Phytochemical prospection and evaluation of antimicrobial, antioxidant and antibiofilm activities of extracts and essential oil from leaves of Myrsine umbellata Mart. (Primulaceae).

The species Myrsine umbellata is a native plant of Brazil, whose barks are traditionally used in herbal medicine to treat liver disorders and combat leprosy. Therefore, the aim of the study was to identify the phytochemical prospection of ethanolic (EE) and acetonic (EA) extracts by colorimetric tests and by gas chromatography coupled to mass spectrometry (GC-MS) of the essential oil (EO) of M. umbellata leaves; evaluate the antimicrobial activity in front of standard ATCC strains by the broth microdilution technique; the antioxidant potential by DPPH reduction method and antibiofilm action by crystal violet assay and cell viability was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) based on optical density. Phytochemical prospection of EE and EA detected the presence of free steroids, alkaloids, flavonoids (flavones, flavononoids, flavonols and xanthons) and tannins in both extracts (EE and EA) and saponins only in EE. In EO, the majority compounds identified were elixene, caryophyllene (E), spatulenol, d-Cadinene and aromadendrene. EA showed antimicrobial activity with MIC and MBC/MFC values ranging from 3.12 to 100 mg.mL-1, highlighting its efficiency on the Gram-positive strain S. epidermidis. EE showed antimicrobial potential in the range of 3.12 to 200 mg.mL-1, and the Gram-negative E. coli strain was the most susceptible. However, OE showed bacteriostatic potential against S. Typhimurium, S. Abaetetuba, P. aeruginosa, and S. epidermidis strains. The ability to sequester free radicals was evident in EA extract with antioxidant activity of 89.55% and in EE with 63.05%. The antibiofilm potential was observed in EE extract which eradicated the mature biofilm biomass of all tested bacteria with high activity (50% to 84.28%) and EO also showed antibiofilm effect on mature biofilm of UEL enteroaggregative E. coli, S. aureus and S. Enteritidis strains with biomass reduction percentage of 63.74%, 68.04% and 86.19%, respectively. These results indicate the potential of M. umbellata extracts and as a source of plant bioactivity for the development of new alternative strategies for the control of planktonic or biofilm-resistant microorganisms.

Toll-like receptor 2 deficiency improves insulin sensitivity and hepatic insulin signalling in the mouse.

AIMS/HYPOTHESIS: Substantial evidence suggests a link between elevated inflammation and development of insulin resistance. Toll-like receptor 2 (TLR2) recognises a large number of lipid-containing molecules and transduces inflammatory signalling in a variety of cell types, including insulin-responsive cells. Considering the contribution of the fatty acid composition in TLR2-depedent signalling, we hypothesised that the inflammatory signals transduced by TLR2 contribute to insulin resistance. METHODS: Mice deficient in TLR2 were used to investigate the in vivo roles of TLR2 in initiating and maintaining inflammation-associated insulin resistance and energy homeostasis. RESULTS: We first recapitulated the observation with elevated expression of TLR2 and inflammatory cytokines in white adipose tissue and liver of ob/ob mice. Aged or high-fat-fed TLR2-deficient mice were protected from obesity and adipocyte hypertrophy compared with wild-type mice. Moreover, mice lacking TLR2 exhibited improved glucose tolerance and insulin sensitivity regardless of feeding them regular chow or a high-fat diet. This is accompanied by reductions in expression of inflammatory cytokines and activation of extracellular signal-regulated kinase (ERK) in a liver-specific manner. The attenuated hepatic inflammatory cytokine expression and related signalling are correlated with increased insulin action specifically in the liver in TLR2-deficient mice, reflected by increased insulin-stimulated protein kinase B (Akt) phosphorylation and IRS1 tyrosine phosphorylation and increased insulin-suppressed hepatocyte glucose production. CONCLUSIONS/INTERPRETATION: The absence of TLR2 attenuates local inflammatory cytokine expression and related signalling and increases insulin action specifically in the liver. Thus, our work has identified TLR2 as a key mediator of hepatic inflammation-related signalling and insulin resistance.

Isosporosis and unizoite tissue cysts in patients with acquired immunodeficiency syndrome.

