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Biomedical subjects

L Castro

Publications and source records attributed to L Castro.

At least 19 recordsLinked to original sources
PubMed2006

Modular changes of cis-regulatory elements from two functional Pit1 genes in the duplicated genome of Cyprinus carpio.

The pituitary-specific transcription factor Pit1 is involved in its own regulation and in a network of transcriptional regulation of hypothalamo-hypophyseal factors including prolactin (PRL) and growth hormone (GH). In the ectotherm teleost Cyprinus carpio, Pit1 plays an important role in regulation of the adaptive response to seasonal environmental changes. Two Pit1 genes exist in carp, a tetraploid vertebrate and transcripts of both genes were detected by RT-PCR analysis. Powerful comparative analyses of the 5'-flanking regions revealed copy specific changes comprising modular functional units in the naturally evolved promoters. These include the precise replacement of four nucleotides around the transcription start site embedded in completely conserved regions extending upstream of the TATA-box, an additional transcription factor binding site in the 5'-UTR of gene-I and, instead, duplication of a 9 bp element in gene-II. Binding of nuclear factors was assessed by electro mobility shift assays using extracts from rat pituitary cells and carp pituitary. Binding was confirmed at one conserved Pit1, one conserved CREB and one consensus MTF1. Interestingly, two functional Pit1 sites and one putative MTF1 binding site are unique to the Pit1 gene-I. In situ hybridization experiments revealed that the expression of gene-I in winter carp was significantly stronger than that of gene-II. Our data suggest that the specific control elements identified in the proximal regulatory region are physiologically relevant for the function of the duplicated Pit1 genes in carp and highlight modular changes in the architecture of two Pit1 genes that evolved for at least 12 MYA in the same organism.

Animals↗
PubMed2005

Low temperature during winter elicits differential responses among populations of the Mediterranean evergreen cork oak (Quercus suber).

Populations of cork oak (Quercus suber L.) were assessed for seasonal and inter-population variability in, and temperature responses of, the ratio between light-induced variable and maximum fluorescence of chlorophyll, Fv/Fm, considered a surrogate for the maximum photochemical efficiency of photosystem II (PSII). Seedlings from 10 populations throughout the distribution range of Q. suber in the Mediterranean basin were grown in a common garden in central Spain. The Fv/Fm ratio of dark-adapted leaves was measured at dawn every month for 2 years. Air temperature was recorded at a nearby climatic station. During the summer, when maximum air temperatures reached 40 degrees C, there were no significant differences in Fv/Fm among populations, but significant differences were seen during the winter. In colder months, Fv/Fm ranged in all populations between 0.5-0.6 and 0.2-0.3 in 2001 and 2002, respectively. The variance explained by the population effect was greatest during winter months, especially in 2002, reaching a peak value of 10% when minimum air temperature was below -10 degrees C. Populations originating from warmer sites showed the largest decline in Fv/Fm between the end of 2001 and the beginning of 2002. Thus, a negative linear relationship was established between mean annual temperature at the population source and population mean Fv/Fm recorded in the coldest month in 2002 and normalized by the Fv/Fm spring measurement.

Cold Temperature↗
PubMed2005

Performance-costs evaluation for urban storm drainage.

The design process of urban stormwater systems incorporating BMPs involves more complexity unlike the design of classic drainage systems for which just the technique of pipes is likely to be used. This paper presents a simple decision aid methodology and an associated software (AvDren) concerning urban stormwater systems, devoted to the evaluation and the comparison of drainage scenarios using BMPs according to different technical, sanitary, social environmental and economical aspects. This kind of tool is particularly interesting so as to help the decision makers to select the appropriate alternative and to plan the investments especially for developing countries, with important sanitary problems and severe budget restrictions.

Cities↗
PubMed2005

Infectious diseases surveillance activities in the north of Portugal, during the EURO 2004 football tournament.

