Uniform Cu/chitosan beads as a green and reusable catalyst for facile synthesis of imines via oxidative coupling reaction

A nonprecious metal and biopolymer-based catalyst, Cu/chitosan beads, has been successfully prepared by using a software-controlled flow system. Uniform, spherical Cu/chitosan beads can be obtained with diameters in millimeter-scale and narrow size distribution (0.78 ± 0.04 mm). The size and morphology of the Cu/chitosan beads are reproducible due to high precision of the flow rate. In addition, the application of the Cu/chitosan beads as a green and reusable catalyst has been demonstrated using a convenient and efficient protocol for the direct synthesis of imines via the oxidative self- and cross-coupling of amines (24 examples) with moderate to excellent yields. Importantly, the beads are stable and could be reused more than ten times without loss of the catalytic performance. Furthermore, because of the bead morphology, the Cu/chitosan catalyst has greatly simplified recycling and workup procedures.

Uniform, spherical Cu/chitosan beads prepared using a software-controlled flow system as a green and conveniently recyclable catalyst for the efficient synthesis of various imines in short reaction time.     

Significantly increased recovery of intestinal parasites on routine stool specimen evaluation

Three hundred thirty-six stool samples from October 2001 through October 2002 were analyzed for the presence of intestinal parasites. Fifty-six of these (16.7%) were positive for a total of 66 parasites; 65/66 (98.5%) were detected by iodine and dimethyl sulfoxide-modified acid-fast (DMSO-mAFB) stained smears of fresh and formalin-ethylacetate sedimentation concentrated samples. Saline, iodine, and DMSO-mAFB stained smears of fresh stool samples alone detected significantly fewer parasites, finding only 50/66 (75.8%) (p < 0.05). Stool samples analyzed by trichrome stained specimens preserved in Zinc sulfate polyvinyl alcohol (Zinc PVA) detected only 41/ 66 (62.2%) of the parasites. In our study population, it was necessary to perform the National Committee for Clinical Laboratory Standard (NCCLS) recommended to accurately detect intestinal parasites. The concentration technique is simple and significantly increased the detection of intestinal parasites.     

Multifocal cutaneous and systemic plasmablastic lymphoma in an infant with combined living donor small bowel and liver transplant

Abstract:  Small bowel allograft recipients have a relatively high risk (approximately 20%) of developing PTLD. Onset of PTLD is usually soon after transplant (median of eight months). Children are at a higher risk than adults. Although PBL was originally described in 1997 by Delecluse et al. as a human immunodeficiency virus-associated neoplasm typically presenting in the oral cavity, it is now recognized as a PTLD. We describe an unusual and interesting case and to our knowledge the first case of an infant who developed diffuse multifocal cutaneous and systemic PBL shortly after small bowel and liver transplant. We report a case of a 14-month-old female child who received a small bowel and liver transplant from her father. She had excellent graft function with no rejection episodes. Five months post-transplant she developed a sudden gastrointestinal bleed and was noted to have a constantly rising EBV titer despite ongoing maximal antiviral therapy. A patchy erythematous rash was noted on her abdomen that was diagnosed as PBL–PTLD. By the time of this diagnosis, she had developed multiorgan failure unresponsive to therapy.     

Molecular characterization of clinical Burkholderia pseudomallei isolates from India

Multilocus sequence typing of seven isolates of Burkholderia pseudomallei from India showed considerable diversity, with six different sequence types. Possible dissemination of melioidosis by historical trading routes is supported by links to strains from Southeast Asia, China, and Africa and the presence of the Burkholderia mallei allele of the bimA gene.     

