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M C Pinto

Publications and source records attributed to M C Pinto.

At least 19 recordsLinked to original sources
PubMed2006

Isolation and isoenzyme characterization of Leishmania (Viannia) braziliensis from a case of human cutaneous leishmaniasis in northeast centre of the state of São Paulo.

The diagnosis of human cutaneous leishmaniasis in small towns is sometimes made without the species identification of the Leishmania, even in areas without previous epidemiological surveys. Here we report the isolation of a Leishmania strain from a patient of Rincão, state of São Paulo, that was identified by isoenzyme characterization as L. (Viannia) braziliensis. Sand fly collections were made in the area where the patient live in order to investigate the likely vector species.

Animals↗
PubMed2001

Phlebotomine sandfly responses to carbon dioxide and human odour in the field.

Responses of Lutzomyia sandflies (Diptera: Psychodidae: Phlebotominae) to carbon dioxide (CO2) and human odour were investigated by field experiments in Parana State, southern Brazil. Catches of two predominant species: Lu. intermedia (Antunes & Coutinho) and Lu. whitmani Lutz & Neiva, were compared between traps baited with a human adult or with CO2 emitted at the human-equivalent rate. When the baits were only 40 cm apart, no difference of attractiveness was detected. When baits were separated by 20 m, however, significantly fewer sandflies (44% Lu. intermedia, 46% Lu. whitmani) were trapped with CO2 compared with human bait. This is the first field evidence that anthropophilic sandflies are attracted by human kairomones in addition to CO2. For both species [Lutzomyia intermedia and Lu. whitmani] [corrected], the proportion of human attractiveness attributable to CO2 was significantly more [corrected] for males than females; for Lu. intermedia males human bait was no more attractive than CO2 alone. Gender differences in sandfly olfactory sensitivity are likely to be associated with behavioural differences on the host, where females feed on blood and males find mates. With traps 20 m apart, both Lutzomyia spp. showed roughly linear increased responses (log-log scale) to 0.08-0.55% CO2 equivalent to 0.5-4 humans. This would explain why host size is generally proportional to attractiveness, as observed for other species of phlebotomine sandflies.

Adult↗
PubMed2001

Resistance of Musca domestica L. populations to cyromazine (insect growth regulator) in Brazil.

Five field populations of Musca domestica L. collected in poultry farms were bioassayed in order to detect possible resistance to the larvicide cyromazine in Brazil. The concentrations used were 0, 0.5, 0.1, 0.2, 0.4, 1, 2, 4 and 8 ppm. Three populations (Petrópolis, RJ, Montes Claros, MG and Promissão, SP) were resistant, while the other two populations (Ibiuna, SP and Monte Mor, SP) were more susceptible than the reference pathern used by the World Health Organization. The presence of three resistant house fly populations to cyromazine in Brazilian poultry farms strongly suggests that the operational aspects of larvicide use are important for the resistance development. Cyromazine is applied as a feed-through, both in Brazil and in the USA, where resistance has already been documented. However, in Denmark, where it was approved only as a topical manure spray, no case of resistance has yet been detected.

Animals↗
PubMed2000

Chemical reactivity studies with naphthoquinones from Tabebuia with anti-trypanosomal efficacy.

The biological activities of the naphthoquinones lapachol and its cyclization product beta-lapachone, extracted from trees of the genus Tabebuia, have been intensively studied. Given continuity to the studies about heterocyclic derivatives obtained from the reaction of these naphtoquinones with amino-containing reagents, 22 derivatives of beta-lapachone, nor-beta-lapachone and lapachol were synthesised and their activities against trypomastigote forms of T. cruzi were evaluated. The compounds were grouped as oxazolic, imidazolic, phenoxazinic, indolic, pyranic and cyclopentenic derivatives. The variability of the new structures is based on the great electrophilicity of 1,2-quinoidal carbonyls towards reagents containing nitrogen or carbon as nucleophilic centres. In relation to the trypanocidal activity of the synthesised compounds, in view of their structural diversity, tendencies only could be verified. Among the cyclofunctionalised products the oxazolic and imidazolic derivatives showed +/- 1.5 to 34.8 times higher activity than crystal violet, the standard drug for the sterilization of stored blood. These results corroborate the tendency of trypanocidal activity in imidazolic skeletons, and indicate that this moiety could be used as a guide for architectural delineation of molecules with potential value for the chemotherapy of Chagas disease.

