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Biomedical subjects

A Monteiro

Publications and source records attributed to A Monteiro.

At least 19 recordsLinked to original sources
PubMed2001

The generation and diversification of butterfly eyespot color patterns.

BACKGROUND: A fundamental challenge of evolutionary and developmental biology is understanding how new characters arise and change. The recently derived eyespots on butterfly wings vary extensively in number and pattern between species and play important roles in predator avoidance. Eyespots form through the activity of inductive organizers (foci) at the center of developing eyespot fields. Foci are the proposed source of a morphogen, the levels of which determine the color of surrounding wing scale cells. However, it is unknown how reception of the focal signal translates into rings of different-colored scales, nor how different color schemes arise in different species. RESULTS: We have identified several transcription factors, including butterfly homologs of the Drosophila Engrailed/Invected and Spalt proteins, that are deployed in concentric territories corresponding to the future rings of pigmented scales that compose the adult eyespot. We have isolated a new Bicyclus anynana wing pattern mutant, Goldeneye, in which the scales of one inner color ring become the color of a different ring. These changes correlate with shifts in transcription factor expression, suggesting that Goldeneye affects an early regulatory step in eyespot color patterning. In different butterfly species, the same transcription factors are expressed in eyespot fields, but in different relative spatial domains that correlate with divergent eyespot color schemes. CONCLUSIONS: Our results suggest that signaling from the focus induces nested rings of regulatory gene expression that subsequently control the final color pattern. Furthermore, the remarkably plastic regulatory interactions downstream of focal signaling have facilitated the evolution of eyespot diversity.

Animals↗
PubMed2001

Phylogeny of Bicyclus (Lepidoptera: Nymphalidae) inferred from COI, COII, and EF-1alpha gene sequences.

Despite the fact that Bicyclus anynana has become an important model species for wing-pattern developmental biology and studies of phenotypic plasticity, little is known of the evolutionary history of the genus Bicyclus and the position of B. anynana. Understanding the evolution of development as well as the evolution of plasticity can be attempted in this species-rich genus that displays a large range of wing patterns with variable degrees of phenotypic responses to the environment. A context to guide extrapolations from population genetic studies within B. anynana to those between closely related species has been long overdue. A phylogeny of 54 of the 80 known Bicyclus species is presented based on the combined 3000-bp sequences of two mitochondrial genes, cytochrome oxidase I and II, and the nuclear gene, elongation factor 1alpha. A series of tree topologies, constructed either from the individual genes or from the combined data, using heuristic searches under a variety of weighting schemes were compared under the best maximum-likelihood models fitted for each gene separately. The most likely tree topology to have generated the three data sets was found to be a tree resulting from a combined MP analysis with equal weights. Most phylogenetic signal for the analysis comes from silent substitutions at the third position, and despite the faster rate of evolution and higher levels of homoplasy of the mitochondrial genes relative to the nuclear gene, the latter does not show substantially stronger support for basal clades. Finally, moving branches from the chosen tree topology to other positions on the tree so as to comply better with a previous morphological study did not significantly affect tree length.

Animals↗
PubMed2001

Butterfly eyespot patterns: evidence for specification by a morphogen diffusion gradient.

In this paper we describe a test for Nijhout's (1978, 1980a) hypothesis that the eyespot patterns on butterfly wings are the result of a threshold reaction of the epidermal cells to a concentration gradient of a diffusing degradable morphogen produced by focal cells at the centre of the future eyespot. The wings of the nymphalid butterfly, Bicyclus anynana, have a series of eyespots. each composed of a white pupil, a black disc and a gold outer ring. In earlier extirpation and transplantation experiments (Nijhout 1980a; French and Brakefield, 1995) it has been established that these eyespots are indeed organised around groups of signalling cells active during the first hours of pupal development. If these cells were to supply the positional information for eyespot formation in accordance with Nijhout's diffusion-degradation gradient model, then, when two foci are close together. the signals should sum, and this effect should be apparent in the detailed shape of the resulting pigment pattern. We give an equation for the form of the contours that would be obtained in this manner. We use this to test the morphogen gradient hypothesis on measurements of the outlines of fused eyespots obtained either by grafting focal cells close together, or by using a mutation (Spotty) that produces adjacent fused eyespots. The contours of the fused patterns were found to satisfy our equation, thus corroborating Nijhout's hypothesis to the extent possible with this particular type of experiment.

Animals↗
PubMed1999

Short-term intensive consolidation therapy after all-trans retinoic acid in acute promyelocytic leukemia.

