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Biomedical subjects

M Costa

Publications and source records attributed to M Costa.

At least 37 records · Page 2Linked to original sources
PubMed2004

Flexible treatment of gestational diabetes modulated on ultrasound evaluation of intrauterine growth: a controlled randomized clinical trial.

OBJECTIVES: In order to prevent abnormalities of fetal growth still characterizing pregnancies complicated by Gestational Diabetes (GDM), in the present study we evaluated a therapeutic strategy for GDM based on ultrasound (US) measurement of fetal insulin-sensitive tissues. METHODS: All GDM women diagnosed before 28th week immediately started diet and self-monitoring of blood glucose; after 2 weeks they were randomized to conventional (C) or modified (M) management. In C the glycemic target (GT) was fixed at 90 fasting/120 post-prandial mg/dl; in M GT varied, according to US measurement of the Abdominal Circumference (AC) centile performed every 2 weeks: 80/100 if AC > or =75th, 100/140 if AC<75th. Therapy was tailored to mean fasting (FG) and postprandial glycemia (PPG). RESULTS: Globally, 229 women completed the study, 78 in C, 151 in M. Use of insulin was 16.7% in C, 30.4% in M (total groups), significantly more frequent in M than in C (59.7% vs 15.4%) when considering only women with AC > or =75th c. Mean metabolic data were similar in the 2 groups, but in M a tightly-optimized subgroup, resulting from the lowering of GT due to AC > or =75th, coexisted with a less-controlled one, whose higher GT was justified by AC<75th. Pregnancy outcome was better in M, with lower (p<0.05*) rate of LGA* (7.9% vs 17.9%), SGA (6.0% vs 9.0%) and Macrosomia* (3.3% vs 11.5%). CONCLUSIONS: Our data show the value of a flexible US-based approach to the treatment of GDM. This model does not necessarily involve a generalized aggressive treatment, allowing to concentrate therapeutical efforts on a small subgroup of women showing indirect US evidence of fetal hyperinsulinization. Such a selective approach allowed to obtain a near-normalization of fetal growth, with clear advantages on global pregnancy outcome.

Adult↗
PubMed2004

Sperm aneuploidy and recurrent pregnancy loss.

Experiments of double target in-situ hybridization were performed separately for chromosomes 1-17, 8-18 and sex chromosomes on sperm samples from 20 couples suffering from three or more recurrent first trimester abortions. For a subset of this study population, additional experiments of multicolour fluorescence in-situ hybridization for chromosomes 4, 7, 12, 13, 15, 18, 21, and 22, were performed on the bases of the available data from abortive tissue karyotyping. A markedly high rate of sperm disomy (14.5-15.5%) was scored in only two cases. For three other patients, the cumulative disomy rates for chromosomes 1, 17, 8, 18, X and Y also increased but at a lower level (7.8-9.5%). For the remaining 15 patients, the frequency of sperm aneuploidy was moderately increased or normal. Men with recurrent pregnancy loss (RPL) and poor semen quality had baseline sperm aneuploidy and diploidy rates higher than men with normal semen parameters (with or without RPL). Using probes for chromosomes 1, 17, 8, 18, X and Y, significantly elevated frequencies of sperm aneuploidy (not diploidy) were found in 10% of men with a history of RPL. Their rate of sperm aneuploidy was 30-34%. For the other men, changes in sperm aneuploidy were not thought to affect RPL. Poor semen quality per se impacted negatively on sperm aneuploidy and diploidy, thus making the interpretation of clinical data more difficult.

Abortion, Habitual↗
PubMed2004

Flavonoids from Achyrocline satureioides with relaxant effects on the smooth muscle of Guinea pig corpus cavernosum.

Ethanol extract of the aerial parts of Achyrocline satureioides (Lam.) DC. (Asteraceae) showed a significant, dose dependent, relaxant effect on the smooth muscle of corpus cavernosum strips, obtained from Guinea pig (65.5 +/- 4.1% of relaxation at the dose of 25.0 mg/ml). Bioassay guided fractionation of this extract furnished two flavonoids, quercetin and quercetin 3-methyl ether, with important vasorelaxing effects on the corpus cavernosum strips (79.8 +/- 8.4 and 66.0 +/- 4.8% of relaxation respectively at the dose of 0.075 mg/ml). Two methyl derivatives of quercetin obtained by synthesis, quercetin 3,7,3',4'-tetramethylether and quercetin 3,5,7,3',4'-pentamethylether, showed similar relaxant effects at the dose of 0.075 mg/ml (86.4 +/- 8.5 and 67.31 +/- 1.4% of relaxation respectively). The results show that the ethanol extract of A. satureioides and the assayed compounds exhibit significant vasorelaxing properties. Additionally, it is shown that the number of methyl groups in the quercetin nucleus has no significant influence on the effectiveness of these compounds.

