High genetic diversity and low structure in an endemic long-lived tree, Yucca capensis (Asparagaceae).

Endemic species distributed in fragmented habitats are highly vulnerable to extinction because they may have low genetic diversity. However, some life-history traits can mitigate the effect of genetic drift on populations. We analysed the level and distribution of genetic variation and ancestral population size of Yucca capensis, a long-lived endemic plant of the Baja California Peninsula, Mexico. Its populations are scattered across a habitat that is suffering accelerated transformation. We used six nuclear microsatellites to genotype 224 individuals from 17 locations across the entire species' geographic range. We estimated polymorphisms, heterozygosity and genetic structure. We also evaluated the ancestral and recent effective size and time since the population started to change. We found high heterozygosity, high polymorphism and low differentiation among locations, suggesting a panmictic population across the range. We also detected a large ancestral effective population size, which suffered a strong reduction in the Mid-Holocene. Despite changes in environmental conditions caused by habitat modification, the high diversity and low differentiation in Y. capensis may result from its large ancestral effective size and life-history traits, such as plant longevity, clonal growth and mating system, which reduce the rate of loss of genetic variation. However, the dependence on a specialist pollinator that displays short flight range can reduce gene flow among the plant populations and could, shortly, lead them into an extinction vortex.

Fibrosis assessment in patients with nonalcoholic fatty liver disease: Adherence to proposed algorithms and barriers to complying with them.

INTRODUCTION AND AIMS: Fibrosis staging in patients with nonalcoholic fatty liver disease (NAFLD) is carried out through the application of stepwise algorithms but there is little real-world data on their use. Our aim was to calculate the number of patients with NAFLD and indeterminate or high risk for fibrosis, assessed through noninvasive scores, that consequently underwent further staging evaluation. MATERIALS AND METHODS: A cross-sectional multicenter cohort study was conducted on patients with NAFLD evaluated by hepatologists within the time frame of June 1 and July 31, 2018. The FIB-4 and NAFLD fibrosis scores were calculated in all the patients, and if at least one of the scores suggested indeterminate or high risk for fibrosis, we believed the patient should have undergone additional fibrosis staging assessment. RESULTS: The study included 238 patients. The median time interval from NAFLD diagnosis and inclusion in the analysis was 12.2 months (IQR 3.0-36.5). A total of 128 (54%) patients had at least one noninvasive score that suggested indeterminate or high risk for fibrosis but studies to confirm the fibrosis grade (elastography, biopsy, etc.) were performed on only 72 (56%). The main barriers encountered by the physicians for applying the staging algorithms were related to health insurance coverage and imaging study costs. CONCLUSIONS: A high percentage of patients with NAFLD were at indeterminate or high risk for fibrosis, according to noninvasive scores, but additional studies were carried out on only half of them, showing low adherence to current recommendations.

Rice recycling: a simple strategy to improve conidia production in solid-state cultures.

Here we studied at a laboratory scale a potential strategy to revalorize the residual rice remaining at the end of a conventional conidia production process in solid-state culture. The conidia production of Trichoderma asperellum Th-T4 (3) and Metarhizium robertsii Xoch-8.1 started with the use of fresh rice (unrecycled rice) as the substrate (cycle one), and continued with the use of recycled rice in successive cycles of conidia production. The rice remaining at the end of the first cycle was reused without any further sterilization or reinoculation. As a result, it was observed that the conidia production and productivity significantly increased in both fungi. Conidia production in T. asperellum Th-T4 (3) increased from 1 × 109 (first cycle) to 2·9 × 109 conidia per gram of initial dry substrate (con⋅gds-1 ) (second cycle using recycled rice), while in M. robertsii Xoch-8.1, this parameter increased form 5·7 × 108 to 1·4 × 109 con⋅gds-1 . Both fungi grew faster and conidiated earlier when recycled rice was used as the substrate, therefore, conidia productivity was also significantly improved. Furthermore, the use of recycled rice did not affect conidia viability. This is the first report about a recycling methodology completely free of extra-processing steps, and useful to increase conidia production and productivity.

Fibrosis assessment in patients with nonalcoholic fatty liver disease: Adherence to proposed algorithms and barriers to complying with them. / Evaluación de fibrosis en pacientes con enfermedad por hígado graso no alcohólico: adherencia a los algoritmos propuestos y barreras para cumplir con ellos.

