A truncating variant of RAD51B associated with primary ovarian insufficiency provides insights into its meiotic and somatic functions.

Primary ovarian insufficiency (POI) causes female infertility by abolishing normal ovarian function. Although its genetic etiology has been extensively investigated, most POI cases remain unexplained. Using whole-exome sequencing, we identified a homozygous variant in RAD51B -(c.92delT) in two sisters with POI. In vitro studies revealed that this variant leads to translation reinitiation at methionine 64. Here, we show that this is a pathogenic hypomorphic variant in a mouse model. Rad51bc.92delT/c.92delT mice exhibited meiotic DNA repair defects due to RAD51 and HSF2BP/BMRE1 accumulation in the chromosome axes leading to a reduction in the number of crossovers. Interestingly, the interaction of RAD51B-c.92delT with RAD51C and with its newly identified interactors RAD51 and HELQ was abrogated or diminished. Repair of mitomycin-C-induced chromosomal aberrations was impaired in RAD51B/Rad51b-c.92delT human and mouse somatic cells in vitro and in explanted mouse bone marrow cells. Accordingly, Rad51b-c.92delT variant reduced replication fork progression of patient-derived lymphoblastoid cell lines and pluripotent reprogramming efficiency of primary mouse embryonic fibroblasts. Finally, Rad51bc.92delT/c.92delT mice displayed increased incidence of pituitary gland hyperplasia. These results provide new mechanistic insights into the role of RAD51B not only in meiosis but in the maintenance of somatic genome stability.

[Who is the user of socio-health interventions and what are their needs?]. / ¿Quién es el receptor de intervenciones sociosanitarias y cuáles son sus necesidades?

Socio-health interventions include performance and care intended to attend to the needs of people who have suffered a decrease in their personal autonomy because of their age, illness or disability. Oriented towards achieving an improvement in the quality of life of people in that situation, they try to meet the requirements of people in an integrated way. To intervene in those situations involves providing technical aids and environmental, custom and social changes as well as personal care needed to improve their quality of life and enhance their skills and well-being. Scientific advances and demographic and social changes have determined a change in the profile of socio-health interventions' receivers, highlighting longevity, chronicity of processes and aging of the informal caregiver. The aim of this work is to characterize the person receiving the social-health interventions and to reflect on what their needs are. To do this we have conducted a biomedical studies' review through literature searches at ScienceDirect as well as a review of national institutional documentation related to people in dependent situations and their family caregivers. People who need socio-health help establish a heterogeneous population in respect of their needs. Both the person with disabilities and their informal caregiver need to be considered as an object of interest and attention.

Impact of acid mine drainages on surficial waters of an abandoned mining site.

Weathering of sulphide minerals produces a great variety of efflorescences of soluble sulphate salts. These minerals play an important role for environmental pollution, since they can be either a sink or a source for acidity and trace elements. This paper aims to characterise surface waters affected by mining activities in the Sierra Minera of Cartagena-La Union (SE, Spain). Water samples were analysed for trace metals (Zn, Cd, Pb, Cu, As and Fe), major ions (Na(+), K(+), Ca(2+) and Mg(2+)) and anions (F(-), Cl(-), NO3 (-), CO3 (2-), SO4 (2-)) concentrations and were submitted to an "evaporation-precipitation" experiment that consisted in identifying the salts resulting from the evaporation of the water aliquots sampled onsite. Mineralogy of the salts was studied using X-ray diffraction and compared with the results of calculations using VISUAL MINTEQ. The study area is heavily polluted as a result of historical mining and processing activities that has produced large amount of wastes characterised by a high trace elements content, acidic pH and containing minerals resulting from the supergene alteration of the raw materials. The mineralogical study of the efflorescences obtained from waters shows that magnesium, zinc, iron and aluminium sulphates predominate in the acid mine drainage precipitates. Minerals of the hexahydrite group have been quantified together with minerals of the rozenite group, alunogen and other phases such as coquimbite and copiapite. Calcium sulphates correspond exclusively to gypsum. In a semiarid climate, such as that of the study area, these minerals contribute to understand the response of the system to episodic rainfall events. MINTEQ model could be used for the analysis of waters affected by mining activities but simulation of evaporation gives more realistic results considering that MINTEQ does not consider soluble hydrated salts.

[Analysis of the management of occult fractures of the scaphoid through early magnetic resonance imaging]. / Análisis del manejo de fracturas ocultas de escafoides mediante la realización precoz de resonancia magnética.

