Ideal Cardiovascular Health in the southern cone of Latin America.

OBJECTIVE: The American Heart Association developed the concept of 'Ideal Cardiovascular Health', which is based on the presence of ideal levels across seven health factors. The goal of this study is to assess the prevalence of Ideal Cardiovascular Health in the Southern Cone of Latin America. STUDY DESIGN: We conducted a cross-sectional analysis as part of CESCAS I cohort. METHODS: This report included 5458 participants aged between 35 and 75 years who were selected using stratified multistage probability sampling in Argentina, Chile and Uruguay. Interviews included demographic information, the International Physical Activity Questionnaire, and a food frequency questionnaire on dietary habits. Participants were classified as current, former or non-smokers. Weight, height and blood pressure were measured by trained personnel, and fasting cholesterol and glucose plasma levels were measured. RESULTS: Only 0.1% (95% confidence interval [CI]: 0.0-0.2) met the seven criteria that define the Ideal Cardiovascular Health. The least prevalent healthy behaviour was having a healthy diet: 0.5% (95% CI: 0.3-0.7), while the least prevalent health factor was having blood pressure < 120/80 mmHg: 23.6% (95% CI: 22.1-25.0). CONCLUSIONS: The prevalence of Ideal Cardiovascular Health is very low in a representative sample of population from the Southern Cone of Latin America, and the levels of healthy lifestyle behaviours are even lower than ideal biochemical parameters. These results highlight the challenge of developing strategies to improve the levels of Ideal Cardiovascular Health at primary prevention levels.

Celecoxib in a 12-year-old boy with familial adenomatous polyposis.

Familial Adenomatous Polyposis (FAP) is an autosomal dominant disorder characterized by colonic polyps in early adult life. Children with this disease are at risk for colonic cancer, so prophylactic colectomy is the standard treatment to prevent this complication. Chemoprevention experience with NSAIDs in children is exceptional. This case report describes our experience with Celecoxib, a COX-2 inhibitor, in a 12-year-old boy.

Frequency of Mycobacterium bovis as an etiologic agent in extrapulmonary tuberculosis in HIV-positive and -negative Mexican patients.

Mycobacterium bovis can be an important etiological agent for extrapulmonary (EP) manifestations of tuberculosis, especially in HIV-infected persons. From January 2000 to December 2003, M. bovis as a cause of EP tuberculosis was investigated at the Pneumonology Service, Hospital General de Mexico, Mexico City. Eighty HIV-positive (HIV+) patients and 83 HIV-negative (HIV-) with EP involvement (ganglionar, genitourinary, meningeal, cutaneous, peritoneal, and pericardial) were analyzed using clinical, immunological, bacteriological, histopathological, and molecular biology methods. Mycobacterium species were identified by hsp65-RFLP analysis and species of M. tuberculosis complex isolates by spoligotyping. M. bovis was present in 6 HIV- cases (7.2%; 3 with lymphadenitis and 3 genitourinary) vs 11 in HIV+ cases (13.75%; 7 with lymphadenitis, 3 genitourinary, and 1 meningeal). Favorable response to retroviral and specific M. bovis chemotherapy was observed. Spoligotyping showed a unique profile in each isolate, 16 belonging to BOV1 lineage and 1 to BOV2 lineage. M. bovis is an significant re-emerging cause of EPTB in Mexico. Consumption of unpasteurized dairy products is the most likely source of transmission. Successful treatment depends on the adequate and opportune identification of the agent responsible.

Risk-reduction surgery in BRCA mutation carriers in a Spanish population: adherence and results

OBJECTIVE: To analyse the level of adherence to prophylactic surgery of breast and/or ovarian cancer in female carriers of the BRCA1 or BRCA2 mutation in a referential genetic counselling unit in Spain. METHODS: Between January 1998 and November 2006, a total of 684 families with several cases of breast and/or ovarian cancer were selected by the Genetic Counselling Unit at the Hospital Clínico Universitario San Carlos. Some of them opted for prophylactic surgery after genetic counselling and genetic testing. RESULTS: The pathogenic mutation was found in 57 families out of a total of 449 families who fulfilled the hereditary breast/ovarian cancer criteria. Out of a total of 238 individuals who were carriers of the mutation, 136 (57%) were offered risk-reducing prophylactic surgery. Prophylactic surgery was chosen by 58 (43%) women out of a total of 136 who were offered this possibility; the histological findings observed 7% malignant lesions in the breast and, in the ovarian-fallopian complex, 2 cases (8%) of a borderline tumour and one case (4%) of papillary adenocarcinoma. CONCLUSION: This is the first study published on the role of prophylactic surgery in BRCA mutation carriers in the Spanish population. The incidence of occult carcinoma in these cases is lower than in other series (AU)

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Evaluation of the polymerase chain reaction in the diagnosis of miliary tuberculosis in bone marrow smear.