Complete remission induced by all-trans retinoic acid (ATRA) in acute promyelocytic leukemia is short lived, and several consolidation chemotherapy courses usually are given to reduce the relapse rate. To assess the value of short-term intensive consolidation, 38 patients with newly diagnosed acute promyelocytic leukemia entered a prospective study in which induction therapy with ATRA immediately was followed by a single course of mitoxantrone plus high-dose cytarabine (3 g/m2 every 12 hours, days 1-4), with no further treatment. Complete remission was achieved in 31 patients (81.6%) after a median time of 49 days of ATRA (to which chemotherapy was added at entry in 10 patients with leukocytosis). Thirty patients received the planned consolidation course. After a median follow-up of 36 months, four of these patients have relapsed and 24 are still in first complete remission, for an estimated disease-free survival of 75% at 60 months. The authors conclude that this single course consolidation of ATRA-induced remission provides excellent long-term control of acute promyelocytic leukemia.

Adult↗
PubMed1999

Pharmacokinetics of enrofloxacin and danofloxacin in plasma, inflammatory exudate, and bronchial secretions of calves following subcutaneous administration.

Enrofloxacin (2.5 mg/kg of body weight) and danofloxacin (1.25 mg/kg) were administered subcutaneously to ruminating calves (n = 8) fitted with subcutaneous tissue cages. Concentrations of enrofloxacin, its metabolite ciprofloxacin, and danofloxacin in blood (plasma), tissue cage exudate (following intracaveal injection of 0.3 ml of 1% [vol/wt] carrageenan), and bronchial secretions were measured by high-performance liquid chromatography (HPLC) and microbiological assay (enrofloxacin plus ciprofloxacin and danofloxacin). Mean maximum concentrations (C(max)) +/- standard deviations of enrofloxacin (0.24 +/- 0.08 microg/ml), ciprofloxacin (0.11 +/- 0.03 [total, 0.34 +/- 0.10] microg/ml), and danofloxacin (0.23 +/- 0.05 microg/ml) were detected in the plasma of calves by HPLC. The C(max) were 0.49 +/- 0.17 microg/ml (enrofloxacin equivalents) and 0.24 +/- 0.03 microg/ml (danofloxacin) when they were measured by microbiological assay. Mean C(max) in exudate (HPLC) were 0.18 +/- 0.07 microg/ml (enrofloxacin), 0.10 +/- 0.04 microg/ml (ciprofloxacin), 0.27 +/- 0.09 microg/ml (enrofloxacin plus ciprofloxacin), and 0.19 +/- 0.05 microg/ml (danofloxacin), and concentrations in exudate exceeded those in plasma from 8 h (enrofloxacin and ciprofloxacin) or 6 h (danofloxacin) after drug administration. The C(max) were 0.34 +/- 0.09 microg/ml (enrofloxacin equivalents) and 0.22 +/- 0.04 microg/ml (danofloxacin) in exudate when they were measured by the microbiological assay. The maximum mean concentration achieved in bronchial secretions (HPLC) were 0.07 +/- 0.04 microg/ml (enrofloxacin), 0.04 +/- 0.07 microg/ml (ciprofloxacin), 0.10 +/- 0. 05 microg/ml (enrofloxacin plus ciprofloxacin), and 0.12 +/- 0.09 microg/ml (danofloxacin). The maximum mean concentration in bronchial secretions from a limited number of animals from which samples were available for microbiological assay were 0.27 +/- 0.11 microg/ml (n = 4 [enrofloxacin equivalents]) and 0.14 +/- 0.02 microg/ml (n = 3 [danofloxacin]). With predictive models of efficacy (C(max)/MIC and area under the concentration-time curve/MIC ratios in plasma) for Pasteurella multocida (MIC of enrofloxacin, 0.06 microg/ml [24]; MIC of danofloxacin, 0.06 microg/ml [6]), enrofloxacin produced scores of 8.17 and 52.00, respectively, compared to those of danofloxacin, which were 4.02 and 23.05, respectively. With the dosing rates recommended in some markets by manufacturers, enrofloxacin and danofloxacin achieved concentrations above the MICs for important pathogenic organisms in plasma, tissue cage exudate, and bronchial secretion. Since fluoroquinolones display concentration-dependent activities, C(max)/MIC ratios may be critical to efficacy. In the United States enrofloxacin is currently the only fluoroquinolone licensed for food animals and dosages for acute respiratory disease are 2.5 to 5 mg/kg for 3 days or 7.5 to 12. 5 mg/kg once. The higher dosages on a single occasion are likely to confer C(max)/MIC ratios that are associated with greater clinical efficacy.

Animals↗
PubMed1998

[Left ventricular filling in young patients with systemic lupus erythematosus in stable phase].

