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Biomedical subjects

M Castro

Publications and source records attributed to M Castro.

At least 19 recordsLinked to original sources
PubMed2003

Prevention of hypertension attenuates albuminuria and renal expression of fibronectin in diabetic spontaneously hypertensive rats.

BACKGROUND/AIM: The aim of this study was to evaluate the effect of preventing hypertension on renal disease in a model of genetic hypertension and diabetes. METHODS: Four-week-old spontaneously hypertensive rats (SHR) with streptozotocin-induced diabetes were randomized for no treatment, or for treatment with captopril, losartan or triple therapy (hydrochlorothiazide, reserpine and hydralazine) for 16 weeks. RESULTS: Increase in systolic blood pressure was equally prevented by captopril (128 +/- 3 mm Hg), losartan (128 +/- 2) and triple therapy (129 +/- 2, p < 0.0001). Albuminuria was similarly reduced by captopril (499 (404-659)), losartan (622 (470-976)) and triple therapy (479 (362-600) microg/24 h (p < 0.0001)). Renal fibronectin expression increased in diabetic SHR (125 +/- 13 densitometric unit) as compared to the controls (51 +/- 9, p < 0.0001), and decreased (p < 0.0001 vs. diabetic SHR) with captopril (32 +/- 8), losartan (27 +/- 4) and triple therapy (35 +/- 6). CONCLUSION: The prevention of hypertension in diabetic SHR by captopril, losartan or triple therapy was equally efficacious in impeding increase of albuminuria and the expression of renal fibronectin. Under these conditions, tight blood pressure control was the main determinant in attenuating nephropathy.

Albuminuria↗
PubMed2003

Transverse-momentum and collision-energy dependence of high-pT hadron suppression in Au+Au collisions at ultrarelativistic energies.

We report high statistics measurements of inclusive charged hadron production in Au+Au and p+p collisions at sqrt[s(NN)]=200 GeV. A large, approximately constant hadron suppression is observed in central Au+Au collisions for 5<p(T)<12 GeV/c. The collision energy dependence of the yields and the centrality and p(T) dependence of the suppression provide stringent constraints on theoretical models of suppression. Models incorporating initial-state gluon saturation or partonic energy loss in dense matter are largely consistent with observations. We observe no evidence of p(T)-dependent suppression, which may be expected from models incorporating jet attenuation in cold nuclear matter or scattering of fragmentation hadrons.

Journal Article↗
PubMed2003

Multiple paternity in Norway lobster (Nephrops norvegicus L.) assessed with microsatellite markers.

We investigated genetic diversity and the mating system of the Norway lobster (Nephrops norvegicus) in a wild population off the Portuguese coast. Approximately 100 individuals were screened for 2 microsatellite loci. For 11 ovigerous lobsters both the female and a sample of her offspring (24 eggs) were genotyped. High genetic diversity was observed for the 2 markers in the population. Paternity within broods was analyzed by comparing multilocus genotypes of each egg with the corresponding mother, and the male parent contribution was then deduced. Multiple paternity was observed in 6 of the 11 broods studied. In those cases, 2 to 3 male parents were likely to have contributed to the fertilization of the eggs. When multiple paternity was involved, the comparative reproductive success of the male parents was quite even. This is the first report of multiple paternity in the Norway lobster. Comparisons with other taxa are presented, and consequences of multiple paternity are discussed.

Animals↗
PubMed2003

Phenotype and genotype correlation of the microconversion from the CYP21A1P to the CYP21A2 gene in congenital adrenal hyperplasia.

