Comparison of the antimicrobial effects of semipurified cyclotides from Iranian Viola odorata against some of plant and human pathogenic bacteria.

AIMS: Cyclotides are mini-proteins that are synthesized via the ribosomal pathway. They have a variety of biological activities such as antimicrobial, antitumour, anti-HIV activities. Because of their various bioactivities and unique stability, they are suitable candidate in drug design applications. The main aim of this study was to determine new antimicrobial agents, which can be used instead of chemical antibiotics. For this reason, we compared the antimicrobial effects of semipurified cyclotides against human and plant pathogenic bacteria. METHODS AND RESULTS: The cyclotides were isolated from the Iranian plant Viola odorata by fractionation methods and semipurified on a SPE-C18 column chromatography. Antimicrobial activities of extracted cyclotides were studied by radial diffusion assays (RDAs), minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). Data analysis showed that MIC of semipurified cyclotides was 1.6 mg ml(-1) against Staphylococcus aureus, gram-positive bacteria. It was also revealed they are the most susceptible among human pathogenic bacteria used in this research. On the other hand, plant pathogenic bacteria are more susceptible than human pathogenic bacteria. CONCLUSION: The results of the study show that cyclotides from Iranian V. odorata have potent antimicrobial activity against gram-negative, plant pathogenic bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is a part of our extended researches on finding new pharmaceutical potentials of plants and on developing new peptides for special purposes in a way that does not have harmful side effects or have the least side effects.

Adsorption of chromium (VI) from aqueous solution by sugar beet bagasse-based activated charcoal.

Chromium (VI) is known to be potentially carcinogenic and mutagenic in humans. A low-cost industrial solid bioadsorbent, bagasse-based activated charcoal (BAC), has been investigated for removal of chromium from aqueous solution. All the experiments were carried out in batch process with laboratory-prepared samples to study the effects of adsorbent dose, contact time, pH and initial concentration of Cr(VI). The removal of chromium ion was found to be highly dependent on the pH of the solution, adsorbent dose and contact time. Also the equilibrium adsorption was analyzed by the Freundlich and Langmuir isotherm models. It was found that the Freundlich isotherm model best described the sorption of chromium by sugar beet bagasse-based activated charcoal (r2 > 0.9927). Experimental data of kinetic studies were fitted to pseudo-first-order, pseudo-second-order and modified pseudo-first-order models. The results showed pseudo-second order kinetics was best fitted to the collected data (r2 > 0.9893). Optimum conditions for adsorption were determined at pH 2 and a contact time of 180 minutes (92.7% removal). These retention capacities suggest that BAC can provide a simple, effective, and cheap method for removing Cr(VI) ions from effluents and water resources.

The investigation of interactions of kappa-Hefutoxin1 with the voltage-gated potassium channels: a computational simulation.

Kappa-Hefutoxin1 is a K(+) channel-blocking toxin from the scorpion Heterometrus fluvipes. It is a 22-residue protein that adapts a novel fold of two parallel helices linked by two disulfide bridges without beta-sheets. Recognition of interactions of kappa-Hefutoxin1 with the voltage-gated potassium channels, Kv1.1, Kv1.2, and Kv1.3, was studied by 3D-Dock software package. All structures of kappa-Hefutoxin1 were considered during the simulations, which indicated that even small changes in the structure of kappa-Hefutoxin1 considerably affected both the recognition and the binding between kappa-Hefutoxin1 and the Kv1 channels. kappa-Hefutoxin1 is located around the extracellular part of the Kv1 channels, making contacts with its helices. Lys 19, Tyr 5, Arg 6, Trp 9, or Arg 10 in the toxin and residues Asp 402, His 404, Thr 407,Gly 401, and Asp 386 in each subunit of the Kv potassium channel are the key residues for the toxin-channel recognition. Moreover, the simulation result demonstrates that the hydrophobic interactions are important in interaction of negatively charged toxins with potassium channels. The results of our docking/molecular dynamics simulations indicate that our 3D model structure of the kappa-Hefutoxin1-complex is both reasonable and acceptable and could be helpful for smarter drug design and the blocking agents of Kv1 channels.