A European football tournament (EURO 2004) took place in Portugal, from the 12 June to the 4 July 2004. Portugal's Northern Regional Health Authority serves a population of 3.2 million people. This region hosted 12 matches, more than any other region. We describe the communicable disease surveillance activities in the region, during EURO 2004. Ten foodborne outbreaks, seven cases of meningococcal disease and one case of legionnaires disease, were detected. Visitors were not affected, furthermore, cases among residents seemed not to be influenced by the presence of thousands of visitors. A similar pattern has been observed at other mass gatherings where special surveillance activities were implemented. This does not reduce the importance of public health surveillance during such mass gatherings. Furthermore, evaluation of this special activities should be an opportunity to put, issues of communicable disease surveillance resources, priorities, organisation and training back on the agenda.

Communicable Diseases↗
PubMed2004

Clinical features of ten cases of osteopoikilosis.

A retrospective study was carried out of the ten cases of osteopoikilosis seen at this Orthopedic Unit over a 15-year period in order to determine the reasons why patients seek consultation, preliminary diagnosis, and associated lesions. Eight patients consulted for problems not related to the locomotor apparatus, and diagnosis was by chance; the other two presented joint pain. The preliminary diagnosis was osteoblastic metastasis in five patients and osteopoikilosis in the other five. None of the patients displayed skin or visceral involvement, but three presented bone alterations. Definitive diagnosis was made by measurement of biochemical markers of bone remodeling, radiography of both hands, and bone scan. Bone biopsy was performed in one case. Although rare, the radiographic symptoms of osteopoikilosis are sufficiently specific to avoid false diagnoses, which may give rise to rigorous and expensive studies for other important disorders.

Adult↗
PubMed2004

[Voluminous hypothalamic hamartoma in a 5-month-old boy: Epilepsy and surgery].

The authors report the case of 5-month-old boy with a hypothalamic hamartoma and persistent gelastic seizures in spite of a wide combination of different antiepileptic drugs. It was decided to carry out only partial removal of the tumor for decompression and to decreasing the activity of the epileptogenic focus. Surgical therapy revealed as a valid option in the treatment of the uncontrollable gelastic seizures.

Anticonvulsants↗
PubMed2004

Plasma retinol concentration according to pubertal maturation in school children and adolescents of Medellín, Colombia.

AIM: To describe plasma retinol values according to age, gender and pubertal maturation. TYPE OF STUDY: Comparative, transverse and descriptive. PLACE: Medellín, Colombia. SUBJECTS AND METHODS: Plasma retinol values were determined in 588 boys and 531 girls aged between 6 and 18 y. For this, we used spectrophotometry by UV oxidation of retinol, results below 0.87 mmol/l were confirmed by high-performance liquid chromatography. RESULTS: Mean retinol plasma concentrations were slightly higher in girls under 10 y. However, above this age, values are generally higher in boys. Plasma retinol concentrations increased with pubertal maturation in both boys and girls in a statistically significant manner. The highest values were observed in girls with mammary development grades 3 and 4 (P<0.05) and in boys with external genitalia development grades 1 and 2 (P<0.05). Vitamin A deficiency based on plasma retinol concentration (<0.70 mmol/l), was observed in 3.6% of all individuals regardless of gender. CONCLUSIONS: Plasma retinol concentration is correlated to pubertal maturation in both boys and girls. Vitamin A deficiency in school children and adolescents of Medellín is not a major health problem.

Adolescent↗
PubMed2004

Infliximab induces clinical, endoscopic and histological responses in refractory ulcerative colitis.

BACKGROUND: infliximab is a monoclonal antiTNF-ct antibody that has repeatedly shown to be effective in the management of Crohn's disease. However, data are scarce about its efficacy in ulcerative colitis. AIM: to describe the joint experience of three Spanish hospitals in the use of infliximab in patients with active refractory ulcerative colitis. PATIENTS AND METHODS: we present seven cases of ulcerative colitis (6 with chronic active disease despite immunosuppressive therapy, and one with acute steroid-refractory ulcerative colitis) treated with infliximab 5 mg/kg of body weight. Clinical response was evaluated by means of the Clinical Activity Index at 2, 4 and 8 weeks after initial infusion. Biochemical (erythrocyte sedimentation rate and C-reactive protein), endoscopic, and histological changes were also assessed. RESULTS: mean age of patients was 45.8 +/- 17 years (range 23-77); 4 were female. No adverse effects were recorded. Inflammatory activity diminished significantly in 6 of 7 patients (85.7%; CI 95%: 42-99%) both from a clinical (p = 0.01) and biochemical (p <0.05) point of view. Five out of six patients (83.3%; 36-99%) with corticosteroid-dependent disease could be successfully weaned off these drugs. Five patients were endoscopicly controlled both before and after therapy, and a positive endoscopic and histological response could be recorded in all of them. CONCLUSION: infliximab may be an effective and safe therapy for some patients with ulcerative colitis refractory to other forms of therapy, although controlled studies are needed to assess its role in the general management of this disease.

