Relationship between mast cells and E-cadherin in odontogenic keratocysts and radicular cysts

Clinical Oral Investigations - This study aimed to evaluate tryptase and E-cadherin protein expression in odontogenic keratocysts (OKCs) and radicular cysts (RCs) and their relationship with lesion...     

Immunohistochemical expression of TFIIH and XPF in oral tongue squamous cell carcinoma

European Archives of Oto-Rhino-Laryngology - The query for biomarkers that indicate tumor aggressiveness and the host’s response to treatment is still one of the leading aims of cancer...     

Photocatalytic degradation of ibuprofen using titanium oxide: insights into the mechanism and preferential attack of radicals

The present work studied ibuprofen degradation using titanium dioxide as a photocatalyst. Mechanistic aspects were presented and the preferred attack sites by the OH˙ radical on the ibuprofen molecule were detailed, based on experimental and simple theoretical-computational results. Although some previous studies show mechanistic proposals, some aspects still need to be investigated, such as the participation of 4-isobutylacetophenone in the ibuprofen degradation and the preferred regions of attack by OH˙ radicals. The photodegradation was satisfactory using 0.03 g of TiO₂ and pH = 5.0, reaching 100% decontamination in 5 min. The zeta potential curve showed the regions of attraction and repulsion between TiO₂ and ibuprofen, depending on the pH range and charge of the species, influencing the amount of by-products formed. Different by-products have been identified by GC-MS, such as 4-isobutylacetophenone. Ibuprofen conversion to 4-isobutylacetophenone takes place through decarboxylation reaction followed by oxidation. The proposed mechanism indicates that the degradation of ibuprofen undergoes a series of elementary reactions in solution and on the surface. Three different radicals (OH˙, O₂⁻˙ and OOH˙) are produced in the reaction sequence and contribute strongly to the oxidation and mineralization of ibuprofen and by-products, but the hydroxyl radical has a greater oxidation capacity. The simple study using the DFT approach demonstrated that the OH˙ radical attacks preferentially in the region of the ibuprofen molecule with high electronic density, which is located close to the aromatic ring (C C bond). The presence of the OH˙ radical was confirmed through a model reaction using salicylic acid as a probe molecule.

The degradation of ibuprofen undergoes a series of elementary reactions, generating different radicals which attack preferentially in the region of the ibuprofen with high electron density.     

Supplementation with Herbal Extracts to Promote Behavioral and Neuroprotective Effects in Experimental Models of Parkinson's Disease: A Systematic Review

Parkinson's disease (PD) consists of a neurodegenerative pathology that has received a considerable amount of attention because of its clinical manifestations. The most common treatment consists of administering the drugs levodopa and biperiden, which reduce the effectiveness of the disease and the progress of its symptoms. However, phytotherapy treatment of PD has shown great potential in retarding the loss of dopaminergic neurons and minimizing the behavioral abnormalities. The aim of this study is to systematically review the use of supplemental herbal plants with cellular protective effect and behavioral activity in in vivo and in vitro experimental models. A total of 20 studies were summarized, where the effectiveness of herbal extracts and their isolated bioactive compounds was observed in animal models for PD. The main neurochemical mechanisms found in these studies are schematically represented. The herbal extracts and their biocompounds have antioxidant, anti‐apoptotic, and antiinflammatory properties, which contribute to avoiding neuronal loss. Reports show that besides acting on the biosynthesis of dopamine and its metabolites, these compounds prevent D2 receptors' hypersensitivity. It is suggested that further studies need be conducted to better understand the mechanisms of action of the bioactive compounds distributed in these plants. Copyright © 2017 John Wiley & Sons, Ltd.     

