Coherent control of two Jaynes-Cummings cavities.

We uncover new features on the study of a two-level atom interacting with one of two cavities in a coherent superposition. The James-Cummings model is used to describe the atom-field interaction and to study the effects of quantum indefiniteness on such an interaction. We show that coherent control of the two cavities in an undefined manner allows novel possibilities to manipulate the atomic dynamics on demand which are not achievable in the conventional way. In addition, it is shown that the coherent control of the atom creates highly entangled states of the cavity fields taking a Bell-like or Schrödinger-cat-like state form. Our results are a step forward to understand and harness quantum systems in a coherent control, and open a new research avenue in the study of atom-field interaction exploiting quantum indefiniteness.

Follistatin-like 1 (FSTL1) levels as potential early biomarker of cardiovascular disease in a Mexican population.

Cardiovascular diseases (CVD) are the leading cause of death globally. In recent years, follistatin-like protein 1 (FSTL1) has been proposed as an emerging potential clinical biomarker of CVD, since its concentration is upregulated in heart failure. The aim of the present study was to evaluate the association of FSTL1 levels and classic biomarkers with the risk of CVD in Mexican population. A case-control study was carried out in patients with cardiovascular diseases (CVD), arterial hypertension, but not CVD (cardiovascular risk factor-CRF), and healthy controls (control group) from the Mexican Institute of Social Security. Lipid profile, homocysteine (Hcys), serum amyloid A (SAA), FSTL1 concentration, PON1 concentration and activities [Arylesterase (ARE), and Lactonase (LAC)] were evaluated. High levels of FSTL1 were found in the CRF group and a positive association of FSTL1 (OR = 4.55; 95% CI 1.29-16.04, p = 0.02) with the presence of arterial hypertension, as well as Hcys (OR, 3.09; 95% CI 1.23-7.76, p = 0.02) and SAA (OR, 1.03; 95% CI 1.01-1.05, p < 0.01) with the presence of CVD. LAC activity (OR, 0.26; 95% CI 0.07-0.94, p = 0.04) and PON1 concentration (OR, 0.17; 95% CI 0.05-0.62, p = 0.01) were associated with a decrease in OR belonging to the group with CVD. Our results suggest that FSTL1 may be a useful biomarker for monitoring cardiovascular risk in clinical settings. However, longitudinal studies are needed to evaluate how FSTL1 could influence the association of PON1 activity and Hcys with CVD.

Total retardance measurements based on the complex Fourier coefficients for the rotating polarizer analyzer system.

We propose a demodulation algorithm based on the calculus of the complex Fourier coefficients; we used a dual rotating polarizer-analyzer polarimeter to show the feasibility of our proposal. Our demodulation algorithm considers the frequency response obtained by the system, and its possible to calculate the total retardation, fast axis orientation and ellipticity of a sample. Our proposal does not require recovering the full Mueller matrix from getting those parameters. In addition, as the proposal does not use retarders for the measurement, the system presents potential applications for multi-wavelength measurements on phase retardation samples. We show experimental results showing the capabilities of our proposal in characterizing a polarization retardance sample.

Preliminary survey of the occurrence of mycotoxins in cereals and estimated exposure in a northwestern region of Mexico.

Mycotoxins have several toxicological implications. In the present study, we evaluate the presence of aflatoxin B1 (AFB1), ochratoxin A (OTA), and fumonisin (FB1) in paddy rice, polished rice, and maize from the fields and markets in Nayarit State (Mexico). The results indicated the presence of AFB1 in 21.21% of paddy rice samples and 11.11% of market maize samples. OTA was present in only 3.03% (one sample) of paddy rice samples. FB1 was detected in 87.50% and 88.88% of maize samples from field and market, respectively. The estimated human exposure was calculated for FB1 using the probable daily intake (PDI), which suggested that FB1 could contribute to the development of diseases through the consumption of contaminated maize. Positive samples indicated that some rice and maize samples were not suitable for human consumption. Further efforts are needed to continue monitoring mycotoxins and update national legislation on mycotoxins accordingly.

PON1 status and homocysteine levels as potential biomarkers for cardiovascular disease.

