Descriptive epidemiology and risk factors of primary central nervous system tumors: Current knowledge.

Although comparisons are difficult due to differences in methodologies, the annual incidence rates of central nervous system (CNS) tumors range from 8.5 to 21.4/100,000 population according to cancer registries, with a predominance of neuroepithelial tumors in men and meningiomas in women. An increase in the incidence of CNS tumors has been observed during the past decades in several countries. It has been suggested that this trend could be due to aging of the population, and improvements in diagnostic imaging and healthcare access, but these factors do not explain differences in incidence by gender and histological subtypes. Several etiological hypotheses related to intrinsic (sociodemographic, anthropometric, hormonal, immunological, genetic) and exogenous (ionizing radiation, electromagnetic fields, diet, infections, pesticides, drugs) risk factors have led to analytical epidemiological studies to establish relationships with CNS tumors. The only established environmental risk factor for CNS tumors is ionizing radiation exposure. However, for other risk factors, studies have been inconsistent and inconclusive due to systematic differences in study design and difficulties in accurately measuring exposures. Thus, the etiology of CNS tumors is complex and may involve several genetic and/or environmental factors that may act differently according to histological subtype.

Drinking-water exposure to a mixture of nitrate and low-dose atrazine metabolites and small-for-gestational age (SGA) babies: a historic cohort study.

BACKGROUND: Groundwater, surface water and drinking water are contaminated by nitrates and atrazine, an herbicide. They are present as a mixture in drinking water and with their endocrine-disrupting activity, they may alter fetal growth. OBJECTIVES: To study an association between drinking-water atrazine metabolites/nitrate mixture exposure and small-for-gestational-age(SGA). METHODS: A historic cohort study based on birth records and drinking-water nitrate and pesticide measurements in Deux-Sèvres (France) between 2005 and 2009 was carried out. Exposure to drinking-water atrazine metabolites/nitrate mixture was divided into 6 classes according to the presence or absence of atrazine metabolites and to terciles of nitrate concentrations in each trimester of pregnancy. Regression analysis of SGA by mixture exposure at second trimester was subsequently conducted. RESULTS: We included 11,446 woman-neonate couples of whom 37.0% were exposed to pesticides, while 99.9% of the women were exposed to nitrates. Average nitrate concentration was from 0 to 63.30 mg/L. In the second trimester of pregnancy, the risk of SGA was different with mixture exposure when drinking-water atrazine metabolites, mainly 2 hydroxyatrazine and desethylatrazine, were present and nitrate dose exposure increased: compared to single first tercile of nitrate concentration exposure, single second tercile exposure OR was 1.74 CI 95% [1.10; 2.75] and atrazine metabolites presence in the third tercile of nitrate concentration exposure OR was 0.87 CI 95% [0.45;1.67]. CONCLUSIONS: It is possible that the association found at the second trimester of exposure with regard to birth weight may likewise be observed before birth, with regard to the estimated fetal weight, and that it might change in the event that the atrazine metabolites dose were higher or the nitrate dose lower. It would appear necessary to further explore the variability of effects.

SRD5A2 gene mutations and polymorphisms in Spanish 46,XY patients with a disorder of sex differentiation.

One hundred and forty-six index patients with 46,XY DSD in whom gonads were confirmed as testes were consecutively studied for a molecular diagnosis during the period 2002-2010. AR gene was analysed in all patients as the first candidate gene, yielding a mutation in 42.5% of cases and SRD5A2 gene was analysed as the second candidate gene, resulting in the characterization of 10 different mutations (p.Y91D, p.G115D, p.Q126R, p.R171S, p.Y188CfsX9, p.N193S, p.A207D, p.F219SfsX60, p.R227Q and p.R246W) in nine index patients (6.2% of the total number of 46,XY DSD patients). One of the mutations (p.Y188CfsX9) has never been reported. In addition, we genotyped SRD5A2 gene p.V89L and c.281+15T>C polymorphisms in 46,XY DSD and in 156 normal adult males and found that patients with SRD5A2 mutations or without a known molecular diagnosis presented a higher frequency of homozygous p.L89, homozygous TT and combined CCTT genotypes compared with controls. This result suggests that 46,XY DSD patient phenotypes may be influenced by SRD5A2 polymorphism genotypes. SRD5A2 gene mutations may not be as infrequent as previously considered in 46,XY DSD patients with variable degrees of external genitalia virilization at birth and normal T production and appears to be the second aetiology in our series.