INTRODUCTION AND AIMS: Fibrosis staging in patients with nonalcoholic fatty liver disease (NAFLD) is carried out through the application of stepwise algorithms but there is little real-world data on their use. Our aim was to calculate the number of patients with NAFLD and indeterminate or high risk for fibrosis, assessed through noninvasive scores, that consequently underwent further staging evaluation. MATERIALS AND METHODS: A cross-sectional multicenter cohort study was conducted on patients with NAFLD evaluated by hepatologists within the time frame of June 1 and July 31, 2018. The FIB-4 and NAFLD fibrosis scores were calculated in all the patients, and if at least one of the scores suggested indeterminate or high risk for fibrosis, we believed the patient should have undergone additional fibrosis staging assessment. RESULTS: The study included 238 patients. The median time interval from NAFLD diagnosis and inclusion in the analysis was 12.2months (IQR 3.0-36.5). A total of 128 (54%) patients had at least one noninvasive score that suggested indeterminate or high risk for fibrosis but studies to confirm the fibrosis grade (elastography, biopsy, etc.) were performed on only 72 (56%). The main barriers encountered by the physicians for applying the staging algorithms were related to health insurance coverage and imaging study costs. CONCLUSIONS: A high percentage of patients with NAFLD were at indeterminate or high risk for fibrosis, according to noninvasive scores, but additional studies were carried out on only half of them, showing low adherence to current recommendations.

Evolving concepts in ventral hernia repair and physical therapy: prehabilitation, rehabilitation, and analogies to tendon reconstruction.

PURPOSE: The abdominal wall and musculoskeletal tendons share many anatomic, physiologic, and functional characteristics. This review aims to highlight these similar characteristics and to present a rationale why the treatment principles of successful musculoskeletal tendon reconstruction, including principles of surgical technique and physical therapy, can be used in the treatment of complex abdominal wall reconstruction or ventral hernia repair. METHODS: The MEDLINE/PubMed database was used to identify published literature relevant to the purpose of this review. CONCLUSIONS: There are several anatomical and functional similarities between the linea alba and musculoskeletal tendons. Because of this reason, many of the surgical principles for musculoskeletal tendon repair and ventral hernia repair overlap. Distribution of tension is the main driving principle for both procedures. Suture material and configuration are chosen to maximize tension distribution among the tissue edges, as seen in the standard of care multistrand repairs for musculoskeletal tendons, as well as in the small bites for laparotomy technique described in the STITCH trial. Physical therapy is also one of the mainstays of tendon repair, but surprisingly, is not routine in ventral hernia repair. The evidence surrounding physical therapy prehabilitation and rehabilitation protocols in other disciplines is significant. This review challenges the fact that these protocols are not routinely implemented for ventral hernia repair, and presents the rationale and feasibility for the routine practice of physical therapy in ventral hernia repair.

[Bacteriological-clinical association and characterization in Pyogenic Spondylodiscitis]. / Caracterización y asociación clínico bacteriológica en la espondilodiscitis piógena.

OBJECTIVE: Determine the association between clinical characteristics and laboratory studies with the type of isolated microorganism in blood cultures of patients with Pyogenic Spondylodiscitis. MATERIAL AND METHODS: It is a cross-analytical study, clinical records of patients with Pyogenic Spondylodiscitis were reviewed from January 2013 to January 2017. Univariate descriptive analysis was performed using frequencies and percentages for qualitative variables, central trend measures and dispersion for quantitative ones. Bivariate analysis by testing of 2 or Fishers exact test. Analysis of quantitative variables using T Student or Mann-Whitney U. Spearmans correlation coefficient was used. Considering statistical significance p 0.05. RESULTS: A sample of 34 patients was obtained, 20 (58%) were women, median (Me) of age 60 years (52-66). Was isolated into blood cultures, Gram-positive bacteria 11 (32.4%) gram negatives 23 (67.6%). The microorganism most common isolate was Escherichia coli 12 (35.3%). Patients with Gram-negative spondylodiscitis had mild pain and globular sedimentation rate (VSG) Me 26 mm/hra P (18-36), patients with Gram-positive spondylodyscitis had severe pain and VSG Me 38 mm/h P (34-40) (p= 0.000 and 0.028, respectively). VSG and pain in the group of patients with gram-negative bacteria spondylodiscitis had a moderate Spearman correlation coefficient of 0.418, (p = 0.047); in the Gram positives group, a low correlation coefficient of Spearman 0.228, (p = 0.507). CONCLUSION: There is a clinical and statistical association significant between types of isolated microorganism in blood culture, pain intensity valued on analog visual scale (EVA) and VSG levels.

