[Renovascular hypertension in children and adolescents: diagnosis and treatment over 19 years]. / Hipertensión vasculo-renal en niños y adolescentes: diagnóstico y tratamiento durante 19 años.

SUMMARY Sixty seven hypertensive children age 2-18 with at least one possible clinical sign of renovascular hypertension (RVH) were enrollment into a screening program for diagnose and treatment of RVH over a 19 year period. Patients underwent a variety of biochemical and imaging studies, but in all cases, renal arteriography was used to determine the precise diagnosis and treatment strategy. Of the 67 patients 21 (31.3%) were identified with renal artery stenosis Group 1, 14 (66.6%) unilateral, 5 (23.8%) bilateral and 2 (9.6%) branches. The mean age was 13.9 +/- 3.73 years, with 26.4 +/- 35.2 months of known hypertension, mean systolic blood pressure 191.1 +/- 30.6 mmHg, mean diastolic blood pressure 135.3 +/- 21.2 mmHg and 69% due to fibromuscular dysplasia. Three therapeutic modalities were chosen: percutaneous transluminal angioplasty (PTA), surgery (autotransplant, and nephrectomy), pharmaceutical therapy with antihypertensive drugs and combination of these. The aim of the treatment was blood pressure control, prevention of chronic renal disease and renal function and organ damage preservation. The outcome was categorized as cure, improvement or no change in hypertension. PTA treated eleven patients, 2 combined with surgery (one nephrectomy and 1 autotransplant). Blood pressure was normalized in 9/11 (81.8%) after a mean follow-up of 11.5 years (range 1-18 years). All 6 RVH cases treated by surgery procedure (one after PTA) were cured and 4 cases were managed medically (pharmacological treatment). On december 2004, 19/21 (90%) RVH adolescents blood pressure was normalized with normal serum creatinina, 10 (48%) of these completed cured, 9/21 (43%) improved (normotensión with decrease in medication requirements) and 2 (9%) other cases ware lost of follow-up. The 46 non-RVH adolescents (68.7%) were treated with long term antihypertensive medications; all of these have adequate BP control and normal renal function. We conclude that our work-up used in order to make a proper and timely diagnosis and treatment of renovascular hypertension in adolescent was successful in our population.

Hipertensión vasculorenal en niños y adolescentes: diagnóstico y tratamiento durante 19 años / Clinical, analytics and imagine studies results in hypertensive adolescents over a 19 years period

En el periodo comprendido desde enero de 1986 hasta diciembre del 2004, se recibieron 67 niños y adolescentes por sospecha de padecer hipertensión vasculo-renal (HTA-VR). Los pacientes fueron sometidos a estudios bioquímicos e imagenológicos, pero en todos los casos la arteriografía por sustracción digitálica (ASD) fue determinante para el diagnóstico y la estrategia de tratamiento. Al concluir el estudio, 21 (31,3%) pacientes (Grupo 1) fueron diagnosticados de HTA-VR por estenosis arterial, 14 (66,7%) unilateral, 4 (19,0%) bilateral y 3 (14,3%) en rama. En el resto de los 46 (68,7%) pacientes (Grupo 2), no se identificó causa etiológica. Grupo I: promedio de edad 13,9 ± 3,7 años, raza blanca 66%, varones 48%, tiempo de hipertensión conocido 26,4 ± 35,3 meses, tensión arterial máxima referida 191 ± 30,5 mmHg para la sistólica y 135 ± 21 mmHg para la diastólica. Grupo 2: promedio de edad 14,7 ± 3,7 años, raza blanca 67%, varones 74%, tiempo de hipertensión conocido 24,2 ± 30,19 meses, tensión arterial máxima referida 163 ± 27,7 mmHg para la sistólica y 108 ± 17 mmHg para la diastólica. La etiología más frecuente de HTAVR fue la displasia fibromuscular 69% de los casos. Se seleccionaron tres modalidades terapéuticas: 1) angioplastia transluminal percutánea (ATP) que se utilizó en 11 pacientes, 2 combinados con cirugía (1 autotrasplante y 1 nefrectomía posterior a trombosis arterial), con 81,8% de control (curado + mejorado) de la hipertensión con un seguimiento promedio de 11,5 años (1 a 18 años); 2) cirugía (autotrasplante o nefrectomía) en 5 casos, más la nefrectomía post-ATP referida, con cura de la hipertensión en todos ellos, y 3) 4 pacientes fueron tratados con hipotensores y diuréticos. En diciembre del 2004, 19/21 (90%) de los pacientes con HTA-VR estaban normotensos con creatinina sérica normal, 10 (48%) curados y 9 (43%) mejorados con algún soporte de hipotensores o diurético), y en 2 (9%) de los pacientes se perdió el seguimiento. Los restantes 46 (68,8%) niños no- HTA-VR tratados, tuvieron adecuado control de la TA con función renal normal. Conclusiones: La pauta de estudio empleada fue útil para el diagnóstico de HTA-VR en nuestro grupo adolescentes hipertensos con signos de clínicos de sospecha de padecer esta entidad. La gammagrafía pre-post-captopril fue la prueba más sensible