BACKGROUND: Cardiovascular disease (CVD) is the leading cause of death. The mainly risks factors for CVD are diabetes, hypertension and high levels of homocysteine (Hcys), among others. Paraoxonase 1 (PON1) has been proposed as an antiatherogenic target for its ability to hydrolyzing oxi-Low-Density-Lipoproteins (LDL) and Hcys-thiolactone. Thus, the aim of the present study was to evaluate the association of Hcys levels, and the activities and concentration of PON1, as well as vitamin B from the diet with a risk for CVD. METHODS: A case-control study was carry out in patients with cardiovascular diseases (CVD), Arterial hypertension, but not CVD (AH), and in healthy controls (control group) from the Mexican Institute of Social Security. Lipid profile, intake of vitamin B, Hcys, serum amyloid A (SAA), PON1 concentration, and PON1 activities (Arylesterase activity (ARE), Lactonase activity (LAC), and CMPA activity (CMPA)) were evaluated. RESULTS: The CVD group had the highest concentration of Hcys and SAA than in the AH and control groups (p < 0.01). ARE, LAC, and CMPA activities and PON1 concentration were lowest in the CVD group. A positive-independent association between Hcys levels and CVD was found (OR = 2.09; 95% CI: 1.69-2.56) and this increase when it was adjusted by age, BMI, ApoA1, vitamin B intake, SAA, and PON1 (OR = 14.41; 95% CI: 1.75-118.71). LAC and CMPA, as well as PON1 concentration, were inversely associated with CVD. CONCLUSION: LAC activity, PON1 concentration, and Hcys levels might be good biomarkers for CVD and their association could be modified by the intake of vitamin B.

Asociación de insuficiencia renal aguda con mortalidad y complicaciones en pacientes hospitalizados con cirrosis hepática / Association of acute renal failure with mortality and complications in hospitalized patients with liver cirrhosis

Resumen ANTECEDENTES: la insuficiencia renal aguda es una de las complicaciones más severas de la cirrosis y conlleva un pronóstico ominoso. Los estudios que han utilizado definiciones más actuales de daño renal agudo, como AKIN (Acute Kidney Injury Network) o RIFLE (The Risk, Injury, Failure, Loss and End-stage kidney disease criteria) se enfocan en pacientes admitidos en unidades de cuidados intensivos y no pueden generalizarse a otros pacientes hospitalizados. El Club Internacional de Ascitis (ICA por sus siglas en inglés) recientemente adoptó una definición dinámica de insuficiencia renal crónica en pacientes con cirrosis, definiéndola como el incremento de la creatinina sérica mayor o igual de 0.3 mg/dL en las últimas 48 horas o un incremento de más de 50% de la creatinina basal conocida ocurrida en los últimos siete días, estadificándose de acuerdo con los incrementos de la creatinina. OBJETIVO: evaluar la repercusión de la severidad de la insuficiencia renal aguda de acuerdo con la clasificación del Club Internacional de Ascitis en la mortalidad de los pacientes con cirrosis hepática hospitalizados, así como conocer los principales desencadenantes de insuficiencia renal aguda en pacientes con cirrosis hepática hospitalizados, los patrones de recuperación o progresión de la misma. PACIENTES Y MÉTODO: estudio transversal, observacional, no aleatorizado y multicéntrico, en el que se utilizó la definición de insuficiencia renal aguda propuesta por el Club Internacional de Ascitis. Los pacientes se captaron en un lapso de cuatro meses, del 1 de abril al 31 de julio de 2015, en el Hospital General Ticomán y en el Hospital General de Ecatepec; se solicitó consentimiento informado de los pacientes o en caso pertinente, del familiar responsable del mismo. Se excluyeron los pacientes menores de 18 años, sujetos con insuficiencia hepática aguda y los pacientes con enfermedad renal crónica. RESULTADOS: se incluyeron 45 pacientes con cirrosis hepática, de los que 36 eran hombres, con edad promedio de 46.2 años. La causa de la cirrosis hepática fue por alcohol en 40 pacientes (89%), viral en 3 (7%) y mixta en 2 (4%); la estadificación de insuficiencia renal aguda inicial fue: estadio 1: 36 (80%), estadio 2: 8 (18%) y estadio 3: 1 (2%). Ocurrieron siete defunciones (15.5%); de éstas, todos los pacientes estaban en la categoría C de la clasificación Child-Pugh, con insuficiencia renal aguda en estadio inicial 1; en 6 (13%) pacientes con progresión a estadio 3 y en estadio inicial 2; en 1 (2%) paciente con progresión a estadio 3. La severidad de la cirrosis en la escala MELD (Model for End-Stage Liver Disease) fue de 31.07±8.44 puntos en los pacientes que fallecieron versus 22.98±9.64 puntos (p=1.21) en los supervivientes. El puntaje de Child-Pugh en el grupo de pacientes fallecidos fue de 14.29±0.9 vs 0.29±2.31 en los supervivientes (p=0.001). CONCLUSIONES: la mortalidad en pacientes con cirrosis hepática e insuficiencia renal aguda fue más frecuente en pacientes con progresión al estadio de insuficiencia renal aguda y en sujetos con mayor severidad de la cirrosis hepática, valorada por Child-Pugh o por la escala MELD. Se requieren estudios de cohorte en nuestra población para validar la reciente clasificación del Club Internacional de Ascitis de la insuficiencia renal aguda en cirrosis y para determinar los factores asociados con incremento en la mortalidad en este grupo de pacientes.