OBJETIVO: Determinar la asociación entre las características clínicas y estudios de laboratorio con el tipo de microorganismo aislado en hemocultivos de pacientes con espondilodiscitis piógena. MATERIAL Y MÉTODOS: Es un estudio transversal analítico, se revisaron expedientes clínicos de pacientes con espondilodiscitis piógena desde Enero de 2013 hasta Enero de 2017. Se realizó análisis descriptivo univariado usando frecuencias y porcentajes para variables cualitativas, medidas de tendencia central y dispersión para las cuantitativas. Análisis bivariado mediante prueba de 2 o test exacto de Fisher. Análisis de variables cuantitativas mediante t Student o U de Mann-Whitney. Se usó coeficiente de correlación de Spearman. Considerando significancia estadística p 0.05. RESULTADOS: Se obtuvo una muestra de 34 pacientes, 20 (58%) fueron mujeres, mediana (Me) de edad 60 años (52-66). Se aisló en hemocultivos, bacterias Gram positivas 11 (32.4%) y Gram negativas 23 (67.6%). El microorganismo aislado más frecuente fue Escherichia coli 12 (35.3%). Los pacientes con espondilodiscitis por Gram negativas presentaron dolor leve y velocidad de sedimentación globular (VSG) Me 26 mm/hra P (18-36), los pacientes con espondilodiscitis por Gram positivas presentaron dolor severo y VSG Me 38 mm/h P (34-40) (p = 0.000 y 0.028, respectivamente). La VSG y dolor en el grupo de pacientes con espondilodiscitis por bacterias Gram negativas tuvo un coeficiente de correlación de Spearman moderado 0.418, (p = 0.047); en el grupo de Gram positivas, un coeficiente de correlación de Spearman bajo 0.228, (p = 0.507). ­. CONCLUSIÓN: Existe una asociación clínica y estadística de manera significativa entre los tipos de microorganismo aislado en hemocultivo, la intensidad del dolor valorado en escala visual análoga (EVA) y los niveles de VSG.

Nefrolitotomía percutánea bilateral simultánea: Eficacia y seguridad" / Simultaneous bilateral percutaneous nephrolithotomy: Effectiveness and safety

Objetivos: Evaluar la efectividad y seguridad de la nefrolitotomía percutánea bilateral simultánea realizada en pacientes afectados de litiasis renales bilaterales. Material y métodos: Estudio prospectivo, período de septiembre de 2012 a noviembre de 2016. Se incluyeron pacientes diagnosticados de litiasis renales bilaterales por TC abdominal. Técnica quirúrgica posición en prono, punción renal guiada por fluoroscopia y dilatación del tracto hasta 24Ch. Se revisaron las características demográficas y de las litiasis, la tasa libre de litiasis, el éxito clínico, las complicaciones y el seguimiento. Resultados: Durante el período de estudio, se realizaron 732 nefrolitotomías percutáneas. Dieciocho pacientes (36 unidades renales; 2,5%), 13 hombres y 5 mujeres con una mediana de edad de 58 años y un rango intercuartílico (RIC) de 40-66. Tamaño de la litiasis mediana de 228 mm2 (RIC 134-389), tiempo operativo mediana de 150 min (RIC 97-180) y una estancia hospitalaria mediana de 5 días (RIC 5-15). La tasa libre de litiasis fue del 80%. Se reportaron litiasis residuales en 8 unidades renales (22,2%) que requirieron técnicas complementarias para su completa resolución, 4 litotricias extracorpóreas por ondas de choque, una ureterolitotomía por laparotomía, 2 ureteroscopias y un segundo procedimiento. Complicaciones mayores incluyeron 4 hemorragias manejadas mediante embolización por angiografía. Mediana de seguimiento 36 meses (rango 26-46). Conclusiones: La nefrolitotomía percutánea bilateral simultánea es un procedimiento eficaz y seguro en pacientes afectados con cálculos renales bilaterales. Es un desafío quirúrgico que debe realizarse en pacientes seleccionados y en centros con experiencia