INTRODUCTION: We aimed to evaluate the usefulness of magnetic resonance imaging (MRI) in the diagnosis of occult fractures of the scaphoid and to determine the advantages and cost in comparison with the traditional follow-up protocol. MATERIAL AND METHOD: The traditional approach at our center consisted of immobilization and periodic clinical and radiological follow-up (plain-film X-rays and computed tomography in the final phase of the process). The new protocol called for a limited MRI study consisting of coronal T1- and T2-weighted fat suppression sequences if the findings at plain-film X-rays continued to be negative at the first follow-up examination with the traumatologist (10 days after trauma). We evaluated the MRI findings, the time the patient was immobilized, the cost of each protocol, and the dose of radiation received. RESULTS: We included 33 cases of patients with clinically suspected fractures of the scaphoid and negative findings on plain-film X-rays. In 13 patients, the MRI findings were negative. In 12 patients, the MRI findings confirmed the diagnosis of a fracture of the scaphoid, which was associated with other pathology in 6 cases. In 8 patients, another pathological process was diagnosed. The cost of the new protocol was €131.06 per patient; the cost of the traditional protocol was €114.41 or €151.06 per patient, depending on the follow-up studies required. The new protocol reduced the dose of radiation by eliminating successive radiologic studies. CONCLUSIONS: The new protocol improved the management of these patients, reducing the time of immobilization, improving joint rigidity, and reducing the time off work. The limited MRI study makes it possible to diagnose other radiologically occult lesions. The cost of the new protocol is similar to that of the traditional protocol and even lower in some cases. The new protocol results in a reduction in the dose of radiation.

Molecular characterization of the black Aspergillus isolates responsible for ochratoxin A contamination in grapes and wine in relation to taxonomy of Aspergillus section Nigri.

This work examines ochratoxigenic mycobiota in grapes by ap-PCR analysis sequence analysis of the ITS and IGS regions and ability to produce OTA. A comparison was also made with many reference strains of Aspergillus section Nigri. Based on ap-PCR profiles, derived from two microsatellite primers, three main groups were obtained by UPGMA cluster analysis corresponding to A. carbonarius, A. niger and A. tubingensis. The cophenetic correlation values corresponding to ap-PCR UPGMA analysis revealed a higher genetic variability in A. niger and A. tubingensis than in A. carbonarius. In addition, no genotypical differences could be established between OTA producers and nonproducers in all species analysed. Phylogenetic relationships inferred from ITS and IGS sequences are, mostly, congruent with earlier works. A. niger and A. tubingensis strains were closely related, but not identical, and they clustered into two distinct groups within the A. niger aggregate. Sequence analysis also showed genetic divergences between strains of A. foetidus and the rest of the Aspergillus section Nigri. Additionally, the phylogenetic analysis was consistent in separating a new group of ochratoxigenic strains, frequently isolated from grapes, named A. tubingensis-like. All strains of A. carbonarius analysed by sequence analysis had identical ITS and IGS sequences confirming the lack of significant genetic variability within this important ochratoxigenic species.

Mycobiota and mycotoxin producing fungi from cocoa beans.

The present study reports on the natural mycobiota occurring in cocoa beans, paying special attention to the incidence of fungal species that are potential producers of mycotoxins. The results show that predominant fungi were different species of the genus Aspergillus belonging to section Flavi and Nigri. Of the 214 strains of Aspergillus section Flavi collected from cocoa beans, 120 were identified as A. flavus and 94 as A. tamarii. Of Aspergillus section Nigri 138 strains were isolated, with 132 belonging to A. niger aggregate and 6 to A. carbonarius species. Potential ability to produce aflatoxins (AFs) B1, B2, G1 and G2, cyclopiazonic acid (CPA) and ochratoxin A (OTA) was studied by isolate culture followed by HPLC analysis of these mycotoxins in the culture extracts. Results indicated that 64.1% and 34.2% of the A. flavus strains produced AFs and CPA, respectively. Most of the A. flavus strains presented moderate toxigenicity with mean levels of AFs ranging from 100 ng g(-1) to 1000 ng g(-1). All the CPA-producing strains of A. flavus were highly toxigenic producing >30 microg g(-1) of CPA. Furthermore, 98% of A. tamarii strains produced CPA and over 50% of them were highly CPA toxigenic. With respect to OTA-producing fungi, a high percentage of black aspergilli strains (49.2%) were able to produce OTA. Additionally, most of the OTA-producing isolates were of moderate toxigenicity, producing amounts of OTA from 10 microg g(-1) to 100 microg g(-1). These results indicate that there is a possible risk factor posed by AFs, CPA and OTA contamination of cocoa beans, and consequently, cocoa products.

Ameloblastoma. Diagnosis by means of FNAB. Report of two cases.