Adult↗
PubMed2002

Central administration of mCPP, a serotonin 5-HT(2B/2C) agonist, decreases water intake in rats.

In the present study, we investigated in rats the effect of third ventricle injections of 1-(3-chlorophenyl)piperazine (mCPP), a 5-HT(2) receptor agonist, on water intake induced by three different physiological stimuli: fluid deprivation, acute salt load and hypovolemia. Injections of mCPP in the doses of 80 and 160 nmol/rat were able to decrease water intake in all three conditions studied. Third ventricle injections of mCPP (160 nmol/rat) were no longer able to diminish water intake in the groups of rats pretreated with central injections of an equimolar amount of (+)-cis-4,5,7a,8,9,10,11,11a-octahydro-7H-10-methylindolo[1,7-bc][2,6]-naphthyridine (SDZ SER 082), a selective 5-HT(2B/2C) antagonist. The central administration of mCPP (160 nmol/rat) was not able to modify the intake of a 0.1% saccharin solution. It is suggested that the central activation of a 5-HT(2B/2C) component is able to impair the drive for water intake induced by the physiological stimuli represented by fluid deprivation, acute salt load and hypovolemia. This effect seems not to be consequent on a general nonspecific central nervous system depression or on a locomotor deficit, because saccharin intake is not affected by third ventricle injections of mCPP.

Animals↗
PubMed2002

[Stereotactic brain biopsy: review of 80 cases. The need of ct-scan in the first hours].

OBJECTIVE: Evaluate the efficacy of the stereotactic brain biopsies performed in the Neurosurgery Department of the São João Hospital in order to diagnose intracerebral damage and to determine the existence of post-biopsy haemorrhage. METHODS: The authors evaluated 80 consecutive cases of patients submitted to a stereotactic brain biopsy. 63 of them had a control CT-scan from 4 to 6 hours after the proceeding. RESULTS: Stereotactic biopsy yield a conclusive diagnosis in 75 of the 80 patients which corresponds to 93.7% of the cases. Inconclusive results occurred in 5 patients (6.25%). Significant morbidity occurred in 4 cases (5%) and there was no mortality. Control CT-scan revealed no alterations in 25 patients and vestigial haemorrhage in 27. In the remaining 11 the haemorrhage was of little significance. CONCLUSIONS: Stereotactic biopsy is a safe and effective method to diagnose brain lesions. The realization of a control CT-scan within few hours after biopsy allows the identification of a sub-group of patients without intracerebral haemorrhage that may be discharged from hospital on the same day.

Adolescent↗
PubMed2002

[Predicting factors of vesicoureteral evolution in children].

BACKGROUND: Despite the large number of children with reflux, management among urologists is still controversial. One of the most debated aspects is the choice between observation treatment or surgical treatment. METHODS: We assessed the natural course of children with vesico-ureteral reflux in the period 1990-1995, to correlate factors and identify patients with high risk of renal damage. We retrospectively reviewed the clinical course of 80 children with vesicoureteral reflux. Thirty-two were diagnosed during prenatal ultrasound scan. In the other cases urologic evaluation was requested because of urinary tract infections. The following data were analyzed: medical records, diagnostic and follow-up cystogram, renal imaging, medical therapy or surgical treatment carried out according to the reflux grade, diagnostic age, congenital reflux nephropathy or postnatal acquired scarring, voiding patterns, spontaneous resolution during medical management. Follow up ranged from 5 to 10 years. RESULTS: Vesicoureteral reflux resolved spontaneously in 29 patients: 25 were affected from moderate reflux, 4 from IV grade reflux. Surgical correction was carried out in 32 patients. Endoscopic treatment was performed in 25. Twenty-two children are still receiving prophylaxis and 12 were lost to follow-up. Congenital renal pathology correlate with poor outcome. CONCLUSIONS: The conclusion is drawn that there is a wide clinical variability in children with vescicoureteral reflux. The most important is host's susceptibility to urinary tract infection, but the severity of reflux, age of patients and congenital reflux nephropathy influence prognosis and long-term outcome.