Effective factors in thermostability of thermophilic proteins.

Thermostability of proteins in general and especially thermophilic proteins has been subject of a wide variety of studies based on theoretical and experimental investigation. Thermostability seems to be a property obtained through many minor structural modifications rather than certain amino acids substitution. In comparison with its mesophile homologue in a thermostable protein, usually a number of amino acids are exchanged. A wide variety of theoretical studies are based on comparative investigation of thermophilic proteins characteristics with their mesophilic counterparts in order to reveal their sequences, structural differences and consequently, to relate these observed differences to the thermostability properties. In this work we have compared a dataset of thermophilic proteins with their mesophilic homologues and furthermore, a mesophilic proteins dataset was also compared with its mesophilic homologue. This strategy enabled us first, to eliminate noise or background differences from signals and moreover, the important factors which were related to the thermostability were recognized too. Our results reveal that thermophilic and mesophilic proteins have both similar polar and nonpolar contribution to the surface area and compactness. On the other hand, salt bridges and main chain hydrogen bonds show an increase in the majority of thermophilic proteins in comparison to their mesophilic homologues. In addition, in thermophilic proteins hydrophobic residues are significantly more frequent, while polar residues are less. These findings indicate that thermostable proteins through evolution adopt several different strategies to withstand high temperature environments.

M(r) 92,000 type IV collagenase is increased in plasma of patients with colon cancer and breast cancer.

Overproduction of matrix metalloproteinases (MMPs) is a common characteristic of metastatic cancer cells. Since MMPs can be identified in plasma, we proposed that enhanced MMP-9 secretion by invasive cancer cells may be detected by plasma assay. To this end, we developed a specific sandwich enzyme-linked immunosorbent assay which uses two mouse monoclonal antibodies to human M(r) 92,000 type IV collagenase (MMP-9). The plasma concentration of MMP-9 (mean +/- SD) in 60 healthy subjects (9 +/- 11 ng/ml), 136 patients without cancer, and 179 patients with cancer of the lung, genitourinary tract, or lymphomas-leukemias did not differ significantly. In contrast, plasma MMP-9 was significantly increased (P < 0.01) in 122 patients with gastrointestinal tract cancer and breast cancer (18 +/- 23 and 21 +/- 22 ng/ml, respectively). Whereas carcinoembryonic antigen levels were significantly increased in patients with stage IV gastrointestinal cancer, MMP-9 concentrations were not significantly increased in patients with metastatic disease as compared to those with nonmetastatic cancer. Combining both assays improves sensitivity of detection of colon cancer. MMP-9 was also significantly increased during pregnancy which is consistent with the extensive ongoing tissue remodeling and the leaching of the tissue proteinase into plasma.

Serious infections in adults following splenectomy for trauma.

Postsplenectomy sepsis in children is a well-recognized hazard. Few reports discuss the risk of sepsis in the asplenic adult. Case reports of 47 adults with serious infections following splenectomy for trauma were examined. We conclude that fulminant sepsis after splenectomy for trauma in adults is indeed a potential risk and that all such patients should receive penicillin prophylaxis and pneumococcal vaccine.

Rarity of failure of penicillin prophylaxis to prevent postsplenectomy sepsis.

All splenectomized individuals are at risk of developing pneumococcal sepsis, but most reports fail to mention how many patients are given prophylactic penicillin therapy. Fourteen reported cases of postsplenectomy bacterial sepsis in patients receiving prophylactic penicillin therapy are reviewed. In only five cases, the patients had penicillin-sensitive pneumococcal infection. Hence, the exact frequency of the failure of penicillin prophylaxis cannot be calculated, but it appears to be very rare. Continuous antibiotic prophylaxis used indefinitely and pneumococcal vaccine are both strongly recommended for all children and adults undergoing splenectomy.

