[Reconstruction of painful neuroma of superficial branch of radial nerve after first dorsal compartment release: presentation of two cases]. / Reconstrucción de neuroma de nervio radial superficial con injerto autólogo de nervio sural: presentación de dos casos.

INTRODUCTION: nerve lesions are potentially catastrophic injuries. They can cause motor loss, severe pain and neuroma formation. The superficial branch of the radial nerve is at risk during first dorsal compartment release, its injury can cause neuroma formation. Autologous nerve reconstruction is the gold standard for treatment of small nerve gaps. CASES PRESENTATION: we present two cases of adult women (F/47 y F/51) with a prior history of first dorsal compartment release in another institution. Both patients developed debilitating neuropathic pain, as well as allodynia in the surgical site. They were diagnosed with superficial radial nerve neuroma. Oral medication and physical therapy was attempted without success. Surgical exploration and autologous nerve reconstruction was performed. Both patients had excellent relief of pain from visual analogue scale (VAS 9-10 to VAS 1-2). Postoperatively, both patients recovered partial sensitivity to pain in the zones distal to the repair. CONCLUSIONS: neuromas are feared complications that occur with unrecognized nerve lesions during surgery, they are difficult to treat and require multidisciplinary management. These two cases demonstrate that autologous nerve reconstruction is an excellent option for recovering function in small gaps of nerve tissue.

INTRODUCCIÓN: las lesiones iatrogénicas de nervio son complicaciones devastadoras de cualquier procedimiento quirúrgico. Ocasionan pérdida motora, dolor y formación de neuromas. En el abordaje para la liberación del primer compartimiento extensor de la muñeca, la rama superficial del nervio radial debe identificarse y protegerse previo a la liberación tendinosa. La lesión de este nervio sensitivo puede ocasionar dolor postoperatorio clínicamente significativo. La reconstrucción nerviosa con nervio autólogo ha demostrado en diversos escenarios buenos resultados para mejorar el dolor y recuperar la conducción nerviosa. PRESENTACIÓN DE LOS CASOS: se presentan dos casos de mujeres adultas (F/47 y F/51) con antecedente de liberación de primer compartimiento dorsal de muñeca en otro centro hospitalario. Desarrollaron posteriormente dolor incapacitante y alodinia en sitio quirúrgico, así como limitación funcional. Fueron evaluadas y diagnosticadas como neuroma de rama superficial del nervio radial. No hubo mejoría con terapia física, por lo que se realizó reconstrucción nerviosa con injerto autólogo de nervio sural. Ambas pacientes tuvieron alivio del dolor de EVA 9-10 hasta EVA 1-2. A los cuatro meses de seguimiento, las dos mujeres recuperaron parcialmente la sensibilidad distal al sitio del neuroma, sin recurrencia del dolor presentado. CONCLUSIONES: los neuromas son complicaciones devastadoras que ocurren con lesiones inadvertidas de nervios motores y sensitivos. La reconstrucción con nervio autólogo es una excelente opción para reconstrucción de pequeños tramos de nervio periférico.

Metal Concentrations in Wild-Harvested Phaeophyta Seaweed from the Atlantic Ocean (Canary Islands, Spain).

Seaweeds are being consumed more often worldwide and are a source of essential minerals, fiber, vitamins, amino acids, and various bioactive compounds that have many beneficial effects on human health. However, marine pollution and the high capacity of seaweed to absorb metals may mean this food can also be dangerous to human health. The concentrations of some trace elements (B, Ba, Fe, Ni, Li, and V) and toxic metals (Al, Cd, and Pb) were determined in various species of wild seaweeds in the Phaeophyta group of brown algae from the Atlantic Ocean. Inductively coupled plasma atomic emission spectrometry revealed high concentrations of Al (256 mg/kg dry weight), Pb (3.92 mg/kg dry weight), and Cd (0.20 mg/kg dry weight) in Padina pavonica. Pb contributed the most to the tolerable daily intake (TDI) of toxic metals in these samples; 57.2 and 45.3% of the TDI for Pb was found in 5 g of dehydrated P. pavonica and Halopteris scoparia, respectively. This percent contribution is half of the recommended TDI for this metal, which is 34.24 µg/day; therefore, high consumption of these species is discouraged. The maximum TDIs established by various institutions for the other metals were not exceeded from the daily consumption of 5 g of the other dehydrated seaweeds evaluated in this study.

