Purification and Properties of an <Emphasis Type="Italic">N</Emphasis>-acetylglucosaminidase from <Emphasis Type="Italic">Streptomyces cerradoensis</Emphasis>

An N-acetylglucosaminidase produced by Streptomyces cerradoensis was partially purified giving, by SDS-PAGE analysis, two main protein bands with Mr of 58.9 and 56.4 kDa. The K_m and V_max values for the enzyme using p-nitrophenyl-β-N-acetylglucosaminide as substrate were of 0.13 mM and 1.95 U mg⁻¹ protein, respectively. The enzyme was optimally activity at pH 5.5 and at 50 °C when assayed over 10 min. Enzyme activity was strongly inhibited by Cu²⁺ and Hg²⁺ at 10 mM, and was specific to substrates containing acetamide groups such as p-nitrophenyl-β-N-acetylglucosaminide and p-nitrophenyl-β-D-N,N′-diacetylchitobiose.     

Effect of the period of resting in elite judo athletes

The purpose of this study was to evaluate the effect of the resting period on hematological and copper-zinc-dependent antioxidant indices in Brazilian elite judo athletes (n=7). Venous blood samples were collected after 24-h and 5-d periods of resting following a competition, with an interval of 30 d between collections. Two months prior to and during the study, each athlete received an individualized adequate diet. Body composition was determined at both study periods. The following were analyzed: in whole blood, hemoglobin, hematocrit, red cell count, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, red cell distribution width, and white cell count; in plasma, zinc, copper, iron, ceruloplasmin, and total iron-binding capacity; in erythrocytes, metallothionein, copper/zinc superoxide dismutase, and osmotic fragility. Dietary intake and body composition did not affect the biochemical measurements. A significant reduction in ceruloplasmin and superoxide dismutase activity was found after 5 d compared to 24 h of resting. A significant correlation between erythrocyte metallothionein and red cell distribution width was observed after 24 h of resting (r=−0.83, p=0.02) whereas positive correlations of metallothionein with hemoglobin, red cell count, and mean corpuscular hemoglobin concentration were observed after 5 d of resting (r≥0.76, p≤0.05). Our results suggest that a longer resting period favors homeostatic adjustments in the erythrocyte population and in the copper/zinc-dependent antioxidant system in elite judo athletes.     

Response of melon fly (Diptera: Tephritidae) to weathered SPLAT-Spinosad-Cue-Lure

Studies were conducted in Hawaii to measure attraction of male melon fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae), to SPLAT-Cue-Lure (C-L) and SPLAT-Melo-Lure (M-L) (raspberry ketone formate). Direct field comparisons of SPLAT-C-L and SPLAT-M-L at low (5%) and high (20%) concentrations indicated few differences in attraction over a 15-wk period. Subsequently, only SPLAT-Spinosad-C-L (5%) was compared with Min-U-Gel C-L with naled (standard used in California) in weathering studies. Treatments were weathered for 1, 2, 4, and 8 wk in Riverside, CA, and shipped to Hawaii for attraction/toxicity tests under field and semifield conditions by using released males of controlled ages, and for feeding tests in the laboratory. In terms of attraction, SPLAT-Spinosad-C-L compared favorably to, or outperformed the current standard of Min-U-Gel-C-L with naled. In terms of toxicity, the cumulative 24-h mortality did not differ between the two insecticide-containing C-L treatments in field cage studies after 8 wk. However, in feeding studies in which individual males were exposed for 5 min to the different C-L treatments after 4 wk of weathering, SPLAT-Spinosad-C-L demonstrated reduced mortality compared with the Min-U-Gel-C-L with naled, suggesting reduced persistence of the spinosad material. Spinosad has low contact toxicity and when mixed with SPLAT and C-L offers a reduced risk alternative for control of B. cucurbitae and related C-L-responding species, without many of the negative effects to humans and nontargets of broad-spectrum contact poisons such as naled.     

The Sesquiterpenes Polygodial and Drimanial in vitro Affect Glutamatergic Transport in Rat Brain

Natural products including those derived from plants, have over the years greatly contributed to the development of therapeutic drugs. Polygodial and drimanial are sesquiterpenes isolated from the bark of the plant Drymis Winteri (Winteraceae) that exhibit antinociceptive properties. Since peripheral glutamate presents nociceptive actions, in this study it was investigated the effects of hydroalcooholic extracts from Drymis winteri (polygodial and drimanial) on the glutamatergic system in rat brain. Polygodial and drimanial inhibited glutamate uptake by astrocytes, as well as by cortical, hippocampal and striatal slices, and increased synaptosomal glutamate release. These concurrent effects would predispose to an increase in the extracellular glutamate concentrations, leading to possible neurotoxic effects (excitotoxicity) of these natural compounds, which would suggest the need for some caution in their therapeutic application.     

