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Biomedical subjects

D Ferreira

Publications and source records attributed to D Ferreira.

At least 19 recordsLinked to original sources
PubMed2003

Microbial transformation of the phthalideisoquinoline alkaloid, (-)-beta-hydrastine.

The phthalideisoquinoline alkaloid (-)-beta-hydrastine is one of the main active constituents of the medicinal plant, Hydrastis canadensis, which is used in many dietary supplements intended to enhance the immune system. Treatment of hydrastine with the fermentation broth of Polyporous brumalis (ATCC 34487) as a model for mammalian metabolism, gave a new alkaloid, (1S)-hydroxyhydrastine. Structure elucidation was based primarily on NMR and chiroptical studies.

Alkaloids↗
PubMed2001

Detection of Epstein-Barr virus in tonsillar tissue of children and the relationship with recurrent tonsillitis.

Recurrent tonsillitis has been the subject of much investigation. Events considered to predispose to or cause recurrent tonsillitis (RT) include the misuse of antibiotic therapy in acute bouts, alterations in the microflora, structural changes in crypt epithelium and certain viral infections. Epstein-Barr Virus (EBV) infection usually occurs in early childhood and can persist in palatine tonsil lymphocytes to induce tonsillitis at a later date. We have examined the presence of EBV in palatine tonsils in order to assess the relationship between this virus and recurrent acute tonsillitis. Tonsils were obtained from 85 patients, 2--14 years old (mean 5.6 years old) who underwent tonsils and adenoid (T&A) removal because of recurrent tonsillitis (RT) or T&A hypertrophy (TH). Tissues specimens were processed for non-isotopic in situ hybridization (ISH) using EBER 1/2 oligonucleotides (EBER RNA). The indications for surgery were RT in 42 patients and TH in 43 patients. In 25 out of 85 cases (29.4%) a positive EBER RNA reaction (15 RT and 33 TH) was found. The chi(2)-test showed no statistically significant difference in frequency of positive results between RT and TH group. We conclude that tonsils of children can be colonized by EBV and that the virus may be implicated in RT and TH.

Adolescent↗
PubMed2001

Structure and stereochemistry of triflavanoids containing both ether and carbon-carbon interflavanyl bonds.

The first triflavanoids with both C-C and C-O-C interflavanyl bonds, epioritin-(4beta-->6)-epioritin-(4alpha-->4)-epioritin-4beta-ol, epioritin-(4beta-->3)-epioritin-(4beta-->6)-epioritin-4beta-ol and epioritin-(4beta-->3)-epioritin-(4beta-->6)-epimesquitol-4alpha-ol, were identified in the heartwood of Acacia caffra. The ethereal interflavanyl bond is readily susceptible to reductive cleavage with sodium cyanoborohydride in trifluoroacetic acid/dichloromethane which hence permits the unequivocal assignment of the absolute configuration of constituent flavanyl units.

Ethers↗
PubMed2001

A weakly antimalarial biflavanone from Rhus retinorrhoea.

The biflavanone (2S,2"S)-7,7"-di-O-methyltetrahydroamentoflavone and five known flavonoids, 7-O-methylnaringenin, 7,3'-O-dimethylquercetin, 7-O-methylapigenin, 7-O-methylluteolin, and eriodictyol were isolated from the leaves of Rhus retinorrhoea Steud, Ex Olive. The biflavanone exhibited moderate antimalarial activity with IC50 0.98 microg/ml against Plasmodium falciparum (W2 Clone) and weak activity against P. falciparum (D6 Clone) with IC50 2.8 microg/ml. Nevertheless, it did not display any cytotoxicity. 7-O-Methylnaringenin showed weak antimicrobial activity against Candida albicans, C. krusei, Staphylococcus aureus, Mycobacterium smegmatis, M. intracellulare, and M. xenopi with MIC approximately 100 microg/ml. Characterization of each compound was based on spectral analysis and comparison with reported data.

Animals↗
PubMed2001

Blunted adenosine A2a receptor function in platelets in patients with major depression.

There is provisional evidence of involvement of adenosine in depression. In this study, the second messenger intracellular calcium response in platelets was measured in patients with major depression and controls using spectrofluorometry. The primary result of this study was a statistically significantly blunted second messenger response to agonist stimulation in the depressed group compared to the control group at the 50 and 100 nM and 1 microM dosage levels. This suggests that dysregulation of the adenosine A2a receptor may be present in depression.

Adenosine↗
PubMed2001

[Prognosis of mitral commissurotomy. Study of 1134 mitral patients 20 years later].

