Reduced synthesis of hepatic microsomal cytochroma P450 in the bile duct ligated rat

Cholestasis produced by bile duct ligation was associated with a 50% reduction in hepatic microsomal cytochrome P₄₅₀ content. Tentative identification of cytochrome P₄₅₀ in washed microsomal fractions was achieved on SDS-urea polyacrylamide gels by its physical properties, half-life and response to pharmacologic agents. The relative synthesis rate of P₄₅₀ apoprotein, determined by a double isotope method, was significantly reduced 3 days after bile duct ligation. P₄₅₀ apoprotein degradation was markedly reduced, with the half-life increasing from 24 to 50 hours. These data indicate that a reduced rate of synthesis, rather than increased degradation, is responsible for reduction of P₄₅₀ in cholestasis.     

Regional peculiarities of some deep mycoses

Summary Some observations suggest that some deep mycoses would show epidemiological and clinical dissimilarities in different countries.In some tropical zones the atypical, non lymphangitic, fixed forms of sporotrichosis are more frequently reported than the lymphangitic, typical forms. This difference has been ascribed to the uneven ability of the reporting authors to recognize the atypical forms, to early or late diagnosis as the lymphangitis has a tendency to disappear 3 to 4 months after the infection, to an inhibitory effect of high ambient temperatures on the growth of the fungus in the tissues and to reinfections in partially resistant people.The frequency of chromoblastomycosis coincides with its predominance in the lower limbs and therefore some causes of susceptibility to infection of the skin of the lower limbs are analized: non use of footwear, unbalanced diets, parasitic diseases and modifications of reactivity due to specific and non-specific sensitization.Some records are indicative that the first stage of the infection byNocardia brasiliensis may be a chancriform syndrome with lymphangitis showing a tendency toward self-limitation. The same causes which have been considered favorable for the development of chromoblastomycosis might have an influence on the frequency of mycetomas.Several factors may have an influence on the characteristics of histoplasmosis: presence or abscence of starlings, permanently high ambient temperature and humidity or alternance of warm-humid and cold seasons, early or late infection of children.Dissimilarities in the features of South American blastomycosis in different countries have still not been reported with accuracy. The frequency offer remarkable differences and the disease is recorded especially in subtropical humid areas of continental Latin America. The habitat of the fungus is unknown.

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Peculiaridades regionales de algunas micosis profundas

Resumen Algunas observaciones son sugestivas en el sentido de que algunas micosis profundas mostrarían diferencias epidemiológicas y clínicas en diferentes países.En algunas zonas tropicales cálidas las formas atípicas, no linfangíticas, fijas, de la esporotricosis son más frecuentemente registradas que las formas lifangíticas, típicas. Esta diferencia ha sido atribuída a la desigual habilidad de los diferentes autores para reconocer las formas atípicas, al diagnóstico precoz o tardío dado que la linfangítis tiende a desaparecer 3 a 4 meses despues de la infección, a un efecto inhibitorio de elevadas temperaturas ambientales sobre la vida del hongo en los tejidos y a reinfecciones en poblaciones parcialmente resistentes.La frecuencia de la cromoblastomicosis coincide con su predominancia en los miembros inferiores y en consecuencia se analiza algunas causas de susceptibilidad a la infección de la piel de las extremidades inferiores: no uso de calzado, dietas carenciadas, enfermedades parasitarias y modificaciones de la reactividad debida a sensibilización específica e inespecífica.Existen observaciones que indican que el primer estadio de la infección porNocardia brasiliensis puede ser un sindrome chancriforme con linfangitis con tendencia a auto-limitación. Las mismas causas que han sido consideradas como favos recedoras del desarrollo de la cromoblastomicosis podrían tener influencia en los micetomas y su frecuancia.Varios factores pueden tener influencia en las características de la histoplasmosis: pululación o ausencia de estorninos, temperaturas permanentemente delevadas y alto grado higrométrico en algunos países y alternancia de estaciones en otros, infección temprana o tardía de los niños.Diferencias en aspectos de la blastomicosis sudamericana en diferentes países aún no han sido relatadas con precisión. La frecuencia ofrece notables divergencias y la enfermedad es registrada especialmente en zonas sub-tropicales húmedas de América Latina continental. El habitat de su agente es desconocido.

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Read at the Official Meeting of The Medical Mycological Society of the Americas held in Mexico D. F., August 8, 1970.     