Metal Concentrations in Samples of Frozen Cephalopods (Cuttlefish, Octopus, Squid, and Shortfin Squid): An Evaluation of Dietary Intake.

Cephalopods are an important source of nutrients and some of the most widely consumed marine foods. However, because of contamination of the oceans and the bioaccumulative nature of toxic metals, these foods may pose a health risk. For this reason, the concentrations of some trace elements (chromium [Cr], lithium, strontium [Sr], copper [Cu], and nickel) and toxic metals (aluminum [Al], cadmium, and lead) were determined in 65 frozen samples of cuttlefish, octopus, common squid, and shortfin squid by inductively coupled plasma optical emission spectrometry to evaluate dietary intake and toxic risk. Sr was the major trace element (3.03 mg/kg) in cuttlefish; however, Cu (1.57 mg/kg) was found in the highest concentration in common squid. Among the toxic metals, Al had the highest concentration (3.09 mg/kg) in common squid. Al can pose an important health risk to individuals with kidney problems and to children because these groups are most vulnerable to the toxic effects. Significant differences among the four cephalopod types were found in the concentrations of most of the metals examined. Taking into account the average consumption of cephalopods, the contribution of toxic metals does not pose a risk to the health of adults.

Metals in edible seaweed.

The concentration levels of 20 metals were analyzed by ICP-OES in edible seaweed (Chondrus, Eisenia, Gelidium, Himanthalia, Laminaria, Palmaria, Porphyra, Undaria), from two origins (Asia vs EU) according to their cultivation practices (conventional vs organic). Red seaweed showed higher concentrations of trace and toxic elements. Porphyra may be used as a potential bioindicator for metals. Significant differences were found between the Asian vs European mean contents. The mean Cd level from the conventional cultivation (0.28 mg/kg) was two points higher than the organic cultivation (0.13 mg/kg). A daily consumption of seaweed (4 g/day) contributes to the dietary intake of metals, mainly Mg and Cr. The average intakes of Al, Cd and Pb were 0.064, 0.001 and 0.0003 mg/day, respectively. Based on obtained results, this study suggests that exposure to the toxic metals analyzed (Al, Cd and Pb) through seaweed consumption does not raise serious health concerns, but other toxic metals should be monitored.

[Intercarpal fusion as a salvage procedure in Kienböck disease]. / Artrodesis intercarpiana como tratamiento de salvamento en pacientes con enfermedad de Kienböck.

INTRODUCTION: Functional results of four surgical techniques to resolve the IIIB-IV Litchman's stage of the Kienböck disease were analyzed. We observed the evolution from 2000 to 2015. MATERIAL AND METHODS: Transversal retrospective study of 33 patients treated with different surgical techniques and evaluated with Quick-DASH scale, dynamometer and EVA. RESULTS: Less functional limitation was found in the patients who underwent the intercarpal fusion with or without neurotomy of the posterior interosseous. DISCUSSION: It was shown that the fact of making a less aggressive surgery is enough to evolve into an increase in symptoms and a decrease in function and strength; therefore, the intercarpal fusion performed at the right time of the natural history of the disease can achieve better results than other methods used previously and endorsed by international associations. CONCLUSIONS: The surgical technique of choice in our series to prevent disease progression was the intercarpal fusion and neurotomy of the posterior interosseous nerve.