Objectives: To evaluate the effectiveness and safety of simultaneous bilateral percutaneous nephrolithotomy performed in patients affected with bilateral renal calculi. Materials and methods: This is a prospective study from September 2012 to November 2016. Patients diagnosed of bilateral kidney stones with abdominal CT scan were included. Surgical technique prone position, renal puncture guided by fluoroscopy and tract dilation up to 24Ch. We reviewed demographic and stone characteristics, stone free rate, clinical success, complications and follow-up. Results: During the study period, 732 percutaneous nephrolithotomies were performed. Eighteen patients were included (36 renal units, 2.5%), 13 men and 5 women, with a median age of 58 years and an interquartile range (IQR) of 40-66. Median stone burden was 22 8mm2 (IQR 134-389); median operative time, 150 minutes (IQR 97-180); and median hospital stay, 5 days (IQR 5-15). Stone free rate was 80%. Residual calculi were encountered in 8 renal units (22.2%) and required other complementary techniques for their complete tesolution 4 external shockwave lithotripsies, one open ureterolithotomy, 2 ureteroscopies and one second look. Major complications included 4 cases of severe hemorrhage managed with angiographic embolization. The median follow-up was 36 months (range 26-46). Conclusions: Simultaneous bilateral percutaneous nephrolithotomy is an effective and safe procedure in patients affected with bilateral renal calculi. It is a surgical challenge that should be performed in selected patients and in centers with experience

Nuestra experiencia en el manejo del cáncer de próstata en pacientes trasplantados renales / Our experience in the management of prostate cancer in renal transplant recipients

Introducción y objetivos: El manejo del cáncer de próstata (CP) en receptores de trasplante renal (RTR) es un reto y muchos aspectos siguen siendo controvertidos. Actualmente no hay consensos sobre el manejo de esta enfermedad. El objetivo del estudio fue analizar nuestra experiencia en el diagnóstico y tratamiento del CP en RTR. Método: Estudio monocéntrico retrospectivo de una base de datos prospectiva y consecutiva del 2003-2017. Inclusión de RTR diagnosticados de CP. Estadificación y tratamiento según guías contemporáneas. Los principales parámetros evaluados incluyeron estadificación clínica, tipo de tratamiento, resultados oncológicos y seguimiento. Resultados: De 1.330 trasplantes renales (787 varones), se diagnosticó CP en 33 RTR (4,2%), con una edad media de 66 años ± 6,3 (51-78). La media de PSA fue de 8,8 ng/ml y PSA ratio de 0,19. El tiempo medio entre el trasplante renal y el diagnóstico de CP fue de 130 meses ± 90 (2-236). Tratamiento: prostatectomía radical (PR) (n = 22; 66,7%), radioterapia (RT) más terapia de privación androgénica (TDA) (n = 7; 21,2%), vigilancia activa (n = 3; 9,1%) y TDA (n = 1; 3%). No se reportaron pérdidas del injerto ni deterioro de la función renal atribuibles al tratamiento del CP. Tras PR, 2 pacientes (9,1%) presentaron recurrencia bioquímica, tratados con RT. La remisión fue del 100% y el seguimiento medio, de 61 meses ± 37 (6-132). Conclusiones: El CP en trasplantados renales puede ser manejado con las mismas opciones terapéuticas que en la población general. La vigilancia activa debería también considerarse en los RTR a pesar de estar bajo tratamiento inmunosupresor

Introduction and objectives: The management of Prostate cancer (PCa) in renal transplant recipients (RTR) is challenging and remain controversial. Currently there is no consensus about this condition. The aim of the study was to analyse our experience in the diagnosis and management of PCa in RTR. Method: Retrospective monocentric study of a prospective and consecutive database from 2003-2017. Inclusion of RTR diagnosed of PCa. Staging and treatment in agreement with the contemporary guidelines. The main outcome measures included clinical staging, type of treatment, oncological outcomes and follow-up. Results: 1,330 renal transplants were performed (787 males), diagnosed of PCa in 33 RTR (4.2%), mean age 66 years ± 6.3 (51-78). Median PSA was 8.8 ng/ml and PSA ratio 0.19. Mean time between renal transplantation and PCa diagnosis 130 months ± 90 (2-236). Treatments: Radical prostatectomy (RP) (n = 22; 66.7%), Radiation therapy (RT) with Androgen deprivation therapy (ADT) (n = 7; 21.2%), Active surveillance (n = 3; 9.1%), ADT (n = 1; 3%). No graft loss neither impaired renal function due to PCa treatment was reported. After RP two patients (9.1%) presented biochemical recurrence treated with RT. Remission of the 100%. Mean follow-up was 61months ± 37 (6-132). Conclusions: PCa in renal transplant patients can be managed with the same therapeutic options as in the general population. Active surveillance should also be provided in RTR despite being under immunosuppressive therapy

Simultaneous bilateral percutaneous nephrolithotomy: Effectiveness and safety. / Nefrolitotomía percutánea bilateral simultánea: Eficacia y seguridad".