Animals↗
PubMed2004

Enteric motor and interneuronal circuits controlling motility.

The enteric nervous system regulates intestinal motility. It contains intrinsic sensory neurones, several types of interneurones and excitatory and inhibitory motor neurones. This review summarizes our knowledge of motor neurones and interneurones in simple motility reflex pathways (ascending and descending excitation, descending inhibition) and it focuses on guinea-pig ileum. Excitatory circular muscle motor neurones contain choline acetyltransferase (ChAT) and tachykinins and project orally 0.5-10 mm. They transmit via muscarinic acetylcholine receptors and tachykinins acting at NK1 and NK2 receptors. Inhibitory circular muscle motor neurones contain nitric oxide synthase (NOS), vasoactive intestinal peptide (VIP) and pituitary adenylyl cyclase activating peptide (PACAP), project anally up to 25 mm and transmit via ATP, nitric oxide and/or VIP. Ascending interneurones project up to 10 mm orally and contain ChAT and tachykinins. They transmit to each other via ACh at nicotinic receptors (nAChR), but to excitatory motor neurones via both nAChR and NK3 receptors. There are at least three types of descending interneurones and one transmits to inhibitory motor neurones via ATP acting at P2X receptors. NOS-containing descending interneurones receive input via P2Y receptors from other interneurones. Transmission to and from the other descending interneurones (ChAT/5-HT, ChAT/somatostatin) is yet to be characterized.

Animals↗
PubMed2004

How many kinds of visceral afferents?

Most afferent signals from the viscera do not give rise to conscious experience and yet they participate in the complex neural control of visceral functions. Surprisingly little information is available on the origin, morphology, and receptor functional characteristics of the nerve endings of most primary afferent neurones to the digestive tract. This review deals with the morphological nature of the afferent neurones that supply the gastrointestinal tract specifically.

Animals↗
PubMed2004

Body size and flight distance in stingless bees (Hymenoptera: Meliponini): inference of flight range and possible ecological implications.

We examined the spatial implications of maximum flight distance for several species of stingless bees. Data suggested that maximum flight distance in Meliponini is a function of body size, especially generalized wing size, which can be estimated through principal component analysis. For six species of stingless bees, flight distances and generalized wing sizes were highly correlated (r = 0.938). This indicates that species of Meliponini occupy an effectively larger area as body size increases, which has important implications in the spatial dynamics of local populations restricted to forest fragments. We also used the fitted linear regression model to estimate the maximum flight distance for 12 other species of Meliponini. The results of this research may provide insights for future studies of biological conservation.

Animals↗
PubMed2003

Effects of a bacteriocin-like inhibitory substance from Carnobacterium piscicola against human and salmon isolates of Listeria monocytogenes.

The aim of this study was to characterize the antagonism of a bacteriocin-like inhibitory substance (BLIS) produced by Carnobacterium piscicola L103 against Listeria monocytogenes strains isolated from salmon and human samples. The inhibitory effect of the BLIS was evaluated in Tryptic soy agar (TSA) during different growth phases of L. monocytogenes at 5 degrees C, using the well diffusion method. Also, the type of inhibition, either bacteriostatic or bactericidal of the BLIS in Tryptic soy broth (TSB), was studied and the development of resistant cells investigated. Results showed an antagonistic effect of the BLIS on all the strains of L. monocytogenes. Four selected strains presented a higher sensitivity to the BLIS in the exponential growth phase and were more resistant in the stationary phase. In TSB, the inhibitory substance showed a partially bactericidal effect on L. monocytogenes. After inactivation of the BLIS with a protease, however, a regrowth of L. monocytogenes was found. The isolate most affected by the action of the BLIS was one of salmon origin. From the 86 isolated colonies that grew in the presence of the BLIS, 93% showed total resistance and 7% partial resistance, which was maintained through five consecutive culture cycles in the absence of the BLIS.

Animals↗
PubMed2003

Safety and efficacy of laparoscopic radiofrequency ablation of hepatocellular carcinoma in patients with liver cirrhosis.