INTRODUCCIÓN: Se analizaron los resultados funcionales de cuatro técnicas quirúrgicas de salvamento para resolver la etapa IIIB-IV de Litchman de la enfermedad de Kienböck. Observamos la evolución de los procedimientos quirúrgicos de salvamento realizados del 2000 al 2015. MATERIAL Y MÉTODOS: Estudio retrospectivo transversal de 33 pacientes tratados con cuatro técnicas quirúrgicas distintas a quienes se les realizó la escala Quick-DASH, dinamometría y EVA. RESULTADOS: Se encontró menor limitación funcional al año postquirúrgico en los individuos a los cuales se les realizó la artrodesis intercarpiana con o sin neurotomía del nervio interóseo posterior, con una media de 16.4, una mediana de 16.35, una moda de 15.3 y una p 0.05. DISCUSIÓN: Se demostró que una cirugía poco agresiva es suficiente para evolucionar a un aumento sintomatológico y un descenso de la función y fuerza, por lo que la artrodesis intercarpiana logra mejores resultados que otros procedimientos usados con anterioridad y avalados por las grandes asociaciones internacionales. CONCLUSIONES: La técnica quirúrgica de salvamento de elección en nuestra serie, que sugiere evitar la progresión de la enfermedad de Kienböck, es la artrodesis intercarpiana más neurotomía del nervio interóseo posterior, ya que presenta menor número de complicaciones.

Evaluation of content and estimation of daily intake of cadmium and lead in several varieties of potatoes (Solanum tuberosum L.) cultivated in the Canary Islands (Spain).

Monitoring the metal content in foods such as potatoes is an important aspect of food safety and regulation. Samples of nine varieties of potatoes (73 samples of local potatoes and 77 samples of imported potatoes) were randomly obtained from supermarkets, farmers markets, and farmer plots in Tenerife (Canary Islands, Spain). The edible portion (pulp) was the only part considered for analysis because Spaniards traditionally eat only peeled potatoes. Cadmium (Cd) and lead (Pb) were determined using graphite furnace atomic absorption spectrometry. Cd concentrations ranged from 0.006 mg/kg in the Cara and Negra varieties to 0.019 mg/kg in the Bonita variety, and Pb concentrations ranged from 0.007 mg/kg in the Up-to-date variety to 0.023 mg/kg in the Recara variety. The mean concentrations of Cd (0.01 mg/kg) and Pb (0.014 mg/kg) were below the limits established by European regulations for potatoes (0.1 mg/kg of wet weight for each metal). Based on a mean consumption of 143.2 g of potato per person per day for the Canary Islands population, the mean daily intakes of Cd (0.015 mg/day) and Pb (0.023 mg/day) were below the legislated respective tolerable weekly intakes. Thus, the samples analyzed were considered safe to eat with regard to the metal concentrations found.

[Mineral composition of different types of Canarian gofio; factors affecting the presence of Na, K, Mg, Ca, Mn, Fe, Cn and Zn]. / Composición mineral de los distintos tipos de gofio canario; factores que afectan a la presencia de Na, K, Mg, Ca, Mn, Fe, Cu y Zn.

The contents of Na, K, Mg, Ca, Mn, Fe, Cu and Zn were analyzed and evaluated in 181 samples of various types of gofio produced from different roasted cereal grains. Samples were analyzed by ICP-OES. Based on a daily gofio intake of 30 g/day for adults and 15 g/day for children, the daily intake of each metal, and its percentage contribution to the RDAs established for the Spanish population, were estimated. The metal with the highest concentration was K (2189 ± 766 mg/kg). The lowest concentration was observed for Cu in corn gofio samples (2.05 ± 0.36 mg/kg). With respect to daily intake, it is noteworthy that gofio contributes significantly to the recommended allowance of copper (53.77%-71.45% of the RDI), depending on the population group considered and on the type of gofio.

En este trabajo se ha estudiado la composición mineral de Na, K, Mg, Ca, Mn, Fe, Cu y Zn en 181 muestras de diversos tipos de gofio elaborados con diferentes cereales. Las muestras se analizaron mediante espectrometría de emisión óptica con plasma acoplado inductivamente (ICP-OES). Considerando un consumo medio diario de 30 g de gofio en adultos y de 15 g de gofio en niños, se estimaron las ingestas diarias de cada metal y sus contribuciones porcentuales a las IDRs establecidas para la población española. El elemento que presentó la mayor concentración de todos los estudiados fue el K en muestras de gofio de cereales, con una concentración media de 2189 ± 766 mg/kg. El de menor concentración fue el Cu en muestras de gofio de maíz, con 2,05 ± 0,36 mg/kg. Con respecto a la ingesta, cabe destacar que el gofio contribuye de manera significativa a la ingesta de cobre (53,77%- 71,45% de la IDR), en función del grupo de población que se trate y del tipo de gofio.