Abstract BACKGROUND: Acute renal failure is one of the most severe complications of cirrhosis and entails a bad prognosis. The studies that had used most current definitions of acute kidney injury such as AKIN (Acute Kidney Injury Network) or RIFLE (The Risk, Injury, Failure, Loss and End-stage kidney disease criteria) has focused in patients admitted to the critical care units, and thus they can not be generalized to other hospitalized patients. Recently, the International Club of Ascites (ICA) adopted a dynamic definition of acute kidney failure in patient with cirrhosis, defined like increase of the creatinine level ≥0.3 mg/dL in the last 48 h; or a increase ≥50% from the basal creatinine in the last seven days, staged according the increase of creatinine. OBJECTIVES: To evaluate the impact of acute kidney injury severity according to the classification of the International Club of Ascites in the mortality of hospitalized patients with liver cirrhosis. To know the main triggers of acute kidney failure in hospitalized patients with liver cirrhosis, and to know the patterns of recovery and progression of renal failure. PATIENTS AND METHOD: A transversal, observational, no-randomized multicentric study designed. We used the definition of acute kidney failure proposed for the ICA. Patients were included from the General Hospital Ticoman and the General Hospital of Ecatepec in Mexico, in a four-month-period, from 1st April to 31st July of 2015; informed consent was obtained from the patients or in the pertinent case from the responsible familiar. Patients with less than 18 years old, with acute liver failure or chronic renal failure were excluded. RESULTS: They were included 45 patients with liver cirrhosis, 36 men, with a mean age of 46.2 years old. The etiology of the liver cirrhosis was alcohol in 40 patients (89%), viral in 3 (7%) and mixed in 2 (4%). The stage of acute liver failure was stage 1: 36 (80%), stage 2: 8 (18%) and stage 3: 1 (2%). Seven deaths occurred (15.5%), from there all the patients were classified in the C stage of the Child-Pugh Classification; death occurred with acute renal failure in initial stage 1; in 6 (13%) with progression to the stage 3 and in initial stage 2 in 1 (2%) with progression to stage 3. The severity of cirrhosis accord to the MELD classification was 31.07±8.44 points in the mortality cases, compared with 22.9±9.64 points (p=1.21) in the survivals. Child-Pugh score in the cases of death was 14.29±.9 vs 0.29±2.31 in survivals (p=0.001). CONCLUSION: Mortality in patients with liver cirrhosis and acute kidney failure was more frequent in patients with progression of the acute kidney failure, and in those with a more severe liver damage in the MELD or Child-Pugh scores. There are necessary cohort studies for the validation of the recent classification of the International Club of Ascites for Acute kidney failure in cirrhosis, and to determine the factors associated to the increase of mortality in this group of patients.

Changes in objectively measured physical activity in adolescents with Down syndrome: the UP&DOWN longitudinal study.

