Undergraduate dental sudents' perspectives about experiences in primary care for their education in the field of health / Perspectivas de graduandos em odontologia acerca das experiências na atenção básica para sua formação em saúde

Supervised training periods in primary care have been used as spaces for teaching and extension in the area of health, making it feasible to include undergraduates in concrete teaching-learning scenarios. The aim of this study was to analyze the perceptions of dental students about the importance of supervised training periods in Family Health Units to their professional education. The sample consisted of 185 students who answered the question: What is your opinion about the importance of this training period in SUS to your professional education? Comment on this experience and its positive and negative aspects The responses were analyzed by the quali-quantitative Collective Subject Discourse (CSD) technique. The students appreciated learning through practice in the service; contact with professionals from other areas; opportunity for technical-operative improvement and demonstrated sensitivity in the face of social reality, although they appeared to be concerned about being absent from the faculty, arguing that they were being prejudiced as regards their intramural clinical productivity, exhaustively demanded of them. It was concluded that students placed value on the extramural experience, however, it was perceived that there was still a predominant influence of focus on intramural clinical training.

Os estágios supervisionados na atenção básica vêm sendo utilizados como espaços de ensino e extensão nas áreas da saúde, viabilizando a inserção dos graduandos em cenários concretos de ensino-aprendizagem. O objetivo deste estudo foi analisar as percepções de acadêmicos de odontologia sobre a importância do estágio supervisionado em Unidades de Saúde da Família, para sua formação profissional. A amostra foi constituída por 184 acadêmicos que responderam à questão: Qual a sua opinião em relação à importância deste estágio no SUS para a sua formação profissional? Comente esta experiência e seus aspectos positivos e negativos. As respostas foram analisadas através da técnica qualiquantitativa do discurso do sujeito coletivo. Os alunos valorizaram o aprendizado através da prática no serviço, do contato com profissionais de outras áreas, da oportunidade de aperfeiçoamento técnico-operatório e demonstraram sensibilização frente à realidade social, embora tenham aparentado incômodo por se ausentarem da faculdade, sob o argumento de serem prejudicados quanto à produtividade da clínica intramuros, exaustivamente cobrada. Concluiu-se que os alunos valorizaram a experiência extramural, entretanto, percebeu-se que ainda há uma hegemonia do foco no treinamento clínico intramuros.

Anti-melanogenic effects of black, green, and white tea extracts on immortalized melanocytes

Tea contains polyphenols and is one of the most popular beverages consumed worldwide. Because most tyrosinase inhibitors that regulate melanogenesis are phenol/catechol derivatives, this study investigated the inhibitory effects of Camellia sinensis water extracts (CSWEs), including black tea, green tea, and white tea extracts, on melanogenesis using immortalized melanocytes. CSWEs inhibited melanin accumulation and melanin synthesis along with tyrosinase activity in a concentration-dependent manner. These inhibitory effects were superior to those of arbutin, a well-known depigmenting agent. The anti-melanogenic activity of black (fermented) tea was higher than that of a predominant tea catecholamine, epigallocatechin gallate. CSWEs, especially black tea extract, decreased tyrosinase protein levels in a concentration-dependent manner. These results suggest that the anti-melanogenic effect of CSWEs is mediated by a decrease in both tyrosinase activity and protein expression, and may be augmented by fermentation. Thus, CSWEs could be useful skin-whitening agents in the cosmetic industry.

Development of bioconjugate from Streptomyces tyrosinase and gold nanoparticles for rapid detection of phenol constituents.

Most of the phenol compounds are toxic and have been considered as hazardous pollutants. Several physicochemical and biological methods are available to detect and monitor the phenol pollutants in water and soil. In the present study, phenol constituents of winery, paper and plastic industrial effluents were successfully detected employing tyrosinase-gold nanoparticles bioconjugate. The synthesis of extracellular tyrosinase and gold nanoparticles was achieved by a single isolate of Streptomyces sp. DBZ-39. Enhanced production (369.41 IU) of tyrosinase was produced in submerged bioprocess employing response surface method with central composite design. Extracellular gold nanoparticles synthesized (12-18 nm) by Streptomyces sp. DBZ-39 were characterized with TEM, EDAX and FTIR analysis. A rapid detection (within 10 min) of phenol constituents from winery effluents was achieved by bioconjugate, when compared to tyrosinases and gold nanoparticles independently. Streptomyces tyrosinase could exhibit relatively a better performance than commercially available mushroom tyrosinase in the detection of phenol constituents. Winery effluent has shown much higher content (0.98 O.D) of phenol constituents than paper and plastic effluents based on the intensity of color and U.V absorption spectra.