Deficiency of 21-hydroxylase is the most common form of congenital adrenal hyperplasia (CAH-21OH). We determined by allele-specific PCR the frequency of microconversion in the CYP21A2 gene in 50 Brazilian patients with the classical (salt wasting: SW and simple virilizing: SV) forms and nonclassical (NC) form of CAH-21OH and correlated genotype with phenotype. Genotypes were classified into three mutation groups (A, B, and C) based on the amount of enzymatic activity in in vitro studies using adrenal cells. In 94 unrelated alleles, we diagnosed 76% of the affected alleles after screening for 7 microconversions. The most frequent point mutations observed in this series were I172N (19%), V281L (18%), and IVS2,A/C>G,-12 (15%). In the SW form, the most frequent mutation was IVS2,A/C>G,-12 (38%), in the SV form it was I172N (53%), and in the NC form it was V281L (57.7%). We observed a good correlation between genotype and phenotype. Discordance between genotype and phenotype was found in one SV patient with a mild mutation in one of the alleles (R356W/V281L). However, we cannot rule out the presence of an additional mutation in these alleles. We also observed a good correlation of genotype with 17alpha-hydroxyprogesterone, testosterone, and androstenedione levels. The severity of external genitalia virilization correlated with the severity of mutation. In conclusion, the frequencies described in the present study did not differ from worldwide studies, including the Brazilian population. The few differences observed may reflect individual sample variations. This new Brazilian cohort study suggests the presence of new mutations in Brazilian patients with different forms of CAH-21OH.

Adrenal Hyperplasia, Congenital↗
PubMed2003

Susceptibility and exposure biomarkers in people exposed to PAHs from diesel exhaust.

Xenobiotic metabolizing enzymes, especially CYP1A1 and GSTM1, are involved in the activation and conjugation of PAHs and are controlled by polymorphic genes. PAHs released from diesel emissions in many cities of the world, especially in developing countries, contribute significantly to the toxic effects of airborne inhalable particles. We have evaluated the gene-environment interaction in Santiago of Chile, studying the contribution of CYP1A1 and GSTM1 polymorphisms on 1-OH-P urinary levels used as the PAHs exposure biomarker. The study was performed on 59 diesel exposed (38 diesel revision workers and 21 subjects working in an urban area as established street vendors) and 44 non-exposed subjects living in a rural area. The 1-OH-P urinary levels of the urban (P=0.043) and rural (P=0.040) populations showed, without considering the genotypes, significant differences between smokers and non-smokers, but no significant differences were found between smokers and non-smokers among the diesel plant workers (P=0.33). Non-smoking subjects of the diesel plants and the urban area showed similar 1-OHP levels (P=0.466) which were significantly higher than those of the subjects living in the rural area (P<0.05). When 1-OH-P levels were related with genotypes, an association was observed for the CYP1A1*2A genotype, so that the diesel-exposed workers carrying the CYP1A1*2A allele showed significantly higher 1-OH-P levels than the subjects from the rural area with the same genotype (P=0.008). On the other hand, there was no significant correlation between urinary 1-OH-P levels and GSTM1 null genotype, although higher levels of the urinary metabolite were found in individuals carrying the combined CYP1A1*2A and GSTM1 null genotype (P=0.055). These results may suggest an association between levels of the exposure biomarker 1-OH-P and presence of the CYP1A1*2A genotype, a potential genetic susceptibility biomarker which might be useful in identifying individuals at higher risk among people exposed to high PAH levels in diesel exhaust.

Adult↗
PubMed2003

Evidence from d+Au measurements for final-state suppression of high-p(T) hadrons in Au+Au collisions at RHIC.

We report measurements of single-particle inclusive spectra and two-particle azimuthal distributions of charged hadrons at high transverse momentum (high p(T)) in minimum bias and central d+Au collisions at sqrt[s(NN)]=200 GeV. The inclusive yield is enhanced in d+Au collisions relative to binary-scaled p+p collisions, while the two-particle azimuthal distributions are very similar to those observed in p+p collisions. These results demonstrate that the strong suppression of the inclusive yield and back-to-back correlations at high p(T) previously observed in central Au+Au collisions are due to final-state interactions with the dense medium generated in such collisions.

Journal Article↗
PubMed2003

Narrowing of the balance function with centrality in Au+Au collisions at the square root of SNN = 130 GeV.

The balance function is a new observable based on the principle that charge is locally conserved when particles are pair produced. Balance functions have been measured for charged particle pairs and identified charged pion pairs in Au+Au collisions at the square root of SNN = 130 GeV at the Relativistic Heavy Ion Collider using STAR. Balance functions for peripheral collisions have widths consistent with model predictions based on a superposition of nucleon-nucleon scattering. Widths in central collisions are smaller, consistent with trends predicted by models incorporating late hadronization.

Journal Article↗
PubMed2003

Disappearance of back-to-back high-pT hadron correlations in central Au+Au collisions at sqrt[s NN ] =200 GeV.