Modification of C/TiO2@MCM-41 with nickel nanoparticles for photocatalytic desulfurization enhancement of a diesel fuel model under visible light.

Ni metal nanoparticles were attached on the C/TiO2@MCM-41 (CTM-41) via facile and fast method based on dispersing of C/TiO2@MCM-41 in aqueous solution containing nickel ions by ultrasonic bath. Then, for the first time, the Ni ions were converted to Ni nanoparticles under UV light (photo-assisted deposition, PAD method), without using reducing agents and hydrogen gas. This process was carried out under the relatively mild conditions. The results showed that Ni (II) was reduced to Ni metallic nanoparticle in the size of about 2.7 nm on the surface of CTM-41 (Ni/CTM-41) with specific surface area of 754.37 m(2) g(-1). The photocatalytic ultra-deep desulfurization of a fuel-like n-octane containing dibenzothiophene (DBT) was conducted over the Ni/CTM-41 nanophotocatalyst. Using this method, the total sulfur content efficiently decreased under mild conditions in one phase and without using an oxidant. The synthesized Ni/CTM-41 (3% Ni) exhibited the maximum photocatalytic desulfurization of DBT for all different ratios of Si/Ti. In contrast, the synthesized CTM-41 (without Ni) exhibited the maximum photocatalytic desulfurization of DBT only for minimum ratio of Si/Ti. The Ni/CTM-41 was characterized by several techniques including N2 adsorption-desorption isotherms, XRD, TEM, and atomic absorption spectroscopy techniques. The results confirmed that Ni was highly dispersed on the support phase. The GC-MS analysis confirmed the photocatalytic removal of DBT. Based on the experimental results, it is proposed that the hydroxyl radical and hole have key role in the photocatalytic desulfurization process.

Pure red-cell aplasia in patients with chronic lymphocytic leukemia.

Four cases of pure red-cell aplasia (PRCA) in association with chronic lymphocytic leukemia (CLL) are summarized. In addition, all reported cases of CLL-PRCA (27, including our 4 cases) are reviewed to consolidate their clinical features and compare them with those of 26 patients with CLL who were anemic (Stage III) and 52 who were not anemic (Stages O-II). The incidence of PRCA in our patients with CLL is about 6%. Eighty-seven percent of patients with PRCA had B-lymphocyte (B-cell) CLL and 13% had T-lymphocyte (T-cell) CLL. In 4 of 17 patients PRCA was the presenting feature, and in 13 of 17 it developed in patients previously diagnosed as having CLL. In the latter group, the average time from the diagnosis of CLL to the development of PRCA was 50.2 months (range, 1 to 96). The average age at presentation with PRCA was 61.6 years (range, 37 to 79), and the male to female ratio was 1.6 to 3:1. Eighty-one percent had splenomegaly and 65% had lymphadenopathy. The average hematocrit was 17 +/- 3.6% with zero reticulocyte count, and the lymphocyte count was 134 X 10(3)/microliter. Normoblasts were absent in the marrow and lymphocytes constituted 50 to 100% of the marrow cells. In patients with B-cell CLL and those with T-cell CLL, the T cells were found to inhibit the growth of the marrow erythroid progenitors in in vitro cultures. These abnormal T cells (Tr cells) possessed IgG Fc receptors on their surface, which may be responsible for induction of PRCA in these patients. Continued administration of cyclophosphamide and prednisone in moderate doses appears to induce remission from PRCA, but not until the leukemic mass and abnormal Tr cells are markedly reduced. Daily or alternate-day cyclophosphamide administration in small to moderate doses seems to be essential to maintain remission.

Type IV collagenase/gelatinase (MMP-2) is not increased in plasma of patients with cancer.