[Prophylactic thyroidectomy in multiple endocrine neoplasia syndrome]. / Tiroidectomía profiláctica en el síndrome de neoplasia endocrina múltiple.

Multiple endocrine neoplasia (MEN) 2a consists on medullary thyroid carcinoma, pheochromocytoma and hyperparathyroidism. The identification of the RET proto-oncogene in 1993 has changed the prognosis of the disease. We have retrospectively studied the patients diagnosed of MEN 2a in our centre for the last 7 years in order to establish the most adequate age to undergo surgery. We present ten patients diagnosed with MEN 2a, whose ages ranged from 1.5 to 11 years old. Mean age at time of operation: 6,4 years An ultrasound study, calcitonin determinations and cathecholamines and urinary metanephrine levels were obtained before surgery. The surgical treatment is based on total total thyroidectomy, in selected cases lymph node resection in the central zone lf the neck. The most frequent RET mutation is the one affecting codon 634 (exon 10), which was found in children. Both of them had an alteration in codon 611 (exon11). No complications appeared after surgery and hospital discharge took place in the 2nd-4th day after surgery. Pathological findings were medullary thyroid microcarcinoma (MTMC) in 3 out of 10 patients, calcitonin preoperative tests were high in one of them. No tumoral cells were found in the lymph nodes. During the follow up period, 9 out of 10 from the operated patients, maintained normal calcitonin, CEA, PTH, calcium, cathecholamines and urinary metanephrine levels. Since there are 3 cases of MTC in patients between 3 and 6 years old, and diagnostic test data are not conclusive, we thoroughly recommend prophyilactic thyroidectomy at early ages, from 3 to 4 years old.

Maternal cumulative exposure to extremely low frequency electromagnetic fields and pregnancy outcomes in the Elfe cohort.

OBJECTIVES: To study the relations between maternal cumulative exposure to extremely low frequency electromagnetic fields (ELF EMF) and the risk of moderate prematurity and small for gestational age within the Elfe cohort. METHODS: The Elfe study included 18,329 infants born at 33weeks of gestation or more in France in 2011 and was designed to follow the children until 20years of age. Gestational age and anthropometric data at birth were collected in medical records and small for gestational age was defined according to a French customized growth standard. During interviews, mothers were asked to report their job status during pregnancy. If employed, their occupation was coded according to the International Standard Classification of Occupations 1988 and the date on which they stopped their work was recorded. Cumulative exposure to ELF EMF during pregnancy was assessed, for both mothers who worked and those who did not during pregnancy, using a recently-updated job-exposure matrix (JEM). Cumulative exposure was considered as a categorical variable (<17.5, 17.5-23.8, 23.8-36.2, 36.2-61.6 or ≥61.6µT-days), a binary variable (<44.1 and ≥44.1µT-days) and a continuous variable. Associations were analyzed by logistic regression, adjusting for the mother's lifestyle factors, sociodemographic characteristics and some mother's medical history during and before pregnancy. Analyses were restricted to single births and to complete values for the pregnancy outcomes (n=16,733). RESULTS: Cumulative exposure was obtained for 96.0% of the mothers. Among them, 37.5% were classified in the 23.8-36.2µT-days category, but high exposures were rare: 1.3% in the ≥61.6µT-days category and 5.5% in the ≥44.1µT-days category. No significant association was observed between maternal cumulative exposure and moderate prematurity and small for gestational age in this exposure range. CONCLUSION: This large population-based study does not suggest that maternal exposure to ELF EMF during pregnancy is highly associated with risks of moderate prematurity or small for gestational age.

Gene RRN4 in Saccharomyces cerevisiae encodes the A12.2 subunit of RNA polymerase I and is essential only at high temperatures.