OBJECTIVE: The aim of this study was to evaluate the left ventricle filling pattern in patients with stable systemic lupus erythematosus (SLE). METHODS: This prospective study was performed in 22 healthy controls and in 24 patients with stable SLE. These two groups were submitted to a clinical, electrocardiographic and echocardiographic evaluation. RESULTS: Gender distribution and mean age were similar in both groups (p = NS). Patients with SLE were more symptomatic (21%) than control patients (0%) (p < 0.01). Left ventricular dimensions, wall thickness, and systolic function were not significantly different between the two groups. However, pericardial effusion was more frequently found in patients with SLE (21%) when compared to the control group (0%) (p < 0.05). When compared to the control group, patients with SLE showed an abnormal left ventricular filling pattern. Peak late mitral flow velocity was 0.45 +/- 0.2 m/sec in SLE patients and 0.36 +/- 0.1 m/sec in the control group (p = 0.001). CONCLUSION: These results demonstrate that patients with stable SLE, when compared to healthy controls, are frequently associated with cardiovascular symptoms, asymptomatic pericardial effusion, and an abnormal left ventricular filling pattern.

Adult↗
PubMed1998

[Changes in the geometry of the heart cavities in patients with cardiac tamponade undergoing pericardial drainage].

OBJECTIVES: The objective of our study was to evaluate the changes in cardiac chamber dimension--longitudinal and transversal axis--in patients with cardiac tamponade after drainage of the pericardial effusion. STUDY DESIGN: This is a five year retrospective study (from 1991 to 1995 inclusive) which evaluates patients with cardiac tamponade from a clinical and electrocardiographic, as well as echocardiographic, point of view. MATERIALS AND METHODS: Thirty-nine consecutive patients with cardiac tamponade were evaluated clinically and by ECG and two-dimensional echocardiography, before and after drainage of the pericardial effusion. The drainage was done by pericardiocentesis alone in 28 cases (72%), pericardiocentesis followed by surgery in seven cases (18%) and surgery alone in four cases (10%). MAIN RESULTS: After drainage we observed a reduction in the diameter of the pericardial effusion from 30.1 +/- 8 to 8.1 +/- 7 mm; the occurrence of jugular vein turgescence decreased from 87% to 5% (p < 0.001) and heart rate also decreased from 100 +/- 20 beats/minute to 79 +/- 17 beats/minute (p < 0.001). Systolic blood pressure increased from 107.8 +/- 20.4 mmHg to 134.6 +/- 20.3 mmHg (p < 0.001). All longitudinal and transversal diameters of the cardiac chambers increased after drainage. The greatest increase was observed in the transversal diameters of the right chambers. CONCLUSIONS: Cardiac tamponade affects both right and left cardiac chambers which are affected in their transversal as well as longitudinal diameters; the effect of compression was more marked in the right chambers and in the transversal diameters.

Adolescent↗
PubMed1998

Granulocyte-macrophage colony-stimulating factor in post-remission therapy of acute myeloid leukemia.

The impact on occult leukemia of GM-CSF as a sensitizing agent has not been studied. We treated 41 adult patients with de novo acute myeloid leukemia, 25 of whom achieved complete remission and were given 1 to 3 post-remission courses, each course including GM-CSF begun 4 days prior to chemotherapy and given until day 3. After a median follow-up of 32 months, the probability of remaining in continuous complete remission was 17% at 46 months. GM-CSF in this setting was not associated with an improved outcome, arguing against a priming effect.

Acute Disease↗
PubMed1998

[Hernia of the lumbar discs in persons at work. Results of a retrospective study in a series of 189 consecutive patients].

INTRODUCTION: Owing to recent advances in the diagnosis and treatment of lumbar disc pathology, the functional results obtained have improved, although there are still certain factors which affect this. The results in the work place are particularly problematic. OBJECTIVE: With the aim of finding an answer to the problem of relapse of the sciatica syndrome in patients operated on for hernia of the lumbar discs, we describe a study carried out in a consecutive group of patients who had had operations for hernias of lumbar discs whilst at work, within the context of revindication involved in this situation. PATIENTS AND METHODS: We describe the results obtained in a series of 189 patients who had been operated on for lumbar disc pathology. Conventional open surgery was performed in 105 cases. Percutaneous nucleotomy was done in the remainder. In 17.39%, operations were done at more than one level, making a total of 265 discs operated on. RESULTS: These were considered good when the patient returned to his former work. Good results were obtained in 72% of the patients treated by open surgery and 68% of those treated by percutaneous nucleotomy. The re-operation rate was 8.57% for open surgery and 32.14% for percutaneous nucleotomy (p < 0.05). CONCLUSIONS: The main reason for re-operation was a recurrence of disc protrusion. Good results were obtained in 80% of those reoperated. All reoperations were done using open surgery techniques. Overall assessment of the cases, including initial and re-operations, gave good results, reaching 83.59% in the current series.

Adult↗
PubMed1997

The genetics and development of an eyespot pattern in the butterfly Bicyclus anynana: response to selection for eyespot shape.