Sixty seven hypertensive children age 2-18 with at least one possible clinical sign of renovascular hypertension (RVH) were enrollment into a screening program for diagnose and treatment of RVH over a 19 year period. Patients underwent a variety of biochemical and imaging studies, but in all cases, renal arteriography was used to determine the precise diagnosis and treatment strategy. Of the 67 patients 21 (31.3%) were identified with renal artery stenosis Group 1, 14 (66.6%) unilateral, 5 (23.8%) bilateral and 2 (9.6%) branches. The mean age was 13.9 ± 3.73 years, with 26.4 ± 35.2 months of known hypertension, mean systolic blood pressure 191.1 ± 30.6 mmHg, mean diastolic blood pressure 135.3 ± 21.2 mmHg and 69% due to fibromuscular dysplasia. Three therapeutic modalities were chosen: percutaneous transluminal angioplasty (PTA), surgery (autotransplant, and nephrectomy), pharmaceutical therapy with antihypertensive drugs and combination of these. The aim of the treatment was blood pressure control, prevention of chronic renal disease and renal function and organ damage preservation. The outcome was categorized as cure, improvement or no change in hypertension. PTA treated eleven patients, 2 combined with surgery (one nephrectomy and 1 autotransplant). Blood pressure was normalized in 9/11 (81.8%) after a mean follow-up of 11.5 years (range 1-18 years). All 6 RVH cases treated by surgery procedure (one after PTA) were cured and 4 cases were managed medically (pharmacological treatment). On december 2004, 19/21 (90%) RVH adolescents blood pressure was normalized with normal serum creatinina, 10 (48%) of these completed cured, 9/21 (43%) improved (normotensión with decrease in medication requirements) and 2 (9%) other cases ware lost of follow-up. The 46 non-RVH adolescents (68.7%) were treated with long term antihypertensive medications; all of these have adequate BP control and normal renal function. We conclude that our work-up used in order to make a proper and timely diagnosis and treatment of renovascular hypertension in adolescent was successful in our population

Identification of Leishmania selenoproteins and SECIS element.

Selenoproteins result from the incorporation of selenocysteine (Sec-U) at an UGA-stop codon positioned within a gene's open reading frame and directed by selenocysteine insertion sequence (SECIS) elements. Although the selenocysteine incorporation pathway has been identified in a wide range of organisms it has not yet been reported in the Kinetoplastida Leishmania and Trypanosoma. Here we present evidence consistent with the presence of a selenocysteine biosynthetic pathway in Kinetoplastida. These include the existence of SECIS-containing coding sequences in Leishmania major and Leishmania infantum, the incorporation of (75)Se into Leishmania proteins, the occurrence of selenocysteine-tRNA (tRNA (sec) (uca)) in both Leishmania and Trypanosoma and in addition the finding of all genes necessary for selenocysteine synthesis such as SELB, SELD, PSTK and SECp43. As in other eukaryotes, the Kinetoplastids have no identifiable SELA homologue. To our knowledge this is the first report on the identification of selenocysteine insertion machinery in Kinetoplastida, more specifically in Leishmania, at the sequence level.

[Atherosclerotic renovascular hypertension: clinical findings and results of treatment over 15 years]. / Hipertensión vasculo-renal aterosclerótica: hallazgos clínicos y resultados del tratamiento durante 15 años.