Child↗
PubMed2001

Reaction of peroxynitrite with Mn-superoxide dismutase. Role of the metal center in decomposition kinetics and nitration.

Manganese superoxide dismutase (Mn-SOD), a critical mitochondrial antioxidant enzyme, becomes inactivated and nitrated in vitro and potentially in vivo by peroxynitrite. Since peroxynitrite readily reacts with transition metal centers, we assessed the role of the manganese ion in the reaction between peroxynitrite and Mn-SOD. Peroxynitrite reacts with human recombinant and Escherichia coli Mn-SOD with a second order rate constant of 1.0 +/- 0.2 x 10(5) and 1.4 +/- 0.2 x 10(5) m(-)1 s(-)1 at pH 7.47 and 37 degrees C, respectively. The E. coli apoenzyme, obtained by removing the manganese ion from the active site, presents a rate constant <10(4) m(-)1 s(-)1 for the reaction with peroxynitrite, whereas that of the manganese-reconstituted apoenzyme (apo/Mn) was comparable to that of the holoenzyme. Peroxynitrite-dependent nitration of 4-hydroxyphenylacetic acid was increased 21% by Mn-SOD. The apo/Mn also promoted nitration, but the apo and the zinc-substituted apoenzyme (apo/Zn) enzymes did not. The extent of tyrosine nitration in the enzyme was also affected by the presence and nature (i.e. manganese or zinc) of the metal center in the active site. For comparative purposes, we also studied the reaction of peroxynitrite with low molecular weight complexes of manganese and zinc with tetrakis-(4-benzoic acid) porphyrin (tbap). Mn(tbap) reacts with peroxynitrite with a rate constant of 6.8 +/- 0.1 x 10(4) m(-)1 s(-)1 and maximally increases nitration yields by 350%. Zn(tbap), on the other hand, affords protection against nitration. Our results indicate that the manganese ion in Mn-SOD plays an important role in the decomposition kinetics of peroxynitrite and in peroxynitrite-dependent nitration of self and remote tyrosine residues.

Binding Sites↗
PubMed2001

Co-occurrence of aflatoxins B1, B2, G1, G2, zearalenone and fumonisin B1 in Brazilian corn.

Two hundred and fourteen unprocessed corn samples (1997-98 harvest), collected at wholesale markets in different regions in Brazil, were surveyed for the occurrence of mycotoxins. The samples were analysed for aflatoxins B1, B2, G1, G2, zearalenone and fumonisin B1 using in-house validated methods. The occurrence of aflatoxin B1, zearalenone and fumonisin B1 was found in 38.3, 30.4 and 99.1% of the samples, respectively. Aflatoxin B1, zearalenone and fumonisin B1 contamination levels varied from 0.2 to 129, 36.8 to 719, and 200 to 6100 microg/kg, respectively. The co-occurrence of the two carcinogenic mycotoxins aflatoxin B1 and fumonisin B1 was observed in 100% of the aflatoxin-contaminated samples (82 samples). Co-occurrences of aflatoxin B1: zearalenone: fumonisin B1 and aflatoxin B1: aflatoxin B2: fumonisin B1 were found in 18 and 43 samples, respectively.

Aflatoxin B1↗
PubMed2001

Endothelial transcytosis of myeloperoxidase confers specificity to vascular ECM proteins as targets of tyrosine nitration.