The normally circular eyespots on the wing of the butterfly Bicyclus anynana were selected to become elliptical in two divergent lines, with antero-posterior elongation of the eyespots in one line and proximodistal elongation in the other. Selection was continued for nine generations, and symmetrical realized heritabilities of approximately 15% were achieved initially. The elliptical eyespot shapes characteristic of each line were still produced when the signaling center of the eyespot (the focus) was surgically rotated by 90 or 180 degrees or when an eyespot was induced ectopically by localized damage. We conclude that selection changed general properties of the epidermis that responds to signals emanating from the eyespot focus but did not affect the mechanism of focal signaling.

Animals↗
PubMed1996

[Antihypertensive effect of fosinopril in mild hypertension].

The aim of this double-blind randomized placebo-controlled study was to evaluate the antihypertensive and safety of fosinopril in mild essential hypertension. After a 2-week placebo period, patients received either placebo or fosinopril 20 mg, once daily. Thirty-four patients finished the study (18 patients in the placebo group and 16 patients in the fosinopril group). Systolic blood pressure decreased from 160.1 +/- 22.1 mmHg to 156.0 +/- 24.2 in the placebo group (NS) and from 151.8 +/- 14.0 mmHg to 141.5 +/- 14.5 in the fosinopril group (p < 0.005); diastolic blood pressure decreased from 100.1 +/- 2.4 mmHg to 94.3 +/- 7.4 mmHg in the placebo group (p < 0.005) and from 100.8 +/- 4.8 mmHg to 88.1 +/- 9.0 mmHg in the fosinopril group (p < 0.001). Mean decrease in diastolic blood pressure was 5.7 mmHg in the placebo group and 12.6 mmHg in the fosinopril group (p < 0.05). A statistically significant difference was seen between the percentage of controlled patients in the two groups: 16.6% in the placebo group vs 56.2% in the fosinopril group (p < 0.05). No statistically significant difference in biochemical parameters was seen between the two groups. Tolerance was good and no patients were withdrawn from the study for adverse events.

Adolescent↗
PubMed1996

[Correlation between aortic transvalvular gradient obtained with Doppler ultrasonography and with hemodynamics study. Role of the underlying etiology].

In aortic stenosis, a good correlation was found between the gradients obtained by catheterization and Echo-Doppler. However, the correlation of these two methods in subgroups of patients with different etiologies of aortic stenosis is unknown. The aim of this study was to evaluate, whether the correlation between catheterization and Echo-Doppler was similar in patients with different etiologies of aortic stenosis. Patients with concomitant valvular disease were excluded. Only patients with a clearly defined etiology (based on clinical history, echocardiography, angiography and/or pathology) were included in this study. We evaluated 106 patients with aortic stenosis. Forty-nine patients had degenerative aortic stenosis, 32 bicuspid aortic stenosis and 25 rheumatic aortic stenosis. The percentage of male patients in each group were as follows: 57.1% in the denerative aortic group; 62.5% in the bicuspid aortic stenosis group; and 76% in the rheumatic aortic stenosis group. Mean age (years) was 69 +/- 6.7 in the degenerative aortic stenosis group, 58.1 +/- 7.5 in the bicuspid aortic stenosis group, and 64 +/- 7.1 in the rheumatic aortic stenosis group. In our study we found different correlations between the gradients obtained by the two methods-catheterization and Eco-Doppler-among the patients with different etiologies of aortic stenosis. The correlation coefficient (r2) was 0.54 (p < 0.001) in the rheumatic aortic stenosis group, 0.37 (p < 0.001) in the bicuspid aortic stenosis group and 0.21 (p = 0.001) in the degenerative aortic stenosis group. In conclusion, a good overall correlation was found between the two methods in aortic stenosis, however, this correlation is different in the three etiologies of aortic stenosis. The correlation is better in rheumatic valves, intermediate in bicuspid valves, and worse in degenerative valves. Changes in aortic valve morphology in these subgroups of patients are probably responsible for these different results.

Aged↗
PubMed1995

[The Bland-White-Garland syndrome or an anomalous origin of the left coronary from the pulmonary artery. Apropos a case of a continuous murmur in an adult].

The authors report a case of anomalous origin of the left coronary artery from the trunk of pulmonary artery in an adult without significant symptoms, diagnosed by the presence of a continuous thoracic murmur. Because its low incidence and great mortality in the beginning of life, the appearance in the adult is extremely uncommon, especially without symptoms of cardiac failure, angina pectoris or myocardial infarction. In the present case, the patient was asymptomatic and was submitted to various echocardiograms before the diagnosis was suspected and confirmed with angiography. Surgical treatment was performed successfully with reimplantation of the anomalous vessel in the aorta.

Adult↗