We have developed a sensitive and specific sandwich-type enzyme-linked immunosorbent assay to detect M(r) 72,000 type IV collagenase [matrix metalloproteinase 2 (MMP-2)] in human plasma. As a result of the linkage between MMP-2 production by cancer cells and the metastatic phenotype, we undertook this study to compare plasma MMP-2 levels in healthy individuals, patients with various types of cancer, and hospitalized patients with chronic diseases other than cancer. The results demonstrate that MMP-2 levels are not increased in cancer patients regardless of the extent of disseminated malignancy. In an effort to explain this data, we compared MMP-2 secretion by human umbilical vein endothelial cells and lung cancer cells passaged as cell lines. Endothelial cells secreted higher levels of MMP-2 than did lung cancer cells propagated in vitro. We propose that blood vessel lining cells make a sizable contribution to plasma levels of MMP-2 and may thereby obfuscate the detection of increased levels of MMP-2 originating from extravascular sources such as solid tumors.

Immunoassay of type IV collagenase/gelatinase (MMP-2) in human plasma.

We have developed a sensitive and specific sandwich type enzyme-linked immunosorbent assay (ELISA) to detect type IV collagenase (MMP-2) in human plasma which employs the combination of affinity purified rabbit polyclonal antibodies and mouse monoclonal antibodies to human MMP-2. The MMP-2 ELISA detects latent and activated MMP-2, MMP-2 complexed with TIMP and MMP-2 complexed with alpha 2 macroglobulin (65% efficiency). To determine whether physiologic conditions associated with increased connective tissue turnover are accompanied by increased MMP-2 levels in plasma, we compared enzyme levels in pregnant and nonpregnant women. Plasma MMP-2 (mean +/- standard deviation) was significantly increased (p less than 0.05) in the second half of pregnancy (650 +/- 312) as compared to early pregnancy (356 +/- 139) or the nonpregnant state (387 +/- 193). As a result of the linkage between type IV collagenase production by cancer cells and the metastatic phenotype, the assay of MMP-2 in plasma is of potential clinical value in cancer.

Babesiosis in splenectomized adults. Review of 22 reported cases.

Since 1957, there have been 22 reported cases of human babesiosis in splenectomized persons, representing about one third of all clinical human babesiosis. Splenectomy had been performed one month to 36 years (mean 8.7 years, median 6.0 years) earlier for a variety of reasons. Four of the seven European cases were from Babesia divergens whereas 12 of the 15 United States cases were from B. microti. Most of the 22 patients had moderate to severe clinical disease including hemolytic anemia, yet all but six recovered. Three patients had transfusion-acquired babesiosis. Treatments employed included the use of chloroquine, quinine, pyrimethamine, pentamidine, clindamycin, dialysis, and exchange transfusion. Splenectomized and/or otherwise immunocompromised hosts should be advised to avoid visiting endemic areas for babesiosis such as Nantucket Island or Martha's Vineyard in Massachusetts and Shelter Island and other parts of Long Island, New York. Babesiosis must be considered as one of the not uncommon organisms responsible for the postsplenectomy sepsis syndrome and one for which there is no current prophylaxis.

IgM myeloma, a distinct entity in the spectrum of B-cell neoplasia.

The distinction between multiple myeloma and Waldenström's macroglobulinemia can usually be made on the basis of clinical, histologic, and immunologic findings. However, some patients have features of both diseases. Two patients who had IgM monoclonal gammopathies and plasma cell neoplasia are presented. Both had bone lesions, monoclonal IgMk, and bone marrow infiltration with plasma cells. The presence of plasma cells was verified by electron microscopy. Immunoperoxidase studies in both cases showed positive staining with mu and kappa antisera only, suggesting that these plasma cells were the source of the IgMk protein. Using the criteria of monoclonal IgM, plasma cell neoplasia, and bone lesions, 28 similar cases were found. The analysis of clinical data revealed an increased incidence of lytic bone lesions, decreased IgG and IgA, renal failure, hypercalcemia, and Bence-Jones proteinuria, as are commonly seen in multiple myeloma. It also demonstrated an increased incidence of hyperviscosity symptoms, lymphadenopathy, hepatosplenomegaly, and mucous membrane bleeding, as are often seen in Waldenström's macroglobulinemia. Other common findings were anemia and plasma cell leukemia. These data suggest that, although rare, IgM myeloma should be considered a distinct clinical entity in the spectrum of B-cell malignancies with characteristics of both multiple myeloma and Waldenström's macroglobulinemia.

