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Biomedical subjects

H Costa

Publications and source records attributed to H Costa.

At least 19 recordsLinked to original sources
PubMed2006

Distribution of (125)I-labeled crotamine in mice tissues.

Crotamine is a strong basic polypeptide from Crotalus durissus terrificus (Cdt) venom composed of 42 amino acid residues tightly bound by three disulfide bonds. It causes skeletal muscle spasms leading to spastic paralysis of hind limbs in mice. The objective of this paper was to study the distribution of crotamine injected intraperitoneally (ip) in mice. Crotamine was purified from Cdt venom by gel filtration followed by ion exchange chromatography, using a fast-performance liquid chromatography (FPLC) system. Purified crotamine was irradiated at 2 kGy in order to detoxify. Both native and irradiated proteins were labeled with (125)I using chloramine T method, and separated by gel filtration. Male Swiss mice were injected ip with 0.1 mL (2 x 10(6)cpm/mouse) of (125)I native or irradiated crotamine. At various time intervals, the animals were killed by ether inhalation and blood, spleen, liver, kidneys, brain, lungs, heart, and skeletal muscle were collected in order to determine the radioactivity content. The highest levels of radioactivity were found in the kidneys and the liver, and the lowest in the brain.

Animals↗
PubMed2005

Anaphylaxis to povidone in a child.

Povidone is an allergic agent present in numerous substances, food and medicines. The authors present the clinical case of a 9-yr-old male child admitted in the emergency room with anaphylaxis, in two occasions separated by a 6-month period. The first episode occurred 5 min after the first oral administration of Fluvermal (flubendazole) and the second occurred 10 min after cutaneous application of Betadine (povidone iodine solution). Previous cutaneous application of this solution and ingestion of mebendazole occurred without apparent adverse reactions. The allergy study revealed eosinophilia, an elevated total IgE level and positive prick-by-prick test for both drugs. A cutaneous prick-by-prick test with povidone (the sole common constituent) was also positive. This is probably the first case described in the literature of anaphylaxis induced by povidone in a child.

Anaphylaxis↗
PubMed2001

The posterior interosseous flap: a review of 81 clinical cases and 100 anatomical dissections--assessment of its indications in reconstruction of hand defects.

Based on our experience of 100 cadaveric dissections and a series of 81 clinical cases, we have assessed the indications for the posterior interosseous flap in reconstruction of the hand. Large fasciocutaneous island flaps can be harvested, even when the radial or ulnar pedicles are damaged, sacrificing only vessels of secondary importance to the perfusion of the hand. Compound flaps can be dissected based on muscular, musculoperiosteal and fascioperiosteal branches. The primary indications for using this flap are dorsal hand defects up to the metacarpal joints, reconstruction of the first web space up to the interphalangeal joint of the thumb and extensive lesions on the ulnar border of the hand.

Adolescent↗
PubMed2001

Effects of (60)Co gamma radiation on crotamine.

Ionizing radiation can change the molecular structure and affect the biological properties of biomolecules. This has been employed to attenuate animal toxins. Crotamine is a strongly basic polypeptide (pI 10.3) from Crotalus durissus terrificus venom composed of 42 amino acid residues. It induces skeletal muscle spasms leading to a spastic paralysis of hind limbs in mice. The objective of the present study was to carry out a biochemical study and a toxic activity assay on native and irradiated crotamine. Crotamine was purified from C.d. terrificus venom by Sephadex G-100 gel filtration followed by ion-exchange chromatography, and irradiated at 2 mg/ml in 0.15 M NaCl with 2.0 kGy gamma radiation emitted by a 60Co source. The native and irradiated toxins were evaluated in terms of structure and toxic activity (LD50). Irradiation did not change the protein concentration, the electrophoretic profile or the primary structure of the protein although differences were shown by spectroscopic techniques. Gamma radiation reduced crotamine toxicity by 48.3%, but did not eliminate it.