UNLABELLED: The aim of this study was to present our clinical experience and results of different treatments in 83 atherosclerotic renovascular hypertensive patients treated in the last 15 years in the Instituto de nefrologia in Havana. Regardless of the type of treatment the patients were divided in two groups. Group I: 52 (62.3%) cases with standard oral hypotensive drugs alone and control of other cardiovascular risk factors (mean age 53 years old, sex m/f 50/50%, race white/no-white 75/25%, mean known hypertension follow-up 10.2 +/- 10 years, mean SBP 208 +/- 30 mmHg, mean DBP 123 +/- 17 mmHg, mean serum creatinina 1.62 mg/dl and increase peripheral plasma renin value in 61.6% of patients) and group II: 31 (37.7%) cases treated with revascularización procedures (PTA or surgery) or nephrectomy in selected patients (mean age 50 years old, sex m/f 68/32%, race white/no-white 16/84%, mean known hypertension follow-up 8.5 +/- 8.6 years, mean SBP 214 +/- 32 mmHg, mean DBP 1.31 +/- 16 mmHg, mean serum creatinina 1.85 mg/dl and increase peripheral plasma renin value 78.3% of patients). As end point for treatment results we selected: 1) hypertension cure or control, 2) evolution of the serum creatinine value and 3) kidney and patients survival. RESULTS: In those cases with a follow up for more than one year, in 82.9% the blood pressure was cure (21.4%) or controlled (61.4%). The proportion of failed was superior in group I (20.9%) than in group II (11.1%). All 18 cases treated by PTA with a follow up period longer than a year, blood pressure cure in 10 (55.6%), ameliorate in 5 (27.8%) and in 3 (16.6%) was unchanged (one patient lost of follow up). Nine patients were treated by surgery (3 revascularization and 6 nephrectomy), 5 (55.5%) cases cured and 4 (44.5%) ameliorate his blood pressure. Patients in group II maintain normal renal function in more cases than in group I (48.4% vs 30.8%). Both group had similar percentage of normal-normal + pathology-normal renal function (G I: 65.4% vs G II: 77.4%) p = 0.29. When chronic renal function was present at the base line study none of the revascularization procedure were superior. Patient and Kidney actuarial survivals rate do not showed superiority for any treatment procedure after 10 years of follow up. CONCLUSIONS: In atherosclerosis renovascular hypertension patients treated with intervention procedure had better BP control than those treated by hypotensive drugs. Not significant different between intervention procedures and drugs treatment in renal function preservation or in patient and kidney actuarial survival rate were found in these patients.

End processing precedes mitochondrial importation and editing of tRNAs in Leishmania tarentolae.

All mitochondrial tRNAs in Leishmania tarentolae are encoded in the nuclear genome and imported into the mitochondrion from the cytosol. One imported tRNA (tRNA(Trp)) is edited by a C to U modification at the first position of the anticodon. To determine the in vivo substrates for mitochondrial tRNA importation as well as tRNA editing, we examined the subcellular localization and extent of 5'- and 3'-end maturation of tRNA(Trp)(CCA), tRNA(Ile)(UAU), tRNA(Gln)(CUG), tRNA(Lys)(UUU), and tRNA(Val)(CAC). Nuclear, cytosolic, and mitochondrial fractions were obtained with little cross-contamination, as determined by Northern analysis of specific marker RNAs. tRNA(Gln) was mainly cytosolic in localization; tRNA(Ile) and tRNA(Lys) were mainly mitochondrial; and tRNA(Trp) and tRNA(Val) were shared between the two compartments. 5'- and 3'-extended precursors of all five tRNAs were present only in the nuclear fraction, suggesting that the mature tRNAs represent the in vivo substrates for importation into the mitochondrion. Consistent with this model, T7-transcribed mature tRNA(Ile) underwent importation in vitro into isolated mitochondria more efficiently than 5'-extended precursor tRNA(Ile). 5'-Extended precursor tRNA(Trp) was found to be unedited, which is consistent with a mitochondrial localization of this editing reaction. T7-transcribed unedited tRNA(Trp) was imported in vitro more efficiently than edited tRNA(Trp), suggesting the presence of importation determinants in the anticodon.

