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Biomedical subjects

D Alonso

Publications and source records attributed to D Alonso.

At least 37 records · Page 2Linked to original sources
PubMed1998

Neuronal and inducible nitric oxide synthase and nitrotyrosine immunoreactivities in the cerebral cortex of the aging rat.

Neuronal and inducible nitric oxide synthase (nNOS and iNOS) and nitrotyrosine immunoreactivities were localized and semiquantitatively assessed in the cerebral cortex of aged rats by means of light microscopic immunocytochemistry and Western blotting, using a new series of specific polyclonal antibodies. In the aged rats the strongly nNOS-immunoreactive multipolar neurons found in layers II-VI of the cortex of young rats were seen in similar numbers, but showed varicose, vacuolated, and fragmented processes, with an irregular outline and loss of spines. A large number of more weakly nNOS-positive neurons, characterized by a ring of immunoreactive cytoplasm, and not seen in young rats, were observed in layers II-VI of aged rat cortex. While no iNOS-immunopositive neurons were found in the cortex of young rats, a large number of such neurons appeared throughout the aged rat cortex. Nitrotyrosine-positive cells outnumbered total NOS-positive neurons in the cortex of young rats, but this relation was inverted in the aged rats, although these showed a slight increase in the number and staining intensity of nitrotyrosine-positive cells. Western blots of brain extracts showed a several-fold increase in both nNOS- and iNOS-immunoreactive bands in the aged rat, but a less marked increase in nitrotyrosine-containing proteins. The results suggest that while nNOS and iNOS expression is substantially increased in the aged rat cortex, this is not necessarily accompanied by a proportionate increase in nitric oxide synthesis. The mechanisms underlying the increased expression of nNOS and iNOS, and the functional implications of this increase, require elucidation.

Aging↗
PubMed1998

Burn injuries following explosion of car heaters.

We report four cases of burn injuries inflicted by hot coolant after the explosion of the heating unit in four motor-vehicles of the same make and version, in similar circumstances while the patients were driving their cars. Burns of this type can cause considerable morbidity with an accompanying high risk of a traffic accident.

Accidents, Traffic↗
PubMed1998

Cytotoxic activity of selected plants used as antitumorals in Mexican traditional medicine.

Crude extracts from nine plants widely used in Mexican traditional medicine for the treatment of cancer have been subjected to a bioscreening study to detect cytotoxic activity against human tumor cells. Three different extracts (petroleum ether, ethylacetate, and methanol) from each plant species, were tested towards KB, HCT-15 COLADCAR and UISO-SQC-1 cell cultures. The results showed that three plants Colubrina macrocarpa (Cav.) Don (Rhamnaceae), Acacia pennatula (Schltdl. and Cham.) Benth (Leguminosae) and Hemiangium excelsum (HBK.) Smith (Hippocrateaceae), exhibited important cytotoxic activity showing a certain degree of selectivity against the tested cells in culture.

Antineoplastic Agents, Phytogenic↗
PubMed1997

Effect of methadone addiction on glucose metabolism in rats.

Female albino rats were exposed to methadone over a 35-day period by addition of the drug in their drinking water. The final dose of the drug was 1.8 mg/kg body weight per day. After this period, the drug was withdrawn from some animals for 30 days (postexposure). Compared to unexposed controls, serum glucose levels rose during exposure and returned to control levels postexposure. Oral glucose tolerance tests showed impairment in 35-day drug-exposed animals compared to controls and postexposure. The activities of three key enzymes of glycolysis and three key enzymes of gluconeogenesis were measured in liver during and at the end of the exposure period, as well as postexposure. Compared to unexposed controls and postexposure, specific activities of two glycolytic enzymes in livers of exposed animals-hexokinase and phosphofructokinase 1-were significantly reduced, whereas the activity of a third glycolytic enzyme-pyruvate kinase-was unchanged. The specific activities of two gluconeogenic enzymes-glucose-6-phosphatase and fructose-1,6-biphosphatase-were significantly elevated in the drug-exposed animals compared to controls, whereas the activity of a third enzyme-phosphoenolpyruvate carboxykinase-was unchanged. These data indicate that methadone addiction produces a metabolic state similar to insulin-resistant diabetes.

Animals↗
PubMed1996

Bioactive polyacetylenes from Bidens pilosa.

From the methanolic extract of the whole plants of Bidens pilosa the new beta-D-glucopyranosyloxy-3-hydroxy-6(E)-tetradecen-8, 10,12-triyne besides a known polyine has been isolated and identified mainly by IR and NMR methods. The new compound showed overgrowing action against normal and transformed human cell lines in culture.

Alkynes↗
PubMed1996

Atrial natriuretic factor (ANF)-like immunoreactivity and secretory granules in internal gills tadpoles of South American toad Bufo arenarum (Hensel).