BACKGROUND: The optimal treatment for hepatocellular carcinoma (HCC) is surgical resection. However, only a small percentage of patients are operative candidates. Percutaneous radiofrequency interstitial thermal ablation (RITA) has been shown to be efficacious in the treatment of unresectable HCC. Recent advances in laparoscopic ultrasound have greatly improved the accuracy in detecting intrahepatic HCC nodules, many of which were missed by computed tomography. Our objective was to introduce a novel operative combination of laparoscopic ultrasound with laparoscopic RITA in the treatment of HCC. METHODS: Eighty-eight patients with HCC in liver cirrhosis were submitted to laparoscopic RITA under sonographic guide. Most patients were in Child's A class of liver function. Patients with large tumors (> 5 cm), portal vein thrombosis, or severe liver disease (Child's C class) were excluded. RESULTS: The laparoscopic RITA procedure was completed in 86 of 88 patients (98% feasibility rate). Laparoscopy with laparoscopic ultrasound identified 23 new malignant lesions (27%) in comparison with the results of preoperative imaging. A total of 127 lesions were treated by RITA. There was no operative mortality. Sixty-one patients had no complication (71%). After a mean follow-up of 14.3 +/- 11.6 months, a complete response with a 100% necrosis was achieved in 70 of 83 patients examined (86%). During follow-up, 9 patients (11%) locally recurred at the RITA site and 38 patients (46%) had new malignant nodules. CONCLUSIONS: Laparoscopic RITA of HCC proved to be a safe and effective technique in the short term. This technique may be indicated when the percutaneous approach to the lesion is very difficult or if the patient is too ill to undergo laparotomy.

Adult↗
PubMed2003

Argentinian plant extracts with relaxant effect on the smooth muscle of the corpus cavernosum of guinea pig.

Extracts of different polarity from Baccharis trimera, Haplopappus rigidus Huperzia saururus, Maytenus ilicifolia, Satureja parvifolia and Senecio eriophyton were tested for their relaxant activity on smooth muscle using L-phenylephrine precontracted strips of corpus cavernosum obtained from Guinea pigs. Highly significant and dose dependent results were obtained with the dichloromethane extracts of H. saururus (87% of relaxation at the dose of 10 mg/ml), S. parvifolia (95% of relaxation at 2.5 mg/ml) and S. eriophyton (94% of relaxation at 5 mg/ml). Similar effects were observed with the methanol extracts of H. saururus (88% of relaxation at 10 mg/ml) and S. parvifolia (84% of relaxation at 10 mg/ml). These results were comparable to those obtained with the dichloromethane and methanol extracts of the well known Mexican species Turnera diffusa. Moreover, the aqueous extract of H. rigidus and the aqueous and methanol extracts of S. eriophyton were highly effective in a dose dependent manner (more than 90% of relaxation at the dose of 10 mg/ml). Significant results, but with a lower overall relaxant activity (about 70% of relaxation at 10 mg/ml), could also be obtained with the aqueous extract of S. parvifolia and with the dichlormethane and methanol extracts of B. trimera and M. ilicifolia. The positive controls with Sildenafil citrate at doses ranging from 0.35 to 35 microg/ml yielded moderate effects (up to 46% of relaxation at 35 microg/ml). The effects observed in the present study seem to validate the folk medicinal use of the tested plants and open new ways in the search for natural products with vasodilatory effects.

Animals↗
PubMed2002

Molecular mechanisms of nickel carcinogenesis.

Humans are exposed to carcinogenic nickel (Ni) compounds both occupationally and environmentally. In this paper, molecular mechanisms of nickel carcinogenesis are considered from the point-of-view of the uptake of nickel sulfide particles in cells, their dissolution and their effects on heterochromatin. Molecular mechanisms by which nickel induces gene silencing, DNA hypermethylation and inhibition of histone acetylation, will be discussed.

Acetylation↗
PubMed2002

Simultaneous HPLC determination of 5-fluorouracil and its metabolites in plasma of cancer patients.

5-Fluorouracil (5-Fu) is a commonly used anticancer agent for treatment of solid tumours. Certain studies have reported conflicting results between individual plasma concentration levels and toxicity or therapeutic effects. For this reasons some authors proposed to evaluate the plasma levels of 5-Fu metabolites 5-fluorouridine, 5-fluoro-2'-deoxyuridine and 5-fluoro-5,6-dihydro-uracil. The aim of the present work is to develop and validate a new HPLC method simultaneously determining 5-fluorouracil and its three metabolites, to be used to study the plasma levels, therapeutic effects and toxicity in cancer patients. The analytes were separated on a 4.6 x 250 mm ODS1 (5 micro m) not end-capped column, operating at room temperature. Elution was performed under isocratic conditions, employing a 1.5 mM K(3)PO(4) mobile phase (pH 5). 5-Bromo-5,6-dihydro-uracil was used as internal standard. The limits of quantitation were 0.5 micro g/mL for 5-fluorouracil, 1 micro g/mL for 5-fluoro-5,6-dihydro-uracil, 3 micro g/mL for 5-fluoro-2'-deoxyuridine and 5-fluorouridine; the stability, recovery, linearity, accuracy and specificity of the compounds were evaluated according to the criteria widely accepted. Using this method we measured plasma samples of 18 cancer patients treated with folinic acid (100 mg/m(2)) by intravenous administration, followed by an i.v. bolus of 5-Fu (400 mg/m(2)). The concentration levels of 5-fluorouracil and for 5-fluoro-5,6-dihydro-uracil were detectable in all the subjects while 5-fluorouridine and 5-fluoro-2'-deoxyuridine were present only in eight patients.

