cell samples were sorted according to CD4 expression. Based on a three-color immunofluorescence analysis, the mean relative fluorescence intensity of HLA-DR was smaller on CD34+/CD4+ cells in comparison with CD34+/ CD4- cells. CXCR-4 mRNA was found in 5 of 8 CD34+/CD4+ samples and in 7 of 8 CD34+/CD4- samples, whereas CKR-5 mRNA was detected in 2 CD34+/CD4+ samples and in 1 CD34+/CD4- cell sample. Looking at the total number of CD34+ cell samples examined, the proportion of specimens containing CXCR-4 mRNA was 84% in comparison with 24% of specimens positive for CKR-5 mRNA. These data suggest that CD34+/CD4+ hematopoietic progenitor cells, including true stem cell candidates, could be susceptible to HIV-1 infection. Considering the relatively low incidence of CD34+ cell samples containing CKR-5 mRNA, CD34+/CD4+ cells appear to be particularly prone for HIV-1 infection via the CXCR-4 coreceptor. Because this chemokine receptor allows T-cell-tropic HIV-1 strains to infect cells, CD34+ cells expressing CD4 and CXCR-4 might be infected by HIV-1 during later stages of the disease, following a viral phenotype switch from macrophage- to T-cell-tropic HIV-1 strains.

Evidence of linkage between the serotonin transporter and autistic disorder

The serotonin transporter gene (HTT) is a primary candidate in autistic disorder based on efficacy of potent serotonin transporter inhibitors in reducing rituals and routines. We initiated a candidate gene study of HTT in trios consisting of probands with autistic disorder and both parents. Preliminary transmission/disequilibrium test (TDT) analysis with 86 families revealed no evidence for linkage or linkage disequilibrium between autistic disorder and a polymorphism in the second intron of HTT. However, preferential transmission of a short variant of the HTT promoter was found in the same 86 trios (TDT chi 2 = 4.69, 1 d.f., P = 0.030). In further analyses, we considered haplotypes of the HTT promoter variant and second intron locus as alleles in a multiallelic TDT. Results confirmed the significance of the effect of this region (TDT chi 2 = 11.85, 4 d.f., P = 0.018). This provides preliminary evidence of linkage and association between HTT and autistic disorder.

MALT-type lymphoma of the stomach is associated with Helicobacter pylori strains expressing the CagA protein

BACKGROUND & AIMS

Helicobacter pylori is considered to be involved in the pathogenesis of gastric lymphoma of mucosa-associated lymphoid tissue (MALT) type. Strains expressing the CagA protein (CagA+ strains) have been strongly associated with severe gastritis, duodenal ulceration, and gastric adenocarcinoma. The aim of this study was to determine the presence of H. pylori as well as incidence of CagA+ strains in gastric MALT-type lymphoma.

METHODS

Sera of 68 patients with gastric MALT-type lymphoma (22 with low grade, 36 with high grade, and 10 with secondary high grade) were obtained, and the serological response to CagA was studied by immunoblotting using a purified recombinant CagA protein, a CagA+ strain, and the corresponding isogenic CagA- mutant.

RESULTS

Of the patients with MALT-type lymphoma, 98.5% (67 of 68 patients) were H. pylori seropositive. In the only seronegative patient, the bacterium was detected histologically by Warthin-Starry staining. Of the seropositive patients, 95.5% had serum immunoglobulin G antibodies to CagA compared with 67% of an H. pylori-positive control group (33 of 49 patients; P = 0.000037) with chronic active gastritis.

CONCLUSIONS

These results indicate infection of almost all patients with MALT-type lymphoma by CagA+ H. pylori strains. Strains expressing the CagA protein seem to play a crucial role in the pathogenesis of gastric MALT-type lymphoma.

[Ambulatory therapy of multiple myeloma with vincristine, adriamycin and dexamethasone]

BACKGROUND AND OBJECTIVE

If multiple myeloma (MM) progresses in patients after chemotherapy with alkylating agents, the combination of vincristine, adriamycin and dexamethasone (VAD) can achieve a response in 40-70% of cases. Because of its low toxicity for haematopoetic stem-cells this form of chemotherapy is often undertaken before high-dose blood stem-cell transplantation. It was the objective of this study to examine effectiveness and complications of ambulant VAD treatment.

PATIENTS AND METHODS

Within four years VAD chemotherapy was given to 62 ambulant MM patients, administered by microprocessor-regulated pumps via intravenously polyurethane catheters with a safety valve. Response to treatment, treatment-associated complications and infections were documented prospectively and analysed.

RESULTS

VAD treatment achieved tumour reduction of more than 25% in 50 of 62 patients. This treatment had to be discontinued in two of 192 pump-infusions because of irreversible catheter occlusion. Eight patients were hospitalised because of infections and two for noninfectious complications. Severe infectious complications (> or = WHO grade III) occurred in 4% of treatment cycles.

CONCLUSION

VAD chemotherapy can be performed with a low rate of infection in ambulant patients despite the need for prolonged intravenously infusion of the drugs. But to avoid complications by intravenously catheters, random prospective tests should first be done with oral alkylating agents.