Selective importation of RNA into isolated mitochondria from Leishmania tarentolae.

All mitochondrial tRNAs in kinetoplastid protozoa are encoded in the nucleus and imported from the cytosol. Incubation of two in vitro-transcribed tRNAs, tRNA(Ile)(UAU) and tRNA(Gln)(CUG), with isolated mitochondria from Leishmania tarentolae, in the absence of any added cytosolic fraction, resulted in a protease-sensitive, ATP-dependent importation, as measured by nuclease protection. Evidence that nuclease protection represents importation was obtained by the finding that Bacillus subtilis pre-tRNA(Asp) was protected from nuclease digestion and was also cleaved by an intramitochondrial RNase P-like activity to produce the mature tRNA. The presence of a membrane potential is not required for in vitro importation. A variety of small synthetic RNAs were also found to be efficiently imported in vitro. The data suggest that there is a structural requirement for importation of RNAs greater than approximately 17 nt, and that smaller RNAs are apparently nonspecifically imported. The signals for importation of folded RNAs have not been determined, but the specificity of the process was illustrated by the higher saturation level of importation of the mainly mitochondria-localized tRNA(Ile) as compared to the level of importation of the mainly cytosol-localized tRNA(Gln). Furthermore, exchanging the D-arm between the tRNA(Ile) and the tRNA(Gln) resulted in a reversal of the in vitro importation behavior and this could also be interpreted in terms of tertiary structure specificity.

Evolution of RNA editing in trypanosome mitochondria.

Two different RNA editing systems have been described in the kinetoplast-mitochondrion of trypanosomatid protists. The first involves the precise insertion and deletion of U residues mostly within the coding regions of maxicircle-encoded mRNAs to produce open reading frames. This editing is mediated by short overlapping complementary guide RNAs encoded in both the maxicircle and the minicircle molecules and involves a series of enzymatic cleavage-ligation steps. The second editing system is a C(34) to U(34) modification in the anticodon of the imported tRNA(Trp), thereby permitting the decoding of the UGA stop codon as tryptophan. U-insertion editing probably originated in an ancestor of the kinetoplastid lineage and appears to have evolved in some cases by the replacement of the original pan-edited cryptogene with a partially edited cDNA. The driving force for the evolutionary fixation of these retroposition events was postulated to be the stochastic loss of entire minicircle sequence classes and their encoded guide RNAs upon segregation of the single kinetoplast DNA network into daughter cells at cell division. A large plasticity in the relative abundance of minicircle sequence classes has been observed during cell culture in the laboratory. Computer simulations provide theoretical evidence for this plasticity if a random distribution and segregation model of minicircles is assumed. The possible evolutionary relationship of the C to U and U-insertion editing systems is discussed.

[Arterial hypertension in Cuba. General overview of the past 25 years]. / Hipertensión arterial en Cuba. Panorámica general de los últimos 25 años.

A general overview of hypertension as a major health problem in Cuba in the last 25 years are presented. In the first period, 1974-1990 was created a National Hypertension High Commission by the Minister of Public and the First national program for prevention and Control of Hypertension in Cuba was launched. To define high blood pressure in adults 15 years and older the cut-off point was set at 160/95 mmHg. The prevalence found was 15% in urban areas and 7-8% in rural areas. The second period, 1991-1998 the original National program was re-evaluated in 1990 and 1995. The new blood pressure cut-off point was set at 140/90 mmHg. The prevalence increased to 30.6% in urban areas and 15% in rural areas and incidence of 2.5% annual. A total of 862,303 hypertensive patients were registry at the end of 1997 which represents less than 40% of the total number of possible hypertensive patients. A National Campaign was launched in 1998. In 9 months the preliminary reports were: 25% increase in prevalence, registry and follow-up of hypertensive patients 15 years old and older (8.5% to 12.5%); 92.9% of primary care doctors and 89.5% of primary care nurses received training; improvement in public education and social support; improvement in risk factor awareness in general public and improvement of hypotensive drugs availability and splygmomanometers supplies.

C to U editing of the anticodon of imported mitochondrial tRNA(Trp) allows decoding of the UGA stop codon in Leishmania tarentolae.