Second neoplasms in Hodgkin's disease: current controversies.

Aggressive, multimodal treatment of Hodgkin's disease has led to dramatic increases in survival but not without significant early toxicity and late complications. The most serious late complication is the development of a secondary neoplasm. These secondary cancers include acute nonlymphocytic leukemia, non-Hodgkin's lymphoma, and various solid tumors.

Middle Eastern intestinal lymphoma: report of a case and review of the literature.

A 20-year-old Persian man with Middle Eastern lymphoma is described, and 84 additional cases from the literature are reviewed. Basically, the disease is a malignant lymphoma which involves the upper small intestine (duodenum and proximal jejunum). It is associated with clubbing of the fingers, abdominal pain, weight loss, diarrhea, vomiting, and malabsorption, and frequently occurs in a younger age group than "Western Hemisphere" intestinal lymphoma. Some patients also have alpha heavy chain disease. The sex ratio is equal, and the disease occurs only in Middle Eastern and North African Moslems and Jews. Upper gastrointestinal radiographs are frequently diagnostic, and per oral small intestinal biopsy is nearly always diagnostic. Pathologically, the following features are characteristic for Middle Eastern lymphoma: partial or total villous atrophy with only mildly abnormal surface epithelium, sparsity of crypts, lymphatic dilatation, and infiltration of lamina propria by pleomorphic mononuclear cells which pepetrate the muscularis mucosa. The etiology and pathogenesis of this disease are unknown, but several hypotheses are discussed. Treatment by a variety of modalities is far from satisfactory, and the prognosis is much poorer than that observed in patients with the "Western" form of intestinal lymphoma. Other differences between Middle Eastern lymphoma and Western lymphoma are described in detail,

Pneumococcal sepsis and meningitis in vaccinated subjects: a review of 55 reported cases.

Fifty-five cases of the occurrence of serious pneumococcal infections in both splenectomized and nonsplenectomized individuals who received pneumococcal vaccine were reviewed from the literature. Reasons for vaccine failure included the occurrence of non-vaccine-type pneumococcal infections (18 cases), possible poor antibody response to the vaccine, especially if it is given postsplenectomy and/or following intensive steroid or other immunosuppressive therapy, and decline in antibody titer over time. Although the total number of vaccinated individuals is unknown, the overwhelming majority of the many thousands of vaccinees have been successfully protected with pneumococcal vaccine. In spite of very rare vaccine failures, pneumococcal vaccination (and perhaps penicillin prophylaxis) is strongly recommended for patients at high risk of developing serious pneumococcal infections, including all individuals undergoing splenectomy for any reason, or for those who have had a splenectomy or have functional asplenia.

Child care: implications for overweight / obesity in Canadian children?

INTRODUCTION: Over recent decades, two prominent trends have been observed in Canada and elsewhere: increasing prevalence of childhood overweight and obesity, and increasing participation of women (including mothers) in the paid labour force and resulting demand for child care options. While an association between child care and children's body mass index (BMI) is plausible and would have policy relevance, its existence and nature in Canada is not known. METHODS: Using data from the National Longitudinal Survey of Children and Youth, we examined exposure to three types of care at age 2/3 years (care by non-relative, care by relative, care in a daycare centre) in relation to change in BMI percentile (continuous and categorical) between age 2/3 years and age 6/7 years, adjusting for health and sociodemographic correlates. RESULTS: Care by a non-relative was associated with an increase in BMI percentile between age 2/3 years and age 6/7 years for boys, and for girls from households of low income adequacy. CONCLUSION: Considering the potential benefits of high-quality formal child care for an array of health and social outcomes and the potentially adverse effects of certain informal care options demonstrated in this study and others, our findings support calls for ongoing research on the implications of diverse child care experiences for an array of outcomes including those related to weight.