Antimetabolites, Antineoplastic↗
PubMed2002

Total and methylmercury in a Brazilian estuary, Rio de Janeiro.

Guanabara Bay, in Rio de Janeiro state, is impacted by organic matter, oil and heavy metals. The present study evaluated the total mercury (THg) and methylmercury (MeHg) concentrations and the MeHg to THg ratio (%MeHg) in water samples from different points of the bay and in 245 organisms of three different trophic levels sampled between 1990 and 2000. Dissolved mercury concentration in estuarine water samples ranged from 0.72 to 5.23 ngl(-1). THg and MeHg in mussel, ranging from 11.6 to 53.5 microg THg kg(-1) wet wt. and 4.5-21.0 microg MeHg kg(-1) wet wt., varied according to sampling point and water quality. Planktivorous fish and mussel presented similar MeHg concentrations, meanwhile THg in planktivorous fish were lower than in mussel. Carnivorous fish showed higher THg and MeHg concentrations (199.5 +/- 119.3, 194.7 +/- 112.7 microg kg(-1) wet wt. respectively) than organisms from other feeding habits and lower trophic levels. There was a significant difference in the %MeHg among trophic levels: mussel presented lower MeHg percentage (33%) than planktivorous fish (54%) and carnivorous fish (98%).

Animals↗
PubMed2002

Enhanced expression of a novel protein in human cancer cells: a potential aid to cancer diagnosis.

Cap43 is a protein whose RNA is induced under conditions of severe hypoxia or prolonged elevations of intracellular calcium. Cap43 protein is expressed at low levels in normal tissues; however, in a variety of cancers, including lung, brain, melanoma, liver, prostate, breast, and renal cancers, Cap43 protein is overexpressed in cancer cells. The low level of expression of Cap43 in some normal tissues compared to their cancerous counterparts combined with the high stability of Cap43 protein and mRNA makes the Cap43 gene a new, important cancer marker. We hypothesize that the mechanism of Cap43 overexpression in cancer cells involves a state of hypoxia characteristic of cancer cells where the Cap43 protein becomes a signature for this hypoxic state.

Blotting, Western↗
PubMed2002

Semen analysis following allogeneic bone marrow transplantation. Additional data for evidence-based counselling.

Knowledge of the impact of different conditioning regimens used in bone marrow transplantation on spermatogenesis is important in pre-BMT counselling for three reasons: (1) Most young patients who have not had children are concerned with their subsequent fertility; (2) For a number of diseases there are competing therapeutic options that may affect spermatogenesis more or less seriously; (3) Since spontaneous recovery of spermatogenesis is rare, it would be necessary to offer cryopreservation as soon as possible after diagnosis and prior to any treatment. This retrospective study evaluates 99 semen samples obtained in 64 patients who underwent BMT between 1982 and 1996. Recovery of spermatogenesis was observed in 90% of patients conditioned with cyclophosphamide (CY), in 50% of patients with CY plus busulphan (BU) or thiotepa and in 17% of patients with CY plus total body irradiation (TBI) or thoracoabdominal irradiation (TAI). Sperm quality following CY was within the normal range (WHO) in the majority of patients, whereas it was consistently severely impaired in patients who received irradiation or two alkylating agents. Following CY, spermatogenesis recovery was observed in 60% of patients tested 1 year post transplant and it was accomplished within the third year in 80% of cases. Following CY + TBI/TAI recovery of spermatogenesis never occurred before the 4th year post transplant and was demonstrated as late as 9 years in one patient who was azoospermic 1 year earlier. No statistical correlation between age and recovery of spermatogenesis could be demonstrated. The overall high incidence of azoospermia (70.3%) supports the indication for semen cryopreservation in young patients undergoing BMT. These results have implications for semen sample timing before and after BMT and underline a need to collect further data through prospective multi-center studies.

Adolescent↗
PubMed2002

T-cell reactivity to glutamic acid decarboxylase in stiff-man syndrome and cerebellar ataxia associated with polyendocrine autoimmunity.