BACKGROUND: It is a priority to understand that physical activity behaviour over time is a priority in Down syndrome population in order to design and promote succesfull interventions to maintain or increase levels of physical activity. We aimed to study 1 and 2-year changes in objectively measured physical activity among a relatively large sample of adolescents with Down syndrome. METHODS: This study comprised a total of 99 adolescents with Down syndrome (38 girls) aged from 11 to 20 years old at baseline. Participants with valid accelerometer data at baseline and at least one of the follow-up visits were included in the analysis. RESULTS: Overall, levels of physical activity observed in adolescents with Down syndrome declined from baseline to follow-ups, but these changes were not significant (all P > 0.05). Moderate-to-moderately high tracking of physical activity was observed in adolescents with Down syndrome (all P < 0.001). Youths who met physical activity guidelines at baseline demonstrated a greater decline in physical activity in 1 and 2-year changes (P < 0.05), although they were also more likely to meet physical activity guidelines at 1 and 2-year follow-ups (P < 0.05). CONCLUSIONS: Adolescents with Down syndrome do not change their levels of physical activity at 2-year follow-ups, but those who met physical activity guidelines presented stronger declines in physical activity over time.

Mueller-matrix modeling and characterization of a dual-crystal electro-optic modulator.

A general mathematical model based on Mueller-matrix calculation is presented to describe the optical behavior of a dual-crystal electro-optic modulator. The two crystals inside the modulator are oriented at ± 45° with respect to the horizontal, thereby cancelling natural birefringence and temperature-induced birefringence. We describe the behavior of the modulator as a function of the ellipticity of the crystals, the rotation angles of the crystals and the applied voltage. By fitting the measured data with a Mueller-matrix model that uses values for the ellipticity and orientation angles of the crystals, the simulated data and the experimental measurements could be matched. This Mueller-matrix includes physical properties of the thermally compensated electro optic modulator, and the matrix can be used in simulations where these device-specific properties are important, for instance in the modeling of a polarization-sensitive optical coherence tomography system.

[CD200 protein, bad prognostic in patients with multiple myeloma]. / Proteína CD200 de mal pronóstico en pacientes con mieloma múltiple.

BACKGROUND: Multiple myeloma (MM) is a monoclonal gammopathy characterized by abnormal proliferation of malignant plasma cells. The median overall survival rate has changed from 2-3 to 5-6 or more years with the introduction of novel agents. Recently CD200 protein has been described as an immunosuppressive protein that confers a poor prognostic factor in several neoplastic diseases, including MM. The purpose of our study was to determine CD200 protein in plasma cells of newly diagnosed patients with MM and in CD3+ lymphocytes of healthy donors. METHODS: 35 newly diagnosed MM patients and 25 healthy donors were studied. For flow cytometry tests, a FacsCalibur device and CellQuestPro software were used. Monoclonal antibodies for CD38 (PeCyC5), CD138 (APC), and CD200 (PE) were used. The statistical analysis was performed with SPSS 19v. Mann-Whitney U test, Kaplan-Meier survival curves with Log-Rank tests were done when indicated. RESULTS: The frequencies of anemia, hypercalcemia, increased in LDH, serum creatinine and b2-microglobulin were 68%, 34%, 20%, 22% and 45% respectively. The treatment consisted in MPT 20 (57%), Thal-Dex 8 (23%), and VAD 7 (20%). Five patients (14%) achieved complete response, 17 (49%) partial response, and 13 (37%) minor response or failure to treatment. CONCLUSION: CD200 is a poor prognostic factor for overall survival in multiple myeloma patients. Bone marrow CD3 lymphocytes from MM patients express CD200 protein in higher proportion than healthy donors.

Introducción: el mieloma múltiple (MM) es una gammopatía monoclonal caracterizada por la proliferación anormal de células plasmáticas malignas. La proteína CD200 se ha descrito como una proteína con funciones inmunosupresoras y que es un factor de mal pronóstico en algunas enfermedades malignas, incluyendo al MM. El objetivo de este artículo es determinar la cantidad de proteína CD200 en células plasmáticas de pacientes con MM de reciente diagnóstico y en linfocitos CD3+ de donadores sanos. Métodos: se estudiaron 35 pacientes con diagnóstico reciente de MM y 25 individuos sanos. Se usaron los anticuerpos monoclonales para CD38 (PeCyC5), CD138 (APC), y CD200 (PE). El análisis estadístico fue realizado con el programa SPSS 19v. Se utilizaron las pruebas estadísticas U de Mann Whitney, curvas de supervivencia de Kaplan y Meier y la prueba de log-rank. Resultados: las frecuencias de anemia, hipercalcemia, elevación de DHL, creatinina sérica y beta-2 microglobulina fueron de 68%, 34%, 20%, 22% y 45% respectivamente. El tratamiento administrado fue MPT 20, Tal-Dex 8, y VAD 7. Cinco pacientes lograron respuesta completa, 17 respuesta parcial, y 13 respuesta menor o falla al tratamiento. Conclusiones: el CD200 es un factor de mal pronóstico para supervivencia global en pacientes con mieloma múltiple. Los linfocitos CD3+ de medula ósea de pacientes con MM expresan en mayor proporción CD200 en comparación con sujetos sanos.