Glyceollins, a novel class of soybean phytoalexins, inhibit SCF-induced melanogenesis through attenuation of SCF/c-kit downstream signaling pathways

The anti-melanogenesis effect of glyceollins was examined by melanin synthesis, tyrosinase activity assay in zebrafish embryos and in B16F10 melanoma cells. When developing zebrafish embryos were treated with glyceollins, pigmentation of the embryos, melanin synthesis and tyrosinase activity were all decreased compared with control zebrafish embryos. In situ expression of a pigment cell-specific gene, Sox10, was dramatically decreased by glyceollin treatment in the neural tubes of the trunk region of the embryos. Stem cell factor (SCF)/c-kit signaling pathways as well as expression of microphthalmia-associated transcription factor (MITF) were determined by western blot analysis. Glyceollins inhibited melanin synthesis, as well as the expression and activity of tyrosinase induced by SCF, in a dose-dependent manner in B16F10 melanoma cells. Pretreatment of B16F10 cells with glyceollins dose-dependently inhibited SCF-induced c-kit and Akt phosphorylation. Glyceollins significantly impaired the expression and activity of MITF. An additional inhibitory function of glyceollins was to effectively downregulate intracellular cyclic AMP levels stimulated by SCF in B16F10 cells. Glyceollins have a depigmentation/whitening activity in vitro and in vivo, and that this effect may be due to the inhibition of SCF-induced c-kit and tyrosinase activity through the blockade of downstream signaling pathway.

Immunomodulation by 'Immuplus (AquaImmu)' in giant freshwater prawn, Macrobrachium rosenbergii (De Man).

ImmuPlus, a polyherbal commercial formulation was used to modulate the immune system of commercially important giant freshwater prawn M. rosenbergii. The prawns were fed with basal diet supplemented with ImmuPlus at 1g/kg feed for 4 weeks. Results showed that the phenoloxidase activity (PO), haemagglutination and lysozyme activities were significantly elevated in ImmuPlus-fed prawn up to 3 weeks of feeding and declined after 4 weeks of feeding. The total protein level in ImmuPlus-fed prawn raised up to 2nd week of feeding. Incorporation of ImmuPlus at the rate of 1g/kg feed in the diet of prawn for 3 weeks may be beneficial in raising the immune status of prawn.

Lag kinetics of tyrosinase: its physiological implications.

The various theories put forward to explain the characteristic lag kinetics of oxidation of L-tyrosine by tyrosinase a rate regulatory step in the biosynthesis of melanin are reviewed Examination of the evidence in the literature and from experiments in the author's laboratory indicate that one of the hypotheses, that is, competition of tyrosine and dopa for met-tyrosinase and the formation of a dead-end complex of met-enzyme with tyrosine as explanation for lag kinetics is not consistent with available information. The alternative hypothesis that tyrosinase is an allosteric enzyme with tyrosine having negative effector site on the enzyme and dopa competing for it as an explanation for lag kinetics of tyrosinase is not yet disproved. Irrespective of the actual explanation for the lag kinetics of tyrosinase, it is suggested that the highly conserved lag kinetics may serve a physiological function. It is suggested that this function is to keep the enzyme essentially inactive during its transport to the specific organelle, namely the melanosome, in which an acidic environment exists. Only at acidic pH is the enzyme able to catalyze the biosynthesis of melanin.

Tyrosinase exhibits lag at pH 6.8 under steady state concentrations of tyrosine and 3,4-dihydroxy phenyl alanine in melanoma tissue.