We have previously isolated mutants of Saccharomyces cerevisiae that are primarily defective in transcription of 35S rRNA genes by RNA polymerase I and have identified genes (RRN1 to RRN9) involved in this process. We have now cloned the RRN4 gene by complementation of the temperature-sensitive phenotype of the rrn4-1 mutant and have determined its complete nucleotide sequence. The following results demonstrate that the RRN4 gene encodes the A12.2 subunit of RNA polymerase I. First, RRN4 protein expressed in Escherichia coli reacted with a specific antiserum against A12.2. Second, amino acid sequences of three tryptic peptides obtained from A12.2 were determined, and these sequences are found in the deduced amino acid sequence of the RRN4 protein. The amino acid sequence of the RRN4 protein (A12.2) is similar to that of the RPB9 (B12.6) subunit of yeast RNA polymerase II; the similarity includes the presence of two putative zinc-binding domains. Thus, A12.2 is a homolog of B12.6. We propose to rename the RRN4 gene RPA12. Deletion of RPA12 produces cells that are heat but not cold sensitive for growth. We have found that in such null mutants growing at permissive temperatures, the cellular concentration of A190, the largest subunit of RNA polymerase I, is lower than in the wild type. In addition, the temperature-sensitive phenotype of the rpa12 null mutants can be partially suppressed by RPA190 (the gene for A190) on multicopy plasmids. These results suggest that A12.2 plays a role in the assembly of A190 into a stable polymerase I structure.

RPC82 encodes the highly conserved, third-largest subunit of RNA polymerase C (III) from Saccharomyces cerevisiae.

RNA polymerase C (III) promotes the transcription of tRNA and 5S RNA genes. In Saccharomyces cerevisiae, the enzyme is composed of 15 subunits, ranging from 160 to about 10 kDa. Here we report the cloning of the gene encoding the 82-kDa subunit, RPC82. It maps as a single-copy gene on chromosome XVI. The UCR2 gene was found in the opposite orientation only 340 bp upstream of the RPC82 start codon, and the end of the SKI3 coding sequence was found only 117 bp downstream of the RPC82 stop codon. The RPC82 gene encodes a protein with a predicted M(r) of 73,984, having no strong sequence similarity to other known proteins. Disruption of the RPC82 gene was lethal. An rpc82 temperature-sensitive mutant, constructed by in vitro mutagenesis of the gene, showed a deficient rate of tRNA relative to rRNA synthesis. Of eight RNA polymerase C genes tested, only the RPC31 gene on a multicopy plasmid was capable of suppressing the rpc82(Ts) defect, suggesting an interaction between the polymerase C 82-kDa and 31-kDa subunits. A group of RNA polymerase C-specific subunits are proposed to form a substructure of the enzyme.

A34.5, a nonessential component of yeast RNA polymerase I, cooperates with subunit A14 and DNA topoisomerase I to produce a functional rRNA synthesis machine.

A34.5, a phosphoprotein copurifying with RNA polymerase I (Pol I), lacks homology to any component of the Pol II or Pol III transcription complexes. Cells devoid of A34.5 hardly affect growth and rRNA synthesis and generate a catalytically active but structurally modified enzyme also lacking subunit A49 upon in vitro purification. Other Pol I-specific subunits (A49, A14, and A12.2) are nonessential for growth at 30 degrees C but are essential (A49 and A12.2) or helpful (A14) at 25 or 37 degrees C. Triple mutants without A34.5, A49, and A12.2 are viable, but inactivating any of these subunits together with A14 is lethal. Lethality is rescued by expressing pre-rRNA from a Pol II-specific promoter, demonstrating that these subunits are collectively essential but individually dispensable for rRNA synthesis. A14 and A34.5 single deletions affect the subunit composition of the purified enzyme in pleiotropic but nonoverlapping ways which, if accumulated in the double mutants, provide a structural explanation for their strict synthetic lethality. A34.5 (but not A14) becomes quasi-essential in strains lacking DNA topoisomerase I, suggesting a specific role of this subunit in helping Pol I to overcome the topological constraints imposed on ribosomal DNA by transcription.

A novel subunit of yeast RNA polymerase III interacts with the TFIIB-related domain of TFIIIB70.

There is limited information on how eukaryotic RNA polymerases (Pol) recognize their cognate preinitiation complex. We have characterized a polypeptide copurifying with yeast Pol III. This protein, C17, was found to be homologous to a mammalian protein described as a hormone receptor. Deletion of the corresponding gene, RPC17, was lethal and its regulated extinction caused a selective defect in transcription of class III genes in vivo. Two-hybrid and coimmunoprecipitation experiments indicated that C17 interacts with two Pol III subunits, one of which, C31, is important for the initiation reaction. C17 also interacted with TFIIIB70, the TFIIB-related component of TFIIIB. The interaction domain was found to be in the N-terminal, TFIIB-like half of TFIIIB70, downstream of the zinc ribbon and first imperfect repeat. Although Pol II similarly interacts with TFIIB, it is notable that C17 has no similarity to any Pol II subunit. The data indicate that C17 is a novel specific subunit of Pol III which participates together with C34 in the recruitment of Pol III by the preinitiation complex.