OBJECTIVES: To evaluate the effectiveness and safety of simultaneous bilateral percutaneous nephrolithotomy performed in patients affected with bilateral renal calculi. MATERIALS AND METHODS: This is a prospective study from September 2012 to November 2016. Patients diagnosed of bilateral kidney stones with abdominal CT scan were included. Surgical technique prone position, renal puncture guided by fluoroscopy and tract dilation up to 24Ch. We reviewed demographic and stone characteristics, stone free rate, clinical success, complications and follow-up. RESULTS: During the study period, 732 percutaneous nephrolithotomies were performed. Eighteen patients were included (36 renal units, 2.5%), 13 men and 5 women, with a median age of 58 years and an interquartile range (IQR) of 40-66. Median stone burden was 228mm2 (IQR 134-389); median operative time, 150minutes (IQR 97-180); and median hospital stay, 5 days (IQR 5-15). Stone free rate was 80%. Residual calculi were encountered in 8 renal units (22.2%) and required other complementary techniques for their complete tesolution 4 external shockwave lithotripsies, one open ureterolithotomy, 2 ureteroscopies and one second look. Major complications included 4 cases of severe hemorrhage managed with angiographic embolization. The median follow-up was 36 months (range 26-46). CONCLUSIONS: Simultaneous bilateral percutaneous nephrolithotomy is an effective and safe procedure in patients affected with bilateral renal calculi. It is a surgical challenge that should be performed in selected patients and in centers with experience.

Our experience in the management of prostate cancer in renal transplant recipients. / Nuestra experiencia en el manejo del cáncer de próstata en pacientes trasplantados renales.

INTRODUCTION AND OBJECTIVES: The management of Prostate cancer (PCa) in renal transplant recipients (RTR) is challenging and remain controversial. Currently there is no consensus about this condition. The aim of the study was to analyse our experience in the diagnosis and management of PCa in RTR. METHOD: Retrospective monocentric study of a prospective and consecutive database from 2003-2017. Inclusion of RTR diagnosed of PCa. Staging and treatment in agreement with the contemporary guidelines. The main outcome measures included clinical staging, type of treatment, oncological outcomes and follow-up. RESULTS: 1,330 renal transplants were performed (787 males), diagnosed of PCa in 33 RTR (4.2%), mean age 66years±6.3 (51-78). Median PSA was 8.8ng/ml and PSA ratio 0.19. Mean time between renal transplantation and PCa diagnosis 130months±90 (2-236). TREATMENTS: Radical prostatectomy (RP) (n=22; 66.7%), Radiation therapy (RT) with Androgen deprivation therapy (ADT) (n=7; 21.2%), Active surveillance (n=3; 9.1%), ADT (n=1; 3%). No graft loss neither impaired renal function due to PCa treatment was reported. After RP two patients (9.1%) presented biochemical recurrence treated with RT. Remission of the 100%. Mean follow-up was 61months±37 (6-132). CONCLUSIONS: PCa in renal transplant patients can be managed with the same therapeutic options as in the general population. Active surveillance should also be provided in RTR despite being under immunosuppressive therapy.

Integration of a high-NA light microscope in a scanning electron microscope.

We present an integrated light-electron microscope in which an inverted high-NA objective lens is positioned inside a scanning electron microscope (SEM). The SEM objective lens and the light objective lens have a common axis and focal plane, allowing high-resolution optical microscopy and scanning electron microscopy on the same area of a sample simultaneously. Components for light illumination and detection can be mounted outside the vacuum, enabling flexibility in the construction of the light microscope. The light objective lens can be positioned underneath the SEM objective lens during operation for sub-10 µm alignment of the fields of view of the light and electron microscopes. We demonstrate in situ epifluorescence microscopy in the SEM with a numerical aperture of 1.4 using vacuum-compatible immersion oil. For a 40-nm-diameter fluorescent polymer nanoparticle, an intensity profile with a FWHM of 380 nm is measured whereas the SEM performance is uncompromised. The integrated instrument may offer new possibilities for correlative light and electron microscopy in the life sciences as well as in physics and chemistry.