OBJECTIVE: Miliary tuberculosis (MTB) is difficult to diagnose. When prompt diagnosis is necessary, the polymerase chain reaction (PCR) to detect mycobacterial DNA may be valuable. SETTING: Tuberculosis clinic in an academic tertiary-level hospital in Mexico. DESIGN: Bone marrow (BM) aspiration samples from 30 consecutive clinically suspected MTB patients and 58 non-tuberculosis hematologic patients were evaluated by in-house PCR using a fragment of the insertion sequence IS6110; results were compared with those obtained by acid-fast-stained smears, culture in Löwenstein-Jensen medium, histology, and serology. RESULTS: Tuberculosis diagnosis was confirmed in all MTB suspects, 28 by microscopy and culture in pulmonary or extra-pulmonary samples other than BM, and two by clinical and radiologic improvement after antituberculosis treatment. In fresh BM specimens, in-house PCR was positive in 21/30 (70%) suspects, contrasting with only one positive (3.3%) in staining and culture, and four with compatible histologic findings (13.3%). BM samples from the control group showed negative results in bacteriologic and histologic studies, except in nine who had positive PCR results. These nine control cases had malignant processes. CONCLUSION: PCR in aspirates of BM is a useful diagnostic assay in cases of MTB, mainly when bacteriological results are negative.

Tuberculosis is still a major cause of cervical lymphadenopathies in adults from developing countries.

To establish the frequency of infectious aetiology in Mexican adult patients with cervical lymphadenopathies (CLAs), 87 consecutive patients with enlarged cervical lymphatic nodes, HIV negative and without anti-tuberculous treatment, were selected from a tertiary-level speciality concentration hospital. Histopathological studies, investigation of acid-fast bacilli, cultures in Löwenstein Jensen and Mycobacterium growth indicator tube (MGIT) media, and in-house polymerase chain reaction (PCR) with IS6110-based primers for Mycobacterium tuberculosis complex were performed in resected lymphatic nodes. Non-infectious aetiology corresponded to 45 cases (52 %). Tuberculosis was suspected in 42 cases (48%) by histology and confirmed positive results were obtained by staining in 8 (19%), by culture in 23 (55%), and by PCR in 34 (81 %) patients. All were confirmed after therapeutic success. In addition to the epidemiological transition process occurring in Mexico, tuberculosis remains an important cause of CLA. Histopathology with confirmatory studies including PCR can detect tuberculous aetiology.

Forensic anthropology in Latin America.

Forensic anthropology has been one of the fastest growing medico-legal disciplines both in its contribution to the practical needs of the legal system and research accomplishments. New anthropological standards were developed to apply to a specific population of a region. The purpose of this paper is to analyze a large sample of anthropological forensic cases and to review pertinent literature that deals with anthropological standards developed for the population of the continent of Central and South America. Using Uruguay as an example, there was not a single office or anthropologist assigned to analyze human skeletal remains in Uruguay. In 1991 the Laboratorio de Antropología Forense at the Morgue Judicial of Montevideo was created. A total of 189 forensic anthropological cases (276 individuals) were analyzed since this date. Twenty six percent of cases involving human remains were positively identified. The majority came from the Departamento de Montevideo, the largest population district of the country. Most of the cases fell into the 60 to 69 years old age range (35%). Females represented 32% of the total. Since the establishment of the laboratory, the number of forensic cases increased considerably from 20 in 1991 to 40 in 1997. The case studies were accompanied with skull-photo superimposition and facial reconstruction when no other evidence for positive identification was available. This service provided by the laboratory was quickly known to coroners, law enforcement agencies, and other legal authorities and thus utilized not only in Uruguay but also in several other countries in the continent. Because of the obvious need for an anthropologist, there are now university programs to provide forensic anthropological education. Yet, research has lagged behind considerably. Deficiencies are obvious in basic osteological standards of estimating age, calculating stature, determining sex and assessing race that can be applied to populations of the continent. Regional standards are also needed to estimate postmortem interval, to identify culture specific causes of trauma and other forensic phenomena. Some of these can be remedied if there is a database where the available literature is stored and osteometric information is shared.

Tyrosine is involved in protection from oxidative stress in Saccharomyces cerevisiae.