With a test sample (n = 323), consisting of the answers to an inquiry about the patients with operated mitral stenosis (n = 1134), between 1952 and 1978, in "Hospital Pulido Valente", Lisbon, we compared the group of survivors with the decreased in the relation to sex, age, valvular lesion, type of surgery, valvular area before and after surgery and existence of incompetence. We concluded that mitral stenosis was more frequent in females (4/1), but it had a worse prognosis in males. The lower the age at the time of surgery the better long time prognosis. Digital and instrumental valvulotomy had similar mortality. Valvular incompetence had a worse prognosis and is associated with larger valvular area.

Adolescent↗
PubMed2000

Structure and synthesis of the first procassinidin dimers based on epicatechin, and gallo- and epigallo-catechin.

The range of natural dimeric procassinidins is extended by identification of cassiaflavan-(4alpha-->8)-epicatechin, cassiaflavan-(4alpha 8)-epigallocatechin, cassiaflavan-(4beta-->8)-epicatechin, cassiaflavan-(4beta-->8)-epigallocatechin, cassiaflavan-(4beta-->8)-gallocatechin, ent-cassiaflavan-(4beta-->8)-epicatechin and cassiaflavan-(4alpha-->6)-epicatechin in the bark of Cassia petersiana. Their structures and absolute configuration were confirmed by synthesis.

Cassia↗
PubMed2000

Podophyllotoxin.

Podophyllin, an ethanolic extract of Podophyllum peltatum L. or P. emodi Wall (syn. P. hexandnum Royle), is a good source of the aryltetralin-type lignan, podophyllotoxin. The latter compound, as well as its congeners and derivatives exhibit pronounced biological activity mainly as strong antiviral agents and as antineoplastic drugs. The podophyllotoxin derivatives etoposide, etopophos (etoposide phosphate), and teniposide are thus successfully utilized in the treatment of a variety of malignant conditions. Continued research on the Podophyllum lignans is currently focused on structure optimization to generate derivatives with superior pharmacological profiles and broader therapeutic scope, and the development of alternative and renewable sources of podophyllotoxin.

Podophyllotoxin↗
PubMed2000

Tyrosinase catalysed biphenyl construction from flavan-3-ol substrates.

Mushroom tyrosinase catalysed oxidation of three flavan-3-ols, viz. catechin, fisetinidol and mesquitol, was conducted to construct biphenyl bonds. Exposure of the flavan-3-ols to tyrosinase and subsequent trapping of the o-quinone intermediates resulted in the formation of novel flavan-3-ol derivatives, the structures of which were elucidated by mono- and two-dimensional 1H-NMR experiments. Application of the methodology resulted in the improved synthesis of the natural flavan-3-ol dimer, mesquitol-[5-->8]-catechin, previously isolated from Prosopis glandulosa.

Agaricales↗
PubMed2000

Polyphenols, condensed tannins, and other natural products in Onobrychis viciifolia (Sainfoin).

An acetone/water extract of the fodder legume Onobrychis viciifolia afforded arbutin, kaempferol, quercetin, rutin, afzelin, the branched quercetin-3-(2(G)-rhamnosylrutinoside), the amino acid L-tryptophan, the inositol (+)-pinitol, and relatively high concentrations of sucrose (ca. 35% of extractable material). Acid-catalyzed cleavage of the condensed tannins with phloroglucinol afforded catechin, epicatechin and gallocatechin as the terminal and extender units, but epigallocatechin was only present in extender units. The condensed tannins in O. viciifolia presumably consist of hetero- and homopolymers containing both procyanidin and prodelphinidin units. Comparison of data from the present study and the literature suggests that sainfoin tannins have a highly variable composition with cis:trans ratios ranging from 47:53 to 90:10 and delphinidin:cyanidin ratios from 36:64 to 93:7. The composition of terminal and extender units in sainfoin tannins seems to be cultivar specific.

Biological Products↗
PubMed2000

[Diagnosis of a cardiac mass--a case report].

The authors describe a case of a recidivant pericardial effusion associated to a mass with an unusual, filamentous aspect that involved the upper part of right atrium and surrounded the upper vena cava. Despite the diagnostic techniques employed--transesophageal echocardiography and magnetic resonance imaging, the etiologic diagnosis could not be done, so a biopsy of the mass was made by percutaneous approach using transesophageal echocardiography to control the procedure. The histopathological result was an angiosarcoma of the right atrium. The authors make a brief review of the literature about this rare condition.

Echocardiography, Transesophageal↗
PubMed1999

Evaluation of the antimicrobial potency of tannins and related compounds using the microdilution broth method.