Proteomic Analysis of Rickettsia parkeri Strain Portsmouth

Rickettsia parkeri, a recently recognized pathogen of human, is one of several Rickettsia spp. in the United States that causes a spotted fever rickettsiosis. To gain insights into its biology and pathogenesis, we applied the proteomics approach to establish a two-dimensional gel proteome reference map and combined this technique with cell surface biotinylation to identify surface-exposed proteins of a low-passage isolate of R. parkeri obtained from a patient. We identified 91 proteins by matrix-assisted laser desorption ionization-tandem time of flight mass spectrometry. Of these, 28 were characterized as surface proteins, including virulence-related proteins (e.g., outer membrane protein A [OmpA], OmpB, β-peptide, and RickA). Two-dimensional immunoblotting with serum from the R. parkeri-infected index patient was utilized to identify the immunoreactive proteins as potential targets for diagnosis and vaccine development. In addition to the known rickettsial antigens, OmpA and OmpB, we identified translation initiation factor 2, cell division protein FtsZ, and cysteinyl-tRNA synthetase as immunoreactive proteins. The proteome map with corresponding cell surface protein analysis and antigen detection will facilitate a better understanding of the mechanisms of rickettsial pathogenesis.Rickettsia parkeri, a member of the spotted fever group Rickettsia (SFGR), was first isolated from the Gulf Coast tick, Amblyomma maculatum, in 1937 (29). In 2004, the first confirmed human infection with R. parkeri was reported in a 40-year-old man from the Tidewater area of coastal Virginia. The agent was isolated in cell culture from an eschar biopsy specimen and designated the Portsmouth strain (28). Recently, the first recognized case of tick bite-associated human infection was described (43); however, the epidemiology of R. parkeri is not well defined. In the United States, R. parkeri has been detected in A. maculatum and A. americanum; the geographical overlap between R. parkeri and these ticks with that of the vectors of R. rickettsii (the etiological agent of Rocky Mountain spotted fever [RMSF]) suggests that many cases of R. parkeri infection have been misidentified as RMSF (27, 35). For example, Western blot analysis of serum specimens from 15 U.S. patients previously diagnosed with RMSF identified four serum specimens reactive with a 120-kDa protein of R. parkeri, suggesting infection with R. parkeri rather than R. rickettsii (30). However, a serologic test specific for this pathogen is not available (43), and little is known about its biology.Due to their obligate intracellular nature, genetic manipulation of Rickettsia has proven difficult. Alternatively, protein expression profiles (proteomes) are utilized to identify the mechanisms of pathogenesis and differentiate rickettsial species recognizing host immune response specificity to cell surface molecules, referred to as outer membrane proteins (Omps). The presence or absence of some Omps allows for differentiation between the typhus group and the SFGR, and the response to some species within the SFGR is specific (2). Proteomes have been developed for R. prowazekii (7), R. conorii (31), and R. felis (26) by using two-dimensional liquid chromatography-tandem mass spectrometry (2D LC-MS/MS), two-dimensional polyacrylamide gel electrophoresis (2D PAGE) and MS, or sodium dodecyl sulfate (SDS)-PAGE and nanoLC-MS/MS, respectively. More recently, an emphasis has been placed on better understanding surface protein expression profiles for obligate intracellular bacteria in the family Anaplasmataceae since it is well recognized that Omps for these bacteria are critical for host cell invasion (12, 13). Likewise, the rickettsial Omps are critical for bacterial attachment and invasion of host cells (21, 23, 40).To better understand the molecular basis of virulence of R. parkeri, we utilized 2D PAGE with a pH 3-10 immobilized pH gradient (IPG) coupled with matrix-assisted laser desorption ionization-tandem time of flight (MALDI-TOF/TOF) MS in order to establish the protein expression profile of a low-passage strain of R. parkeri isolated from an infected patient. This reference map will be useful for comparative analyses of protein profiling of R. parkeri as it is maintained under differing microenvironments (e.g., in the arthropod vector and vertebrate host). Biotinylation of cell surface proteins and 2D immunoblotting analysis were also used to identify the surface-exposed proteins and immunoreactive proteins as potential targets for diagnosis and vaccine development.     

Re-evaluation of commercially available enzyme-linked immunosorbent assay for the detection of Giardia lamblia and Cryptosporidium spp from stool specimens

This study aimed to detect Giardia lamblia and Cryptosporidium spp infection from stool specimens. A total of 345 stool specimens were examined by microscopy (both direct smear and formalin concentration) and EIA techniques (ProSpecT Microplate Assay) for G. lamblia and Cryptosporidium spp. Of 73 tests positive for G. lamblia, 41(56.2%) were positive by microscopy, and 71(97.3%) were positive by EIA. Of 16 tests positive for Cryptosporidium spp, 5 (31.3%) were positive by microscopy, and 16(100%) were positive by EIA technique. The results demonstrate that this EIA method is quick, simple, and more sensitive than the microscopy method and should be used for the detection of G. lamblia and Cryptosporidium spp where the prevalence of these protozoan parasites is a public health problem.     

Effect of dihydroartemisinin on the antioxidant capacity of P. falciparum-infected erythrocytes

Many lines of evidence reveal that artemisinin, an antimalarial containing endoperoxide, generates free radicals to kill malaria parasites. The present study re-evaluated the antioxidants of P. falciparum-infected erythrocytes in the absence and presence of 0.25, 0.5 and 1.0 ng/ml of dihydroartemisinin (DHA), the active metabolite of artemisinin. The ratio of reduced to oxidized glutathione (GSH/GSSG) and activities of superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) were determined. The data indicated that malaria infection induced oxidative stress in erythrocytes that resulted in a significant lower GSH in parasitized cells compared to the non-parasitized. DHA showed no effect on the antioxidant levels of non-parasitized erythrocytes treated under similar conditions as P. falciparum-infected erythrocytes. However, significantly lower GSH as well as catalase and GPx activities in parasitized cells were seen at drug concentrations of 0.5 and 1.0 ng/ml (p < 0.05). GSH is the most sensitive indicator of oxidative stress in malaria-infected erythrocytes both in the absence and in the presence of DHA. Parasite GPx might play a more important role than catalase in the elimination of peroxide. Parasite viabilities in the presence of DHA were analyzed simultaneously and were affected to a greater extent than the antioxidant levels. The present observation showed that although DHA killed malaria parasites by generating free radicals from the endoperoxide bridge causing the reduction of antioxidants, but the depletion of parasite antioxidants is not a prerequisite for the parasite death.     

Conserved neutralizing epitopes of HIV type 1 CRF01_AE against primary isolates in long-term nonprogressors

Linear conserved B cell epitopes in envelope glycoprotein of long-term nonprogressors (LTNPs) HIV-1 CRF01_AE were determined. The envelope sequences of HIV-1 subtype E from Thailand were aligned to define consensus sequences. Then the peptides corresponding to these predicted regions were synthesized as peptides represent C1, C2, C3, C5, V2, V3, and gp41 regions. After that, the neutralizing B cell epitopes were determined by neutralized competitive assay with pool sera of typical progressor and LTNP HIV-1 CRF01_AE patients against HIV-1 CRF01_AE 24 primary isolates (PI) and laboratory strains (TCLA). We found that the strength and breadth of neutralization were greater for sera from LTNPs compared with sera from typical progressors. Peptides C1E and C2E could inhibit primary isolates but not the TCLA strain in LTNP sera. The new B cell epitopes, which were located in the C1 and C2 regions of CRF01_AE against primary HIV-1 isolates, were identified in HIV-1 CRF01_AE LTNPs. This may be important in HIV-1 vaccine development and trial.