INTRODUCTION: Ameloblastomas are the most frequent odontogenic tumors of the maxilla. In spite of their benign cytohistological appearance, they behave as invasive recurring tumors, with the possibility of metastasis. FNAB is a rapid, bloodless test that provides a pre-surgical diagnosis, thus, on occasions avoiding the need for diagnostic biopsies. We present the cytological characteristics of two cases of jugal recurrences of mandibular ameloblastomas diagnosed by FNAB, as well as their cytohistological correlation. CLINICAL CASES: Two patients, a 36-year-old woman, and a 62-year-old male who both attended with mandibular swelling of a few months evolution. In both cases the first diagnostic approximation was the histological study of the tumoral mass, together with the radiological studies. Following therapeutic extirpation both cases recurred. The diagnosis of the recurrences was established cytologically by means of FNAB. The cytologic smears revealed a granular background with isolated macrophages and giant multinucleate cells and an abundant epithelial cellularity of basaloid appearance arranged in cohesive groups forming images of peripheral palidasing, as well as small groups of squamous metaplastic cells. DISCUSSION: FNAB is considered to be a rapid, bloodless and reliable method for the diagnosis of ameloblastoma. The cytology of these tumors reveals components of the lesion that, in general, are sufficient for the diagnosis of ameloblastoma, especially in cases of recurrence.

[Localized fibrous tumors of the pleura: clinical and surgical evaluation]. / Tumores fibrosos de localización pleural: valoración clinicoquirúrgica.

Solitary fibrous tumors of the pleura are uncommon and mainly arise in the pleura itself. Such tumors are generally asymptomatic and slow-growing. We report a series of 10 cases (8 men and 2 women with a mean age of 58.6 years) treated over a period of 54 months. The tumors were classified histologically as benign or malignant according to the criteria used by England. The treatment of choice was complete resection of the tumor. Six posterolateral thoracotomies and 4 video-assisted resections were performed. Histology showed a mixture of fibroblast-like cells and collagenous stroma. Sarcomatous degeneration was observed in the excised tumor of 1 patient. The patients were followed for a mean of 23.9 months. We conclude that although fibrous tumors of the pleura are considered benign histologically, complete resection and follow up for all patients are recommended.

[Hepatic steatosis associated with heterozygotic familial hypobetalipoproteinemia]. / Esteatosis hepática asociada a hipobetalipoproteinemia familiar heterocigótica. Presentación de un caso.

Fatty liver disease is now recognized as a major health burden, due to the greater number of cases that are being diagnosed. This trend could partly be explained by the increased use of liver ultrasonography in asymptomatic patients for various reasons, mainly persistent transaminase elevation. The most commonly reported risk factors associated with fatty liver disease are chronic alcohol intake, obesity, type 2 diabetes mellitus, hyperlipidemia, and some drugs. When these factors have been ruled out in a patient with a fatty liver, less frequent causes such as certain inherited metabolic disorders should be considered. Familial hypobetalipoproteinemia is characterized by an alteration of apolipoprotein B (apo B) synthesis, leading to the secretion of truncated forms of the protein, which in turn leads to a marked reduction in excretion of very low-density lipoproteins from the liver and consequently to lipid deposits, especially triglycerides, in the hepatocytes. We report the case of a 23-year-old man who met the diagnostic criteria for heterozygous familial hypobetalipoproteinemia. He presented with mild transaminase elevation and fatty liver. Total cholesterol, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol and apo B were below normal limits, while levels of high-density lipoprotein cholesterol were normal. Lipid profile determination and liver ultrasonography of first and second-degree relatives were also performed. Molecular studies of the index case revealed an unaffected apo B gene.

The unique proline of the Prochlorothrix hollandica plastocyanin hydrophobic patch impairs electron transfer to photosystem I.

A number of surface residues of plastocyanin from Prochlorothrix hollandica have been modified by site-directed mutagenesis. Changes have been made in amino acids located in the amino-terminal hydrophobic patch of the copper protein, which presents a variant structure as compared with other plastocyanins. The single mutants Y12G, Y12F, Y12W, P14L, and double mutant Y12G/P14L have been produced. Their reactivity toward photosystem I has been analyzed by laser flash absorption spectroscopy. Plots of the observed rate constant with all mutants versus plastocyanin concentration show a saturation profile similar to that with wild-type plastocyanin, thus suggesting the formation of a plastocyanin-photosystem I transient complex. The mutations do not induce relevant changes in the equilibrium constant for complex formation but induce significant variations in the electron transfer rate constant, mainly with the two mutants at proline 14. Additionally, molecular dynamics calculations indicate that mutations at position 14 yield small changes in the geometry of the copper center. The comparative kinetic analysis of the reactivity of plastocyanin mutants toward photosystem I from different organisms (plants and cyanobacteria) reveals that reversion of the unique proline of Prochlorothrix plastocyanin to the conserved leucine of all other plastocyanins at this position enhances the reactivity of the Prochlorothrix protein.

