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Biomedical subjects

A De Souza

Publications and source records attributed to A De Souza.

12 recordsLinked to original sources
PubMed2000

The accuracy of citation and quotation in otolaryngology/head and neck surgery journals.

A high rate of errors of citation and quotation has been reported in the publications of many medical specialties. The aim of this study was to determine the prevalence of citation and quotation errors in otolaryngology/head and neck surgery journals. A retrospective analysis was performed based on the first issue for 1997 of each of four journals: Laryngoscope; Annals of Otology, Rhinology and Laryngology; Clinical Otolaryngyology; and Journal of Laryngology and Otology. A sample of 50 references from each journal was randomly selected and each was checked for accuracy against the original referenced paper. Citation errors were categorized as major, intermediate or minor and quotation errors as major or minor. Citation errors occurred in 37.5% of the references, 11.9% of which were considered major errors. Quotation errors occurred in 17%, with 11.1% major errors. This prevalence is similar to the established error rate in medical literature.

Bibliometrics↗
PubMed2000

Vascular endothelial growth factor release following coronary artery bypass surgery: extracorporeal circulation versus 'beating heart' surgery.

AIMS: The aim of this study was to examine the circulating levels of vascular endothelial growth factor, following coronary artery bypass graft surgery performed using both standard cardiopulmonary bypass or the 'octopus technique' on the beating heart. BACKGROUND: Vascular endothelial growth factor has a number of effects that are beneficial in the setting of coronary artery bypass graft surgery including cardioprotection, potent angiogenic activity and amelioration of intimal hyperplasia. Hypoxia is a powerful stimulator of vascular endothelial growth factor expression yet the ability of ischaemia, occurring during coronary artery bypass graft surgery, to induce vascular endothelial growth factor production is unknown. METHODS AND RESULTS: Serum vascular endothelial growth factor levels were determined in patients undergoing coronary artery bypass graft surgery with standard cardiopulmonary bypass (CPB-CABG group; n=20), with off-pump coronary artery bypass; (OP-CABG; n=12) and in patients undergoing non-cardiac major surgery (n=6). The effect of hypoxia on vascular endothelial growth factor release by neonatal rat cardiac myocytes in vitro was studied. In the CPB-CABG group vascular endothelial growth factor levels were significantly increased to 78.5+/-39.3 and 110.5+/-16.3 pg. microl(-1)8 and 24 h post-operatively, declining to 14.9+/-9.9 pg. microl(-1)by 48 h to pre-operative values (14.4+/-8.6 pg. microl(-1)). Significantly higher vascular endothelial growth factor levels were also present in the OP-CABG group 3, 6 and 24 h post-operatively (levels 136. 6+/-29.3, 143+/-26.12 pg. microl(-1)and 93.5+/-20.1 pg. microl(-1), respectively). However, non-cardiac major surgery did not result in elevated vascular endothelial growth factor levels post-operatively (46.36+/-9.76 vs pre-surgery levels of 26.84+/-6.1 pg. microl(-1)). Either 15 min or 3 h of hypoxia stimulated vascular endothelial growth factor release from neonatal rat cardiac myocytes in vitro. Twenty-four and 48 h post hypoxia, levels of vascular endothelial growth factor were significantly elevated by approximately 17.5- and 48.5-fold respectively. CONCLUSIONS: These data demonstrate myocardial ischaemia secondary to CPB-CABG and OP-CABG to be a potent stimulator of vascular endothelial growth factor production, which may have implications for graft endothelialization and cardiovascular haemodynamics post-operatively.

Animals↗
PubMed1997

The surgical management of empyema thoracis.

Empyema thoracis remains a common thoracic problem with challenging management strategies. We analysed retrospectively 107 consecutive patients treated for empyema thoracic over a 5-year period. The majority of patients (75%) were male with a mean age of 51 years. Common presenting symptoms were cough, dyspnoea, chest pain and pyrexia. The mean duration of pre-admission symptoms was 7.5 weeks. The causes of empyema were pneumonia, malignancy, iatrogenic injury and trauma. The most frequently isolated organism was Streptococcus milleri. In 71% of patients there was an underlying systemic disorder. Forty-nine patients (46%) underwent an unsuccessful therapeutic procedure prior to admission to the surgical units. In the units, 24 patients received closed intercostal chest tube drainage, 14 of whom required further intervention. Two patients were treated with repeated thoracocentesis. The majority of patients underwent a surgical procedure in the first instance: rib resection and drainage (5), decortication (22), and more extensive procedures (9) with only two patients requiring further surgery. The mean post-operative stay was 16 days and the hospital mortality was 13%. We recommend early referral of all empyema patients to thoracic units, where assessment and definitive procedures can be performed with high chances of success and moderate risk of morbidity and mortality.