Evaluation of metal concentrations in mentha herbal teas (Mentha piperita, Mentha pulegium and Mentha species) by inductively coupled plasma spectrometry.

Phytopharmaceuticals are gaining popularity worldwide; however, cases of adverse effects and drug interactions have also increased. One reason is in the high metal content both as ingredients but also as contaminants. Metal monitoring in food, like herbal teas, provides basic information on safety aspects in regulatory processes as well as nutritional values. In the present work, Cd, Pb, K, Na, Ca, Mg, Al, B, Ba, Co, Cr, Cu, Fe, Mn, Zn, Li, Ni, and Mo were determined by inductively coupled plasma spectrometry (ICPS) in 36 samples of Mentha sp. Mint tea bags and loose leaves were randomly obtained from supermarkets, traditional markets, herbal stores, and pharmacies in Tenerife (Canary Islands, Spain). Metal contents varied significantly, dependent on the stores the products were purchased in and on tea packaging (loose leaves versus tea bags). Pb analyses revealed levels (0.65±0.71mg/kg) below legal limits. The maximum permissible limit for Cd, 0.3mg/kg, set by the WHO for medicinal plants, was exceeded by 19.44% of the samples (0.22±0.13mg/kg), but all values were below the limit given in the European Pharmacopoeia for this metal (4mg/kg). We observed high Al (151.24±162.73mg/kg) and Li (5.46±3.94mg/kg) levels. B, Ba, Co, Cr, Cu, Fe, Mn, Ni, Zn, and Mo mean levels were 20.51, 14.15, 0.26, 1.65, 10.65, 406.00, 55.05, 1.72, 33.67, and 0.73mg/kg, respectively. Mean Ca, Mg, K, and Na were detected in concentrations of 10.32, 3.83, 7.23 and 1.17g/kg, respectively. In conclusion, metal exposure through herbal mint teas does not seem to be of health concern, as to most of the studied metals, but regulatory limits for Al contents should be imposed.

Palm tree syrup: nutritional composition of a natural edulcorant.

INTRODUCTION: Palm syrup is a typical product from the Canary Islands, traditionally produced from the sap of the tropical palm tree Phoenix canariensis. Its high caloric content has led to its increasing use as a health food supplement for athletes, children and elderly. Furthermore, demand for this natural syrup is continuously increasing due also to its medicinal uses in homeopathic medicine. OBJECTIVE: Palm Tree syrup samples prepared with palm sap from primary producers in La Gomera island (Canary Islands, Spain) were analyzed for their nutritional composition (moisture, ash, sugars, fat, vitamins and minerals). METHODS: 35 syrup samples from five different producing regions in La Gomera island were analyzed. High-performance liquid chromatography (HPLC) was used to determine sugars and vitamins and Flame Atomic Absorption Spectrophotometry (FAAS) was used to analyze the minerals. RESULTS: Major carbohydrates were sucrose (37.8%), glucose (9.50%) and fructose (4.80%), respectively. The presence of arabinose could not be confirmed. Niacin was the water-soluble vitamin with the highest concentration with an average content of 0.003%. Fat content was found to be under 0.20%. Potassium was the mineral with highest contents (0.45%). CONCLUSIONS: Results suggest that palm tree syrup can play an important role as a sugar and mineral source in human nutrition, suggesting that future applications for this product could be developed.

Pesticide residues in tomatoes from greenhouses in Souss Massa Valley, Morocco.