Cholera in ecuador: current relevance of past lessons learnt.

This report analyses the trends in the cholera epidemic that hit Ecuador in 1991. The study is based on personal experiences and analysis of epidemiological databases from the Ministry of Public Health of Ecuador. The number of cases and initial attack rates in an immunologically naive population are described by province. An analysis of the Andean and coastal cholera patterns of transmission are described along with its associated risk factors. The logistical, environmental, and socio-cultural risk factors prevalent during the epidemic and the control measures implemented are also reviewed. Also, the role of the epidemic in the development of the public health and healthcare resources in Ecuador is discussed here. Current data indicate favorable conditions for another outbreak of cholera in Ecuador. In view of the existing risk factors, new strategies are proposed to prevent such an epidemic in the future.

Interleukin-6 and chemokines in the neuropsychiatric manifestations of systemic lupus erythematosus.

OBJECTIVE: To define the cytokine and chemokine profile in cerebrospinal fluid (CSF) from patients with neuropsychiatric systemic lupus erythematosus (NPSLE). METHODS: Forty-two SLE patients who had been hospitalized because of NP manifestations were studied. Patients were evaluated at hospitalization and 6 months later; a CSF sample was obtained at each evaluation. As controls, CSF from 6 SLE patients with septic meningitis, 16 SLE patients with no history of NP manifestations (non-NPSLE), and 25 patients with nonautoimmune diseases were also studied. Soluble molecules, including cytokines (interleukin-2 [IL-2], IL-4, IL-6, IL-10, tumor necrosis factor alpha [TNFalpha], and interferon-gamma [IFNgamma]) and chemokines (monocyte chemotactic protein 1 [MCP-1], RANTES, IL-8, monokine induced by IFNgamma [MIG], and interferon-gamma-inducible 10-kd protein [IP-10]), were measured with the use of cytometric bead array kits. RESULTS: CSF levels of the following molecules were significantly increased in NPSLE patients as compared with non-NPSLE and nonautoimmune diseases control patients, respectively: IL-6 (32.7 versus 3.0 and 2.96 pg/ml), IL-8 (102.8 versus 29.97 and 19.7 pg/ml), IP-10 (888.2 versus 329.7 [P not significant] and 133.6 pg/ml), RANTES (3.8 versus 2.5 and 2.2 pg/ml), MCP-1 (401.7 versus 257.9 [P not significant] and 136.9 pg/ml), and MIG (35.4 versus 11.4 and 3.5 pg/ml). Low levels of IL-2, IL-4, IL-10, TNFalpha, and IFNgamma were found in all groups. All cytokines and chemokines, except TNFalpha, were significantly higher among the SLE patients with septic meningitis than among the NPSLE patients. Six months later and in the absence of NP manifestations, all elevated molecule levels, except RANTES, in patients with NPSLE had decreased significantly, and no differences were noted between the NPSLE and non-NPSLE groups. CONCLUSION: A central nervous system response composed of IL-6 and chemokines, but not Th1/Th2 cytokines, is associated with NP manifestations in SLE patients.

Chlamydial ribonucleotide reductase: tyrosyl radical function in catalysis replaced by the FeIII-FeIV cluster.

Ribonucleotide reductase (RNR) from Chlamydia trachomatis is a class I RNR composed of proteins R1 and R2. In protein R2, the tyrosine residue harboring the radical that is necessary for catalysis in other class I RNRs is replaced by a phenylalanine. Active C. trachomatis RNR instead uses the Fe(III)-Fe(IV) state of the iron cluster in R2 as an initiator of catalysis. The paramagnetic Fe(III)-Fe(IV) state, identified by (57)Fe substitution, becomes electron spin resonance detectable in samples that are frozen during conditions of ongoing catalysis. Its amount depends on the conditions for catalysis, such as incubation temperature and the R1/R2 ratio. The results link induction of the Fe(III)-Fe(IV) state with enzyme activity of chlamydial RNR. Based on these observations, a reaction scheme is proposed for the iron site. This scheme includes (i) an activation cycle involving reduction and an oxygen reaction in R2 and (ii) a catalysis cycle involving substrate binding and turnover in R1.

Trapped tyrosyl radical populations in modified reaction centers from Rhodobacter sphaeroides.