Animals↗
PubMed2000

Phakic intraocular lenses: which to choose.

Phakic intraocular lenses have been increasingly popular with refractive surgeons because of the good refractive results achieved and because there are few serious complications. The purpose of this review is to compare the different types of phakic intraocular lenses, regarding implant selection, surgical technique, refractive outcome, and anatomical evaluation. New uses of phakic intraocular lenses are also presented. Although phakic intraocular lenses have gone a long way, the quest for the ideal lens remains a challenge.

Accommodation, Ocular↗
PubMed2000

Domesticity of Lutzomyia whitmani (Diptera: psychodidae) populations: field experiments indicate behavioural differences.

The sandfly Lutzomyia whitmani (Antunes & Coutinho) is an important vector for cutaneous leishmaniasis throughout much of Brazil, and has recently been shown to consist of more than one mitochondrial lineage. It has frequently been asserted that the degree of adaptation of L. whitmani to human environments varies across its range. As a standardized test of indoor feeding for three geographically distant populations of L. whitmani, catches inside experimental chicken sheds of varying degrees of wall closure (0%, 33%, 67% and 98%) were compared. Each increment in shed closure reduced catches of females (relative to the most open shed) by a similar degree for each population: geometric mean catches dropped by 11-40% with 33% closure, by 41-62% with 67% closure, and by 69-100% with 98% closure. Geometric mean catches of males from the two more northerly populations also decreased with increasing shed closure, by 18% and 22% for 33% closure, 58% and 69% for 67% closure, 91% and 93% for 98% closure. Males from the most southerly population showed significantly different behaviour, with 33% closure causing a 54% increase in geometric mean catch, 67% closure causing a 6% increase, and 98% closure causing a 32% reduction. For this southerly population, sex ratios became more male biased with increasing density in more closed sheds, suggesting aggregation driven by intra-specific communication. Lutzomyia intermedia (Lutz & Neiva) was relatively more likely than L. whitmani to approach baits in the three more closed sheds, rather than the most open shed, offering a behavioural explanation for observed differences in indoor biting rates between the species.

Animals↗
PubMed1999

The use of fluorescein 5'-isothiocyanate for studies of structural and molecular mechanisms of soybean lipoxygenase.

Incubation of fluorescein 5'-isothiocyanate (FITC) with soybean lipoxygenase produces the coupling of 1 mol of fluorophore to 1 mol of enzyme. Derivatized lipoxygenase lost 40% activity through a mixed-type inhibitory mechanism. The quenching by IK of the fluorescence of FITC-labeled lipoxygenase shows that the fluorophore is located near the surface of the protein. The partial impediment of the FITC labeling when the substrate is present in the medium, together with data of the tryptic digestion, suggests that FITC is attached via the access channel of substrate to the catalytic site. Labeling does not induce appreciable modification of the enzyme specificity, suggesting that the position of substrate in the active site is not modified by the labeling. The results obtained strongly suggest that FITC labels soybean lipoxygenase specifically at a lysyl residue which contributes to fixation of the carboxylic end of the substrate to the active center. The experimental data obtained from the quenching of FITC fluorescence by NDGA reveal that this molecule interacts with the protein near the catalytic site.

Binding Sites↗
PubMed1999

Resveratrol is a potent inhibitor of the dioxygenase activity of lipoxygenase.

Resveratrol is a naturally occurring phytoalexin, present in grapes and other food products, with important antioxidant properties. Although still under debate, it is generally assumed that resveratrol has protective effects against heart diseases and probably tumor development. Lipoxygenase is a dioxygenase with peroxidase activity involved in the synthesis of mediators in inflammatory, atherosclerotic, and carcinogenic processes. Lipoxygenase activity is also involved in the generation of flavors and aromas in foods from animal or vegetal sources. The results presented here show that resveratrol was a potent inhibitor of the dioxygenase activity of lipoxygenase, with an IC(50) = 13 microM. Simultaneously, resveratrol was oxidized by the peroxidase activity of lipoxygenase with a V(max) = 0.28 microM min(-1) and a k(M) = 16.6 microM. Furthermore, oxidized resveratrol was as efficient a lipoxygenase inhibitor as in its reduced form. From the data obtained it can be concluded that both resveratrol and its oxidized form can act as inhibitors of the dioxygenase activity of lipoxygenase. In contrast, the hydroperoxidase activity of lipoxygenase was not inhibited by resveratrol. These results suggest that resveratrol may be used as an antioxidant food additive and as a pharmacological agent to prevent the generation of eicosanoids involved in pathological processes.