Eight pesticide residues in tomato samples collected in the area of Souss Massa Valley (Southern Morocco) were analyzed. The detected residue levels ranged from 0.001 to 0.400 mg kg(-1) for dicofol, from 0.003 to 0.170 mg kg(-1) for procymidone, from 0.001 to 0.250 mg kg(-1) for chlorothalonil, from 0.050 to 0.500 mg kg(-1) for bifenthrin, from 0.001 to 0.010 mg kg(-1) for λ-cyhalothrin, from 0.001 to 0.300 mg kg(-1) for cypermethrin, from 0.010 to 1 mg kg(-1) for deltamethrin and from 0.003 to 1.123 mg kg(-1) for endosulfan. European MRL for endosulfan in tomatoes set in 0.500 mg kg(-1), was exceeded in 8 samples, and MRL for deltamethrin set in 0.300 mg kg(-1) for tomatoes was exceeded in 2 samples.

Trace elements and metals in farmed sea bass and gilthead bream from Tenerife Island, Spain.

The aim of this study was to determine the levels of metals (Ca, K, Na, Mg) and trace metals (Ni, Fe, Cu, Mn, Zn, Pb, Cd) in two fish species (gilthead bream [Sparus aurata] and sea bass [Dicentrarchus labrax]) collected from fish farms located along the coast of Tenerife Island. Ca, K, Na, Mg, Fe, Cu, Zn, and Mn were measured by flame atomic absorption spectrometry, whereas Pb, Cd, and Ni were determined using graphite furnace atomic absorption spectrometry. Mean Fe, Cu, Mn, and Zn contents were 3.09, 0.59, 0.18, and 8.11 mg/kg (wet weight) in S. aurata and 3.20, 0.76, 0.24, and 10.11 mg/kg (wet weight) in D. labrax, respectively. In D. labrax, Ca, K, Na, and Mg levels were 1,955, 2,787, 699.7, and 279.2 mg/kg (wet weight), respectively; in S. aurata, they were 934.7, 3,515, 532.8, and 262.8 mg/kg (wet weight), respectively. The Pb level in S. aurata was 7.28 ± 3.64 µg/kg (wet weight) and, in D. labrax, 4.42 ± 1.56 µg/kg (wet weight). Mean Cd concentrations were 3.33 ± 3.93 and 1.36 ± 1.53 µg/kg (wet weight) for D. labrax and S. aurata, respectively. All Pb and Cd levels measured were well below the accepted European Commission limits, 300 and 50 µg/kg for lead and cadmium, respectively.

Faloplastia mediante colgajo libremicroquirúrgio antebraquial radial con doble tunelización. A propósito de un caso / Microsurgical penile reconstruction with a radial forearm

La reconstrucción del pene sigue siendo uno de los mayores retos de la Cirugía Plástica debido a la complejidad inherente que conlleva el conseguir tanto la forma anatómica como la función urológica del pene. El objetivo ideal del cirujano al realizar una falo plastia inclúyela construcción, en una sola etapa, de un pene estéticamente aceptable y con sensibilidad erógena y táctil, que permita al paciente orinar de pie y mantener relaciones sexuales. La multitud existente de colgajos que pueden ser utilizados para la reconstrucción del pene sólo demuestra que ninguna de estas técnicas se considera ideal. Sin embargo, el colgajo radial es el que se utiliza más frecuentemente es considerado universalmente como la técnica estándar. Las desventajas relativas de la misma son el número más elevado de fístulas que aparecen inicialmente, la cicatriz residual en el antebrazo y las complicaciones urológicas potenciales a largo plazo. Presentamos una reconstrucción de pene realizada mediante un colgajo libre radial ante braquial con un nuevo diseño geométrico bidimensional que permite la creación tridimensional de un neofalo con excelentes resultados estéticos (AU)

Reconstruction of penile defects remains one of thegreatest challenges in Plastic Surgery because of the inherent complexity of restoring both the anatomical form and the urologic function of the penis. The surgeon’s ideal goals in performing a phalloplasty include the construction, in one-stage procedure, of an aesthetic penis with erogenous and tactile sensation, which enables the patient to void while standing and to have sexual intercourse. The multitude of flaps used for phalloplasty only demonstrates that none of these techniques is considered ideal. Still, the radial forearm flap is the most frequently used one and universally considered as the standard technique. The relative disadvantages of this technique are the rather high number of initial fistulas, the residual scar on the forearm, and the potential long-term urologic complications. We describe a penile reconstruction using a radial forearm free flap with a new two-dimensional geometric design that allows the creation of a three-dimensional neophallus with an excellent aesthetic result (AU)

Content of toxic heavy metals (mercury, lead, and cadmium) in canned variegated scallops (Chlamys varia).