Discrete perturbation theory for continuous soft-core potential fluids.

In this work, we present an equation of state for an interesting soft-core continuous potential [G. Franzese, J. Mol. Liq. 136, 267 (2007)] which has been successfully used to model the behavior of single component fluids that show some water-type anomalies. This equation has been obtained using discrete perturbation theory. It is an analytical expression given in terms of density, temperature, and the set of parameters that characterize the intermolecular interaction. Theoretical results for the vapor-liquid phase diagram and for supercritical pressures are compared with previous and new simulation data and a good agreement is found. This work also clarifies discrepancies between previous Monte Carlo and molecular dynamics simulation results for this potential.

Refractive index and geometrical thickness measurement of thin optical samples by a transmitted Gaussian beam.

We describe a technique for simultaneously measuring the local geometrical thickness and the refractive index of semi-transparent thin plates by means of the diffractive properties of a transmitted Gaussian beam. The technique is based on measuring the semi-width of the transmitted beam and the shift of the Gaussian centroid caused by introducing a tilt on the sample under test. A homodyne technique is devised to accurately characterize the Gaussian beam. Our proposal does not require any prior information of the sample under study. We present analytical support of our technique and we give experimental results.

Refractive index and geometrical thickness measurement of a transparent pellicle in air by Gaussian beam defocusing.

We demonstrate that it is possible to measure the local geometrical thickness and the refractive index of a transparent pellicle in air by combining the diffractive properties of a Gaussian beam with the analytical equations of the light that propagates through a thin layer. We show that our measurement technique is immune to inherent piston-like vibrations present in the pellicle. As our measurements are based on characterizing properly the Gaussian beam in a plane of detection, a homodyne technique for this purpose is devised and described. The feasibility of our proposal is confirmed by measuring local geometrical thicknesses and the refractive index of a commercially available stretch film.

Targets for antibiotic and healthcare resource stewardship in inpatient community-acquired pneumonia: a comparison of management practices with National Guideline Recommendations.

PURPOSE: Community-acquired pneumonia (CAP) is the most common infection leading to hospitalization in the USA. The objective of this study was to evaluate management practices for inpatient CAP in relation to Infectious Diseases Society of America/American Thoracic Society (IDSA/ATS) guidelines to identify opportunities for antibiotic and health care resource stewardship. METHODS: This was a retrospective cohort study of adults hospitalized for CAP at a single institution from 15 April 2008 to 31 May 2009. RESULTS: Of the 209 patients with CAP who presented to Denver Health Medical Center during the study period and were hospitalized, 166 (79 %) and 43 (21 %) were admitted to a medical ward and the intensive care unit (ICU), respectively. Sixty-one (29 %) patients were candidates for outpatient therapy per IDSA/ATS guidance with a CURB-65 score of 0 or 1 and absence of hypoxemia. Sputum cultures were ordered for 110 specimens; however, an evaluable sample was obtained in only 49 (45 %) cases. Median time from antibiotic initiation to specimen collection was 11 [interquartile range (IQR) 6-19] h, and a potential pathogen was identified in only 18 (16 %) cultures. Blood cultures were routinely obtained for both non-ICU (81 %) and ICU (95 %) cases, but 15 of 36 (42 %) positive cultures were false-positive results. The most common antibiotic regimen was ceftriaxone + azithromycin (182, 87 % cases). Discordant with IDSA/ATS recommendations, oral step-down therapy consisted of a new antibiotic class in 120 (66 %), most commonly levofloxacin (101, 55 %). Treatment durations were typically longer than suggested with a median of 10 (IQR 8-12) days. CONCLUSIONS: In this cohort of patients hospitalized for CAP, management was frequently inconsistent with IDSA/ATS guideline recommendations, revealing potential targets to reduce unnecessary antibiotic and healthcare resource utilization.