Association of TP53 mutation, p53 overexpression, and p53 codon 72 polymorphism with susceptibility to apoptosis in adult patients with diffuse astrocytomas

Clarification of TP53 alterations is important to understand the mechanisms underlying the development of diffuse astrocytomas. It has been suggested that the alleles of TP53 at codon 72 differ in their ability to induce apoptosis in human cancers. The aim of this study was to analyze the possible association of TP53 mutation, p53 overexpression, and p53 codon 72 polymorphism with susceptibility to apoptosis in adult Brazilian patients with diffuse astrocytomas. We analyzed 56 surgical specimens of diffuse astrocytomas for alterations of TP53, using polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) direct sequencing. p53 and cleaved caspase 3 protein expression were assessed by immunohistochemistry. We found TP53 mutations in 19.6% (11 out of 56) of tumors tested, with the lowest mutation rate found in the cases of glioblastomas (8.8%) (p = 0.03). Only 16.1% of tumors tested showed cleaved caspase 3-positive staining, demonstrating that apoptosis is very inhibited in these tumors. All tumors having TP53 mutation and p53 accumulation had no expression of cleaved caspase 3. Additionally, no association was observed in tumors having proline and arginine alleles and expression of cleaved caspase 3. We concluded that clarification of the TP53 alterations allows a better understanding of the mechanisms involved in the progression of diffuse astrocytomas, and the allele status at codon 72 was not associated with apoptosis in these tumors.     

Frequency of natural regulatory CD4+CD25+ T lymphocytes determines the outcome of tolerance across fully mismatched MHC barrier through linked recognition of self and allogeneic stimuli

We show in this study that long-term tolerance to allogeneic skin grafts can be established in the absence of immunosuppression by the combination of the following elements: 1) augmenting the frequency of regulatory CD4(+)CD25(+) T cells (Treg) and 2) presentation of the allogeneic stimuli through linked recognition of allo- and self-epitopes on semiallogeneic F(1) APCs. BALB/c spleen cells enriched for CD4(+)CD25(+) T lymphocytes were transferred either to BALB/c nu/nu mice or to BALB/c nu/nu previously injected with F(1)(BALB/c x B6.Ba) spleen cells, or else grafted with F(1)(BALB/c x B6.Ba) skin (chimeric BALB/c nu/nu-F(1)). Chimeric BALB/c nu/nu-F(1) reconstituted with syngeneic CD25(+)-enriched spleen cells were unable to reject the previously transferred F(1)(BALB/c x B6.Ba) spleen cells or F(1)(BALB/c x B6.Ba) skin grafts, and a specific tolerance to a secondary B6 graft was obtained, with rejection of third-party CBA grafts. BALB/c nu/nu mice reconstituted only with syngeneic CD25(+)-enriched spleen cells rejected both B6 and CBA skin grafts. In contrast, when chimeric BALB/c nu/nu-F(1) were reconstituted with spleen populations comprising normal frequencies of Treg cells, the linked recognition of allo and self resulted in breaking of self tolerance and rejection of syngeneic grafts, strongly suggesting that linked recognition works in both directions, either to establish tolerance to allo, or to break tolerance to self, the critical parameter being the relative number of Treg cells.     

Effect of electromagnetic field on bone regeneration around dental implants after immediate placement in the dog mandible: a pilot study

doi: 10.1111/j.1741‐2358.2011.00525.x Effect of electromagnetic field on bone regeneration around dental implants after immediate placement in the dog mandible: a pilot study Background: Accelerating bone healing around dental implants can reduce the long‐term period between the insertion of implants and functional rehabilitation. Objective: This in vivo study evaluated the effect of a constant electromagnetic field (CEF) on bone healing around dental implants in dogs. Materials and methods: Eight dental implants were placed immediately after extraction of the first pre‐molar and molar teeth on the mandible of two male dogs and divided into experimental (CEF) and control groups. A CEF at magnetic intensity of 0.8 mT with a pulse width of 25 μs and frequency of 1.5 MHz was applied on the implants for 20 min per day for 2 weeks. Result and conclusion: After qualitative histological analysis, a small quantity of newly formed bone was observed in the gap between the implant surface and alveolar bone in both groups.     

The influence of mandibular implant-retained overdentures in masticatory efficiency

doi: 10.1111/j.1741‐2358.2011.00539.x The influence of mandibular implant‐retained overdentures in masticatory efficiency Objective: To evaluate the masticatory efficiency of patients rehabilitated with conventional dentures (CDs) or implant‐retained mandibular overdentures. Background: Despite the evident benefits of implants on mastication as assessed by subjective patient‐based outcomes, the extent of implant overdenture treatment effect on food comminution is not well established. Materials and methods: A randomised clinical trial was carried out with 29 completely edentulous patients divided into two groups. The first group was rehabilitated with a mandibular overdenture retained by two splinted implants with bar‐clip system, while the second group was rehabilitated with a mandibular CD. Both groups also were rehabilitated with maxillary CDs. Masticatory efficiency and patient satisfaction were assessed 3 months after denture insertion. Masticatory efficiency was evaluated through the colorimetric method with the beads as the artificial test‐food. Comparisons for masticatory efficiency and patient satisfaction were performed using Student’s t‐test (α = 0.05). Results: No significant statistical difference was found for masticatory efficiency (p = 0.198). Patient overall satisfaction was significantly higher for the mandibular overdenture (p < 0.001). In addition, mandibular overdenture patients were significantly more satisfied with chewing experience (p < 0.05) and retention of the lower denture (p < 0.005). Conclusion: The results of this study suggest that mandibular overdenture significantly improves chewing experience, although limited effect on masticatory efficiency has been observed.