QMEANclust: estimation of protein model quality by combining a composite scoring function with structural density information

Background  

The selection of the most accurate protein model from a set of alternatives is a crucial step in protein structure prediction both in template-based and ab initio approaches. Scoring functions have been developed which can either return a quality estimate for a single model or derive a score from the information contained in the ensemble of models for a given sequence. Local structural features occurring more frequently in the ensemble have a greater probability of being correct. Within the context of the CASP experiment, these so called consensus methods have been shown to perform considerably better in selecting good candidate models, but tend to fail if the best models are far from the dominant structural cluster. In this paper we show that model selection can be improved if both approaches are combined by pre-filtering the models used during the calculation of the structural consensus.     

Factors influencing in the response of <i>Schizolobium parahybum</i> (Vell) Blake to <i>Ceratocystis paradoxa</i> and <i>C. moniliformis</i>

In the Ecuadorian coast one of the most destructive diseases of the pachaco is vascular wilt or stem rot caused by Ceratocystis complex, so the aim of this study was to determine the factors that affect the efficiency of the reaction of bark pachaco to this disease. This research was conducted under laboratory conditions, using trees pachaco S38, S41, S98, AE-1, AE-2 and AE-3, and pathogenic species Ceratocystis paradoxa and C. moniliformis. The method utilized was tissue stem bark,with bark sections with 4.5 cm², and a suspension of 3x10⁴ units infection and remained in a humid chamber for 96 hours at 25 ± 5 °C. Were determined grades of resistance/ susceptibility using a scale from 0 to 4, depending on the amount of mycelia and peritecio in each plant sample. Three factors were used: four colonies obtained by several transfers from each fungal specie, four ages of colonies of each fungal specie and four volumes of inoculum applied (units of infection), using for each experiment separately Completely Randomized Design with 4 replications factorial arrangement. For comparison between treatment means was used Tukey test at 5% probability of error. For future trials using this technique, you could use 30-day colonies for C. paradoxa and 40 days for C. moniliformis, and an application volume of 100 μL/cm², it would improve the level of response for the formation of perithecium and mycelia in samples cortex.     

Adult peripheral nerve disorders: nerve entrapment, repair, transfer, and brachial plexus disorders

LEARNING OBJECTIVES: After reading this article, the participant should be able to: 1. Describe the pathophysiologic bases for nerve injury and how they apply to patient evaluation and management. 2. Recognize the wide variety of injury patterns and associated patient complaints and physical findings associated with peripheral nerve pathology. 3. Evaluate and recommend further tests to aid in defining the diagnosis. 4. Specify treatment options and potential risks and benefits. SUMMARY: Peripheral nerve disorders comprise a gamut of problems, ranging from entrapment neuropathy to direct open traumatic injury and closed brachial plexus injury. The pathophysiology of injury defines the patient's symptoms, examination findings, and treatment options and is critical to accurate diagnosis and treatment. The goals of treatment include management of the often associated pain and improvement of sensory and motor function. Understanding peripheral nerve anatomy is critical to adopting novel nerve transfer procedures, which may provide superior options for a variety of injury patterns.     

Isocitrate dehydrogenase 1 R132C mutation occurs exclusively in microsatellite stable colorectal cancers with the CpG island methylator phenotype

The CpG Island Methylator Phenotype (CIMP) is fundamental to an important subset of colorectal cancer; however, its cause is unknown. CIMP is associated with microsatellite instability but is also found in BRAF mutant microsatellite stable cancers that are associated with poor prognosis. The isocitrate dehydrogenase 1 (IDH1) gene causes CIMP in glioma due to an activating mutation that produces the 2-hydroxyglutarate oncometabolite. We therefore examined IDH1 alteration as a potential cause of CIMP in colorectal cancer. The IDH1 mutational hotspot was screened in 86 CIMP-positive and 80 CIMP-negative cancers. The entire coding sequence was examined in 81 CIMP-positive colorectal cancers. Forty-seven cancers varying by CIMP-status and IDH1 mutation status were examined using Illumina 450K DNA methylation microarrays. The R132C IDH1 mutation was detected in 4/166 cancers. All IDH1 mutations were in CIMP cancers that were BRAF mutant and microsatellite stable (4/45, 8.9%). Unsupervised hierarchical cluster analysis identified an IDH1 mutation-like methylation signature in approximately half of the CIMP-positive cancers. IDH1 mutation appears to cause CIMP in a small proportion of BRAF mutant, microsatellite stable colorectal cancers. This study provides a precedent that a single gene mutation may cause CIMP in colorectal cancer, and that this will be associated with a specific epigenetic signature and clinicopathological features.     

