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Biomedical subjects

A Reyes

Publications and source records attributed to A Reyes.

At least 19 recordsLinked to original sources
PubMed2006

Antigenotoxic effect of Saccharomyces cerevisiae on the damage produced in mice fed with aflatoxin B(1) contaminated corn.

The potential of Saccharomyces cerevisiae (Sc) was evaluated for reducing the micronucleated normochromatic erythrocytes (MNNE) rate in mice fed AFB(1) contaminated corn. The study included two groups fed AFB(1) contaminated corn (0.4 and 0.8 mg/kg), a control fed uncontaminated corn, another group fed uncontaminated corn and 0.3% of Sc (1 x 10(8) live cells/g), and two groups fed AFB(1) contaminated corn (0.4 and 0.8 mg/kg) plus 0.3% Sc. Weight and MNNE were determined weekly for six weeks. Subsequently, the same determinations were made for another three-week period, but in mice receiving only a normal diet, without AFB(1) and Sc. Results in the first period revealed the following: control and Sc fed mice had similar constant weight increase, and low MNNE rate; mice fed only AFB(1) showed weight decrease and significant MNNE increase; finally, Sc improved weight gain and reduced MNNE produced by AFB(1). In the second period, results exhibited a tendency similar to that of the previous phase in the control and Sc fed mice; the weight and MNNE values improved in the other groups. We also determined the capacity of Sc for adsorbing and modifying the mycotoxin structure. The mixture was filtered to obtain two phases, and AFB(1) content was measured. Sc revealed a potent adsorbent capacity; however, chromatographic determination suggested no structural modification.

Adsorption↗
PubMed2006

Autosomal dominant polycystic kidney disease with congenital absence of contralateral kidney.

Autosomal dominant polycystic kidney disease is the most frequent hereditary kidney disorder, accounting for 8-10% of the cases of end-stage renal disease. It is characterized by bilateral multiple renal cysts, nevertheless, asymmetric enlargement of the kidneys is frequently observed, and this can lead to diagnostic confusion. We report the rare occurrence of autosomal dominant polycystic disease confined to a right kidney and congenital absence of the contralateral one. Unexpected early onset of terminal renal failure in this hypertensive 23-year-old male is discussed with the review of the literature.

Adult↗
PubMed2006

[Hypersensitivity reaction to systemic corticosteroids in a hemodialysis patients].

Hypersensitivity reactions are a feared complication of hemodialysis considering their potential for a serious and eventually fatal course. This association could reflect a number of different exposures, including concomitant medications. Like this, systemic steroid-induced hypersensitivity reactions do occur, althought their incidence is extremely rare. A few reactions related to metylprednisolone have been reported in renal transplantation. The diagnosis could be confirmed by the patient history and performing skin testing, oral or parenteral challenge or by the evidence of specific IgE. We report on a 39-year-old woman undergoing dialysis therapy in whom severe bronchospasm was induced by corticosteroids. She has a positive systemic reaction on the oral steroid challenge test. A successful desensitization regimen for safe administration was achieved. The recognition of high-risk subjects and alternative therapeutic approach are critical, mainly in the management of patients while receiving corticosteroids or a renal allograft.

Adrenal Cortex Hormones↗
PubMed2005

Study of the mitochondrial transcription factor A (Tfam) gene in the primate Presbytis cristata.

The mitochondrial transcription factor A (Tfam) is a member of the HMG-box protein family, necessary for both transcription and maintenance of mitochondrial DNA. The gene is structured in seven exons and six introns and it is estimated to span about 10 kb in mouse, human and rat. In addition to the full length mRNA of Tfam, a shorter mRNA isoform lacking exon 5 has been found to be widely distributed in human and rat tissues. Here we present the isolation and characterization of Tfam gene in the primate Presbytis cristata which belongs to the Cercopithecidae family. We have determined the complete CDS sequence, the size of all the six introns, the complete sequences of the three shorter ones (I, III, VI) and the partial sequences of the long introns (II, IV, V). The comparison with other available Tfam sequences from mammals has revealed a high degree of conservation (above 90%) both in CDS and introns. By in situ hybridization (FISH) experiments we have mapped Tfam gene on chromosome 12 which, according to other cytogenetics studies, is the homologous region of chromosome 10, where human Tfam has been mapped. Moreover we have searched for the presence of alternatively spliced isoforms through several approaches, such as RT-PCR and differential hybridization. In Presbytis cristata we have not detected the presence of any spliced isoforms lacking exons; however we have identified one isoform in which part of the intron I is retained in the mRNA. The inclusion of this portion of intron I would originate an early stop codon if translated.