Emigration patterns of cancer cases in Alberta, Canada.

Cancer registries are a unique source of data for population-based analysis of survival of cancer cases, but information on current vital status is essential. This paper describes a method to determine the last known vital status of cases and the emigration pattern of cancer cases diagnosed in Alberta. Data from the Alberta Cancer Registry (ACR) for the years 1985 1993 (83,446 cases), were linked to the Alberta Health Care Insurance Plan (AHCIP) registration file to identify cases that had left the province, and the date they emigrated. Ninety-nine percent of the ACR cases linked correctly to the AHCIP registration file. Three percent of cases had left Alberta by March 1998; For the first five years of follow-up between 0.6% and 0.8% of cases alive at the beginning of each year of follow-up left the province in the succeeding year. Seven percent of those diagnosed under 45 years of age left the province compared to less than 2% of those aged 65 and over. There was no difference in emigration patterns between the sexes. The cancer sites with good prognosis tended to have the highest proportion of emigrants.

Crystal structure of low-potential cytochrome c549 from Synechocystis sp. PCC 6803 at 1.21 A resolution.

The crystal structure of low-potential cytochrome c549, an extrinsic component of the photosystem II (PS II) from Synechocystis sp. PCC 6803, was obtained directly from single-wavelength 1.21 A resolution diffraction data. This is the first monodomain bis-histidinyl monoheme cytochrome c to be structurally characterized. The extended N-terminal region of c549 builds up a two-strand antiparallel beta-sheet in a hairpin motif, which extends through two molecules owing to crystal packing. Both peptide termini are involved in crystal contacts, which may explain their protrusion out of the globular fold. The C-terminus is preceded by a 9 A-long hydrophobic finger extending from a positively charged base and could be involved in PSII interactions, as well as a protruding negative patch built by a set of conserved acidic residues among c549 sequences.

A single arginyl residue in plastocyanin and in cytochrome c(6) from the cyanobacterium Anabaena sp. PCC 7119 is required for efficient reduction of photosystem I.

Positively charged plastocyanin from Anabaena sp. PCC 7119 was investigated by site-directed mutagenesis. The reactivity of its mutants toward photosystem I was analyzed by laser flash spectroscopy. Replacement of arginine at position 88, which is adjacent to the copper ligand His-87, by glutamine and, in particular, by glutamate makes plastocyanin reduce its availability for transferring electrons to photosystem I. Such a residue in the copper protein thus appears to be isofunctional with Arg-64 (which is close to the heme group) in cytochrome c(6) from Anabaena (Molina-Heredia, F. P., Diaz-Quintana, A., Hervás, M., Navarro, J. A., and De la Rosa, M. A. (1999) J. Biol. Chem. 274, 33565-33570) and Synechocystis (De la Cerda, B., Diaz-Quintana, A., Navarro, J. A. , Hervás, M., and De la Rosa, M. A. (1999) J. Biol. Chem. 274, 13292-13297). Other mutations concern specific residues of plastocyanin either at its positively charged east face (D49K, H57A, H57E, K58A, K58E, Y83A, and Y83F) or at its north hydrophobic pole (L12A, K33A, and K33E). Mutations altering the surface electrostatic potential distribution allow the copper protein to modulate its kinetic efficiency: the more positively charged the interaction site, the higher the rate constant. Whereas replacement of Tyr-83 by either alanine or phenylalanine has no effect on the kinetics of photosystem I reduction, Leu-12 and Lys-33 are essential for the reactivity of plastocyanin.

A comparative study of the thermal stability of plastocyanin, cytochrome c(6) and Photosystem I in thermophilic and mesophilic cyanobacteria.

Cytochrome c(6) (Cyt) from the thermophilic cyanobacterium Phormidium laminosum has been purified and characterized. It is a mildly acidic protein, with physicochemical properties very similar to those of plastocyanin (Pc). This is in agreement with the functional interchangeability of the two metalloproteins as electron donors to Photosystem I (PS I). The kinetic analyses of the interaction of Pc and Cyt with Photosystem I show that both metalloproteins reduce PS I with similar efficiencies, according to an oriented collisional kinetic model involving repulsive electrostatic interactions. The thermostability study of the Phormidium Pc/PS I system compared with those from mesophilic cyanobacteria (Synechocystis, Anabaena and Pseudanabaena) reveals that Pc is the partner limiting the thermostability of the Phormidium couple. The cross-reactions between Pc and PS I from different organisms demonstrate not only that Phormidium Pc enhances the stability of the Pc/PS I system using PS I from mesophilic cyanobacteria, but also that Phormidium PS I possesses a higher thermostability than the other photosystems.