Antibodies to glutamic acid decarboxilase (GAD-Abs) are present in the serum of 60-80% of newly diagnosed type 1 diabetes (DM1) patients and patients with autoimmune polyendocrine syndrome (APS) associated with DM1. Higher titre of GAD-Abs are also present in the serum of 60% of patients with stiff-man syndrome (SMS) and all reported patients with cerebellar ataxia associated with polyendocrine autoimmunity (CAPA). Several studies suggest that GAD-Abs may play a critical role in the pathogenesis of SMS and CAPA but little is known about T-cell responsiveness to GAD-65 in these neurological diseases. To analyse cell-mediated responses to GAD, we studied the peripheral blood lymphocyte proliferation and cytokine responses to recombinant human GAD-65 in 5 patients with SMS, 6 with CAPA, 9 with DM1, 8 with APS and 15 control subjects. GAD-65-specific cellular proliferation was significantly higher in SMS than in CAPA, DM1, APS or controls. In contrast, only T cells from CAPA patients showed a significantly high production of interferon-gamma after GAD stimulation, compared to all other patients and controls. No differences were found for IL-4 production. These results suggest that, despite similar humoral autoreactivity, cellular responses to GAD are different between SMS and CAPA, with a greater inflammatory response in CAPA, and this difference may be relevant to the pathogenesis of these diseases.

Adolescent↗
PubMed2002

Video-based spatio-temporal maps for analysis of gastric motility in vitro: effects of vagal stimulation in guinea-pigs.

Our aim was to evaluate topographically specific gastric motility changes induced by graded vagal activation. A recently developed method of constructing spatio-temporal maps of motility from video movies was adapted to the in vitro perfused guinea-pig stomach with an intact vagal nerve supply. In the unstimulated preparation, spontaneous activity was low or absent. Bilateral vagal stimulation with frequencies as low as 0.2 Hz triggered weak anally, and in some cases orally, propagating antral contractions at rates of about 5-6 min-1. Upon stimulation with higher frequencies, antral contractions increased significantly in length (starting more proximally) and amplitude, and produced large pressure peaks of up to 25 hPa, with maximal effects at 2-4 Hz. In contrast, the speed of propagation and the interval between peristaltic waves did not change with vagal stimulation at any frequency. Vagal stimulation also produced a significant and frequency-dependent enlargement of the fundus with a maximal effect at 4 Hz. It is concluded that a very low tonic vagal activity is apparently necessary and sufficient to express basic antral motility, while more sustained vagal activity is necessary for high-amplitude gastric contractions and significant sustained fundic relaxation. The constant interval between propagating contractions supports the concept that vagal input impinges on intrinsic enteric neural circuits that have a modulatory role in the myogenic mechanism underlying slow-wave peristalsis, rather than directly on gastric musculature.

Animals↗
PubMed2002

The relevance of continuity of care: a solution for the chaos in the emergency services.

BACKGROUND: In Brazil, there continues to be an excessive use of emergency services by patients with elective medical problems. Those patients who report having a primary care physician are less likely to utilize the emergency department for non-urgent consultations. OBJECTIVE: The objective of this study was to compare patients who have a primary care physician with those who do not in relation to severity of their chief complaint at presentation in the emergency department. METHODS: The study was carried out as a cross-sectional interview-based survey at the Conceição Hospital Emergency Service in Porto Alegre (Brazil). The sample was 553 patients selected through a systematic random sampling, and the response rate was 88%. The data entry and analysis were performed using the software Epi-info, EGRET and SPSS. The analysis included simple statistics to determine the prevalence of the conditions being investigated and the effect of independent variables (regular doctor) in relation to the dependent variable (severity of disease) through logistic regression. RESULTS: The chief complaints were divided up as follows: 15% emergency cases, 46% urgent cases and 39% elective. The chief complaint was defined as urgent or emergency if it exhibited a significantly statistical association with the following independent variables, after being analysed by a logistic regression model: patients who reported having a primary care physician [odds ratio (OR) = 2.98, 95% confidence interval (CI) = 1.84-4.80] and patients who usually go to the emergency room by car (OR = 2.67, 95% CI = 1.75-4.05). CONCLUSION: One strategy to reduce the number of non-urgent consultations at emergency rooms is to establish a close out-patient relationship between patients and physician. There is a need to optimize the health care of patients who have non-urgent problems but still seek the emergency department through strategies at the primary health care level-especially when continuous care is available-and where a comprehensive approach with an emphasis on prevention would stimulate better quality of care at a lower cost.

Brazil↗