Sex attractants in nematodes

Nematodes communicate with each other using pheromones - chemicals secreted by one individual that affect the behaviour of others of the same species. Chemicals secreted into the environment are known to influence host location, dormancy (dauer-larva formation), competitive interactions and mate detection; they benefit the nematode by reducing energy expenditure on less orientated movements. Of these chemicals, sex pheromones associated with mate detection and attraction are of particular interest as potential biological control agents. Here, Barbara MacKinnon discusses these developments.     

三种兰科植物的保护遗传学研究初探

采用随机扩增多态 DNA(RAPD)分析研究了中国3种珍稀濒危兰科植物硬叶兜兰(Paphiopedilum micranthum Tang et Wang)、麻栗坡兜兰(P. malipoense S.C.Chen et Tsi)和独花兰(Changnienia amoena Chien)的遗传多样性与群体遗传结构.12个RAPD引物在2种兜兰中共扩增出131条带.对4个硬叶兜兰群体的检测表明其物种水平的多态条带百分率(PPB)为 71.6%,Nei 的基因多样度(h)为 0.217 1,Shannon多样性指数 (I) 为 0.330 1;4个群体的平均多样性水平为 PPB = 45.2%,h = 0.145 7,I = 0.220 4,低于远交兰花的平均水平.在总遗传变异中,群体间遗传变异占20.31%,略高于远交物种的平均水平.在物种水平上,麻栗坡兜兰的PPB为49.5%,h为0.117 4,I为0.176 4,均大大低于硬叶兜兰.对11个独花兰群体采用16个RAPD引物共扩增出119条带.物种水平PPB=76.5%,h=0.194 1,I=0.305 8;在群体水平上,上述3个指标的平均值则分别为37.2%、0.119 7和0.181 0,均低于远交兰花的平均水平.群体间的遗传变异占45.27%,遗传分化明显高于远交物种的平均水平.导致3个物种遗传多样性偏低而群体间遗传分化较高的主要原因在于人为的过度采挖和生境的片断化.研究结果为兰花保护策略和措施的制定提供了理论基础.     

柠檬酸合酶的分子生物学研究进展

柠檬酸合酶（citrate synthase,CS）是细胞内多种重要代谢途径的关键酶。CS可催化草酰乙酸和乙酰辅酶A之间的缩合反应生成柠檬酸和辅酶A。通常革兰氏阳性细菌、古菌以及真核细胞的CS为同源二聚体,而革兰氏阴性细菌的CS为同源六聚体。根据其在细胞内的定位不同,CS可分为线粒体CS、乙醛酸循环体CS、过氧化物酶体CS。这些同工酶在能量代谢、植物脂肪的代谢、脂肪酸的氧化及细胞解毒过程中起着重要作用。不同来源的CS空间结构、催化机制和动力学性质十分相似。针对其生化特性、空间结构特点、催化机制以及分子进化等研究进展进行综述。     

Characterisation of Structures in Salivary Secretion Film Formation. An Experimental Study with Atomic Force Microscopy

The purpose of the present study was to characterise the structure dynamics of pure salivary secretions retained on controlled surfaces with different surface energies in the early stage of salivary film formation. Germanium prisms prepared to have either low surface energy or medium surface energy were incubated in fresh secretions of either human parotid saliva (HPS) or human submandibular/sublingual saliva (HSMSLS) for 15, 90, and 180 min. After controlled rinsing with distilled water, the surfaces were air dried and thereafter imaged with atomic force microscopy (AFM). The amount of adsorbed material and the size of the structures detected increased with increased saliva exposure time. The film thicknesses varied from 10 to 150 nm, and both HPS and HSMSLS films contained structures with diameters varying from 40 nm to 2 μm. Some of these were clustered into special formations. The HPS films exhibited a more granular morphology than the HSMSLS films. Furthermore, branched lines were detected on the low surface energy germanium prisms incubated in saliva. The results indicate that exposure time, surface energy, and type of salivary secretion all are factors affecting the adsorption characteristics of salivary films.