Tau91, an essential subunit of yeast transcription factor IIIC, cooperates with tau138 in DNA binding.

Transcription factor IIIC (TFIIIC) (or tau) is a large multisubunit and multifunctional factor required for transcription of all class III genes in Saccharomyces cerevisiae. It is responsible for promoter recognition and TFIIIB assembly. We report here the cloning and characterization of TFC6, an essential gene encoding the 91-kDa polypeptide, tau91, present in affinity-purified TFIIIC. Tau91 has a predicted molecular mass of 74 kDa. It harbors a central cluster of His and Cys residues and has basic and acidic amino acid regions, but it shows no specific similarity to known proteins or predicted open reading frames. The TFIIIC subunit status of tau91 was established by the following biochemical and genetic evidence. Antibodies to tau91 bound TFIIIC-DNA complexes in gel shift assays; in vivo, a B block-deficient U6 RNA gene (SNR6) harboring GAL4 binding sites was reactivated by fusing the GAL4 DNA binding domain to tau91; and a point mutation in TFC6 (tau91-E330K) was found to suppress the thermosensitive phenotype of a tfc3-G349E mutant affected in the B block binding subunit (tau138). The suppressor mutation alleviated the DNA binding and transcription defects of mutant TFIIIC in vitro. These results indicated that tau91 cooperates with tau138 for DNA binding. Recombinant tau91 by itself did not interact with a tRNA gene, although it showed a strong affinity for single-stranded DNA.

Kinetics of the action of chymosin (rennin) on a peptide bond of bovine alpha s1-casein. Comparison of the behaviour of this substrate with that of beta- and kappa o-caseins.

The action of chymosin on the Phe23-Phe24 bond of bovine alpha s1-casein, in citrate buffer (pH 6.2) at 30 degrees C, was followed by reversed-phase HPLC quantification of residual alpha s1-casein or fragment 24-199 after different time periods and at different substrate concentrations. This allowed determination of the Michaelian parameters for the reaction under study which were compared with those previously obtained for the action of chymosin on beta- and kappa o-casein under identical reaction conditions. The whole efficiency of the three reactions, as estimated by kcat/Km, was 1.8, 20.6 and 1405.0 for alpha s1-, beta- and kappa o-caseins, respectively. The specificity of chymosin is discussed in the light of these results and of the known sequences of the 3 caseins.

C-terminal labelling of beta-casein.

This paper is the first to report specific labelling of a native protein at its C-terminal end by carboxypeptidase Y-catalyzed transpeptidation between beta-casein and tritiated Phe amide. A tryptic digest of the radiolabelled protein was resolved by reversed-phase HPLC and a single labelled peptide was isolated therefrom. Sequence determination and FAB mass spectrometry showed that the last 2 residues (Val-209, Ile-208) of beta-casein had been deleted and Ile 207 substituted by Phe, deamidation presumably occurring after transpeptidation. Identical results were obtained by transpeptidating the isolated C-terminal tryptic heptapeptide (203-209) of native beta-casein.

A new strategy for primary structure determination of proteins: application to bovine beta-casein.

A new approach has been developed for sequencing proteins. A radioactive label is attached specifically to the C-terminus of the protein. The labelled molecule is subjected to varying proteolysis conditions. From the electrophoretic patterns (SDS-PAGE) of the hydrolysates, appropriate cleavage conditions are selected, giving labelled peptides of different lengths which are purified. The labelled peptides are sequenced in order of increasing size (from 1 to n), peptide (i) being sequenced until the N-terminal sequence of peptide (i-1) is encountered. This approach allows the determination of a complete protein sequence with a minimal number of Edman cycles. The method was successfully applied to bovine beta-casein (209 residues) which was completely resequenced with only 239 Edman cycles.

Arguments against a close relationship between non-phosphorylating and phosphorylating glyceraldehyde-3-phosphate dehydrogenases.