Chediak-Higashi gene in humans. I. Impairment of natural - killer function

Natural-killer (NK)-cell function was profoundly depressed in donors homozygous for the Chediak-Steinbrinck-Higashi syndrome (C-HS) gene when compared with age- and sex-matched normals. This apparent defect was not simply a result of a delayed response because little cytolysis was evident in kinetics experiments even after 24 h of incubation. NK cells from C-HS donors failed to lyse adherent (MDA, CEM, and Alab) or nonadherent (K562 and Molt-4) tumor cell lines or nontransformed human fetal fibroblasts. Therefore, the apparent C-HS defect was not a result of a shift in target selectivities. In addition, the depressed reactivity did not appear to be a result of suppressor cells or factors because: (a) enriched NK populations (nonadherent lymphocytes bearing receptors for the Fc portion of IgG) from C-HS donors were low in NK-cell function, (b) C-HS mononuclear cells did not inhibit the cytotoxicity of normal cells in coculture experiments, and (c) cells from the C-HS donors remained poorly reactive even after culture for up to 7 d. The nature of the defective NK activity in C-HS patients is not clear but may lie within the lytic mechanism rather than at the level of the recognition structure or population size because the frequency of target-binding cells was normal. In vitro NK activity could be partially restored by interferon treatment. Combined with the results presented in the following paper (4), these observations suggest that the C-HS gene causes a selective immunodeficiency disorder, mainly involving NK cells. This finding, in conjunction with the high incidence of spontaneous possibly malignant, lymphoproliferative disorders in these patients, may have important implications regarding the theory of immune surveillance mediated by NK cells.     

Characteristics of human large granular lymphocytes and relationship to natural killer and K cells

Recent evidence, has demonstrated an association between a subpopulation of peripheral blood mononuclear cells, morphologically identified as large granular lymphocytes (LGL), and natural killer (NK) activity. We have now evaluated more directly the role of LGL in both NK activity and antibody- dependent cellular cytotoxicity (ADCC), by using highly enriched populations of LGL, obtained by centrifugation of peripheral blood mononuclear cells on Percoll discontinuous density gradients. Both spontaneous and interferon- augmented NK and ADCC activities were exclusively associated with the LGL- enriched, low density fractions. The majority of LGL formed conjugates with NK-susceptible and antibody-coated target cells. Approximately 20 percent of small conventional lymphocytes also formed conjugates with the target cells for NK, but this was not associated with cytotoxic activity. Virtually all LGL were found to have receptors for the Fc portion of IgG (FcγR). The frequency of LGL among blood leukocytes was 2-6 percent. LGL could be enriched to an average purity of 95 percent by combining discontinuous density gradient centrifugation with subsequent adsorptions of the low density fractions on monolayers of immobilized immune complexes. About 50 percent of LGL were found to be FcγR-bearing T cells (T(G)), forming low affinity rosettes with sheep erythrocytes at 4 degrees C. Only 10-20 percent of LGL formed high affinity rosettes with sheep erythrocytes at 29 degrees C. LGL could be enriched to a purity of more than 90 percent by depleting high affinity rosette-forming cells from low density Percoll fractions. LGL were only a subpopulation of T(G) cells, because some lymphocytes with conventional morphology also adhered to the immobilized immune complex monolayers and formed high affinity rosettes with sheep erythrocytes. Separation of these cells from LGL by discontinuous density gradient centrifugation indicated that they are not cytotoxic, suggesting a morphological and functional subdivision of T(G) cells. The verification in this study that virtually all human NK and K cells have a characteristic morphology adds a useful parameter to the monitoring of human lymphocytes, and the ability to purify these cells by simple physical procedures should be invaluable in their further characterization.     

低氧训练对下丘脑-垂体-肾上腺皮质轴内分泌相关激素的影响

目的:总结低氧训练对下丘脑-垂体-肾上腺皮质轴内分泌相关激素的影响,为科学运动训练提供依据。资料来源:应用计算机检索中国期刊全文数据库1994-01/2006-10的相关文章,检索词"低氧,低氧训练,下丘脑-垂体-肾上腺,激素",并限定文章语言种类为中文。并应用计算机检索美国国立医学图书馆NCBI1980-01/2006-10的相关文章,检索词"Hypoxic Training,organism endocrine system,hormone",并限定文章语言种类为English。资料选择:对资料进行初审,选取低氧训练与下丘脑-垂体-肾上腺分泌的相关激素有关的文献,并作初步分类,同类文献首选近年发表的核心期刊文章。排除重复及综述类文献。资料提炼:共收集到95篇相关文章,其中56篇属于重复及综述类文献,对符合标准38篇文献进行分析整理。资料综合:①高海拔状态下机体对低氧产生应激反应,表现为下丘脑-垂体-肾上腺皮质轴的适应性运转,血中促肾上腺皮质激素浓度增加,以调节机体对应激刺激的适应能力,同时使促肾上腺皮质激素释放因子分泌增加。②高原训练后,睾酮和皮质醇的变化都较明显,其总体变化均趋于降低,睾酮/皮质醇值有升有降,从一定意义上反映了机体的机能状况与疲劳积累程度。③低氧还引起大鼠血浆β-内啡肽浓度升高,可使心房钠尿素增加、前列腺素增加、血管内皮素分泌增加及抑制血管内皮舒张因子的分泌。结论:激素对机体的新陈代谢、生长发育、各种功能活动以及维持内环境稳态等方面发挥重要的调节作用,低氧训练对机体激素的影响一直应该受到人们的关注。     