The concentrations of three toxic heavy metals, mercury (Hg), lead (Pb), and cadmium (Cd), were determined in preserved variegated scallops (Chlamys varia, Bivalvia, Mollusca), which are often consumed in Tenerife (Canary Islands, Spain). A total of 300 samples of seven commercial brands (A, B, D, H, J, L, and M) and one processed product ("scallop sauce") were analyzed. Samples were collected weekly in a major shopping area in Santa Cruz de Tenerife during a 12-month period. The concentrations of lead and mercury were far below the maximum limit permitted for human consumption by the European Communities Commission regulation (EC) 466/2001 (1 and 0.5 mg kg(-1) wet weight for Pb and Hg, respectively). Concentrations of cadmium were close to the maximum limit permitted by regulation (EC) 466/2001 (1 mg kg(-1) wet weight).

El ganglio centinela en el melanoma: nuestra experiencia / The sentinel lymph node biopsy for melanoma: our experience

El ganglio centinela ha sido recientemente aceptado como uno de los factores pronósticos más importantes en el melanoma maligno según la AJCC (American Joint Committee on Cancer), a pesar de que su uso sistemático no está aún extendido a todas la unidades de melanoma y su empleo no está exento de controversias. Entre otros aspectos, se discute si la realización de la ampliación de márgenes debe ser realizada en el mismo tiempo quirúrgico que el ganglio centinela para la eficacia del mismo. Se realiza un estudio retrospectivo sobre 78 pacientes intervenidos de ganglio centinela por melanoma entre Mayo 99 y Enero 04, todos ellos remitidos por Dermatología con diagnóstico de melanoma maligno >1mm de espesor de Breslow y adenopatías no palpables (estadio I y II de la AJCC). De ellos,42 son mujeres y 36 varones, con una edad media de 53.5 años. El espesor de Breslow medio es de 2.78mm. La ampliación de márgenes se hizo en un tiempo quirúrgico anterior por parte de Dermatología en 59 casos(76.62%), mientras que en 18 se realizó en el mismo tiempo que el ganglio centinela. La demora media entre la ampliación de márgenes y la realización del ganglio centinela fue de 5.87 meses. En el 19.23% (15 pacientes)no se observó captación gama gráfica, por lo que el estudio del ganglio centinela no pudo llevarse a cabo. De ellos, en 12, la ampliación de márgenes había sido anterior al tiempo del ganglio centinela, con una demora media de 5.06meses.El 50% (39) de los ganglios enviados a Anatomía Patológica fueron negativos para células malignas. El 25.74% (20pacientes) fueron positivos. El seguimiento medio es de 23.12 meses; 18 pacientes presentan en la actualidad metástasis o han fallecido; 47 casos (60%) se encuentran libres de (..) (AU)

The sentinel lymph node biopsy (SLNB) has recently been accepted as one of the most important prognostic factors of the cutaneous primary melanoma by the AJCC (American Joint Committee on Cancer), even its overall use is still not extended to all the melanoma units and there are many controversies about its use. Among other aspects, there is no consensus about if the previous wide local excision can alter the results of the biopsy. This is a retrospective study done over 78 consecutive cases of SLNB for melanoma between May´99 and Jan´04. All of them were remitted from Dermatology with the diagnose of melanoma, tumor thickness >1.0mm and no clinical nodes (AJCC est. I and II). Out of the 78 cases, 42 were women and 36 men, with an average age of 53.5. The average Breslow thickness was of 2.78mm. The wide local excision(WLE) was done by Dermatology at a previous time in 59 cases (76.62%), while 18 patients had the WLE at the time of the SLNB. The delay between the WLE and the SLNB was of 5.87 months. In the 19.23% (15patients) the SLNB was not feasible because there was not found colloid captation by any node; 12 of them had de WLE previous to the SLNB, with a delay of 5.06months; 50% (39) of the nodes were negative for melanoma cells ;25.74% (20patients) were positive. The follow up time was of 23.12months; 18 patients presented metastasis or died, while 47 cases (60%) are actually free of disease. We corroborate that the SLNB is a low morbility technique with an important staging function for the primary cutaneous melanoma. We don´t find any difference in the survival of patients with previous WLE compared with those whom the WLE was done concurrently (AU)