Alternative Splicing↗
PubMed2005

A summary of recent findings on birth outcomes and developmental effects of prenatal ETS, PAH, and pesticide exposures.

Inner-city minority populations are high-risk groups for adverse birth outcomes and also more likely to be exposed to environmental contaminants, including environmental tobacco smoke (ETS), benzo[a]pyrene B[a]P, other ambient polycyclic aromatic hydrocarbons (global PAHs), and residential pesticides. The Columbia Center for Children's Environmental Health (CCCEH) is conducting a prospective cohort study of 700 northern Manhattan pregnant women and newborns to examine the effects of prenatal exposure to these common toxicants on fetal growth, early neurodevelopment, and respiratory health. This paper summarizes results of three published studies demonstrating the effects of prenatal ETS, PAH, and pesticides on birth outcomes and/or neurocognitive development [Perera FP, Rauh V, Whyatt RM, Tsai WY, Bernert JT, Tu YH, et al. Molecular evidence of an interaction between prenatal environment exposures on birth outcomes in a multiethnic population. Environ Health Perspect 2004;12:630-62; Rauh VA, Whyatt RM, Garfinkel R, Andrews H, Hoepner L, Reyes A, et al. Developmental effects of exposure to environmental tobacco smoke and material hardship among inner-city children. Neurotoxicol Teratol 2004;26:373-85; Whyatt RM, Rauh V, Barr DB, Camann DE, Andrews HF, Garfinkel R, et al. Prenatal insecticide exposures, birth weight and length among an urban minority cohort. Environ Health Perspect, in press]. To evaluate the effects of prenatal exposure to ETS, PAHs, and pesticides, researchers analyzed questionnaire data, cord blood plasma (including biomarkers of ETS and pesticide exposure), and B[a]P-DNA adducts (a molecular dosimeter of PAHs). Self-reported ETS was associated with decreased head circumference (P = 0.04), and there was a significant interaction between ETS and adducts such that combined exposure had a significant multiplicative effect on birth weight (P = 0.04) and head circumference (P = 0.01) after adjusting for confounders. A second analysis examined the neurotoxic effects of prenatal ETS exposure and postpartum material hardship (unmet basic needs in the areas of food, housing, and clothing) on 2-year cognitive development. Both exposures depressed cognitive development (P < 0.05), and there was a significant interaction such that children with exposure to both ETS and material hardship exhibited the greatest cognitive deficit (7.1 points). A third analysis found that cord chlorpyrifos, and a combined measure of cord chlorpyrifos, diazinon, and propoxur-metabolite, were inversely associated with birth weight and/or length (P < 0.05). These results underscore the importance of policies that reduce exposure to ETS, air pollution, and pesticides with potentially adverse effects on fetal growth and child neurodevelopment.

Child↗
PubMed2005

[Aortic coarctation and postcoarctation mycotic aneurysm in a woman 20 weeks pregnant: anesthetic management].

A 28-year-old woman, 20 weeks pregnant, was diagnosed with aortic coarctation and postcoarctation mycotic aneurysm. After anesthetic induction, blood pressure was monitored in the radial artery of the right arm and the femoral artery of the right leg for two purposes: to verify hemodynamic stability as required in this type of operation and to determine the pressure gradient between the upper and lower limbs, which was approximately 40 mm Hg. To prevent spinal cord ischemia, an intradural catheter was inserted into the fourth and fifth lumbar space for spinal fluid drainage. A double lumen tube was used for intubation so that the left lung could be blocked, and a centrifugal pump was used instead of extracorporeal circulation. The aneurysm was resected through a left thoracotomy and an aortic prosthesis was placed. Satisfactory outcome was indicated by resolution of the pressure gradient, and fetal viability was verified by ultrasound. The mother suffered no neurological complications and the pregnancy continued to term uneventfully. We review the anesthetic procedure to follow in such cases.