Azimuthal correlations for large transverse momentum charged hadrons have been measured over a wide pseudorapidity range and full azimuth in Au+Au and p+p collisions at sqrt[s(NN)]=200 GeV. The small-angle correlations observed in p+p collisions and at all centralities of Au+Au collisions are characteristic of hard-scattering processes previously observed in high-energy collisions. A strong back-to-back correlation exists for p+p and peripheral Au+Au. In contrast, the back-to-back correlations are reduced considerably in the most central Au+Au collisions, indicating substantial interaction as the hard-scattered partons or their fragmentation products traverse the medium.

Journal Article↗
PubMed2003

Azimuthal anisotropy and correlations in the hard scattering regime at RHIC.

Azimuthal anisotropy (v(2)) and two-particle angular correlations of high p(T) charged hadrons have been measured in Au+Au collisions at sqrt[s(NN)]=130 GeV for transverse momenta up to 6 GeV/c, where hard processes are expected to contribute significantly. The two-particle angular correlations exhibit elliptic flow and a structure suggestive of fragmentation of high p(T) partons. The monotonic rise of v(2)(p(T)) for p(T)<2 GeV/c is consistent with collective hydrodynamical flow calculations. At p(T)>3 GeV/c, a saturation of v(2) is observed which persists up to p(T)=6 GeV/c.

Journal Article↗
PubMed2003

Circadian rhythm of hunger sensation in patients affected by cystic fibrosis.

OBJECTIVE: The aim of this study was to investigate the daily pattern of hunger sensation (HS) in patients affected by a non-advanced form of cystic fibrosis (CF) in order to detect how the orectic stimulus (OS) behaves in fibrocystic patients (FP) who are obliged to eat frequently because of their pancreatic exocrine insufficiency. MATERIALS AND METHODS: The study involved 27 out-patients (13 males and 14 females; mean age 18 +/- 4 years; mean BMI 18.77 +/- 2.17 kg/m2) with a non-advanced form of CF, and 19 clinically healthy subjects (CHS, 9 males and 10 females; mean age 24 +/- 2 years; mean BMI 21.00 +/- 1.70 kg/m2). The FP were used to eating frequent small meals between the three main meals of breakfast, lunch and dinner. All of the participants were asked to compile an "orexigram"' which was chrono-biometrically analysed by means of: 1) conventional statistical methods; 2) rhythmometric analysis of circadian rhythm (CR); and 3) spectral analysis of the harmonic structure substantiating the within-day variability of HS. RESULTS: HS in FP had 1) a significantly increased daily mean level; 2) a well-established CR, with a significantly increased oscillatory mesor and amplitude; and 3) a modified orexigram power spectrum affecting the ultradian harmonic components. CONCLUSIONS: Our results suggest that the orectic perception of CF patients is characterised by "daily hyperorexia", with the maintenance of HS CR. This condition seems to be a structured abnormality insofar as there are visible changes in the orexigram spectral resolution, particular in the ultradian harmonic components whose oscillatory frequency is responsible for the diurnal pattern of HS. The hyperorexia of the investigated FP indicates that their frequent small meals are not sufficient to satisfy their HS, which may cause a vicious circle leading to progressively disrupted mealtime behaviour.

Activity Cycles↗
PubMed2003

Prevalence of liver complications in pediatric patients on home parenteral nutrition: indications for intestinal or combined liver-intestinal transplantation.

Parenteral nutrition (PN) is the only treatment for patients affected by chronic intestinal failure (CIF). Home parenteral nutrition (HPN) programs are started when patients need prolonged PN. Unfortunately, many patients on prolonged PN develop liver disease (LD). The aim of our study was to assess the prevalence of LD in our series of patients on HPN. We reviewed our records of patients discharged from the hospital on HPN for CIF. HPN was started when one parent was fully trained in the use of this treatment and if the social and familial home environment was reliable. All patients received total PN by a central venous catheter. All patients with abnormal AST, ALT, ALK, gammaGT, and bilirubin values for more than 3 months were considered affected by PN-related LD. Thirty-six patients (23 of whom were boys and 13 girls) were discharged on HPN. During the study period, for CIF, 16 were affected by short bowel syndrome (SBS), of whom 6 had ultra-short bowel; 16 with functional intestinal failure, and 4 with chronic intestinal pseudobstruction (CIPO). Mean duration of HPN was 2.1 years/patient. Nine of 36 patients (25%) on HPN for CIF showed LD. Seven of the 16 patients (43%) with LD were affected by SBS and 2 (12.5%) patients by functional intestinal failure. No patients with CIPO developed LD. In patients affected by SBS, the onset of LD was very earlier than in patients with ID.