Nitrotyrosine formation is a hallmark of vascular inflammation, with polymorphonuclear neutrophil-derived (PMN-derived) and monocyte-derived myeloperoxidase (MPO) being shown to catalyze this posttranslational protein modification via oxidation of nitrite (NO(2)(-)) to nitrogen dioxide (NO(2)(*)). Herein, we show that MPO concentrates in the subendothelial matrix of vascular tissues by a transcytotic mechanism and serves as a catalyst of ECM protein tyrosine nitration. Purified MPO and MPO released by intraluminal degranulation of activated human PMNs avidly bound to aortic endothelial cell glycosaminoglycans in both cell monolayer and isolated vessel models. Cell-bound MPO rapidly transcytosed intact endothelium and colocalized abluminally with the ECM protein fibronectin. In the presence of the substrates hydrogen peroxide (H(2)O(2)) and NO(2)(-), cell and vessel wall-associated MPO catalyzed nitration of ECM protein tyrosine residues, with fibronectin identified as a major target protein. Both heparin and the low-molecular weight heparin enoxaparin significantly inhibited MPO binding and protein nitrotyrosine (NO(2)Tyr) formation in both cultured endothelial cells and rat aortic tissues. MPO(-/-) mice treated with intraperitoneal zymosan had lower hepatic NO(2)Tyr/tyrosine ratios than did zymosan-treated wild-type mice. These data indicate that MPO significantly contributes to NO(2)Tyr formation in vivo. Moreover, transcytosis of MPO, occurring independently of leukocyte emigration, confers specificity to nitration of vascular matrix proteins.

Animals↗
PubMed2001

Effect of the intracerebroventricular administration of GR 113808, a selective 5-HT4 antagonist, on water intake during hyperosmolarity and hypovolemia.

We demonstrate here that acute third ventricle injections of GR 113808, a highly selective 5-HT4 antagonist, decrease water intake induced by a previous salt load while potentiating drinking elicited by hypovolemia induced by previous subcutaneous administration of polyethylene glycol in male Wistar rats (200 +/- 20 g). At the dose of 160 nmol/rat, third ventricle injections of GR 113808 induced a significant reduction of water intake in salt-loaded animals after 120 min as compared to salt-loaded animals receiving third ventricle injections of saline (salt load + GR = 3.44 +/- 0.41 ml, N = 12; salt load + saline = 5.74 +/- 0.40 ml, N = 9). At the dose of 80 nmol/rat, GR 113808 significantly enhanced water intake in hypovolemic animals after 120 min as compared to hypovolemic animals receiving third ventricle injections of saline (hypovol + GR = 4.01 +/- 0.27 ml, N = 8; hypovol + saline = 2.41 +/- 0.23 ml, N = 12). We suggest that central 5-HT4 receptors may exert a positive drive on water intake due to hyperosmolarity and a negative input on drinking provoked by hypovolemia.

Animals↗
PubMed2000

Cytochrome c nitration by peroxynitrite.

Peroxynitrite (ONOO(-)), the product of superoxide (O(2)) and nitric oxide (.NO) reaction, inhibits mitochondrial respiration and can stimulate apoptosis. Cytochrome c, a mediator of these two aspects of mitochondrial function, thus represents an important potential target of ONOO(-) during conditions involving accelerated rates of oxygen radical and.NO generation. Horse heart cytochrome c(3+) was nitrated by ONOO(-), as indicated by spectral changes, Western blot analysis, and mass spectrometry. A dose-dependent loss of cytochrome c(3+) 695 nm absorption occurred, inferring that nitration of a critical heme-vicinal tyrosine (Tyr-67) promoted a conformational change, displacing the Met-80 heme ligand. Nitration was confirmed by cross-reactivity with a specific antibody against 3-nitrotyrosine and by increased molecular mass compatible with the addition of a nitro-(-NO(2)) group. Mass analysis of tryptic digests indicated the preferential nitration of Tyr-67 among the four conserved tyrosine residues in cytochrome c. Cytochrome c(3+) was more extensively nitrated than cytochrome c(2+) because of the preferential oxidation of the reduced heme by ONOO(-). Similar protein nitration patterns were obtained by ONOO(-) reaction in the presence of carbon dioxide, whereupon secondary nitrating species arise from the decomposition of the nitroso-peroxocarboxylate (ONOOCO(2)(-)) intermediate. Peroxynitrite-nitrated cytochrome c displayed significant changes in redox properties, including (a) increased peroxidatic activity, (b) resistance to reduction by ascorbate, and (c) impaired support of state 4-dependent respiration in intact rat heart mitochondria. These results indicate that cytochrome c nitration may represent both oxidative and signaling events occurring during .NO- and ONOO(-)-mediated cell injury.

Animals↗