Animals↗
PubMed2000

Agelotoxin: a phospholipase A(2) from the venom of the neotropical social wasp cassununga (Agelaia pallipes pallipes) (Hymenoptera-Vespidae).

The neotropical wasp Agelaia pallipes pallipes is aggressive and endemic in southeast of Brazil, where very often it causes stinging accidents in rural areas. By using gel filtration on Sephadex G-100, followed by high performance reversed phase chromatography in a C-18 column under acetonitrile/water gradient, the agelotoxin was purified: a toxin presenting phospholipase A(2) (PLA(2)) activity, which occurs under equilibrium of three different aggregation states: monomer (mol. wt 14 kDa), trimer (mol. wt 42 kDa) and pentamer (mol. wt 74 kDa). The enzyme presents high sugar contents attached to the protein chain (22% [w/w]) and a transition of the values of pH optimum for the substrate hydrolysis from 7.5 to 9.0, under aggregation from monomer to pentamer. All the aggregation states present Michaelian steady-state kinetic behavior and the monomer polymerization caused a decreasing of phospholipasic activity due a non-competitive inhibition promoted by the formation of a quaternary structure. The PLA(2) catalytic activity of agelotoxin changes according to its state of aggregation (from 833 to 12533 micromol mg(-1) min(-1)) and both the monomeric and oligomeric forms present lowest activities than the PLA(2) from Apis mellifera venom and hornetin from Vespa basalis. Agelotoxin is also a very potent direct hemolysin; the monomer of agelotoxin presented hemolytic actions until 200 times higher than the PbTx from P. paulista, 740 times higher than the PLA(2) from A. mellifera, 570 times higher than that of neutral PLA(2) from N. nigricolis and about 1250 times than that of cardiotoxin from Naja naja atra venom.

Animals↗
PubMed2000

Identification of fish species after cooking by SDS-PAGE and urea IEF: a collaborative study.

A collaborative study, to validate the use of SDS-PAGE and urea IEF, for the identification of fish species after cooking has been performed by nine laboratories. By following optimized standard operation procedures, 10 commercially important species (Atlantic salmon, sea trout, rainbow trout, turbot, Alaska pollock, pollack, pink salmon, Arctic char, chum salmon, and New Zealand hake) had to be identified by comparison with 22 reference samples. Some differences in the recoveries of proteins from cooked fish flesh were noted between the urea and the SDS extraction procedures used. Generally, the urea extraction procedure appears to be less efficient than the SDS extraction for protein solubilization. Except for some species belonging to the Salmonidae family (Salmo, Oncorhynchus), both of the analytical techniques tested (urea IEF, SDS-PAGE) enabled identification of the species of the samples to be established. With urea IEF, two laboratories could not differentiate Salmo salar from Salmo trutta. The same difficulties were noted for differentiation between Oncorhynchus gorbuscha and Oncorhynchus keta samples. With SDS-PAGE, three laboratories had some difficulties in identifying the S. trutta samples. However, in the contrast with the previous technique, SDS-PAGE allows the characterization of most of the Oncorhynchus species tested. Only Oncorhynchus mykiss was not clearly recognized by one laboratory. Therefore, SDS-PAGE (Excel gel homogeneous 15%) appears to be better for the identification, after cooking, of fish such as the tuna and salmon species which are characterized by neutral and basic protein bands, and urea IEF (CleanGel) is better for the gadoid species, which are characterized by acid protein bands (parvalbumins). Nevertheless, in contentious cases it is preferable to use both analytical methods.

Animals↗
PubMed1998

[Microsurgical reconstruction of the head and neck: experience of 63 free flaps].