The phenotypic characterization of a Saccharomyces cerevisiae mutant unable to grow under agitated conditions is presented here. When this strain was incubated under aerobic conditions, it did not grow and the viability of the culture decreased. The loss in viability was prevented by the addition of antioxidants or chelating agents to the medium, indicating that this mutant was unable to withstand the oxidative stress generated by aerobic metabolism. This strain was complemented with plasmids from a yeast genomic library. The transformants that were obtained carried plasmids harbouring the TYR1 gene, which codes for one of the enzymes involved in tyrosine biosynthesis. A monogenic S. cerevisiae tyr1 mutant obtained from the Yeast Genetic Stock Center showed higher sensitivity to hydrogen peroxide than a TYR1 strain. This sensitivity was reverted when this strain was complemented with the TYR1 gene. Considering these results, we propose that tyrosine plays a role in the protection against oxidative stress.

GDH3 encodes a glutamate dehydrogenase isozyme, a previously unrecognized route for glutamate biosynthesis in Saccharomyces cerevisiae.

It has been considered that the yeast Saccharomyces cerevisiae, like many other microorganisms, synthesizes glutamate through the action of NADP+-glutamate dehydrogenase (NADP+-GDH), encoded by GDH1, or through the combined action of glutamine synthetase and glutamate synthase (GOGAT), encoded by GLN1 and GLT1, respectively. A double mutant of S. cerevisiae lacking NADP+-GDH and GOGAT activities was constructed. This strain was able to grow on ammonium as the sole nitrogen source and thus to synthesize glutamate through an alternative pathway. A computer search for similarities between the GDH1 nucleotide sequence and the complete yeast genome was carried out. In addition to identifying its cognate sequence at chromosome XIV, the search found that GDH1 showed high identity with a previously recognized open reading frame (GDH3) of chromosome I. Triple mutants impaired in GDH1, GLT1, and GDH3 were obtained. These were strict glutamate auxotrophs. Our results indicate that GDH3 plays a significant physiological role, providing glutamate when GDH1 and GLT1 are impaired. This is the first example of a microorganism possessing three pathways for glutamate biosynthesis.

Saccharomyces cerevisiae has a single glutamate synthase gene coding for a plant-like high-molecular-weight polypeptide.

Purification of the glutamate synthase (GOGAT) enzyme from Saccharomyces cerevisiae showed that it is an oligomeric enzyme composed of three identical 199-kDa subunits. The GOGAT structural gene was isolated by screening a yeast genomic library with a yeast PCR probe. This probe was obtained by amplification with degenerate oligonucleotides designed from conserved regions of known GOGAT genes. The derived amino-terminal sequence of the GOGAT gene was confirmed by direct amino-terminal sequence analysis of the purified protein of 199 kDa. Northern (RNA) analysis allowed the identification of an mRNA of about 7 or 8 kb. An internal fragment of the GOGAT gene was used to obtain null GOGAT mutants completely devoid of GOGAT activity. The results show that S. cerevisiae has a single NADH-GOGAT enzyme, consisting of three 199-kDa monomers, that differs from the one found in prokaryotic microorganisms but is similar to those found in other eukaryotic organisms such as alfalfa.

Glutamine synthesis is a regulatory signal controlling glucose catabolism in Saccharomyces cerevisiae.

The effect of glutamine biosynthesis and degradation on glucose catabolism in Saccharomyces cerevisiae was studied. A wild-type strain and mutants altered in glutamine biosynthesis and degradation were analyzed. Cells having low levels of glutamine synthetase activity showed high ATP/ADP ratios and a diminished rate of glucose metabolism. It is proposed that glutamine biosynthesis plays a role in the regulation of glucose catabolism.

Regulation of the amino acid permeases in nitrogen-limited continuous cultures of the yeast Saccharomyces cerevisiae.

In the yeast Saccharomyces cerevisiae, there is a general amino acid permease, regulated by nitrogen catabolite repression, and several specific permeases whose nitrogen regulation is not well understood. In this study, we used continuous cultures to analyse the effect of nitrogen limitation and pH on the activity of general and several specific amino acid permeases. General permease activity was maximal in severe nitrogen limitation and diminished 400-fold in cells grown under nitrogen excess. For the specific permeases, the maximal uptake activity was found between mild limitation and nitrogen excess, while very small activity was detected under strict limitation. These results indicate that the nitrogen regulation of the general and the specific amino acid carriers is coordinated in such a way that no redundancy exists in amino acid transport. The regulation of the specific permeases was similar to that found for a system with anabolic function in nitrogen metabolism. All of these permeases are supposed to work through a proton symport mechanism, and thus rely on pH gradients to carry out their function. We studied the effect of pH on the kinetic constants of the general permease. Our results show that the effect of pH on the Km was different for acidic, neutral and basic amino acids, while the effect on Vmax was independent of the electrical charge of the amino acids.

Cloning of a yeast gene coding for the glutamate synthase small subunit (GUS2) by complementation of Saccharomyces cerevisiae and Escherichia coli glutamate auxotrophs.