The photosynthetic reaction center from the purple bacterium Rhodobacter sphaeroides has been modified such that the bacteriochlorophyll dimer, when it becomes oxidized after light excitation, is capable of oxidizing tyrosine residues. One factor in this ability is a high oxidation-reduction midpoint potential for the dimer, although the location and protein environment of the tyrosine residue appear to be critical as well. These factors were tested in a series of mutants, each of which contains changes, at residues L131, M160, M197, and M210, that give rise to a bacteriochlorophyll dimer with a midpoint potential of at least 800 mV. The protein environment was altered near tyrosine residues that are either present in the wild type or introduced by mutagenesis, focusing on residues that could act as acceptors for the phenolic proton of the tyrosine upon oxidation. These mutations include Ser M190 to His, which is near Tyr L162, the combination of His M193 to Tyr and Arg M164 to His, which adds a Tyr-His pair, and the combinations of Arg L135 to Tyr with Tyr L164 to His, Arg L135 to Tyr with Tyr L144 to Glu, and Arg L135 to Tyr with Tyr L164 to Phe. Radicals were produced in the mutants by using light to initiate electron transfer. The radicals were trapped by freezing the samples, and the relative populations of the oxidized dimer and tyrosyl radicals were determined by analysis of low-temperature electron paramagnetic resonance spectra. The mutants all showed evidence of tyrosyl radical formation at high pH, and the extent of radical formation at Tyr L135 with pH differed depending on the identity of L144 and L164. The results show that tyrosine residues within approximately 10 A of the dimer can become oxidized when provided with a suitable protein environment.

Dependence of tyrosine oxidation in highly oxidizing bacterial reaction centers on pH and free-energy difference.

The pH and temperature dependences of tyrosine oxidation were measured in reaction centers from mutants of Rhodobacter sphaeroides containing a tyrosine residue near a highly oxidizing bacteriochlorophyll dimer. Under continuous illumination, a rapid increase in the absorption change at 420 nm was observed because of the formation of a charge-separated state involving the oxidized dimer and reduced primary quinone, followed by a slow absorption decrease attributed to tyrosine oxidation. Both the amplitude and rate of the slow absorption change showed a pH dependency, indicating that, at low pH, the rate of tyrosine oxidation is limited by the transfer of the phenolic proton to a nearby base. Below 17 degrees C, the rate of the slow absorption change had a strong exponential dependence on the temperature, indicating a high activation energy. At higher pH and temperature, the overall rate of tyrosyl formation appears to be limited by a proposed conformational change in the reaction center that is also observed in reaction centers that do not undergo tyrosine oxidation. The yield of tyrosyl formation measured using electron paramagnetic resonance spectroscopy decreased significantly at 4 degrees C compared to 20 degrees C and was lower at both temperatures in mutants expected to have a slightly smaller driving force for tyrosyl formation.

Resultados de la descompresión subacromial mediante artroscopia / Results of arthroscopic subacromial decompression

Objetivo. Evaluar los resultados clínicos de la descompresión subacromial artroscópica tras la realización de un protocolo de tratamiento. Material y método. Se estudiaron 44 pacientes diagnosticados de síndrome subacromial clínica y radiológicamente. Todos fueron tratados de forma conservadora con medicación y fisioterapia durante al menos 6 meses. Fueron intervenidos mediante artroscopia, realizándose descompresión subacromial, y evaluados preoperatoriamente y a los 6 meses tras la intervención con la escala de valoración de Constant y Murley. Resultados. La puntuación pasó de 37,72 puntos preoperatoria a 73,43 a los 6 meses de la intervención. La mejoría fue estadísticamente significativa en todos los parámetros de la escala, siendo más llamativa en cuanto al dolor. El 89 por ciento de los pacientes encontró una mejoría subjetiva buena o muy buena. No se presentaron complicaciones durante la cirugía y el procedimiento se pudo realizar en el hospital de día. Conclusiones. La descompresión subacromial artroscópica es un procedimiento con buenos resultados subjetivos y objetivos, con escasas complicaciones y estancia corta (AU)

Correlation of proton release and electrochromic shifts of the optical spectrum due to oxidation of tyrosine in reaction centers from Rhodobacter sphaeroides.

