Biopsia del ganglio centinela en melanomas en nuestro medio / Sentinel node biopsy in patients with melanomas

A sentinel node biopsy is a procedure in which the sentinel lymph node is identified, removed and examined to determine whether cancer cells are present. It´s used most commonly in evaluating breast cancer and melanoma. The sentinel nodes are the first few lymph nodes into which a tumor drains. The sentinel nodes are removed and analyzed in a laboratory. Melanoma is a tumor of melanocyte origin. There is a considerable evidence that early recognition and surgical removal of melanoma makes this a highly curable cancer. Because early detection of melanoma results in a high frequency of cure it is important to recognize the lesion in the earliest stages. Malignant melanoma is a type of cancer that develops from the pigment-containing cells known as melanocytes, and is the most aggressive and life-threatening skin cancer. Sentinel node biopsy is a surgical procedure to determine whether cancer has spread beyond a primary tumor into the lymphatic system. Removal and examination of the sentinel lymph node to which cancer cells are likely to spread from the primary tumor, are supposed to be an useful tool to prevent early this spread. In this paper the authors present their experience with the management of this procedure.

[Infective fungal endocarditis in patients with no previous cardiac disease]. / Endocarditis micótica en pacientes sin cardiopatías previas.

Infective endocarditis is a serious and uncommon condition affecting the endocardium. Less than 10% of these cases are of fungal origin. A growing number of individuals are at high risk, due to insertion of central venous catheters, total parenteral nutrition and prolonged exposure to broad-spectrum antibiotics, even without previous heart diseases. We retrospectively analysed the records of six children with Candida endocarditis, reviewing the comorbidities, clinical outcome, and treatment. The antifungal agents used were amphotericin B, 5-fluorocytosine and fluconazole. Patients underwent surgical excision of vegetation, five tricuspid valve repairs and one mitral valve replacement. There were no hospital deaths, and one child needed a new valvuloplasty one year later. The mean follow up was five years, and all have good valvular function without recurrent endocarditis. A combination of synergistic long-term antifungal treatment and early surgical intervention is recommended.

All-optical generation of states for "Encoding a qubit in an oscillator".

Most quantum computation schemes propose encoding qubits in two-level systems. Others exploit the use of an infinite-dimensional system. In "Encoding a qubit in an oscillator" [Phys. Rev. A 64, 012310 (2001)], Gottesman, Kitaev, and Preskill (GKP) combined these approaches when they proposed a fault-tolerant quantum computation scheme in which a qubit is encoded in the continuous position and momentum degrees of freedom of an oscillator. One advantage of this scheme is that it can be performed by use of relatively simple linear optical devices, squeezing, and homodyne detection. However, we lack a practical method to prepare the initial GKP states. Here we propose the generation of an approximate GKP state by using superpositions of optical coherent states (sometimes called "Schrödinger cat states"), squeezing, linear optical devices, and homodyne detection.

Isolation and characterization of a serine proteinase with thrombin-like activity from the venom of the snake Bothrops asper

A serine proteinase with thrombin-like activity was isolated from the venom of the Central American pit viper Bothrops asper. Isolation was performed by a combination of affinity chromatography on aminobenzamidine-Sepharose and ion-exchange chromatography on DEAE-Sepharose. The enzyme accounts for approximately 0.13 percent of the venom dry weight and has a molecular mass of 32 kDa as determined by SDS-PAGE, and of 27 kDa as determined by MALDI-TOF mass spectrometry. Its partial amino acid sequence shows high identity with snake venom serine proteinases and a complete identity with a cDNA clone previously sequenced from this species. The N-terminal sequence of the enzyme is VIGGDECNINEHRSLVVLFXSSGFL CAGTLVQDEWVLTAANCDSKNFQ. The enzyme induces clotting of plasma (minimum coagulant dose = 4.1 µg) and fibrinogen (minimum coagulant dose = 4.2 µg) in vitro, and promotes defibrin(ogen)ation in vivo (minimum defibrin(ogen)ating dose = 1.0 µg). In addition, when injected intravenously in mice at doses of 5 and 10 µg, it induces a series of behavioral changes, i.e., loss of the righting reflex, opisthotonus, and intermittent rotations over the long axis of the body, which closely resemble the `gyroxin-like' effect induced by other thrombin-like enzymes from snake venoms.

Isolation and characterization of a serine proteinase with thrombin-like activity from the venom of the snake Bothrops asper.

