Biocompatibility and photo-induced antibacterial activity of lignin-stabilized noble metal nanoparticles

One-pot thermal and photochemical syntheses of lignin-doped silver and gold nanoparticles were developed and their antimicrobial properties were studied against Escherichia coli and Staphylococcus aureus. The nature of the lignin as well as the metal are directly involved in the antimicrobial activity observed in these nanocomposites. Whereas one of the nanocomposites is innocuous under dark conditions and shows photoinduced activity only against Staphylococcus aureus, the rest of the lignin-coated silver nanoparticles studied show antimicrobial activity under dark and light conditions for both bacteria strains. Additionally, only photoinduced activity is observed for lignin-coated gold nanoparticles. Importantly, the particles are non-cytotoxic towards human cells at the bactericidal concentrations. Preliminary assays show these silver nanoparticles as potential antimicrobial agents towards S. aureus biofilm eradication.

Natural derived compounds, lignins, can be used as reducing and stabilizing agents to synthesize noble metal nanoparticles with antimicrobial properties.     

Myelosuppressive conditioning improves autologous engraftment of genetically marked hematopoietic repopulating cells in dogs

We have studied the role of different conditioning regimens for engraftment of genetically marked hematopoietic repopulating cells in dogs. Peripheral blood (PB) and/or marrow cells collected after treatment with recombinant canine stem cell factor (rcSCF) or cyclophosphamide were transduced in a vector-containing long-term culture system. Three different vector-producing cell lines with similar viral titers were used. In two of them, the neo-containing LN vector was packaged either in the PA317 cell line with an amphotropic murine retrovirus envelope or the PG13 cell line with the gibbon ape leukemia virus (GALV) envelope. The MFG/GC vector produced in PA317 cells contained the human glucocerebrosidase gene. Nineteen dogs received either no conditioning (group A, n = 5), irradiation to both humeri with 1,000 cGy (group B, n = 5), a sublethal dose of cyclophosphamide 40 mg/kg (group C, n = 4), a sublethal dose of 200 or 300 cGy total body irradiation (TBI) (group D, n = 3), or an otherwise lethal dose of 920 cGy TBI (group E, n = 3) before intravenous (groups A, C, D, E) or intramedullary (group B) infusion of the transduced autologous hematopoietic cells. Transduction efficiency of hematopoietic cells at the time of infusion into the animals was similar among the different conditioning groups. Dogs were observed for at least 6 months. PB granulocytes were obtained at least every 3 weeks after transplant and analyzed by polymerase chain reaction for the presence of the transduced genes. The percentages of positive results in dogs more than 4 weeks after transplantation were 0% without conditioning, 5% with local irradiation, 18% with sublethal cyclophosphamide, 33% with sublethal TBI, and 17% with otherwise lethal TBI. Analyzing the influence of conditioning regimens by a generalized estimating equation (GEE) technique, which considered the use of different retrovirus vectors and the number of mononuclear cells infused as potential confounding variables, we found that engraftment of genetically marked repopulating cells was significantly improved (P < .001) in dogs receiving systemic conditioning with either otherwise lethal TBI, sublethal TBI, or sublethal cyclophosphamide compared to dogs with local irradiation only or no conditioning. Within the limitation of the experimental design, these data suggest that myeloablative or myelosuppressive conditioning improves engraftment of genetically marked hematopoietic repopulating cells.     

Lymph node blast crisis in chronic myeloid leukemia mimicking T-immunoblastic lymphoma.

BACKGROUND: Chronic myeloid leukemia arises from a somatic mutation in a pluripotent stem cell. It generally terminates with a blastic crisis (BC). One third of BC are lymphoid, and most have a pre-B phenotype. Few cases of T-lymphoid BC have been reported. Here we describe a lymph node blast crisis mimicking T-immunoblastic lymphoma. METHODS: Bone marrow and lymph nodes were histologically examined by standard methods and by an immunoperoxidase technique. Cytogenetic studies were also performed on lymph node and blood cells. Analysis of T-cell receptor genes and BCR rearrangements were performed on DNA extracted from both frozen bone marrow and lymph-node cells. RESULTS: Lymph-node histology showed an infiltration by large lymphoid blasts, consistent with a diagnosis of immunoblastic lymphoma. Blast cells were CD2, CD7, TDT positive, and negative for myeloid and mature lymphoid antigens. The Ph1 chromosome was found in both bone marrow and lymph-node cells. BCR rearrangement was found in the DNA from both bone marrow and lymph-node cells. TCR genes were not rearranged. DISCUSSION: The present study provides strong evidence that the lymph-node blast crisis of CML can assume the morphological appearance of immunoblastic lymphoma and may retain the immunological phenotype and genetic features of early T cells with BCR rearrangements.     

Humoral immune function in pediatric patients treated with autologous bone marrow transplantation for B cell non-Hodgkin's lymphoma. The influence of ex vivo marrow decontamination with anti-Y 29/55 monoclonal antibody and complement

Elimination of neoplastic B cell populations from autologous bone marrow grafts also removes normal B lymphocytes. This is potentially hazardous for the reconstitution of the immune system in patients undergoing high-dose chemotherapy and total body irradiation followed by autologous marrow rescue. Five pediatric patients with B cell non- Hodgkin's lymphoma in first remission undergoing such a regimen were studied. They received bone marrow pretreated with anti-Y 29/55 monoclonal antibody and complement. B and T lymphocyte subpopulations reached normal levels within 6 months after autologous bone marrow transplantation (ABMT), and serum immunoglobulin levels became normal within 4 to 9 months. Vaccination with diphtheria and tetanus toxoid, trivalent poliomyelitis vaccine of the Salk type, and pneumococcal capsular antigens (38 to 54 months after transplantation) gave rise to specific antibody production. ABO isoagglutinins could be demonstrated in all patients. The response pattern was similar to that of patients who received unmanipulated autologous bone marrow. It is concluded that ex vivo anti-Y 29/55 depletion of the marrow graft does not induce relevant disturbances of humoral immune functions.     

Coronary anatomy and left ventricular ejection fraction in patients with type 2 diabetes admitted for elective coronary angiography

Patients with diabetes mellitus (DM) have more severe coronary artery disease and a two‐ to fourfold higher risk for myocardial infarction and death as compared to patients without DM. In this study, we analyzed coronary anatomy, left ventricular ejection fraction, and cardiac risk factors in patients with DM referred for coronary angiography and compared them with findings in nondiabetic patients. Coronary anatomy was assessed in a total of 6,234 patients and left ventricular ejection fraction in a subset of 4,767 (76.5%) patients. Diabetic patients (n = 641) were older (60.8 ± 9.6 vs. 58.5 ± 10.5 years; P < 0.0001) and had higher rates of hypertension (65% vs. 47%; P < 0.0001). Three‐vessel disease (DM 44.7% vs. no DM 25.4%; P < 0.0001) and reduced left ventricular ejection fraction (DM 58.4% ± 15.2 vs. no DM 63.9% ± 13.2; P < 0.0001) were significantly associated with DM. After adjustment for age and other vascular risk factors, the presence of DM was associated with a higher atherosclerotic burden. We conclude that advanced coronary heart disease and left ventricular dysfunction are highly prevalent in diabetic patients, independent of age and other cardiovascular risk factors. Thus, cardiac assessment in diabetic patients should, in addition to optimal diabetic control, involve screening for left ventricular dysfunction. Cathet Cardiovasc Intervent 2004;62:432–468. © 2004 Wiley‐Liss, Inc.