Reaction centers from the Y(L167) mutant of Rhodobacter sphaeroides, containing a highly oxidizing bacteriochlorophyll dimer and a tyrosine residue substituted at Phe L167, were compared to reaction centers from the Y(M) mutant, with a tyrosine at M164, and a quadruple mutant containing a highly oxidizing dimer but no nearby tyrosine residue. Distinctive features in the light-induced optical and EPR spectra showed that the oxidized bacteriochlorophyll dimer was reduced by Tyr L167 in the Y(L167) mutant, resulting in a tyrosyl radical, as has been found for Tyr M164 in the Y(M) mutant. In the Y(L167) mutant, the net proton uptake after formation of the tyrosyl radical and the reduced primary quinone ranged from +0.1 to +0.3 H(+)/reaction center between pH 6 and pH 10, with a dependence that is similar to the quadruple mutant but different than the large proton release observed in the Y(M) mutant. In the light-induced absorption spectrum in the 700-1000 nm region, the Y(L167) mutant exhibited unique changes that can be assigned as arising primarily from an approximately 30 nm blue shift of the dimer absorption band. The optical signals in the Y(L167) mutant were pH dependent, with a pK(a) value of approximately 8.7, indicating that the tyrosyl radical is stabilized at high pH. The results are modeled by assuming that the phenolic proton of Tyr L167 is trapped in the protein after oxidation of the tyrosine, resulting in electrostatic interactions with the tetrapyrroles and nearby residues.

Infección subclínica por virus del papiloma humano dentro o fuera de la zona de transformación. ¿Esinteresante sudiscriminación? / Subclinical human papilloma virus infection inside or outside the transformation zone. Is this distinction useful?

Objetivos: Contrastar si la identificación colposcópica de presuntas lesiones subclínicas del virus del papiloma humano dentro o fuera de la zona de transformación es relevante respecto a la patología histológica de la propia zona de transformación. Material y métodos: Durante los años 1995-2001se estudió a 239 pacientes con enfermedad cervical en la Unidad de Patología del Tracto Genital Inferior (TGI) del Hospital Universitario Virgen de las Nieves de Granada. Ciento noventa y seis pacientes presentaban sospecha colposcópica de lesión subclínica por virus del papiloma humano dentro de la zona de transformación, mientras que 43 planteaban dicha sospecha en el epitelio pavimentoso original. Todas fueron documentadas citológicamente e incluyen estudio biópsico de la zona de transformación. Resultados: Se apreciaron diferencias significativas en los siguientes casos: a) cuando hubo sospecha colposcópica de lesión subclínica fuera de la zona de transformación, la valoración colposcópica de la propia zona fue menos grave (cambios menores); b) la extensión de la zona de transformación es más reducida cuando se sospecha lesión por virus del papiloma humano en el epitelio original; c) las imágenes blancas sobreelevadas son más frecuentes cuando la sospecha colposcópica de virus del papiloma humano se encuentra dentro de la zona de transformación, y d) las biopsias de la zona de transformación indican que las lesiones intraepiteliales escamosas son más frecuentes cuando la sospecha colposcópica de virus del papiloma humano se sitúa dentro de la zona de transformación. Conclusión: Los resultados demuestran la necesidad de identificar colposcópicamente las lesiones sospechosas de virus del papiloma humano, fuera o dentro de la zona de transformación, ya que provee diferencias importantes en la gravedad histológica de la lesión cervical (AU)

Influence of the protein environment on the properties of a tyrosyl radical in reaction centers from Rhodobacter sphaeroides.

The influence of the local environment on the formation of a tyrosyl radical was investigated in modified photosynthetic reaction centers from Rhodobacter sphaeroides. The reaction centers contain a tyrosine residue placed approximately 10 A from a highly oxidizing bacteriochlorophyll dimer. Measurements by both optical and electron paramagnetic resonance spectroscopy revealed spectral features that are assigned as arising primarily from an oxidized bacteriochlorophyll dimer at low pH values and from a tyrosyl radical at high pH values, with a well-defined transition that occurred with a pK(a) of 6.9. A model based on the wild-type structure indicated that the Tyr at M164 is likely to form a hydrogen bond with His M193 and to interact weakly with Glu M173. Substitution of Tyr or Glu for His at M193 increased the pK(a) for the transition from 6.9 to 8.9, while substitution of Gln for His M193 resulted in a higher pK(a) value. Substitution of Glu M173 with Gln resulted in loss of the partial formation of the tyrosyl that occurs in the other mutants at low pH values. The results are interpreted in terms of the ability of the residues to act as proton acceptors for the oxidized tyrosine, with the pK(a) values reflecting those of either the putative proton acceptor or the tyrosine, in accord with general models of amino acid radicals.