Adolescent↗
PubMed1991

High and prolonged pulmonary tissue concentrations of azithromycin following a single oral dose.

Antibiotic concentrations in pulmonary tissue samples and plasma were studied in this open investigation. Twenty-nine patients scheduled for elective pulmonary surgery received a single oral dose of 500 mg azithromycin 24, 72, 96 or 120 h prior to the operation; two patients received 250 mg b.i.d. Blood samples were taken before and at the time of resection, and tissue was obtained during surgery. Plasma and tissue concentrations of azithromycin were measured by high performance liquid chromatography (HPLC) and a microbiological bioassay. Only one patient had a detectable plasma concentration of azithromycin (0.13 micrograms/ml), measured 24 h post-dose by HPLC. However, high and sustained levels were found in lung tissue: mean concentrations measured by HPLC were 3.10 micrograms/g (SD +/- 2.17), 2.55 micrograms/g (SD +/- 1.36), 3.94 micrograms/g (SD +/- 2.40) and 3.13 micrograms/g (SD +/- 0.50) at 24, 72, 96 and 120 h, respectively. Bioassay results were similar to those for the HPLC assay. In summary, azithromycin levels in pulmonary tissue remained close to 3 micrograms/g for up to 5 days after a single oral 500 mg dose, in contrast to plasma levels which were much lower. The lung concentrations found are inhibitory for many sensitive respiratory pathogens and short-course azithromycin therapy is therefore a possibility.

Administration, Oral↗
PubMed1991

Elastic-related fibers in the annular ligament of the stapes-oval window articulation. An electron microscopic and histochemical study in the rat and the rabbit.

The annular ligament that attaches the circumference of the base of the stapes to the margin of the oval window (fenestra vestibuli) was stained with selective methods for elastic system fibers and was also studied at the ultrastructural level after tannic acid-glutaraldehyde fixation. Although the annular ligament is devoid of elastic fibers, it is rich in elastic-related fibers (i.e. = oxytalan and elaunin fibers). Elaunin fibers predominate in the annular ligament itself and they are continuous with the oxytalan fibers which are embedded in the matrix of the articular cartilage.

Animals↗
PubMed1990

[Degradation of diazepam in aqueous solution. Simulation essay by action of diluted hydrogen peroxide].

The mild oxidation of diazepam by hydrogen peroxide in neutral medium at room temperature in daylight is reported. The oxidation product has been isolated and purified and its purity determined by thin layer chromatography. It has been identified by spectroscopy, chiefly by infrared and mass spectroscopy. Finally it has been compared, by high pressure liquid chromatography, to the product from an aqueous diazepam solution placed 6 months at room temperature in daylight.

Chromatography, Thin Layer↗
PubMed1987

Evolutive and prognostic aspects in gastric cancer. Analysis of 189 cases.

The cases of 189 patients treated at the Surgery Service for gastric carcinoma from January 1960 to December 1978 and followed until April 1984 were reviewed in terms of evolutive behavior. Correlations between sex, age, duration of symptoms, site of tumors, lymph node metastases, stage of tumors, operability, resectability, treatment and survival were attempted. With respect to age, of the patients not operated on, survival was longer for more advanced age; the opposite occurred for the group of patients who were operated on. The impairment of lymph nodes was decisive in shortening survival; men were affected more than women and had a worse prognosis. When the tumors were located in the proximal third of the stomach, the survival rate was longer than when they were located in the distal portion and middle third of the stomach. Patients who had experienced digestive symptoms for a long time survived longer than those with a short history. It was concluded that the main prognostic factor was resectability and, regardless of any other variables, only patients from the group submitted to gastric resection survived more than 5 years.

Adult↗