Adult↗
PubMed2005

Acute renal failure associated with an accidental overdose of colchicine.

CASE SUMMARY: A 47-year-old man with a history of polyarticular gout was admitted to the nephrology service because of severe renal insufficiency (creatinine 6.25 mg/dl). Three days before admission he had a pain crisis in his knees and ankles and self-administered 20 x 1 mg granules of colchicine p.o. over a period of 4 - 5 hours together with six suppositories each containing 100 mg of indomethacin. The patient began vomiting within 24 hours, experienced diarrhea which persisted for three days and then came to the hospital. The patient reported oliguria during the preceding 24 hours. In hospital, attempts to correct water and electrolyte balance were initiated. The patient became stabilized hemo-dynamically, the diarrhea disappeared within 24 hours, diuresis resumed and the renal function progressively improved. Leukopenia and thrombopenia were diagnosed, the transaminases increased: AST = 79 U/l, ALT = 132 U/l on the eighth day after taking the colchicine. The serology for hepatitis A, B, C and HIV viruses was negative; the serology for CMV and VEB revealed a previous infection. After being discharged from hospital 11 days after admission, the patient presented with the following parameters: hematocrit 39%, leukocytes 5,920/microl (3 470 neutrophils), prothrombin time 13 seconds, urea 44 mg/dl, creatinine 1.29 mg/dl, AST 16 U/l and ALT 35 U/l. DISCUSSION: The patient mistakenly ingested 20 mg ofcolchicine p.o. (0.22 mg/kg). The intoxication was associated with gastroenterocolitis, dehydration and renal failure during the first three days after ingestion. The patient also developed leukopenia, thrombopenia and mild hepatocellular injury. Renal failure due to colchicine intoxication is due to various factors such as depletion of volume/hypotension, rhabdomyolysis and multiorgan failure. In this case, the hypovolemia was probably the fundamental cause of the acute renal insufficiency as demonstrated by the quick recovery after administering fluids. It is possible that indomethacin may have enhanced the toxic effect of colchicine on the kidneys and bone marrow. Some colchicine intoxications, as in this case, are caused by an error in interpreting the dose for treating an acute attack of gout. A way to prevent these errors would be to use a low-dose treatment protocol.

Acute Kidney Injury↗
PubMed2004

Postinfectious diffuse proliferative glomerulonephritis and acute renal failure in an HIV patient.

Postinfectious proliferative glomerulonephritis may occur in HIV-infected patients, although it is not a common cause of severe acute renal failure in them. We report a woman with HIV infection, who developed hypocomplementemic acute nephritic syndrome 10 days after an upper respiratory infection. Systemic diseases were excluded. The serum creatinine level increased to 6.6 mg/dl. Renal biopsy showed diffuse endocapillary proliferative glomerulonephritis, with mesangial and capillary walls, granular deposits of IgG and C3 by immunofluorescence. She was given corticosteroids with progressive normalization of her renal function. No opportunistic infections have occurred during 1-year follow-up.

Acute Kidney Injury↗
PubMed2003

Renal hypomagnesemia, hypercalciuria and nephrocalcinosis in a middle-aged man.

We report a 41-year-old man with hypomagnesemia, hypercalciuria, nephrocalcinosis, myopia and horizontal nystagmus. The hypomagnesemia was due to primary renal magnesium loss. He was diagnosed as having the syndrome of renal hypomagnesemia, hypercalciuria and nephrocalcinosis. This is a rare condition generally diagnosed by the first to third decades of life. Renal failure is common and end-stage renal disease can occur in children or young adults. The patient was treated with oral magnesium, chlorthalidone, potassium citrate and allopurinol and was followed up for 3 years. Treatment resulted in an improvement in hypercalciuria but serum magnesium level could not be normalized. The patient's renal function remains stable, with a mild degree of renal insufficiency.

Adult↗
PubMed2003

[Multicenter study of darbepoetin alfa in the treatment of anemia secondary to chronic renal insufficiency on dialysis].