The antimicrobial activity of a total of 27 tannins and related compounds was evaluated against 8 microorganisms, including 2 Gram-positive (Bacillus subtilis, Staphylococcus aureus), 4 Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis), and 2 yeasts (Candida albicans, Cryptococcus neoformans). The compounds tested were generally found to possess only weak to moderate antibacterial, but fairly high anticryptococcal activities. Attention is given to structure-activity relationships with emphasis on simple galloyl esters, hydrolyzable tannins and proanthcyanidins among this class of secondary products.

Anti-Bacterial Agents↗
PubMed1999

[Thrombolysis in pulmonary embolism - initial experience].

UNLABELLED: Pulmonary embolism (PE) is a clinical situation difficult to diagnose, at times of great clinical instability, above all when it is massive, which leads to difficulties in the approach and treatment of patients. The treatment has not had any major innovations in recent years, being conventional the use of heparin and more rarely embolectomy. Recently, some clinical trials have defended the use of thrombolytics. The objéctive of this paper is to present our experience, although the series is still small. From April 1996 to November 1997, 11 patients were admitted to our Cardiac Intensive Care Unit with the clinical suspicion of PE, 5 of which with great hemodynamic instability and suspicion of massive PE. The clinical presentation was sudden dyspnea and loss of consciousness in 2 patients, dyspnea and hypotension in 2 patients and shock and respiratory arrest in one case. Gasimetry revealed acute hypoxemia and hypocapnia in all cases, average partial blood pressure in O2 (pO2) of 59 mm Hg and CO2 (pCO2) of 19 mm Hg. ECC and thorax x-ray contributed to the diagnosis in 3 patients, transthoracic echocardiography was decisive for the diagnosis in 5 cases, with visualisation of the thrombus by transesophageal echocardiography in 3 patients. All patients were monitored by Swan-Ganz catheter, the average systolic pulmonary artery pressure (PAP) was 74 mm Hg. Thrombolysis with rTPA (10 mg bolus followed by 90 mg in perfusion in 2 hrs) was administered in 6 episodes in 5 patients. Only in the case of the patient in shock were other complications related to the use of thrombolytics namely high digestive hemorrhage. There was a clear clinical improvement in all cases with great relief of dyspnea reduction of cyanosis and jugular engurgitation. The patient in shock recovered systemic pressures and improved the hemodynamic state. A significant reduction in PAP was observed (average of 32.5 mm Hg). PE recurred in two cases: with one death and therapeutic thrombolytic was repeated in the other patient with good results. After discharge, all patients remained asymptomatic under oral anticoagulation. IN CONCLUSION: Despite this small series, the results favour the use of thrombolytics in PE with a clear clinical and hemodynamic improvement.

Adult↗
PubMed1999

Echocardiographic evaluation in 485 aeronautical workers exposed to different noise environments.

INTRODUCTION: Vibroacoustic disease (VAD) is a heterogeneous and systemic entity, caused by long term (> or =10 yr) exposure to noise environments characterized by large pressure amplitude and low frequency (LPALF) (> or =90 dB SPL, < or = 500 Hz), and not explained by other possible etiologic agents. The goal of this study was to identify possible structural changes in hearts of men with suspected VAD. METHODS: A total of 485 men were divided into 3 noise groups: no noise exposure (< or =70 dB), n = 48 (Group I); moderate noise exposure, (>70dB and < 90 dB), n = 113 (Group II); and intense noise exposure (> or =90 dB), n = 324 (Group III). Echo-Doppler studies were performed (HP SONOS 1500) and recorded on coded videotapes. Three observers performed blinded evaluations of 26 echo-Doppler parameters. For the purpose of the present study only 12 morphological parameters were compared among the groups: thickening of the mitral, aortic, tricuspid, and pulmonary valves, pericardium and endocardium; mitral valve regurgitation, prolapse and ruptured chordae tendinae; and inflow velocities. Thickness and severity of the applicable parameters were scored in seven-grade scale (0,0.5,1, ...,3). RESULTS: All evaluated parameters were statistically significantly different in Group I vs. Group III, except flow velocity E. Comparison of Group I vs. Group II revealed statistically significant differences in mitral, aortic, tricuspid and pericardial thickening, with the strongest evidence for mitral and pericardial structures. CONCLUSIONS: This confirms the results of previous studies. Occupational exposure to noise environments characterized by LPALF noise causes structural changes in the heart. Mitral valve and pericardial thickening constitute the first signs of VAD.

Adult↗