Adult↗
PubMed2003

Complications of home parenteral nutrition in a large pediatric series.

When adequate nutrition cannot be provided by enteral route as a consequence of failure of intestinal functions, parenteral nutrition (PN) become the only way to maintain adequate nutrition; however, prolonged periods of PN can lead to severe complications. Furthermore, long hospital admissions for this form of nutrition can be detrimental for the child and the family. In the past 20 years, home parenteral nutrition (HPN) programs have been developed. The aim of our study was to retrospectively evaluate the kind and the frequency of complications in a HPN pediatric case series. We had 61 patients on HPN. Total duration of the program was 27,740 days (76 total years, mean 1.2 years per patient). We observed a total of 58 complications; mean 0.79 per patient per year with a prevalence of central venous catheter-related complications (mechanical, 52%; infective, 26%). We had a very low incidence of metabolic complications (3%) and a low incidence of PN-related hepatic complications (19%). None of the complications described was the cause of death. Half of our patients have been able to stop the program. We had a low incidence (0.20 per patient per year) of septic episodes, lower than we had in patients on hospital PN in the same period (0.38 per patient per year). We had to replace 20 catheters, 18 of them for mechanical problems. Our study shows that HPN still can be a valid alternative to small intestinal transplantation in patients affected by intestinal failure and that only patients with PN-related liver disease must be considered early candidates for combined liver-small bowel transplant.

Adolescent↗
PubMed2003

Intractable diarrhea of infancy with congenital intestinal mucosa abnormalities: outcome of four cases.

Microvillous inclusion disease (MID) and epithelial dysplasia (ED) or tufting enteropathy are the most frequent causes of intractable diarrhea with persistent villous atrophy and indefinite dependence on total parenteral nutrition (PN) from early infancy. Since these are intractable diseases, they have been proposed to be elective indication for early bowel transplantation in order to avoid complications, such as PN-related liver disease, that would require a combined small bowel-liver transplant. We describe four cases of intractable diarrhea, two with MID and two with ED, seeking to discover whether these diseases are really elective, early indications for bowel transplant. Among our four patients, only one with ED underwent transplantation. The prognosis of small bowel transplant is still poor and worse than that of prolonged HPN. Further study is necessary to achieve a safe HPN program. Referral for transplant (small bowel only or combined with liver) should be considered when there is a venous access reduction and/or severe and irreversible liver disease.

Diarrhea↗
PubMed2003

Serological status and abortion rate in progeny obtained by natural service or embryo transfer from Neospora caninum-seropositive cows.

Bovine neosporosis is an important disease in dairy herds in Argentina. Embryo transfer (ET) technology offers the opportunity to minimize vertical transmission of neosporosis. The objective of this work was to compare the serological status and the incidence of abortion between heifers obtained via natural service and heifers obtained by ET from Neospora-infected cows. Progeny from eight Neospora-infected cows belonging to a commercial dairy farm where ET was routinely performed were studied. Between 1996 and 2001, 16 and 15 heifers were obtained by natural service and ET, respectively. Serostatus and reproductive performance were recorded in both progeny. Serostatus was determined by indirect fluorescent antibody test (IFAT). All heifers obtained by natural service were seropositive and six of 16 pregnancies ended in abortion. All heifers obtained by ET were seronegative and only two abortions of 15 pregnancies were recorded.

Abortion, Veterinary↗
PubMed2003

Central tumour necrosis factor-alpha mediates the early gastrointestinal motor disturbances induced by lipopolysaccharide in sheep.