Non-phosphorylating NADP-dependent glyceraldehyde-3-phosphate dehydrogenase (GAPDH) (EC 1.2.1.9) from spinach leaves was purified to homogeneity using an improved purification procedure. Thus, a major contaminant with molecular mass and ion-exchange properties similar to non-phosphorylating GAPDH was eliminated. Using this pure non-phosphorylating GAPDH, cofactor stereospecificity was determined by 1H NMR. Analysis of the NADPH formed from the hydride transfer from glyceraldehyde-3-phosphate to [4-2H]NADP showed that the enzyme belongs to the A-stereospecific dehydrogenase family. This stereospecificity is the same as that described for the aldehyde dehydrogenase (ALDH) superfamily and opposite to that of the phosphorylating GAPDH. Moreover, results from peptide sequencing analysis suggest a similarity in sequence between the non-phosphorylating GAPDH and ALDHs. Thus, the results taken all together strongly suggest that non-phosphorylating GAPDH belongs to the ALDH family and has no close relationship to the phosphorylating GAPDH class.

Absence of variation in facteur thymique sérique activity in moderately and severely malnourished Senegalese children.

Facteur thymique sérique activity was evaluated in relation to different types of malnutrition in Senegalese children aged 5 to 42 months. They were classified in four groups: controls, moderate malnutrition, marasmus, and kwashiorkor, according to anthropometric measurements and clinical examination. The two latter groups were characterized by very depressed levels of total protein, album in, transferrin and prealbumin, and by high cortisol concentrations. Zinc status was marginal in all children. Facteur thymique sérique activity, determined by the rosette assay, was normal in the malnourished patients suggesting that moderate as well as severe malnutrition is not necessarily associated with depressed levels of circulating thymic hormone. These results are discussed in relation to zinc status and infections.

RPC10 encodes a new mini subunit shared by yeast nuclear RNA polymerases.

Yeast RNA polymerases A, B, and C share five small subunits, two of which, ABC10 alpha and ABC10 beta, comigrate on SDS polyacrylamide gels. The gene encoding ABC10 alpha, RPC10, was isolated based on microsequence data. RPC10 is a single copy gene localized on chromosome VIII. It codes for a very basic protein of only 70 amino acids, which contains a zinc binding domain of the form CX2CX13CX2C. Deletion of its gene indicated that, despite its very small size, the ABC10 alpha subunit is essential for yeast cell viability. ABC10 alpha and ABC10 beta have little sequence similarity.

Influence of age on clinical and immunological characteristics of newly diagnosed type 1 diabetic patients.

The aim of this study was to analyse the immunological and clinical characteristics of a group of patients at the onset of type 1 diabetes and to determine if these findings are age related. For this purpose, 68 newly diagnosed type 1 diabetes mellitus patients referred to our hospital between 1997 and 1999 were studied; 42 were adults (mean age 24+/-3.5 years) and 26 children (mean age 6.1+/-4 years). Autoantibody markers islet cell antibodies, glutamic acid decarboxylase antibodies (GADA) and tyrosine phosphatase antibodies (IA-2A), pancreatic reserve (glucagon test) and HbA1c were determined. Some clinical characteristics, such as mode of presentation and insulin requirements, were also analysed. Type 1 diabetes mellitus was found to be autoimmune in 83.8% of the patients and idiopathic in 16.2%, without significant differences between adults and children. In the whole autoimmune group, GADA was more prevalent in adults and IA-2A more frequent in children. On the other hand, adults showing autoimmune markers developed ketosis more frequently and needed higher insulin doses at diagnosis, while children did not exhibit clinically significant differences associated with the presence or absence of antibodies. In conclusion, in children the presence of autoimmune markers is not related to the mode of presentation or characteristics of type 1 diabetes. In adults, however, the autoimmune group presents with more-severe clinical disease than antibody negative patients. Age at onset seems to be an important parameter in the natural history of type 1 diabetes and must be taken into account in epidemiological or intervention studies.

[Familial and hereditary mesangial glomerulonephritis with IgA deposits (author's transl)]. / Glomerulonefritis mesangial con depósitos de IgA, familiar y hereditaria.