El plomo como contaminante alimentario / The lead as a food contaminant

El plomo es un metal pesado caracterizado por ocasionar efectos tóxicos sobre el tracto gastrointestinal, sobre el sistema renal y sobre el SNC y periférico, así como interferencias con sistemas enzimáticos implicados en la síntesis del grupo hemo. A pesar de que en los últimos diez años, los contenidos de plomo de los productos alimenticios se han reducido sensiblemente gracias a los esfuerzos realizados para reducir la emisión de plomo en su origen y por los progresos en la garantía de calidad de los análisis químicos, la dieta sigue siendo una fuente importante de exposición de plomo. Es por ello que, el objetivo a largo plazo de las autoridades sanitarias es el de continuar reduciendo los contenidos medios de plomo en los productos alimenticios con el fin de que las ingestas medias dietéticas de Pb de las poblaciones cumplan con la PTWI (Provisional Tolerable Weekly Intake) de 25 μg Pb/Kg/semana establecida por el Comité Mixto FAO/OMS (AU)

Lead is a heavy metal characterized for its toxic effects on the gastrointestinal tract, on the renal system and on the Central and Peripheral Nervous Systems, as well as its interferences with enzymatic systems involved in hemo group synthesis. In spite of the fact that in the last ten years the lead content in foodstuffs has been notably reduced due to the efforts made in reducing the lead emission in its origin and also due to the progress in quality control of chemical analysis, diet confines to be an important source of lead exposure. This is the reason why the long term objective of the sanitary authorities is to continue to reduce the mean lead contents until the population’s Pb dietary intake meets the PTWI (Provisional Tolerable Weekly Intake) of 25 μg Pb/Kg/week, established by the FAO/OMS Committee (AU)

Dealkylation of phosphonate esters with chlorotrimethylsilane.

Chlorotrimethylsilane completely dealkylates phosphonate esters at elevated temperature in a sealed reaction vessel. These conditions are tolerated by a variety of functional groups and lead to high conversions of dimethyl, diethyl and diisopropyl phosphonates to their corresponding phosphonic acids.

Influx and accumulation of Cs(+) by the akt1 mutant of Arabidopsis thaliana (L.) Heynh. lacking a dominant K(+) transport system.

An extensive literature reports that Cs(+), an environmental contaminant, enters plant cells through K(+) transport systems. Several recently identified plant K(+) transport systems are permeable to Cs(+). Permeation models indicate that most Cs(+) uptake into plant roots under typical soil ionic conditions will be mediated by voltage-insensitive cation (VIC) channels in the plasma membrane and not by the inward rectifying K(+) (KIR) channels implicated in plant K nutrition. Cation fluxes through KIR channels are blocked by Cs(+). This paper tests directly the hypothesis that the dominant KIR channel in plant roots (AKT1) does not contribute significantly to Cs(+) uptake by comparing Cs(+) uptake into wild-type and the akt1 knockout mutant of Arabidopsis thaliana (L.) Heynh. Wild-type and akt1 plants were grown to comparable size and K(+) content on agar containing 10 mM K(+). Both Cs(+) influx to roots of intact plants and Cs(+) accumulation in roots and shoots were identical in wild-type and akt1 plants. These data indicate that AKT1 is unlikely to contribute significantly to Cs(+) uptake by wild-type Arabidopsis from 'single-salt' solutions. The influx of Cs(+) to roots of intact wild-type and akt1 plants was inhibited by 1 mM Ba(2+), Ca(2+) and La(3+), but not by 10 microM Br-cAMP. This pharmacology resembles that of VIC channels and is consistent with the hypothesis that VIC channels mediate most Cs(+) influx under 'single-salt' conditions.