All mitochondrial tRNAs in kinetoplastid protists are encoded in the nucleus and imported into the organelle. The tRNA(Trp)(CCA) can decode the standard UGG tryptophan codon but can not decode the mitochondrial UGA tryptophan codon. We show that the mitochondrial tRNA(Trp) undergoes a specific C to U nucleotide modification in the first position of the anticodon, which allows decoding of mitochondrial UGA codons as tryptophan. Functional evidence for the absence of a UGA suppressor tRNA in the cytosol, using a reporter gene, was also obtained, which is consistent with a mitochondrial localization of this editing event. Leishmania cells have dealt with the problem of a lack of expression within the organelle of this non-universal tRNA by compartmentalizing an editing activity that modifies the anticodon of the imported tRNA.

T7 RNA polymerase-driven transcription in mitochondria of Leishmania tarentolae and Trypanosoma brucei.

The study of RNA editing and other molecular processes in the trypanosome mitochondrion would benefit greatly from the ability to insert and express exogenous DNA in the organelle. However, even with a method to introduce DNA, the current lack of knowledge about mitochondrial transcription would hinder efforts to obtain expression. To circumvent this problem, Leishmania tarentolae promastigotes and Trypanosoma brucei procyclic cells have been transfected with bacteriophage T7 RNA polymerase targeted to the mitochondrion. Mitochondria isolated from the transfectants contained active T7 RNA polymerase, as shown by a comigration in density gradients of mitochondrial marker enzymes and T7 polymerase activity. A DNA cassette under T7 control was introduced into isolated mitochondria from the transfectants by electroporation and the DNA was shown to be transcribed. This system should allow the transcription of foreign genes of choice within the mitochondrial matrix either in a transient assay using electroporation of DNA into isolated mitochondria, or in a stable assay using cells transfected with DNA by the biolistic gun method.

The mitochondrial RNA ligase from Leishmania tarentolae can join RNA molecules bridged by a complementary RNA.

A biochemical characterization was performed with a partially purified RNA ligase from isolated mitochondria of Leishmania tarentolae. This ligase has a K(m) of 25 +/- 0.75 nM and a V(max) of 1.0 x 10(-4) +/- 2.4 x 10(-4) nmol/min when ligating a nicked double-stranded RNA substrate. Ligation was negatively affected by a gap between the donor and acceptor nucleotides. The catalytic efficiency of the circularization of a single-stranded substrate was 5-fold less than that of the ligation of a nicked substrate. These properties of the mitochondrial RNA ligase are consistent with an expected in vivo role in the process of uridine insertion/deletion RNA editing, in which the mRNA cleavage fragments are bridged by a cognate guide RNA.

APT1, but not APT2, codes for a functional adenine phosphoribosyltransferase in Saccharomyces cerevisiae.

The yeast Saccharomyces cerevisiae has two separate genes (APT1 and APT2) that encode two potentially different forms of adenine phosphoribosyltransferase (APRT). However, genetic analysis indicated that only APT1 could code for a complementing activity. Cloning and expression of both the APT1 and APT2 genes in Escherichia coli showed that although discrete proteins (APRT1 and APRT2) were made by these genes, only APRT1 had detectable APRT activity. Northern and Western blot analyses demonstrated that only APT1 was transcribed and translated under normal physiological conditions in yeast. Phylogenetic analysis revealed that APRT1 and APRT2 are evolutionary closely related and that they arise from a gene duplication event. We conclude that APT1 is the functional gene in S. cerevisiae and that APT2 is a pseudogene.

Purification and characterization of MAR1. A mitochondrial associated ribonuclease from Leishmania tarentolae.

A relatively thermostable 22-kDa endoribonuclease (MAR1) was purified more than 10,000-fold from a mitochondrial extract of Leishmania tarentolae and the gene cloned. The purified nuclease has a Km of 100-145 +/- 33 nM and a Vmax of 1.8-2.9 +/- 2 nmol/min, depending on the RNA substrate, and yields a 3'-OH and a 5'-phosphate. Cleavage was limited to several specific sites in the substrate RNAs tested, but cleavage of pre-edited RNAs was generally independent of the addition of cognate guide RNA. The MAR1 gene was expressed in Escherichia coli or in L. tarentolae cells, and the recombinant protein was affinity-purified. The cleavage specificity of the recombinant enzyme from L. tarentolae was identical to that of the native enzyme. The single copy MAR1 gene maps to an 820-kilobase pair chromosome and contains an open reading frame of 579 nucleotides. The 18-amino acid N-terminal sequence shows characteristics of an uncleaved mitochondrial targeting sequence. Data base searching revealed two homologues of MAR1 corresponding to unidentified open reading frames in Caenorhabditis elegans (GenBankTM accession number Z69637) and Archaeoglobus fulgidus (GenBankTM accession number AE000943). The function of MAR1 in mitochondrial RNA metabolism in L. tarentolae remains to be determined.