A Saccharomyces cerevisiae glutamate auxotroph, lacking NADP-glutamate dehydrogenase (NADP-GDH) and glutamate synthase (GOGAT) activities, was complemented with a yeast genomic library. Clones were obtained which still lacked NADP-GDH but showed GOGAT activity. Northern analysis revealed that the DNA fragment present in the complementing plasmids coded for a 1.5kb mRNA. Since the only GOGAT enzyme so far purified from S. cerevisiae is made up of a small and a large subunit, the size of the mRNA suggested that the cloned DNA fragment could code for the GOGAT small subunit. Plasmids were purified and used to transform Escherichia coli glutamate auxotrophs. Transformants were only recovered when the recipient strain was an E. coli GDH-less mutant lacking the small GOGAT subunit. These data show that we have cloned the structural gene coding for the yeast small subunit (GUS2). Evidence is also presented indicating that the GOGAT enzyme which is synthesized in the E. coli transformants is a hybrid comprising the large E. coli subunit and the small S. cerevisiae subunit.

Cloning of a yeast gene coding for the glutamate synthase small subunit (GUS2) by complementation of Saccharomyces cerevisiae and Escherichia coli glutamate auxotrophs.

A Saccharomyces cerevisiae glutamate auxotroph, lacking NADP-glutamate dehydrogenase (NADP-GDH) and glutamate synthase (GOGAT) activities, was complemented with a yeast genomic library. Clones were obtained which still lacked NADP-GDH but showed GOGAT activity. Northern analysis revealed that the DNA fragment present in the complementing plasmids coded for a 1.5kb mRNA. Since the only GOGAT enzyme so far purified from S. cerevisiae is made up of a small and a large subunit, the size of the mRNA suggested that the cloned DNA fragment could code for the GOGAT small subunit. Plasmids were purified and used to transform Escherichia coli glutamate auxotrophs. Transformants were only recovered when the recipient strain was an E. coli GDH-less mutant lacking the small GOGAT subunit. These data show that we have cloned the structural gene coding for the yeast small subunit (GUS2). Evidence is also presented indicating that the GOGAT enzyme which is synthesized in the E. coli transformants is a hybrid comprising the large E. coli subunit and the small S. cerevisiae subunit.

Coordinated regulation of ammonium assimilation and carbon catabolism by glyoxylate in Saccharomyces cerevisiae.

The activities of citrate synthase (EC 4.1.3.7) and NADP+-dependent glutamate dehydrogenase (GDH) (EC 1.4.1.4) of Saccharomyces cerevisiae were inhibited in vitro by glyoxylate. In the presence of glyoxylate, pyruvate and glyoxylate pools increased, suggesting that glyoxylate was efficiently transported and catabolized. Pyruvate accumulation also indicates that citrate synthase was inhibited. A decrease in the glutamate pool was also observed under these conditions. This can be attributed to an increased transamination rate and to the inhibitory effect of glyoxylate on NADP+-dependent GDH. Furthermore, the increase in the ammonium pool in the presence of glyoxylate suggests that NADP+-dependent GDH was being inhibited in vivo, since the activity of glutamine synthetase did not decrease under these conditions. We propose that the inhibition of both citrate synthase and NADP+-dependent GDH could form part of a mechanism that regulates the internal 2-oxoglutarate concentration.

Genetic rearrangements of a Rhizobium phaseoli symbiotic plasmid.

Different structural changes of the Sym plasmid were found in a Rhizobium phaseoli strain that loses its symbiotic phenotype at a high frequency. These rearrangements affected both nif genes and Tn5 mob insertions in the plasmid, and in some cases they modified the expression of the bacterium's nodulation ability. One of the rearrangements was more frequent in heat-treated cells, but was also found under standard culture conditions; other structural changes appeared to be related to the conjugal transfer of the plasmid.

NADP+-dependent glutamate dehydrogenase activity is impaired in mutants of Saccharomyces cerevisiae that lack aconitase.

A mutant of Saccharomyces cerevisiae lacking aconitase did not grow on minimal medium (MM) and had five- to tenfold less NADP+-dependent glutamate dehydrogenase (GDH) activity than the wild-type, although its glutamine synthetase (GS) activity was still inducible. When this mutant was incubated with glutamate as the sole nitrogen source, the 2-oxoglutarate content rose, and the NADP+-dependent GDH activity increased. Furthermore, carbon-limited cultures showed a direct relation between NADP+-dependent GDH activity and the intracellular 2-oxoglutarate content. We propose that the low NADP+-dependent GDH activity found in the mutant was due to the lack of 2-oxoglutarate or some other intermediate of the tricarboxylic acid cycle.