A serine proteinase with thrombin-like activity was isolated from the venom of the Central American pit viper Bothrops asper. Isolation was performed by a combination of affinity chromatography on aminobenzamidine-Sepharose and ion-exchange chromatography on DEAE-Sepharose. The enzyme accounts for approximately 0.13% of the venom dry weight and has a molecular mass of 32 kDa as determined by SDS-PAGE, and of 27 kDa as determined by MALDI-TOF mass spectrometry. Its partial amino acid sequence shows high identity with snake venom serine proteinases and a complete identity with a cDNA clone previously sequenced from this species. The N-terminal sequence of the enzyme is VIGGDECNINEHRSLVVLFXSSGFL CAGTLVQDEWVLTAANCDSKNFQ. The enzyme induces clotting of plasma (minimum coagulant dose = 4.1 microg) and fibrinogen (minimum coagulant dose = 4.2 microg) in vitro, and promotes defibrin(ogen)ation in vivo (minimum defibrin(ogen)ating dose = 1.0 microg). In addition, when injected intravenously in mice at doses of 5 and 10 microg, it induces a series of behavioral changes, i.e., loss of the righting reflex, opisthotonus, and intermittent rotations over the long axis of the body, which closely resemble the ;gyroxin-like' effect induced by other thrombin-like enzymes from snake venoms.

Ordered quantization and the Ehrenfest time scale.

We propose a prescription to quantize classical monomials in terms of symmetric and ordered expansions of noncommuting operators of a bosonic theory. As a direct application of such quantization rules, we quantize a classically time evolved function O(q,p,t), and calculate its expectation value in coherent states. The result can be expressed in terms of the application of a classical operator that performs a Gaussian smoothing of the original function O evaluated at the center of the coherent state. This scheme produces a natural semiclassical expansion for the quantum expectation values at a short time scale. Moreover, since the classical Liouville evolution of a Gaussian probability density gives the same form for the classical statistical mean value, we can calculate the first-order correction in h entirely from the associated classical time evolved function. This allows us to write a general expression for the Ehrenfest time in terms of the departure of the centroid of the quantum distribution from the classical trajectory, provided we start with an initially coherent state for each subsystem. In order to illustrate this approach, we have calculated analytically the Ehrenfest time of a model with N-coupled nonlinear oscillators with nonlinearity of even order.

HLA class I and class II allele distribution in the Peruvian population.

The distribution of HLA-A, -B, -C, -DRB1 and -DQB1 alleles in the Peruvian population was studied and compared with those of other populations in order to provide further information about their anthropological origin. Our data are consistent with the Mestizo character of this population. In terms of genetic distance Peruvians are closest to Bolivians, which is in agreement with the geographical location and the cultural and anthropological background of the two human groups. Several HLA-B alleles originally described in genetically isolated Amerindian tribes are also present in the sample studied here. This fact and the reported finding of these alleles in several Amerindian groups suggests that they were present in the first wave of humans that populated South America (Paleoindians) before they split to give rise to the different South American tribes.

A new HLA-Cw*15 allele, Cw*1508, identified in the Peruvian population.

A novel HLA-Cw*15 allele , Cw*1508, has been found in the Peruvian population. This new allele, initially detected as a polymerase chain reaction with sequence-specific primers (PCR-SSP) variant, shows greatest similarity to Cw*1502. The nucleotide sequence of Cw*1508 only differs from that of Cw*1502 at position 539; this change determines the replacement of Leu by Arg 156 in Cw*1508.

Resistencia de enterococos a los antimicrobianos en Venezuela / Resistance of enterococcus a the antimicrobials in Venezuela

Se analiza la resistencia de Enterococcus sp., según los datos del Proyecto de Vigilancia a la Resistencia Bacteriana en Venezuela. Se utilizó el método de difusión en agar, siguiendo las normas de eficiencia de la NCCLS, en 1925 cepas durante 1988, 1990, 1992 y 1994. El uso de ampicilina o sulbactam/ampicilina en infecciones simples, y la combinación ampicilina más aminoglicósido en infecciones severas, siguen siendo la primera opción. La utilización de eritromicina (48 por ciento), clindamicina (88 por ciento) y tetraciclinas (62 por ciento), al igual que a nivel mundial, no está justificado, debido a los altos porcentajes de resistencia. Venezuela es el primer país latinoamericano en reportar resistencia a vancomicina y, al contrario de lo que ocurre en otros países, se ha mantenido estable en el período estudiado. La alta resistencia de Enterococcus faecalis a los aminoglicósidos es un problema mundial, pero su detección se realiza mediante pruebas especiales, que escapan a los objetivos del proyecto de vigilancia