Testing a process-based model of tree seedling growth by manipulating.

A model was developed that simulated photosynthesis, growth and allocation in tree seedlings. The model was parameterized with data from experiments on seedlings of sycamore (Acer pseudoplatanus L.), Sitka spruce (Picea sitchensis (Bong) Carr.) and young birch trees (Betula pendula Roth.). In these experiments, CO2 concentration ([CO2]) and nutrient addition rate were varied. Parameters quantifying nutrient uptake, translocation and starch synthesis were fitted, based on data from control treatments. Elevated [CO2] and low-nutrient treatments were then used to test the predicted response of growth and allocation against observations. The model accurately predicted total seedling growth in the elevated [CO2] treatments. A response of growth to elevated [CO2] was seen in the birch and sycamore experiments, but not in the Sitka spruce, because of photosynthetic down-regulation. Predictions of allocation were reasonably accurate in the birch and Sitka spruce experiments, but were notably poorer in the sycamore experiments, possibly because of differences in sink strength between root and shoot. In the birch and sycamore experiments, little change in allocation with elevated [CO2] was observed or predicted. This was ascribed to the relative values of K(Tc) and K(Tn), the translocation coefficients that determine the sensitivity of allocation to carbon and nitrogen uptake rates, respectively. Growth and allocation in the low-nutrient treatments were poorly predicted by the model. In Sitka spruce, it was suspected that the photosynthetic parameters measured in August 1994 had been higher earlier in the season, before nutrients became depleted. In sycamore, the discrepancies were thought to relate to differences in sink strength between root and shoot that could not be described by the model.

What are the effects of nitrogen deficiency on growth components of lettuce?

Relationships between nitrogen (N) content and growth are routinely measured in plants. This study determined the effects of N on the separate morphological and physiological components of plant growth, to assess how N-limited growth is effected through these components. Lettuce (Lactuca sativa) plants were grown hydroponically under contrasting N-supply regimes, with the external N supply either maintained continuously throughout the period of study, or withdrawn for up to 14 d. Richards' growth functions, selected using an objective curve-fitting technique, accounted for 99.0 and 99.1% of the variation in plant dry weight for control and N-limited plants respectively. Sublinear relationships occurred between N and relative growth rates under restricted N-supply conditions, consistent with previous observations. There were effects of treatment on morphological and physiological components of growth. Leaf weight ratio increased over time in control plants and decreased in N- limited plants. Shoot:root ratio followed a similar pattern. On a whole-plant basis, assimilation of carbon decreased in N-limited plants, a response paralleled by differences in stomatal conductance between treatments. Changes in C assimilation, expressed as a function of stomatal conductance to water vapour, suggest that the effects of N limitation on growth did not result directly from a lack of photosynthetic enzymes. Relationships between plant N content and components of growth will depend on the availability of different N pools for remobilization and use within the plant.

Antisense gene inhibition by C-5-substituted deoxyuridine-containing oligodeoxynucleotides.

Antisense oligodeoxynucleotides (ODNs) are capable of inhibiting gene expression via a RNase H mechanism in which the complementary RNA is degraded by RNase H. C-5 propyne dU phosphorothioate ODNs bind selectively and with high affinity to RNA within cells leading to potent antisense inhibition of RNA translation. The effect that increasing steric bulk of C-5-substituted deoxyuridine analogs has on affinity for RNA and ability to inhibit gene expression is discussed. The relative binding affinity was measured by thermal denaturation (Tm) analysis, and antisense activity was determined by inhibition of SV40 T-antigen (TAg) expression in CV1 cells. The results show that antisense activity is not directly correlated to Tm measurements. In vitro analysis (RNase H cleavage, on-rates, and off-rates) and pre-formed ODN/RNA experiments indicate that RNase H activity and intracellular dissociation appear to be major determinants of the antisense potency of the various substituted ODNs. The results of our analysis point to the unique ability of C-5 propyne dU ODNs to selectively bind to RNA within cells and activate cleavage of RNA by RNase H leading to potent inhibition of gene expression.