Tyrosine to dopa ratio determines the extent of lag in cresolase activity of tyrosinase when assayed at pH 6.8. The levels of tyrosine and dopa in B-16 murine melanoma tissue were found to be 213 and 13 mmoles/g fresh wt of tissue respectively. Cresolase activity of tyrosinase, when assayed at the above steady state levels of tyrosine and dopa at pH 6.8, exhibited a lag of 5-15 min depending on the amount of enzyme used in the assay mixture and the initial enzyme activity was zero. Under in vivo conditions, the enzyme with zero initial activity can not be active and therefore a far reaching conclusion is that tyrosine to dopa ratio may not regulate the enzyme activity, unlike under in vitro conditions. Possible modes of the regulation of tyrosinase under in vivo conditions are discussed.

Unique metabolic properties of Mycobacterium leprae.

My first contact with Dr. Dharmendra was through correspondence. While working for Ph.D., I wrote to him that a section in his book "Notes on Leprosy" was ambiguous. Instead of ignoring the letter, he replied, agreeing to clarify it in the revised edition. I went to work at Carville at the invitation of Dr. Kirchheimer, who had seen my Ph.D. thesis. Dr. Dharmendra visited Carville to receive the Damien-Dutton award and stayed there for a few days. Carville is an isolated place with no public transportation. I used to take him for afternoon drives to the countryside around Carville. He published some of our papers in Leprosy in India and later in Indian Journal of Leprosy. He was very prompt in acknowledging receipt of manuscripts and suggesting any changes to be made. He also reprinted in the Journal several of our papers published elsewhere, and also a lecture I gave at a meeting of the Japanese Leprosy Association. During one of my visits to India, Dr. M. C. Vaidya had arranged a talk by me at the All India Institute of Medical Sciences, New Delhi. At the invitation of Dr. Dharmendra, I visited him in his home. We used to exchange new year cards and letters. He wrote to me about his eye infection and consequent loss of sight in one eye. He asked me to write an editorial for an issue of Indian Journal of Leprosy (January 1989). The last time I met him was during the International Leprosy Congress held in New Delhi.

Aislamiento y caracterización parcial de la enzima fenoloxidasa de manzana (Malus domestica, var. Anna) / Isolation and partial characterization of phenoloxidase from apple (Malus domestica, var. Anna)

El objetivo de este trabajo fue el aislamiento y la caracterización parcial de la enzima polifenoloxidasa de manzana (Malus domestica Var. Anna), cosechada en la región semidesértica de la Costa de Hermosillo, Sonora, México. Se estudió el efecto que tienen el pH, temperatura, especificidad hacia sustratos y separación bajo condiciones de cromatografía hidrofóbica. La enzima se aisló a partir de manzanas maduras tratadas con acetona fría. Del polvo residual obtenido se extrajo la enzima con regulador de fosfatos, y el extracto se utilizó para realizar caracterización, encontrándose que el pH y temperatura óptimos eran 5.36 y 35§C, respectivamente. La especificidad hacia sustratos mostró ser decreciente desde 4-metil catecol, ácido clorogénico, catecol y ácido cafeico hasta 3.4-dihidroxifenilalanina (DOPA). La enzima resultó ser más termoestable que la generalidad de las oxidasas en el intervalo de temperatura de 35§C a 60§C. El comportamiento del extracto a través de cromatografía hidrofóbica produjo un solo pico con actividad polifenolásica, lográndose una purificación de aproximadamente 300 veces. El contenido de compuestos con grupo fenólico fue de 1.16 g/100 g de fruta fresca. Las características polifenolásicas encontradas se asemejan a las de manzanas de regiones templadas, aunque éstas presentan una mayor termoestabilidad, lo que explica hasta cierto grado la gran influencia que la temperatura ejerce sobre el fenómeno del oscurecimiento enzimático en las condiciones tan cálidas...

Dopa-oxidase activity on ICRC bacilli.

Presence of O-phenoloxidase is regarded as M. leprae specific character. This enzyme activity was found to be present in ICRC bacilli, Strain C-44. Though this strain is cultivable 'in vitro', the expression of DOPA-Oxidase activity strongly suggests that it carries M. leprae genome. The ICRC bacilli, therefore, may thus from a group of M. leprae culture isolates, distinct from other known cultivable mycobacteria which do not possess this enzyme activity.