Negatively charged residues in the H loop of PsaB subunit in Photosystem I from Synechocystis sp. PCC 6803 appear to be responsible for electrostatic repulsions with plastocyanin*.

Wild-type plastocyanin from the cyanobacterium Synechocystis sp. PCC 6803 does not form any kinetically detectable transient complex with Photosystem I (PS I) during electron transfer, but the D44R/D47R double mutant of copper protein does [De la Cerda et al. (1997) Biochemistry 36: 10125-10130]. To identify the PS I component that is involved in the complex formation with the D44R/D47R plastocyanin, the kinetic efficiency of several PS I mutants, including a PsaF-PsaJ-less PS I and deletion mutants in the lumenal H and J loops of PsaB, were analyzed by laser flash absorption spectroscopy. The experimental data herein suggest that some of the negative charges at the H loop of PsaB are involved in electrostatic repulsions with mutant plastocyanin. Mutations in the J loop demonstrate that this region of PsaB is also critical. The interaction site of PS I is thus not as defined as first expected but much broader, thereby revealing how complex the evolution of intermolecular electron transfer mechanisms in photosynthesis has been.

Modulation of systemic hemodynamics by exogenous L-arginine in normal and bacteremic sheep.

OBJECTIVE: To investigate whether exogenous L-arginine, the substrate for nitric oxide synthase, modulates systemic hemodynamics in sepsis. DESIGN: Prospective, controlled study in a sheep model of sepsis. SETTING: Animal research facility in a university hospital. SUBJECTS: Adult sheep weighing between 35 and 55 kg. INTERVENTIONS: Adult sheep sedated and mechanically ventilated, were monitored with a pulmonary arterial catheter and an ileal tonometer. Four groups of sheep were studied: nonseptic, septic, nonseptic treated with L-arginine, and septic treated with L-arginine. Sepsis was induced by the intravenous administration of Escherichia coli (1.5x10(8) colony-forming units/kg for 30 mins). L-arginine was administered as an intravenous bolus (200 mg/kg for 10 mins) before the septic challenge followed by 200 mg/kg/hr for 300 mins. MEASUREMENTS AND MAIN RESULTS: Sepsis induced a state of acidosis, hyperlactatemia, hypoxemia, and gastric intramucosal acidosis. During the first 30 mins after the septic challenge, there was a decrease in cardiac index and blood pressure, and an increase in systemic vascular resistance. Thereafter, blood pressure returned to baseline values, and systemic vascular resistance fell. Treatment with L-arginine in nonseptic sheep did not induce any biochemical or hemodynamic effect. In septic sheep, treatment with L-arginine was associated with a greater increase in systemic vascular resistance during the first 30 mins, and a more marked decrease in blood pressure and systemic vascular resistance after 180 mins. CONCLUSIONS: Exogenous administration of L-arginine does not induce hemodynamic effects in normal animals, exacerbates the acute vasoconstriction associated with the intravenous infusion of E. coli and potentiates the sepsis-induced vasodilation. Our results suggest that a) nitric oxide production is not constitutively modulated by exogenous L-arginine, b) L-arginine probably enhances the sepsis-induced sympathetic discharge, and c) L-arginine becomes rate-limiting for the formation of nitric oxide at approximately 3 hrs after the initiation of the septic challenge.

Site-directed mutagenesis of cytochrome c(6) from Anabaena species PCC 7119. Identification of surface residues of the hemeprotein involved in photosystem I reduction.

A number of surface residues of cytochrome c(6) from the cyanobacterium Anabaena sp. PCC 7119 have been modified by site-directed mutagenesis. Changes were made in six amino acids, two near the heme group (Val-25 and Lys-29) and four in the positively charged patch (Lys-62, Arg-64, Lys-66, and Asp-72). The reactivity of mutants toward the membrane-anchored complex photosystem I was analyzed by laser flash absorption spectroscopy. The experimental results indicate that cytochrome c(6) possesses two areas involved in the redox interaction with photosystem I: 1) a positively charged patch that may drive its electrostatic attractive movement toward photosystem I to form a transient complex and 2) a hydrophobic region at the edge of the heme pocket that may provide the contact surface for the transfer of electrons to P(700). The isofunctionality of these two areas with those found in plastocyanin (which acts as an alternative electron carrier playing the same role as cytochrome c(6)) are evident.