Isospora belli, a coccidian parasite in humans, has been described as causing chronic diarrhea and acalculous cholecystitis in patients with the acquired immunodeficiency syndrome (AIDS). Diagnosis can be made at the tissue level in the epithelium of the small bowel and by fecal examination. Disseminated extraintestinal forms are uncommon. We studied 118 adult patients with AIDS and chronic diarrhea using stool analysis and endoscopy with duodenal biopsy specimen collection. These samples were processed by routine histology and transmission electron microscopy. Isosporosis was diagnosed in 8 cases. In 2 of them, unizoite tissue cysts were present in the lamina propria, with negative results in stool materials. The cysts were located within a large parasitophorous vacuole. There were no structural means of differentiating the species level of Isospora based on morphology using light or electron microscopy. We believe further work should be done to determine if unizoite tissue cysts are part of the cycle of I belli or of other species of Isospora that could be pathogenic in immunocompromised hosts.

Autologous peripheral blood stem cell transplantation using simplified procedures for collection and freezing.

BACKGROUND: High-dose therapy with peripheral blood stem cell (PBSC) transplantation has been used increasingly for chemosensitive malignancies. The conventional procedures for collection and freezing of PBSCs are time-consuming and expensive. The optimal conditions for priming, collection and freezing of PBSCs have yet to be simplified. METHODS: Simplified procedures for mobilization, collection and freezing were developed to provide PBSC transplantation. Twenty-two cancer patients were given intensive chemotherapy with a variety of regimens using granulocyte-colony stimulating factor (G-CSF, filgrastim) 300 micrograms/d subcutaneously to mobilize PBSCs. A rapidly rebounding white blood cell (WBC) count from nadir was used to predict the time of peak PBSC release and plan leukapheresis. Leukapheresis was performed, when the WBC count was greater than 1.0 x 10(9)/l. RESULTS: Leukapheresis was performed in all 22 patients on day 10 to 14 after completing intensive chemotherapy. G-CSF to mobilize PBSCs was administered for a median of 10 days (range, 7-12 days). Twenty-one of 22 patients achieved the target yield of greater than 2 x 10(6) CD34+ cells/kg of body weight (BW). This was achieved in a median of two harvests (range, 2-4), with a median processed blood volume of 10.2 l/apheresis. A median of 6.4 x 10(8) mononuclear cells/kg BW and 5.2 x 10(6) CD34+ cells/kg BW for each patient were obtained. After high-dose cancer chemotherapy and PBSC transplantation, rapid and sustained hematopoietic engraftment occurred in all but one patient who had an inadequate number of CD34+ cells. In patients with an adequate target yield of CD34+ cells, the median times to achieve an absolute neutrophil count of greater than 0.5 x 10(9)/l and a platelet count of greater than 20 x 10(9)/l were nine days (range, 7-12 days) and 12 days (range, 8-14 days), respectively. CONCLUSIONS: Adequate PBSCs can be achieved within a median of two aphereses in most eligible cancer patients. Apheresis should be performed on day 10 to 14 after completing intensive chemotherapy, followed by G-CSF 300 micrograms/d. This simple and effective approach makes PBSC transplantation more practicable for a wider range of malignant diseases.

Characterization of granular particles isolated from postsynaptic densities.

We describe here the isolation and biochemical characterization of a population of protein aggregates from the postsynaptic density (PSD) prepared from pig cerebral cortex. The protein constituents of these aggregates are linked together primarily by disulfide bonds. Negative staining electron microscopy revealed that the isolated protein aggregates were granular objects with an average outside diameter of approximately 21 nm and with small protrusions on their surface. The major constituents of the isolated granular aggregates consist of tubulin and an unidentified protein of 70 kDa in size. Small amounts of the alpha subunit of calcium/calmodulin-dependent protein kinase II and subunits of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid and NMDA subtypes of glutamate receptors were also detected by immunoblotting. Actin, however, was not found in these granular aggregates. We propose that these granular protein aggregates correspond to the approximately 20-nm-diameter granular particles of the PSD on the basis of their biochemical and morphological characteristics. The spatial arrangement of these granular aggregates relative to other components of the postsynaptic terminal is also postulated here.