The authors present the experience of 63 clinical cases of microsurgical reconstruction of the head and neck. These reconstructions were accomplished by different microvascular free flaps which were selected according to the type, size and location of the defects. Fasciocutaneous, osteofasciocutaneous, adipofascial, myo, myocutaneous, myosseous, jejunum and great omentum flaps were applied. The etiology was traumatic in 10 cases, tumoral in 41 cases, congenital in 7 cases, iatrogenic in 3 cases and infectious in 2 cases. The reconstructed anatomical regions were the scalp in 6 cases, the skull base in 1 case, the orbit in 3 cases, the nose in 1 case, the hemiface in 7 cases, the lips in 1 case, the intraoral cavity in 21 cases, the mandible in 8 cases, the intraoral cavity plus mandible in 11 cases and the cervical esophagus in 1 cases. An analysis was made of surgical times, selection and survival rate of the free flaps and the morphofunctional quality of the reconstructions. Considering the good quality of reconstructions, the amelioration of quality of life and the low morbidity in these patients, microvascular free flaps are considered a first choice technique for head and neck reconstruction when the size and location of the defect prevents the use of local flaps.

Adult↗
PubMed1998

[Microsurgical reconstruction of the upper extremity. Experience with 24 free flaps].

The authors present the experience of 24 clinical cases of microsurgical reconstruction of the upper limb. These reconstructions were accomplished by different microvascular free flaps which were selected according to the type, size and location of the defects, having applied fasciocutaneous, adipofascial, myo, myocutaneous, tendofasciocutaneous, omentum flaps and 2nd toe transfers. The etiology was traumatic in 23 cases and tumoral in 1 case. A careful analysis was made for surgical times, selection and survival rate of the free flaps and the morphofunctional quality of the reconstructions. Microvascular free flaps are considered the choice technique for upper limb reconstruction, particularly for the hand in certain defects, considering the better anatomic and functional quality of the reconstructions.

Adolescent↗
PubMed1997

pH dependence of structural and functional properties of oxidized cytochrome c" from Methylophilus methylotrophus.

Cytochrome c" from Methylophilus methylotrophus is an unusual monoheme protein that undergoes a major redox-linked change in the heme arrangement: one of the two axial histidines bound to the iron in the oxidized form is detached upon reduction and a proton is taken up. The kinetics of reduction by sodium dithionite and the spectroscopic properties of the oxidized cytochrome c" have been investigated over the pH range between 1.4 and 10.0. The rate of reduction displays proton-linked transitions of pKa congruent with 5.5 and 2.4, and a spectroscopic transition with a pKa congruent with 2.4 is also observed. The protein displays a complete reversibility after exposure to low pH, and both electronic absorption and resonance Raman spectroscopic properties suggest that the transition at lower pH brings about a drastic change in the heme coordination geometry. Circular dichroism spectra indicate that over the same proton-linked transition, the protein undergoes a marked decrease (approximately 60%) of the alpha-helical content toward a random coil arrangement, which is recovered upon increasing the ionic strength. The structural change at low pH is linked to a concerted two-proton transition, suggesting the detachment and protonation of axial histidine(s). Such kinetic and spectroscopic features along with the remarkable capacity of this protein to recover its native structure after exposure to extremely low pH values makes it a promising model for studying folding processes and stability in heme proteins.

Circular Dichroism↗
PubMed1997

[Reconstruction of the anterior cranial base with a frontal muscle flap in cerebrospinal fluid fistulae].

Craniofacial infection is a major problem for the plastic and neurosurgical team. Previous successful experiences with free muscle and omentum flaps and the galea frontalis myofascial flap have been reported, avoiding disastrous complications after frontofacial advancements and the resection of skull base tumors. The authors report the clinical use of the galea frontalis myofascial flap in the treatment of anterior fossa CSF leaks. This flap provides an adequate sized and vascularized barrier between the cranial and nasal cavities through which the cells of the inflammatory response reach the target area. This technique was used in 11 cases with complete success; in-6 patients, repair of the anterior cranial base bone defect was performed with split calvarium bone grafts, harvested from craniotomy bone. In all the patients, neither the recurrence of the CSF leakage nor post-operative meningitis or its recurrence were observed.

Adult↗
PubMed1993

Prefabricated flaps for the head and neck: a preliminary report.