Antioxidants↗
PubMed1999

Experimental comparison of anthropophily between geographically dispersed populations of Lutzomyia whitmani (Diptera: Psychodidae).

Lutzomyia whitmani, a major vector of cutaneous leishmaniasis in Brazil, occupies diverse habitats from the Amazon forest canopy to suburban animal pens. Three mitochondrial lineages of Lu. whitmani ('Amazonian', 'North-South' and 'North-east') have parapatric distributions coinciding with different ecological zones. We assessed the host preferences of populations representing the three lineages in standardized field experiments, and found that Lu. whitmani in all sites were significantly more attracted to humans than to dogs or chickens. Females from a southerly population of the North-South lineage showed the greatest degree of anthropophily. Lu. whitmani from Amazonia were also strongly attracted to human baits, contradicting previously published accounts. Intraspecific comparisons in non-Amazonian sites suggest that Lu. whitmani is less anthropophilic than Lu. intermedia but more so than Lu. longipalpis. No significant difference was detected in anthropophily between Lu. whitmani in the Amazon and either Lu. dendrophyla or Lu. gomezi. Anthropophilic behaviour was demonstrated in the same site for Lu. complexa, Lu. flaviscutellata and Lu. brachyphalla, but not for Lu. infraspinosa.

Animals↗
PubMed1996

LASIK for high myopia: one year experience.

BACKGROUND AND OBJECTIVE: Laser in situ keratomileusis (LASIK) is a technique combining the advantages of lamellar corneal surgery (not disturbing Bowman's layer) with the precision of excimer laser surgery. It can be used to correct myopia in a wide range of diopters. In this study we present our data on the first 34 consecutive cases of myopia correction by LASIK. PATIENTS AND METHODS: Thirty four eyes of 27 patients with myopia ranging from -10.00 to -22.50 diopters (D) were operated with LASIK. The follow-up was from six months to one year. The mean age was 33.02 +/- 7.98 years, 32.4% were males and 67.6% were females. Surgery was always performed with the Chiron Automated corneal shaper resecting a corneal flap of 160 mu and then ablating the stromal bed (OZ 4.50 mm) with the Summit OmniMed 5.0 excimer laser. The parameters used to assess the results were predictability, safety (variation of spectacle corrected visual acuity), stability, and patient satisfaction. RESULTS: Of the patients, 67.65% were between -1.00 and +1.00 at 6 months; 44.11% of eyes retained the same spectacle corrected visual acuity, 11.76% gained 1 line, 26.47% gained 2 lines, 8.82% lost 1 line and 8.82% lost 2 lines. Refraction at 1 month was 0.07 +/- 1.99 (range, -4.00 to +4.00); at 3 months 0.61 +/- 1.69 (range, -4.25 to +2.25); and at 6 months 0.81 +/- 1.71 (range, -4.75 to +2.25). Of the patients, 85.3% were happy with the procedure. Complications included two dislocated caps in the immediately post-operative period and two cases of epithelial ingrowth under the cap. Two eyes developed irregular astigmatism. These complications were found in the first two sessions of surgery and are related to the learning curve of the method. CONCLUSION: Results suggest that LASIK is a viable method for correction of high myopia with few complications and may have advantages over keratomileusis and PRK as it combines the best features of both methods--it preserves Bowman's layer and has the excimer laser precision. Refining the nomogram of ablation should result in even better results.

Adult↗
PubMed1995

Factors related to the occurrence of postoperative complications following penetrating gastric injuries.