This Spanish single-arm, multicenter, prospective clinical trial assessed the maintenance of hemoglobin concentrations (Hb) between 10-13 g/dL with unit doses of darbepoetin alfa and the safety of the treatment in dialysis patients. Eight-hundred twenty-six patients with chronic renal failure (CRF) (94% receiving haemodialysis and 6% receiving peritoneal dialysis) previously maintained on stable recombinant human erythropoietin (r-HuEPO) therapy with stable hemoglobin (Hb) concentrations (mean Hb concentration = 11.7 g/dL) were switched to darbepoetin alfa at a reduced dosing frequency for 24 weeks (a 20-week titration phase plus a 4-week treatment evaluation phase). Subjects receiving r-HuEPO two or three times weekly were switched to darbepoetin alfa once weekly, and those. who were receiving r-HuEPO once weekly were switched to darbepoetin alfa once every two weeks. The initial dose of darbepoetin alfa was determined from the r-HuEPO dose at inclusion into the study using a formula equating the peptide mass of the two molecules and rounding to the nearest available prefilled syringe dose. Overall, 86.8% of patients completed the 24-weeks of study. Changing the treatment from r-HuEPO to darbepoetin alfa and increasing the dose interval did not result in any clinically significant change in the Hb concentration. From base-line to the evaluation phase, the mean Hb fell 0.09 (95% CI, -0.2; -0.0) g/dl, with an increase of 0.19 (95% CI, 0.0;0.3) g/dL i.v. and a decrease of 0.22 (95% CI, -0.3; -0.1) g/dL s.c.). This maintenance of the mean Hb concentration was accompanied by a mean 9.8% reduction of the darbepoetin alfa dose (19.7% (95% CI, -24.9; -14.2) i.v. and 4.7% (95% CI, -8.5; -0.7) s.c. Treatment with darbepoetin alfa was well tolerated and no unexpected adverse events were reported. In conclusion, the replacement of previous r-HuEPO treatment by darbepoetin alfa in the therapy of anemia secondary to chronic renal failure in diaiyzed patients was effective, well tolerated, and decreased the frequency of dose administration compared with the previous r-HuEPO treatment. Darbepoetin alfa administered once weekly or once every two weeks maintained the baseline Hb levels whilst allowing dose reduction, which was higher in patients receiving i.v. darbepoetin alfa.

Aged↗
PubMed2002

[Spontaneous resolution of an acute subdural hematoma].

Acute postraumatic subdural hematoma is known to have bad prognosis. Traditionally, its treatment consisted in urgent surgical evacuation. Rapid spontaneous resolution of the hematoma has been infrequently observed. We report a case of a patient with an acute traumatic subdural hematoma which disappeared without surgery. CT-scan showed a left-sided subdural hematoma with marked mass effect. A low density layer, which implied involvement of CSF in the subdural space, was observed between the hematoma and the inner wall of the skull. We think that the spontaneous resolution of the hematoma was due to the dilution and washing-out by the CSF through an arachnoid tear. Another suggested mechanism in the literature is blood redistribution in the subdural space. Selected patients with an acute subdural hematoma can be managed with conservative treatment.

Aged↗
PubMed2002

The highly cross-fertile coral species, Acropora hyacinthus and Acropora cytherea, constitute statistically distinguishable lineages.

A major challenge for understanding the evolutionary genetics of mass-spawning corals is to explain the maintenance of discrete morphospecies in view of high rates of interspecific fertilization in vitro and nonmonophyletic patterns in molecular phylogenies. In this study, we focused on Acropora cytherea and A. hyacinthus, which have one of the highest potentials for interspecific fertilization. Using sequences of a nuclear intron, we performed phylogenetic and nested clade analyses (NCA). Both species were polyphyletic in molecular phylogenies, but the NCA indicated that they constitute statistically distinguishable lineages. Phylogenetic analysis using an intergenic region of the mitochondrial DNA (mtDNA), was inconclusive because of low levels of variability in this marker. The position of these two species differed between the nuclear DNA (nDNA) and mtDNA phylogenies and was also at odds with a cladistic analysis based on morphology. We conclude that despite the potential for high levels of hybridization and introgression, A. cytherea and A. hyacinthus constitute statistically distinguishable lineages and their taxonomic status is consistent with the cohesion species concept.

