Biomedical subjects

D Alfonso

Publications and source records attributed to D Alfonso.

5 recordsLinked to original sources

PubMed1997

Bioactive furonaphtoquinones from Tabebuia barbata (Bignoniaceae).

Tabebuia barbata (E. Mey) Sandw. (Bignoniaceae), locally known as "palo de arco", is indigenous to the upper Orinoco and Amazonas rivers. Brine shrimp lethality-directed fractionation and extensive column chromatography, normal-phase preparative TLC and normal-phase HPLC separation of the ethanol extract of the bark of this previously uninvestigated species has led to the isolation of five active compounds 1-5. The combined spectral evidence (UV, IR, 1H and 13C NMR and mass) identified these compounds as naphthoquinones. These compounds, characterized as lapachol (1), 2-acetylnaphtho-[2,3-b]-furan-4,9-dione (2), 2-acetyl-5-hydroxy-naphtho-[2,3-b]-furan-4,9-dione (3), 2-acetyl-8-hydroxy-naphtho-[2,3-b]-furan-4,9-dione (4), and (+)-8-hydroxy-2(1-hydroxy-ethyl) naphtho-[2,3-b]-furan-4,9-dione (5), were reported previously from other species of the genus Tabebuia but not from T. barbata. Compounds 2-5, reference adriamycin, were significantly cytotoxic against A-549 human lung adeno-carcinoma, MCF-7 human breast carcinoma, and HT-29 human colon carcinoma cells. The compounds isolated (1-5) were also shown to be inhibitors of electron transport in rat liver mitochondria, reference to rotenone, with IC50 values in the range of 15 microM to 82.5 microM. In addition, this study demonstrated that screening and activity-directed fractionation, using brine shrimp lethality as a simple and inexpensive bioassay, can effectively lead to potential antitumor compounds.

Animals↗

PubMed1996

SARs of annonaceous acetogenins in rat liver mitochondria.

The Annonaceous acetogenins represent a class of compounds with diverse bioactivities, including promising cytotoxicites. These are due, at least in part, to inhibition of complex I in the oxidative phosphorylation pathway in mitochondria. Fourteen Annonaceous acetogenins were tested in a rat liver mitochondrial oxygen uptake assay to probe additional structure-activity relationships. In this subcellular assay, the activity of non-adjacent bis-THF ring acetogenins depends on the distance between the two THF rings; the activity decreases to that of a mono-THF ring acetogenin if the distance is too long. When one THF ring is replaced with a tetrahydropyran ring, the activity remains comparable. The configuration of the THF ring, in mono ring compounds, seems to be more important than stereochemical differences in the rings of adjacent bis-THF ring compounds. Bullatacin, an adjacent bis-THF ring acetogenin, was used as a standard compound in every run to normalize the data.

Animals↗

PubMed1996

Longifolicin, longicoricin, and gigantetroneninone, three novel bioactive mono-tetrahydrofuran annonaceous acetogenins from Asimina longifolia (Annonaceae).

Longifolicin (1), longicoricin (2) and (2,4-cis and trans)-gigantetroneninone (3), three novel bioactive mono-tetra-hydrofuran (THF) gamma-lactone acetogenins, were isolated from the leaves and twigs of Asimina longifolia (Annonaceae) by directing the fractionation with the brine shrimp lethality test (BST). The structures were elucidated based on spectroscopic and chemical methods. Compounds 1-3 showed selective and potent cytotoxicities to certain human tumor cell lines.

Animals↗

PubMed1994

Flavonoids from Iochroma gesnerioides.

Two aglycones (kaempferol and quercetin) and three glycosides (isoquercitrin, kaempferol 3-sophoroside and quercetin 3-sophoroside) were isolated from Iochroma gesnerioides (Kunth) Miers (Solanaceae). Whereas the aglycones are common for the Solanaceae, their 3-sophorose derivatives are found only in three genera of this family. Their isolation and identification (mainly by 1H- and 13C-nmr) are reported here.

Flavonoids↗

PubMedDate not supplied

[Pulmonary ventricle bypass operations].

UNLABELLED: Cavopulmonary connections have been extensively used in the palliation of complex forms of congenital heart disease requiring some form of right heart bypass. We examine the mid term outcomes of pulmonary ventricle bypass operations in a single institution and performed by the same surgical team. POPULATION: Between March 1999 and April 2006, 62 patients underwent pulmonary ventricle bypass operations: bidirectional cavopulmonary anastomosis (Glenn procedure), total cavopulmonary connections (Fontan procedure) and one and a half ventricle correction in two cases. Age at operation averaged three years (range: 0.42-25 years) for the Glenn procedure and seven years (range: 3-14 years) for the Fontan procedure. There were 36 male patients (58%) and 26 female patients (42%). The most common indication for surgery was the single ventricle defect, present in 66% of patients. Associated lesions included: transposition of the great arteries in 16 patients (35.6%), bilateral superior vena cava in four patients (8.9%), situs ambigus in five patients (11%), situs inversus in another patient (2.2%), Ebstein disease in one patient (2.2) and coronary fistula in another patient (2.2%). Sub-aortic stenosis was present in one patient (2.2%). Palliative surgery was performed in all, but three patients (5%), before the Fontan procedure. RESULTS: Thirty two patients underwent bidirectional cavopulmonary anastomosis and thirty patients underwent cavopulmonary connections, total or 2nd stage. Mean cardiopulmonary bypass times were 50.6+/-21.9 minutes for the Glenn procedure and 88.5+/-26.3 minutes for the Fontan procedure. There was no intra-operative mortality, but two patients (3.2% (died in the first month after surgery; one due to failure of the Glenn circuit and sepsis and the other due to a low cardiac output syndrome and multi-organ dysfunction. Mean ventilation time was 5.2+/-1.7 hours for the Glenn operation and 6.2+/-3.2 hours for the Fontan operation. The mean length of stay in ICU was 3.4+/-2.8 days for patients undergoing the Glenn operation and 4.6+/-3.1 days for patients undergoing the Fontan operation and the mean length of hospital stay was 10.6+/-5.8 days for the Glenn operation and 19.1+/-12.6 days for the Fontan operation respectively. The mean follow up time was 4+/-2.1 years (minimum 0 years and maximum seven years), most patients being in NYHA class I. Epicardiac pacemakers were implanted in three patients due to arrhythmias. Two re-operations (6.7%) were needed, both in the same patient, after the Fontan procedure, this patient eventually died a few years after surgery. CONCLUSIONS: The immediate and mid term outcomes of pulmonary ventricle bypass operations can have excellent results. From our point of view there has been an improvement, namely in the use of the extracardiac conduit technique in the 2nd stage of the Fontan operation.

Adolescent↗