The aim of this study was to determine the relationship between diaphragmatic injury and gross contamination of the peritoneal cavity caused by gastric injuries and the occurrence of postoperative complications, especially those related to the pleural cavity. Charts of 73 patients sustaining gastric injuries due to penetrating trauma were retrospectively reviewed. There were 66 males and mean age was 28 years. Stab wounds were the most frequent mechanism of injury, occurring in 46 cases. Most of the injuries were treated using simple suture and minor debridement. Postoperative morbidity rate was 30 per cent and thoracic complications occurred in 11 patients. Twenty-six patients had diaphragmatic injuries; 54 per cent of them developed postoperative complications. Of the remaining 47 patients without diaphragmatic injuries, only eight developed complications. Of the 26 patients with diaphragmatic injuries, seven developed pleuropulmonary complications compared with 4 of 47 without diaphragmatic injury. Of sixteen patients who had gross contamination secondary to gastric injury, characterized by the presence of food or great amounts of gastric contents in the peritoneal cavity, 10 developed postoperative complications compared with 12 of 57 without gross contamination. Overall mortality rate was 11 per cent mostly due to sepsis. In conclusion, the presence of a diaphragmatic injury as well as gross contamination of the abdominal cavity are important factors related to the development of postoperative infections particularly in the pleural space.

Adolescent↗
PubMed1995

Penetrating cardiac wounds: predictive value of trauma indices and the necessity of terminology standardization.

The authors evaluated the usefulness of different trauma indices in the prediction of outcome following penetrating cardiac wounds. Sixty-three patients were retrospectively reviewed. Age, mechanism of injury, Physiologic Index (PI) on admission, site of injury, associated injuries, ISS, RTS, Penetrating Cardiac Trauma Index (PCTI), Penetrating Thoracic Trauma Index (PTTI), Penetrating Trauma Index (PTI), TRISS and mortality rate were reviewed. There were 34 patients with a gunshot wound (GSW) and 29 with a stab wound (SW). Shock was present on admission in 88.9 per cent. Mortality was 83 per cent for GSW, 44 per cent for SW, and 39 per cent for patients arriving the hospital with measurable blood pressure. RTS, PI, PCTI, PTTI, PTI, and ISS reached statistical significance when comparing survivors and nonsurvivors. The probability of survival (PS) based on the TRISS methodology was 37.84 +/- 5.14. The observed survival rate was 38 per cent. Fourteen patients were considered "fatal" on admission and underwent an emergency thoracothomy. Mortality rate for this selected group was 100 per cent. We conclude that physiologic impairment, shock, and GSW are variables with high significance on mortality. Trauma indices such as PI, RTS, PCTI, PTTI, PTI, and ISS are good predictors of outcome. Trauma indices are an important tool to objectively compare results among different institutions.

Adolescent↗
PubMed1994

Screening of natural and synthetic drugs against Trypanosoma cruzi. 1. Establishing a structure/activity relationship.

The activity of 45 compounds against bloodstream forms of Trypanosoma cruzi was investigated. The aim was to consider new agents which might subsequently be assayed for chemoprophylaxis in donated blood. In a preliminary screening the drugs were assayed (50 to 1,000 microM at 29 degrees C) and those active against bloodstream forms at concentrations below 600 microM were selected for further assays under blood-bank conditions (4 degrees C/24 h). Three compounds isolated from natural sources and six synthetic agents were selected. The active compounds of plant origin included purpurin, a member of the trihydroxylated anthraquinone group, which is known to exhibit trypanocidal activity. Among the active synthetic compounds, five displayed a common structural feature in that they were potentially one-electron acceptors, via reductive functional groups. All five compounds form tricentered C or N intermediates, joined in a hypothetical 'Y' radical pattern. It is possible that the trypanocidal mechanisms initiated by these compounds are similar to those found with crystal violet, since this dye, which is already used in endemic areas for the treatment of banked blood, also conforms to this general Y structural pattern.

Animals↗
PubMed1993

Abnormal progression of a liquid meal through the stomach and small intestine in patients with Chagas' disease.