Animals↗
PubMed2001

Effect of bafilomycin A1, a specific inhibitor of vacuolar (V-type) proton ATPases, on the capacitation of rabbit spermatozoa.

Mammalian spermatozoa maintain precisely regulated ionic gradients that must be modified during capacitation and the acrosome reaction. In other cell types, ionic gradients are mainly regulated by the presence in plasma membranes of three metabolically different types of ATPases. The modifications induced during in vitro capacitation of rabbit spermatozoa by the specific inhibition of V-type H+-ATPases with bafilomycin A were studied. We used chlortetracycline binding to rabbit spermatozoa to monitor capacitation, and the coomassie brilliant blue method to identify acrosome-reacted sperm cells. There was a significant difference between the percentage of epididymal (66 +/- 7%) and ejaculated (43 +/- 11%) spermatozoa capacitated in vitro, after a 6-h incubation period in the presence of Ca2+ without ATPase inhibitor. The presence of bafilomycin significantly reduced these numbers (25 +/- 11 and 16+/- 8%, epididymal and ejaculated spermatozoa, respectively) and eliminated the difference. Ejaculated spermatozoa capacitated in the absence of bafilomycin showed a linear increase in the percentage of acrosome reactions induced by the addition of A23187 (12 +/- 5, 23+/- 6 and 31 +/- 5 after 15, 30 and 45 min). The presence of 0.2 micromol l-1 bafilomycin during the capacitation incubation induced a significant decrease in the acrosome reaction percentages (4 +/- 2, 8 +/- 3 and 14 +/- 4 after 15, 30 and 45 min). The addition of bafilomycin after the capacitating period had no effect upon the induction of the acrosome reaction by A23187. These results indicate that vacuolar ATPases play an important role during rabbit sperm capacitation. However, once the spermatozoa have been capacitated, V-type ATPases do not have a significant participation during the acrosome reaction.

Acrosome Reaction↗
PubMed2001

Evolutionary history of the most speciose mammals: molecular phylogeny of muroid rodents.

Phylogenetic relationships between 32 species of rodents representing 14 subfamilies of Muridae and four subfamilies of Dipodidae were studied using sequences of the nuclear protein-coding genes Lecithin Cholesterol Acyl Transferase (LCAT) and von Willebrand Factor (vWF). An examination of some evolutionary properties of each data matrix indicates that the two genes are rather complementary, with lower rates of nonsynonymous substitutions for LCAT. Both markers exhibit a wide range of GC3 percentages (55%-89%), with several taxa above 70% GC3 for vWF, which indicates that those exonic regions might belong to the richest class of isochores. The primary sequence data apparently harbor few saturations, except for transitions on third codon positions for vWF, as indicated by comparisons of observed and expected pairwise values of substitutions. Phylogenetic trees based on 1,962 nucleotidic sites from the two genes indicate that the 14 Muridae subfamilies are organized into five major lineages. An early isolation leads to the clade uniting the fossorial Spalacinae and semifossorial Rhizomyinae with a strong robustness. The second lineage includes a series of African taxa representing nesomyines, dendromurines, cricetomyines, and the sole living member of mystromyines. The third one comprises only the mouselike hamster CALOMYSCUS: The fourth clade represents the cricetines, myospalacines, sigmodontines, and arvicolines, whereas the fifth one comprises four "traditional" subfamilies (Gerbillinae, Murinae, Otomyinae, and Acomyinae). Within these groups, we confirm the monophyly of almost all studied subfamilies, namely, Spalacinae, Rhizomyinae, Nesomyinae, Cricetomyinae, Arvicolinae, Sigmodontinae, Cricetinae, Gerbillinae, Acomyinae, and Murinae. Finally, we present evidence that the sister group of Acomyinae is Gerbillinae, and we confirm a nested position of Myospalacinae within Cricetinae and Otomyinae within Murinae. From a biogeographical point of view, the five main lineages spread and radiated from Asia with different degrees of success: the first three groups are now represented by a limited number of species and genera localized in some regions, whereas the last two groups radiated in a large variety of species and genera dispersed all over the world.

Animals↗