Idiopathic mesangial glomerulonephritis with IgA deposits was observed in two relatives, father and son, in a family of 5 members. In the father the disease started at age 43 with relapsing macroscopic hematuria, proteinuria, renal failure and hypertension, with a progressive course in the ensuing four years. The affected son, the oldest of three brothers, developed relapsing macroscopic hematuria at age 16; two years later renal function was normal and there was no hypertension, but microhematuria persisted without proteinuria. The mother and the other two brothers had no clinical or biological signs of renal disease. Serum immunoglobulins (IgG, IgA, and IgM) and complement (C3, C4, C3 proactivator) were normal in the patients and their relatives. Histocompatibility typing demonstrated the presence of HLA-Bw35 in the father and the two unaffected sons, being negative in the mother and the affected son. The analysis of HLA-Bw35 in 23 patients with IgA mesangial glomerulonephritis gave positive results in 30% of them, while the control group had a positivity of 15% (p non significant with the X2 test). The present observations suggest that IgA mesangial glomerulonephritis is a potentially familial and hereditary renal disease. HLA-Bw35 antigen appears not to be a genetic marker of the disease in our geographical area.

[Analysis of evaluation process of research projects submitted to the Fondo de Investigación Sanitaria, Spain]. / Análisis del proceso evaluador de los proyectos de investigación en el Fondo de Investigación Sanitaria.

BACKGROUND: At the present time it seems very clear that research improvement is both an unquestionable fact and the right way to develop technological innovation, services and patents. However, such improvement and corresponding finances needs to be done under fine and rigorous evaluation process as an assessment tool under which all the research projects applying to a public or private call for proposals should be submitted to assure a coherence point according to the investment to be made. At this end, the main target of this work has been focused to analysis and study the evaluation process traditionally made by Fondo de Investigación Sanitaria (FIS) as well as to propose most adequate modifications. MATERIAL AND METHOD: A sample of 431 research projects corresponding to year 1998 proposal was analysed. The evaluation from FIS and ANEP (National Evaluation and Prospective Agency) was evaluated and scored (evaluation quality) in its main contents by 3 independent evaluators, the showed results submitted to a comparative frame between these agencies at indoor (FIS) and outdoor (FIS/ANEP) level. RESULTS: FIS evaluation had 20 commissions or areas of knowledge. The analysis indoor (FIS) clearly showed that evaluation quality was correlated to the assigned commission (F = 3.71; p < 0.001) and to the time last of the researched proposal (F = 3.42; p < 0.05) but no related to the evaluator. On the other hand, the quality of ANEP evaluation showed a correlated dependency of the three mentioned facts. In all terms, the ANEP evaluation was better than FIS for the three years time projects, but in did not show significant differences in one or two years time projects. In all cases, the evaluation with final results as negative (financing denied) showed an average quality higher than positive evaluation. CONCLUSIONS: The obtained results advice about the convenience of making some changes in the evaluative structure and to review the sort of FIS technical commissions focusing an improvement of the evaluation process.

[Vitamin A deficiency and food consumption of children aged 6 to 84 months in a Mali rural area]. / Carence en vitamine A et consommation alimentaire chez les enfants de 6 à 84 mois en milieu rural malien.

A cross-sectional study was carried out during the dry season, within the framework of an extension of an existing sanitary program. In December 1991, a cluster sample of 2,631 children was selected in a rural district of Mali, in the district of Koutiala, with good agricultural conditions. A sub-sample of 262 mothers was selected for interviews concerning their knowledge and attitudes about vitamin A deficiency symptoms. Prevalence of clinical symptoms was 2% for night blindness, 0.3% for Bitot's spots and 0.2% for corneal scars. Night blindness was more common after 3 years. The study of weekly consumption of vitamin A rich foods, made on a sample of 519 children, revealed that only 3.3% ate vitamin A rich foods less than seven times a week and 2.7% never ate any. According to the recommended dietary allowances, vitamin A deficiency was not a public health problem in this region. However, these results do not agree with those of the clinical study. It should be noted also that protein energy malnutrition is scarce among the children. These results allowed an estimate of the prevalence of vitamin A deficiency, but were insufficient for the design of strategies to reduce this prevalence. Simple and relatively cheap epidemiological methods like case-control studies are not commonly used in developing countries. These methods could be used to obtain a better estimate of social, cultural and biological risk factors, and therefore, better targeting interventions.