This study describes the abnormal pattern of gastrointestinal progression of a liquid meal in patients with the digestive form of chronic Chagas' disease. This condition is known as a natural model of intramural denervation of the gut. Sixteen patients with clinical and radiographic evidence of esophageal and/or colonic involvement and 18 healthy volunteers were studied. Orocecal transit time after the ingestion of a 10% lactulose solution (180 ml) tagged with 99mtechnetium was measured by a conventional H2 breath technique. Gastric emptying and the arrival of the front of the meal to regions of interest corresponding to proximal and distal areas of the small intestine were assessed by abdominal scintigraphy. Orocecal transit time was significantly greater (P < 0.05) in Chagas' disease patients (N = 13) than in control subjects (N = 18) (mean +/- SD: 100.7 +/- 48.7 min vs 62.9 +/- 18.2 min). Half-time for gastric emptying of liquids in chagasic patients (N = 9) was significantly lower (P < 0.01) than in controls (N = 7) (9.7 +/- 2.7 min vs 26.4 +/- 3.4 min). The time of arrival of the liquid meal to the proximal small intestine was also significantly shorter (P < 0.02) in patients than in controls (5.6 +/- 3.7 vs 11.4 +/- 5.5 min), but there was no difference between the two groups concerning the time the meal first arrived to the distal small intestine (15.0 +/- 11.0 min vs 23.5 +/- 11.4 min, P > 0.05). These results indicate that patients with Chagas' disease have a combination of exceedingly rapid gastric emptying and abnormally delayed transit of liquids through the more distal segments of the small bowel.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Ethical dilemmas in the field of genetics].

After a brief introduction, the role of medical genetics in modern ethical conflicts is emphasized. International working approaches are discussed in an attempt to solve medical conflicts. The studies proposed by Wertz and Fletcher are reviewed in order to assess the strength of consensus on various working approaches. A brief discussion evaluates working approaches to ethical problems in genetics. This discussion also focuses on genetic counselling and screening questions regarding pertinent hereditary diseases. Final considerations point out the demanding role played by the modern geneticist in medical ethics perspectives now broadened by new insights, namely the challenge of human genome mapping.

Ethics, Medical↗
PubMed1991

Hemin and hemeprotein bleaching during linoleic acid oxidation by lipoxygenases.

Hemin and hemoglobin are bleached by lipoxygenases, type 1 (from soybean) or type 2 (from platelets), during linoleic acid oxidation. This process has been found to be related to the inhibition of the lipoxygenase activity, measured as hydroperoxide generation and to produce oxodienes as well. All these parameters have been determined simultaneously from measurements of the absorbance at 234, 285, 375 and 410 nm to detect hydroperoxides, oxodienes, hemin and hemoglobin, respectively, using a diode array spectrophotometer. The inhibition of lipoxygenase activity by these pigments has been found to be competitive with linoleic acid, showing an increase of 4-7-fold of the Km value of linoleic acid in the presence of concentrations of hemin and hemoglobin as low as 0.2 and 0.02 microM, respectively, for the case of platelet lipoxygenase activity. The concentrations of hemin and of hemoglobin producing the inhibition of 50% of lipoxygenase activity are: 0.25 and 0.02 microM for the platelet isoenzyme, and 1.4 and 0.18 microM for the soybean isoenzyme, respectively. From the quenching of the intrinsic fluorescence of soybean lipoxygenase activity by hemin, we have obtained a dissociation constant of hemin-soybean lipoxygenase of 0.5 microM. The results obtained in this paper for the cooxidation process of hemin and hemoglobin by lipoxygenase can be rationalized in terms of hemin binding at or near to the catalytic center, resulting in a lesser binding of linoleic acid and an enhanced release of radicals, and pigment bleaching by radicals and lipid hydroperoxides.

Animals↗
PubMed1988

Comparative fluorescence properties of lipoxygenases.

1. Lipoxygenases purified from tomato, rat liver and soybean show a fluorescence band centered at 648 nm, which is likely to derive from Tyr and Trp. 2. The intensity of this fluorescence range from 0.7 to 1.0% of the intensity of their major intrinsic fluorescence band (lambda max = 343 nm) in all these lipoxygenases. 3. At inhibitory concentrations, ditizone partly quenches the fluorescence of the lipoxygenases above 600 nm. 4. Saturating concentrations of linoleic acid produce 79% quenching of the fluorescence at 648 nm of soybean lipoxygenase inactivated by treatment with 1 mM dithiothreitol. From these data we have obtained an apparent Kd for linoleic acid-lipoxygenase complex dissociation of 34 +/- 3 microM. 5. It is suggested that the fluorescence above 600 nm reveals the presence of aromatic amino acids located near or at the catalytic center.

Animals↗