U-insertion/deletion Edited Sequence Database.

Uridine insertion/deletion RNA editing is a post-transcriptional RNA modification occurring in the mitochondria of kinetoplastid protozoa. The U-insertion/deletion Edited Sequence Database is a compilation of mitochondrial genes and edited mRNAs from five kinetoplastid species. It contains separate files with the DNA, mRNA (both unedited and edited) and predicted protein sequences, as well as alignments of the Leishmania tarentolae and Trypanosoma brucei protein sequences from edited and unedited genes. The sequence files are in GCG format. A 'map' sequence file showing the location of U-deletions, U-insertions and the translated amino acid sequences is also provided for each gene. Genomic maps for each species are also provided with clickable genes, including maxicircle-encoded gRNAs. Sets of aligned nuclear rRNA sequences from kinetoplastid protozoa are also provided, which were used for phylogenetic reconstructions in an analysis of the origin of RNA editing. The database is available through the World Wide Web as an HTML document at the URLhttp://www.lifesci.ucla.edu/RNA/trypanosome/ database.html

Purification and characterization of adenine phosphoribosyltransferase from Saccharomyces cerevisiae.

Adenine phosphoribosyltransferase (APRT) from Saccharomyces cerevisiae was purified approximately 1500-fold. The enzyme catalyzes the Mg-dependent condensation of adenine and 5-phosphoribosylpyrophosphate (PRPP) to yield AMP. The purification procedure included anion exchange chromatography, chromatofocusing and gel filtration. Elution of the enzyme from the chromatofocusing column indicated a pI value of 4.7. The molecular mass for the native enzyme was 50 kDa; however, upon electrophoresis under denaturing conditions two bands of apparent molecular mass of 29 and 20 kDa were observed. We have previously reported the presence of two separate coding sequences for APRT, APT1 and APT2 in S. cerevisiae. The appearance of two bands under denaturing conditions suggests that, unlike other APRTs, this enzyme could form heterodimers. This may be the basis for substrate specificity differences between this enzyme and other APRTs. Substrate kinetics and product inhibition patterns are consistent with a ping-pong mechanism. The Km for adenine and PRPP were 6 microM and 15 microM, respectively and the Vmax was 15 micromol/min. These kinetic constants are comparable to the constants of APRT from other organisms.

The mechanism of U insertion/deletion RNA editing in kinetoplastid mitochondria.

Recent advances in in vitrosystems and identification of putative enzymatic activities have led to the acceptance of a modified 'enzyme cascade' model for U insertion/deletion RNA editing in kinetoplastid mitochondria. Models involving the transfer of uridines (Us) from the 3'-end of gRNA to the editing site appear to be untenable. Two types of in vitrosystems have been reported: (i) a gRNA-independent U insertion activity that is dependent on the secondary structure of the mRNA; (ii) a gRNA-dependent U insertion activity that requires addition of a gRNA that can form an anchor duplex with the pre-edited mRNA and which contains guiding A and G nucleotides to base pair with the added Us. In the case of the gRNA-mediated reaction, the precise site of cleavage is at the end of the gRNA-mRNA anchor duplex, as predicted by the original model. The model has been modified to include the addition of multiple Us to the 3'-end of the 5'-cleavage fragment, followed by the formation of base pairs with the guiding nucleotides and trimming back of the single-stranded oligo(U) 3'-overhang. The two fragments, which are held together by the gRNA 'splint', are then ligated. Circumstantial in vitroevidence for involvement of an RNA ligase and an endoribonuclease, which are components of a 20S complex, was obtained. Efforts are underway in several laboratories to isolate and characterize specific components of the editing machinery.