Comparison of two wild rodent species as sentinels of environmental contamination by mine tailings.

BACKGROUND: Contamination with heavy metals is among the most hazardous environmental concerns caused by mining activity. A valuable tool for monitoring these effects is the use of sentinel organisms. Particularly, small mammals living inside mine tailings are an excellent study system because their analysis represents a realistic approach of mixtures and concentrations of metal exposure. PURPOSE: We analyzed metal tissue concentrations and DNA damage levels for comparison between genders of a sentinel (Peromyscus melanophrys) and a nonsentinel (Baiomys musculus) species. Also, the relationship between DNA damage and the distance from the contamination source was evaluated. METHODS: This study was conducted in an abandoned mine tailing at Morelos, Mexico. Thirty-six individuals from both species at the exposed and reference sites were sampled. Metal concentrations in bone and liver of both species were analyzed by atomic absorption spectrophotometry, and DNA damage levels were assayed using the alkaline comet assay. RESULTS: In general, concentrations of zinc, nickel, iron, and manganese were statistically higher in exposed individuals. A significant effect of the organ and the site on all metal tissue concentrations was detected. Significant DNA damage levels were registered in the exposed group, being higher in B. musculus. Females registered higher DNA damage levels than males. A negative relationship between distance from the mine tailing and DNA damage in B. musculus was observed. CONCLUSIONS: We consider that B. musculus is a suitable species to assess environmental quality, especially for bioaccumulable pollutants--such as metals--and recommend that it may be considered as a sentinel species.

Screening of extracts of algae from Baja California sur, Mexico as reversers of the antibiotic resistance of some pathogenic bacteria.

BACKGROUND AND OBJECTIVES: Sixty ethanol extracts of marine flora of Baja California Sur (Mexico) were screened to evaluate the reversing effect of the bacterial resistance to antibiotics in combination with a sublethal concentration of ampicillin or erythromycin. MATERIALS AND METHODS: The activity was assayed by using a modification of the classical agar-diffusion method against 3 resistant, pathogenic bacteria; Escherichia coil (ATCC BAA196), Staphylococcus aureus (ATCC BAA42), and Streptococcus pyogenes (ATCC BAA946). RESULTS: From the 60 ethanolic extracts, 12 (20%) of them in combination with ampicillin were able to reverse the resistance of Staphylococcus aureus and 8 (13%) with erythromycin yielded the same reversal with Streptococcus pyogenes. An extract from Sargassum horridum was the only one that reversed the resistance to antibiotics against both Staphylococcus aureus and Streptococcus pyogenes. CONCLUSIONS: Our findings suggest that some algae may be source of compounds with the potential to reverse the antibiotic resistance of some bacteria. In addition, of the assayed extracts, 35 (57%) showed inhibitory activity against Staphylococcus aureus, 48 (78%) were active against Streptococcus pyogenes, but none was active against Escherichia coil. The most active extracts were from Laurencia spp., Gelidium robustum, Chnoospora implexa, Padina mexicana, Gracilaria subsecundata, and Dictyopteris undulata.

Acetylcholinesterase and metallothionein in oysters (Crassostrea corteziensis) from a subtropical Mexican Pacific estuary.

Substantial efforts have been devoted to developing and applying biomarkers for ecological risk assessment. Bivalve mollusks, such as mussels and oysters, are commonly used in environmental monitoring programs because of their wide geographical distribution, great sensitivity to environmental pollutants, and ability to accumulate anthropogenically derived chemicals at a high rate. Acetylcholinesterase (AChE) activity and metallothionein (MT's) content are representative specific biomarkers that indicate the presence of anticholinesterasic compounds (like organophosphorus and carbamate pesticides) and metals, respectively. The aim of this study was to evaluate AChE activity and MT's content in Crassostrea corteziensis from Boca de Camichín estuary. The results obtained here showed that AChE activity was 65% lower in oysters from Boca de Camichín than in control organisms. In contrast, MT's content in collected organisms was not statistically different from that in control organisms. AChE activity and MT's content in oysters could be used as early biomarkers of effects and exposure to pesticides and heavy metals, respectively, in aquatic environments.

Discrete perturbation theory for the hard-core attractive and repulsive Yukawa potentials.