El peptido natriuretico auricular y el sistema renina-aldosterona en el anciano normal y en el hipertenso: respuesta a los suplementos del calcio / The natruretia atrial peptide and the renin-aldosterone system in hormal and hypertensive elder, response to calcium

La concentracion plasmatica del peptido natriuretico auricular se encuentra elevada en los ancianos y si son hipertensos, sus valores son mucho mas altos. Con el obejto de estudiar el peptido natriuretico auricular y la respuesta del sistema angiotensina aldosterona, se le administro un suplemento de calcio oral a un grupo de ancianos hipertensos y a otro grupo de normotensos, que nos sirvio de control. Se seleccionaron 22 ancianos hipertensos (2 hombres y 20 mujeres), con una edad de 75 +/- años y 10 ancianos normotensos (2 hombres y 8 mujeres) con igual promedio de edad. Se le practicaron tomas tensionales con esfignomanometro de Hg en 3 posiciones (de cubito, sentado y de pie). Por el metodo de radioinmunoensayo se les dosificaron el peptido natriuretico auricular, de actividad de la renian plasmatica, la aldosterona plasmatica por absorcion atomica se le determino el calcio serico total, antes y despues de recibir 1.5 g/dia de CaCO3, por un periodo de 4 semanas. En los hipertensos se obtuvieron los siguientes resultados: el peptido natriuretico auricular descendio de manera imporatante (P<0.001), en igual forma lo hizo la aldosterona (P<0.001), por el contrario la reina (P<0.001) y el Calcio (P<0.001) aumentaron sus valores. Igualmente se consiguieron las correlaciones inversas entre renina/peptido y entre peptido/calcio, pero no se observo esta relacion entre aldosterona/peptido. En los acnianos normotensos, se obtuvo un descenso del peptido (P<,05) y un incremento del calcio serico total (P<0,05). En los hipertensos descendieron sus cifras tensionales sistolica (P<0.001) y las distolicas (P<0,05). Estos resultados ponene en evidencia las relaciones tan estrecha que existen entre la tension arterial (especialmente la sistolica, peptido, renina, aldosterona, calcio serico en ancianos hipertensos y menos significativos en los normotensos. En conclusion la administracion de calcio oral a ancianos, especialmente hipertensos, determino en ellos una serie de cambios en los grupos hormonales que manejan la homeostasis agua-sodio. Esta accion se ejerce probablemente de manera indirecta, yaque al actuar como hipotensor, se van a corregir lasalteraciones antes mencionadas en los dos grupos hormonales que intervienen en este equilibrio.

The impact of Chilean migration on employment in Patagonia.

PIP: This paper discusses the employment situation of Chilean migrant workers, their impact on labor markets in Patagonia, Argentina, and the government's past and projected responses to this phenomenon. In 1980, Chilean inhabitants of patagonia comprised 11% of the area's population. Chilean migration to patagonia was closely linked to economic activities that began to flourish in the 20th century, such as livestock raising, fruit and vegetable cultivation, and mining for coal and petroleum. No Chilean migrants work in a wide range of sectors. In Patagonia's southern provinces availability and ability to withstand rigorous climate conditions are the main factors which account for the prevalence of Chilean manpower. Chilean migrants do not in general displace local manpower. Legislation and the permeability of the border ensure that most workers enter the country as tourists. Clandestine migration is not an issue. Illegal migrants have provoked negative reactions for several reasons: 1) they comprise a marginal population without formal citizenship; 2) being employed as clandestine workers, they pay no social security, nor do their employers; 3) being illegal, they are obliged to accept lower wages and inferior working conditions which creates unfair competition within labor markets; and 4) as a result of these conditions, xenophobic and endophobic attitudes in relations with Argentine nationalists are reinforced. The government has attempted to solve these problems through various measures. Beginning in 1934, most foreigners entered Argentina with a tourist visa, becoming illegal when they stayed beyond authorized limits. Several measures over the years provided amnesty to illegal migrants. Currently, the law promotes immigration, monitors the admission of foreigners to the country and stipulates their rights and obligations. The law lists 115 articles on immigration promotion and on regulation of the movements of foreigners. Because of the present economic crisis in Argentina, authorities are investigating the effect of Chilean manpower on Argentine labor markets.^ieng