The authors present some clinical applications of the concept of flap prefabrication. Three cases are described where reconstructions around the head and neck were accomplished. The radial vascular territory of the forearm was selected for prefabrication of structures which were then transferred by microsurgical techniques. In two cases, a sensate flap was used, with nerve repair in the neck.

Adolescent↗
PubMed1993

The galea frontalis myofascial flap in anterior fossa CSF leaks.

We report the clinical use of galea frontalis myofascial flaps in the treatment of anterior fossa cerebrospinal fluid leaks after trauma. This flap provides an adequately sized and vascularised barrier between the cranial and nasal cavities through which the cells of the inflammatory response reach the target area. This technique was used in 9 cases with complete success; in 5 out of 9 patients, repair of an anterior cranial base bone defect was also performed with split calvarial bone grafts, harvested from the frontal craniotomy bone. In all patients, neither recurrence of the CSF leakage nor postoperative meningitis or its recurrence were observed.

Adult↗
PubMed1992

[Old-fashioned combined intra- and extra-articular surgery of the knee for chronic lesions of the anterior cruciate ligament. Intermediate results. Indications].

The authors studied the results of a homogeneous group of 60 knees on which were performed intra- and extraarticular ligamentoplasty for chronic anterior laxity. The MacIntosh technique as described by Imbert was used. This consisted of a continuous transplant taken from the extensor apparatus. The patients were operated by the same surgeon but questioned by another. The results were analyzed for stability, pain and resumption of sports (kind and level). Certain parameters were currently found to be unfavorable, such as relatively small transplant diameter, arthrotomy, 3 or more weeks of postoperative plaster immobilization, total discharge, period of 6 or more weeks, lack of extension tolerated until the 16th week, a very slow rate reeducation allowing competition at the prior level only after a year following surgery in particular, do not seem to influence the results. Only 76.6% of the patients had a result considered to be very good or good, and the analysis of average (16.6%) and poor (6.5%) results showed preoperative factors which indicated the prognosis. These included meniscus conservation, age, sports activities, preoperative degenerative lesions, type of accident and the patient's motivation.

Adolescent↗
PubMed1991

One-staged coverage and revascularisation of traumatised limbs by a flow-through radial mid-forearm free flap.

The concept of flow-through circulation in free flaps is an interesting and useful one. Its importance is paramount in the clinical field, if one applies it as a one-staged technique for cover and revascularisation in major trauma of the extremities. This paper describes the practical use of this concept in two clinical cases (hand and foot), in which an uninterrupted arterial and venous flow was established through the radial mid-forearm fasciocutaneous flap, allowing revascularisation of the ischaemic extremity.

Adult↗
PubMed1991

Bricanyl Turbuhaler and Ventolin Rotahaler in exercise-induced asthma in children.

Bricanyl Turbuhaler (0.5 mg terbutaline sulphate) and Ventolin Rotahaler (0.4 mg salbutamol) were compared in a randomized double-blind placebo controlled study on exercise-induced asthma in 19 children (14 boys) aged 7-14 years. The study was carried out on 3 separate days. Asthmatic attacks were provoked by free range running. Peak expiratory flow (PEF) was measured before and after exercise. If PEF decreased by greater than 20%, one inhalation from each of the inhalers was given under supervision of the investigator. Only one of the inhalers (none on the placebo day) delivered active drug. PEF was measured again 5 and 10 min after treatment. Already 5 min after treatment PEF had returned to baseline after active treatment. There was no statistically significant difference between the two active treatments. After placebo treatment, PEF did not return to baseline even at the 10 min post-exercise measurement. Ten children needed extra medication after the last PEF measurement on the placebo day, whereas no child needed extra medication after any of the active treatments. No adverse events were reported in this study. In conclusion, Bricanyl Turbuhaler (0.5 mg) and Ventolin Rotahaler (0.4 mg) were equally efficacious in the treatment of exercise-induced asthma in children.

Acute Disease↗