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Biomedical subjects

G M Soares

Publications and source records attributed to G M Soares.

6 recordsLinked to original sources
PubMed2001

Use of laccase together with redox mediators to decolourize Remazol Brilliant Blue R.

A pure fungal laccase, obtained from a commercial formulation used in the textile industry, did not decolourize Remazol Brilliant Blue R (RBBR). Decolourization was only observed when a small molecular weight redox mediator was added together with the laccase. Under the conditions specified, violuric acid (5.7 mM) was the most effective mediator studied and almost complete decolourization was observed within 20 min. In contrast, 1-hydroxybenzotriazole (HOBT, 11 mM) decolourized RBBR at about a two-fold slower rate and to a lesser extent. Also, higher concentrations of HOBT were inhibitory which could be due to inactivation of laccase by the toxic HOBT radical. The commercial laccase formulation that contained phenothiazine-10-propionic acid as the mediator was least effective, giving 30% decolourization under equivalent conditions. We suggest that similar laccase plus mediator systems could be used for the detoxification of related anthraquinone textile dyes.

Anthraquinones↗
PubMed2001

Decolorization of an anthraquinone-type dye using a laccase formulation.

Decolorization of the dye Remazol Brilliant Blue R (RBBR) was studied, as it is representative of an important class of recalcitrant anthraquinone-type dyes. For this purpose a commercial laccase formulation (CLF) containing laccase, a redox mediator and a non-ionic surfactant was used. Small molecular weight components were removed from the CLF by gel filtration, which made it possible to compare the effect of its laccase alone. Apart from slightly better thermostability of the CLF as compared with the laccase alone, the pH and temperature profiles were similar regardless of the presence of the small molecular weight components. The laccase alone did not decolorize RBBR. A small molecular weight redox mediator (HBT) was necessary for decolorization to occur. A comparison of the kinetics of RBBR decolorization using the CLF and its laccase alone is reported. Provided that a redox mediator is included, it is suggested that laccase may be suitable for the wastewater treatment of similar anthraquinone dyes.

Anthraquinones↗
PubMed2000

[Infections in Senegalese children and adolescents with sickle cell anemia: epidemiological aspects].

Infection is the main factor of morbidity and mortality in children with sickle cell disease (SCD). The objective of this study is to determine it's epidemiologic outline in senegalese children and adolescents with SCD. We retrospectively studied infection data in all the charts of a cohort of 323 patients with SCD (307 SS, 13 SC and 3 s beta + thalassemia) followed at Albert Royer children hospital from january 1991 to december 1997. Serum sampling was systematically made for HIV and antigen HBs serology in all patients we received in the last 3 months (october to december 1997). Patients were aged from 5 months to 22 years (medium age = 8 years). 813 infection episodes were diagnosed, concerning 184 patients (56 per cent). SS patients were more affected (59 per cent) than the others (23 per cent, p = 0.04). ENT and broncho-pulmonary onsets were more frequent but had a generally benign course. Menigitidis, septicemia and osteomyelitis were exclusively diagnosed in SS patients. Their prevalences in this group were respectively: 1.0 per cent, 4.9 per cent and 9.8 per cent. HIV serology was determined in 155 patients, including 41 per cent with blood transfusion antecedents. All tests were negative. HBs antigen was determined in 104 patients and seroprevalence was 7.7 per cent in the whole group and 6.0 per cent in patients with transfusion antecedents and 7.7 per cent for the others. Plasmodium falciparum malaria onset was observed in 9.6 per cent of our patients and there was no case of cerebral malaria. Infection was involved in 9 of the 11 cases of death. Then infection constitute the major problem in children and adolescents with SCD in Dakar. However prevalences of severe onsets are comparable to data in Europe despite our poor follow up conditions. Senegal haplotype may lead to a good tolerance of SCD. Negative HIV serology and low HBs antigen seroprevalence in transfused patients are attributed to a relatively low level of HIV prevalence in the general population and a good transfusion security in Senegal.

Adolescent↗
PubMedDate not supplied

In vivo evaluation of the effects of gravitational force (+Gz) on over-the-wire stainless steel Greenfield inferior vena cava filter in swine.

This study was done to determine the effect of exposure to gravitational force (acceleration stress) on in vivo over-the-wire stainless steel Greenfield inferior vena cava filters. Fifteen pigs underwent venous cut down and placement of a stainless steel Greenfield filter. A 4-week observation period simulated realistic convalescence and allowed sufficient time for epithelialization. Ten pigs were exposed to acceleration stress in a centrifuge (3G run for 15 sec followed by rest until return to baseline heart rate, then a 9G run for 15 sec), with inertial loading in a head-to-tail direction (+Gz). Fluoroscopy during acceleration stress allowed assessment for filter migration. Five pigs were not exposed to acceleration stress. AP and lateral abdominal radiographs were obtained at post-filter placement, convalescence, and centrifuge exposure to determine the position and integrity of the filter. All 15 IVCs were resected and evaluated for gross or histological injury to the vessel wall. IVC filter placement was technically successful in all 15 pigs. Radiographic measurements were limited secondary to differences in pig positioning. Fluoroscopy showed no filter migration. All filters were securely attached to the vena cava by the hooks without gross evidence of perforation or hemorrhage. There were varying degrees of fibroplasia involving the hooks and tip of the filters in both the control and experimental groups. Histologically, there was evidence of prior hemorrhage at the level of the hooks, which was similar between the control and experimental groups. It is concluded that Greenfield filter position and vena caval integrity at the implantation site is unaffected by high acceleration stress.

Acceleration↗
PubMedDate not supplied

Use of a puncture needle for recanalization of an occluded right subclavian vein.

We report a patient in whom we used a puncture needle to initiate percutaneous recanalization of a chronic occlusion of the junction between the right subclavian vein and the right brachiocephalic vein. Under fluoroscopic guidance, an 18-gauge needle was used to puncture the right subclavian vein. When contrast material injected through the needle confirmed intravascular location, the needle was advanced until it deflected and perforated an occlusion balloon target positioned within the right brachiocephalic vein. This technique may be useful in patients with central venous occlusions that are refractory to traversal using traditional catheter and guidewire techniques.

Aged↗