In this work we apply the discrete perturbation theory [A. L. Benavides and A. Gil-Villegas, Mol. Phys. 97, 1225 (1999)] to obtain an equation of state for the case of two continuous potentials: the hard-core attractive Yukawa potential and the hard-core repulsive Yukawa potential. The main advantage of the presented equation of state is that it is an explicit analytical expression in the parameters that characterize the intermolecular interactions. With a suitable choice of their inverse screening length parameter one can model the behavior of different systems. This feature allows us to make a systematic study of the effect of the variation in the parameters on the thermodynamic properties of this system. We analyze single phase properties at different conditions of density and temperature, and vapor-liquid phase diagrams for several values of the reduced inverse screening length parameter within the interval kappa( *)=0.1-5.0. The theoretical predictions are compared with available and new Monte Carlo simulation data. Good agreement is found for most of the cases and better predictions are found for the long-range ones. The Yukawa potential is an example of a family of hard-core plus a tail (attractive or repulsive) function that asymptotically goes to zero as the separations between particles increase. We would expect that similar results could be found for other potentials with these characteristics.

Multiple myeloma-associated amyloidosis is an independent high-risk prognostic factor.

Several prognostic factors have been recognized in patients with multiple myeloma (MM). Among the most important are: the serum levels of beta2-microglobulin, albumin, and LDH; the labeling index; and an abnormal karyotype. Patients with amyloidosis (AL) have poor prognosis; however, little is known concerning the prognostic significance of AL associated to MM. In 201 consecutive patients with de novo MM, we performed a fat-pad biopsy needle aspiration (FPBNA) that was stained with Congo red. Sixty eight (34%) patients had AL and a poorer prognosis disease: lower performance status, presence of B symptoms, higher LDH and calcium values, and worse response to chemotherapy. Cox regression model for overall survival detected three variables having independent prognostic significance: the presence of AL (RR = 3.4, P < 0.004), serum albumin levels <3.5 g/dl (RR 3.2, p < 0.005), and patients not achieving complete remission or very good partial remission (RR 2.9, p < 0.02). In 28% of patients with de novo MM, FPBNA was useful to detect incidental amyloidosis. During follow-up, 69% of these patients had symptoms of AL. Excluding 16 patients with obvious symptoms of AL at diagnosis, overall survival was worse in patients who developed later symptoms of AL. MM-associated AL represents a poorer prognosis disease even in the absence of symptoms at diagnosis, and this specific association may be considered as an independent high-risk prognostic factor. The routine study of periumbilical fat-pad tissue should be mandatory in all patients with MM.

P2X7 and NRAMP1/SLC11 A1 gene polymorphisms in Mexican mestizo patients with pulmonary tuberculosis.

Tuberculosis remains one of the most important infectious diseases worldwide. Several studies have suggested that genetic factors may affect susceptibility to tuberculosis, but the specific genes involved have not yet been fully characterized. NRAMP1/SLC11 A1 and P2X(7) genes have been linked to increased risk for tuberculosis in some African and Asiatic populations. To explore the potential role of these genes in the susceptibility to pulmonary tuberculosis in a Mexican mestizo population, we evaluated the association of D543N and 3'-UTR polymorphisms in NRAMP1/SLC11 A1 and - 762 and A1513C polymorphisms in P2X(7) genes with the risk for tuberculosis. Polymerase chain reaction (PCR) amplification of genomic DNA followed by restriction fragment length polymorphism analysis, and allelic-specific PCR was employed. We found no significant differences in allelic frequency in NRAMP1/SLC11 A1 gene polymorphisms in 94 patients with tuberculosis compared to 100 healthy contacts. Similarly, no significant association of the P2X(7)-762 gene polymorphism with tuberculosis was detected. In contrast, the P2X(7) A1513C polymorphism was associated significantly with tuberculosis (P = 0.02, odds ratio = 5.28, 95% CI, 0.99-37.69), an association that had not been reported previously. However, when the function of P2X(7) was assessed by an L-selectin loss assay, we did not find significant differences in patients compared to healthy contacts or between PPD(+) and PPD(-) control individuals. This study further supports the complex role of P2X(7) gene in host regulation of Mycobacterium tuberculosis infection, and demonstrates that different associations of gene polymorphisms and tuberculosis are found in distinct racial populations.