Cytokines are involved in fever and other symptoms of the acute phase response induced by endotoxins. The aim of this work was to study the involvement of central tumour necrosis factor-alpha (TNF-alpha) in the changes induced by lipopolysaccharide (LPS) on gastrointestinal (GI) motility in sheep. Body temperature and myoelectric activity of the antrum, duodenum and jejunum was recorded continuously. Intravenous (i.v.) administration of LPS (0.1 micro g kg-1)-induced hyperthermia, decreased gastrointestinal myoelectric activity and increased the frequency of the migrating motor complex (MMC). These effects started 40-50 min after LPS and lasted for 6-7 h. TNF-alpha (50 and 100 ng kg-1) mimicked these effects when injected intracerebroventricularly (i.c.v.) but not i.v. Pretreatment with soluble recombinant TNF receptor (TNFR:Fc, 10 micro g kg-1, i.c.v.) abolished the TNF-induced actions and reduced those evoked by LPS. Furthermore, the effects induced by either LPS or TNF were suppressed by prior i.c.v. injection of indomethacin (100 micro g kg-1). In contrast, the i.v. injections of TNFR:Fc or indomethacin were ineffective. Our data suggest that LPS disturbs GI motility in sheep through a central pathway that involves TNF-alpha and prostaglandins sequentially.

Animals↗
PubMed2003

Wortmannin enhances the induction of micronuclei by low and high LET radiation.

In mammalian cells, the repair of DNA double-strand breaks (DSBs) is mainly mediated by DNA non-homologous end joining. DNA-dependent protein kinase (DNA-PK), a nuclear serine-threonine kinase and a member of the phosphaditylinositol-3 kinase-related kinase family that is activated by DSBs, is a key component of this pathway. Wortmannin (WM) is known to be an irreversible and potent inhibitor of DNA-PK and has thus been proposed as an effective sensitizer for ionizing radiation and for radiomimetic compounds. The present study, using the cytokinesis block micronucleus assay, reports on the differential effect of WM on the repair of the DNA damage induced by low LET ((60)Co gamma-radiation) and high LET radiation by the boron neutron capture reaction (alpha and Li particles) in V79 Chinese hamster cells. Significant increases in the number of micronuclei per binucleated cell as well as in the frequency of micronucleated binucleated cells were observed in the presence of different concentrations of WM for high LET radiation from the boron neutron capture reaction. The increases observed reached a maximum of approximately 2-fold in comparison with the respective controls. WM, however, had a more pronounced effect on (60)Co gamma-radiation-induced micronuclei, increasing the genotoxic damage from this radiation by approximately 3- to 4-fold. These results are in general in agreement with the concept that DSBs induced by high LET radiation are not a more suitable substrate for the end joining processes mediated by DNA-PK, yet they do not preclude a role for DNA-PK in high LET-induced damage repair.

Alpha Particles↗
PubMed2003

Gastric electric activity assessed by electrogastrography and gastric emptying scintigraphy in adolescents with eating disorders.

BACKGROUND: Patients with eating disorders can refer to a variety of gastrointestinal symptoms, sometimes to justify reduced food intake and vomiting. The authors investigated whether adolescent patients with eating disorders and dyspeptic symptoms have altered gastric electric activity and abnormal gastric emptying as assessed respectively by electrogastrography and scintigraphy. METHODS: Twenty-eight patients (18 with anorexia and 10 with bulimia) and 16 healthy volunteers underwent electrogastrography; 20 of the 28 patients (14 with anorexia and 6 with bulimia) underwent gastric emptying scintigraphy. Electrogastrography with bipolar recording lasted 1 hour, 30 minutes before and after a standard meal. Before gastric emptying scintigraphy, patients fasted overnight; during testing, they ingested a solid meal labeled with technetium-99m sulfur colloid. The ratio of fasting to postprandial electrogastrographic variables was evaluated using the Wilcoxon matched-pair test. The Mann- Whitney test was used to compare absolute values for electrogastrographic data in each group. The Student paired t test was used to compare scintigraphic results expressed as percentage of gastric emptying at 60 minutes and as the gastric emptying time (T(1/2)). RESULTS: Patients with bulimia significantly differed from those with anorexia and control subjects regarding the amount of normal gastric electric activity and bradygastria, and from patients with anorexia only regarding tachygastria. These electrogastrographic variables did not differ significantly between patients with anorexia and control subjects. Gastric emptying time (T(1/2)) was significantly longer in patients with bulimia than in those with anorexia. CONCLUSIONS: Adolescent patients with bulimia who complain of dyspeptic symptoms have documentable abnormalities of gastric electric activity and emptying, whereas their counterparts with anorexia, probably owing to their shorter disease duration, do not.

Adolescent↗