Role of cellulosic and noncellulosic membranes in hyperhomocysteinemia and oxidative stress

Hyperhomocysteinemia is an independent risk factor for cardiovascular morbidity and mortality in end-stage renal disease (ESRD) with an increased relative risk (RR) of 1% per micromol/L in total homocysteine concentration. In ESRD patients who undergo hemodialysis (HD), the antioxidant system is largely inadequate in correcting the imbalance between generation and scavenging of reactive oxygen species (ROS). To clarify the role of several cellulosic (CMs) and noncellulosic of synthetic membranes (NCMs) upon hyperhomocysteinemia and the oxidative stress, we measured plasma (P) homocysteine (t-HCY), plasma lipid peroxidation (LPO), and erythrocyte (E) concentration of several antioxidant enzymes in 20 normal subjects, in 35 HD patients treated with CMs, and in 29 patients treated with NCMs. Before, during, and after the first session of the week (at times 0', 120', end, 30' after HD end), blood samples were drawn. Plasma (P) homocysteine (t-HCY), cysteine (CYS), malondialdehyde (MDA), erythrocyte (E)-glutathione (GSH), glucose-6-phosphodehydrogenase (G6PD), glutathione reductase (GR), glutathione peroxidase (GPx), catalase (CAT), and superoxide-dismutase (SOD) were determined. The dialytic procedure significantly decreased the three plasma parameters, but none normalized (as a mean). The E-enzymes scavenging ROS (lower than normal before session) increased throughout the session, but the normal range of activity was never reached. Different membranes have shown different effects. When these effects on P and E spaces were pooled, we were able to classify the membranes as follows. In a general sense, cellulosic membranes are less effective than synthetic membranes both on lipoperoxides (LPO) and antioxidant activity (AOA). Among synthetic membranes, PMMA is the best membrane both for plasma values and lesser enzymatic derangement during the session. A practical system for classifying the anti-atherosclerotic action and antioxidant activity of dialytic membranes is proposed.     

Presence of the cfxA gene in Bacteroides distasonis

In this study we investigated the presence of the cfxA gene (encoding a class A beta-lactamase) in 73 strains of the Bacteroides fragilis group belonging to the species B. distasonis (34), B. vulgatus (14), B. thetaiotaomicron (8), B. merdae (6), B. caccae (9) and B. ovatus (2) isolated from human intestinal microflora of healthy children and adults. Employing specific primers to the cfxA gene, a 312-bp amplified fragment was obtained in 2 strains of B. vulgatus and 9 strains, the majority from children, of B. distasonis. The expression of this enzyme was analysed by determining the MICs to cefoxitin and cefotaxime and values varied from 2 to >256 microg/ml of both cefoxitin and cefotaxime. Sequence analysis of the amplicons corresponding to the cfxA gene from B. distasonis and B. vulgatus revealed identical sequences between these isolates and high similarity with other beta-lactamase genes of anaerobes such as cfxA of B. vulgatus (99%) and cfxA2 of Prevotella intermedia (99%), both sequences of which deposited in Genbank under accession numbers U38243 and AF118110, respectively. However, a fragment obtained from a B. distasonis strain (EC17-4) showed a unique RFLP profile and 87% nucleotide similarity with cfxA and cfxA2 genes. These results seem to suggest a dissemination of these resistance determinants among Bacteroides species.