In this study, an ultrastructural and immunohistochemical analysis was carried out on the presence of Atrial Natriuretic Factor-like substance in the internal gills of premetamorphic larval stages of the South American toad. The results of immunohistochemical study indicate that, at larval 27 and following stages, ANF-like immunoreactive cells are seen in internal gills. At electron-microscopy level "secretory granules" similar to those ANF-immunoreactives granules of myoendocrine cells of the same species are seen only in clear cells of gill rakers. Our results reveal the occurrence of ANF-like substance in Bufo arenarum gills and may suggest that "cardiac hormones" might play a paracrine and/or autocrine role in the water and electrolyte balance at internal gills level.

Animals↗
PubMed1995

Functional analysis of Gln-237 mutants of HhaI methyltransferase.

When the HhaI (cytosine-5) methyltransferase (M.HhaI) binds DNA it causes the target cytosine to be flipped 180 degrees out of the helix. The space becomes occupied by two amino acids, Ser-87 and Gln-237, which enter the helix from opposite sides and form a hydrogen bond to each other. Gln-237 may be involved in specific sequence recognition since it forms three hydrogen bonds to the orphan guanosine, which is the partner of the target cytosine. We have prepared all 19 mutants of Gln-237 and tested their biochemical properties. We find that mutations of this residue greatly affect the stability of the M.HhaI-DNA complex without affecting the enzyme's specificity for the target sequence. Surprisingly, all mutants retain detectable levels of enzymatic activity.

Base Sequence↗
PubMed1994

Cytotoxic and antimicrobial screening of selected terpenoids from Asteraceae species.

Twelve pure compounds originally obtained through a systematic chemotaxonomical study with Mexican plants of the Asteraceae, were subjected to a cytotoxic and in vitro antimicrobial screening. Three different cell lines in culture (KB, KB-VI and P388) were used in the cytotoxicity assay, while antimicrobial activity was tested against Gram-positive and Gram-negative bacteria, as well as Candida albicans. Of the twelve terpenoids tested, only taraxasterol showed antimicrobial activity against Staphylococcus aureus. The significant cytotoxic activity exhibited by five sesquiterpene lactones, and the moderate cytotoxicity of an eudesmane, is discussed.

Animals↗
PubMed1992

[Why is intussusception an antireflux mechanism?].

One of the aims of bladder substitution or augmentation using the intestine is to preserve renal function. If reflux impairs renal function, an antireflux mechanism should be attempted. Direct ureteroileal reimplantation with spatulation of the ureter is safer and carries a lower risk of stenosis. The antireflux mechanism is created by ileoileal or ileocecal intussusception without involvement of the ureter. Thus we can diminish the risk of stenosis and reflux at the same time.

Humans↗
PubMed1989

States of stability/lysis in human fetal and adults red blood cells.

In human red blood cells from umbilical cord (NRBC) and from adult (ARBC) blood we measured: (i) the equilibrium distribution (medium/cells) for haemoglobin as a function of medium osmolality (osmotic fragility curve) and (ii) the rate of haemoglobin loss to a hypotonic medium of fixed osmolality. From the analysis of the osmotic (cumulative) fragility curve, a subpopulation of high resistance (young?) cells was individualized only in samples from cord blood. The differences presented in the rate of haemoglobin loss between samples of umbilical cord and adult's blood point to distinct cell surface restrictions (cytoskeleton and/or plasma membrane phospholipid) to haemoglobin leak in both cells. Uniformly distributed (among all cells in both samples) differences could explain the distinct rates of haemoglobin loss. However, marked differences restricted to only a subpopulation of cord blood cells could also explain these results.

Adult↗
PubMed1989

[Goldenhar syndrome].

We present a report on 9 patients with Goldenhar's Syndrome, and the criteria used for the diagnosis. Familiar data and clinical characteristics. Are described and discussed with that of other authors. The medical literature about this syndrome shows a lack of uniformity on the criteria necessary to diagnose the syndrome, as well as the role of the pathogenic factors. The authors propose the adoption of uniform criteria on the basis of their own experience and the report of Feingold and Baum. They can help to better delineate the differences between Hemifacial Microsomia and Goldenhar's Syndrome.

Child↗
PubMed1989

[Liver abscesses due to Klebsiella pneumoniae and acute anterior uveitis].

Liver abscesses are not very frequent and those produced by Klebsiella spp. are quite exceptional. These germs have been related to the development of acute anterior uveitis (AAU) in patients whose susceptibility has been linked to HLA B27. We present a case of a female, HLA B27 negative, who developed AAU during a course of liver abscesses caused by Klebsiella pneumoniae.

Acute Disease↗
PubMed1983

Differential inhibition by aspirin of vascular and platelet prostaglandin synthesis in atherosclerotic patients.

We studied the ability of a single oral dose of aspirin to inhibit prostacyclin synthesis by human arterial and venous tissue and to inhibit thromboxane A2 synthesis by platelets in 70 patients who were undergoing aortocoronary bypass. A dose of 40, 80, or 325 mg of aspirin was administered 12 to 16 hours before surgery. The generation of thromboxane in serum--which provides an estimate of platelet thromboxane production--was reduced from the control value by 77, 95, and 99 per cent after single doses of 40, 80, and 325 mg of aspirin, respectively. By contrast, prostacyclin production in aortic tissue that was removed at operation was reduced by only 35, 38, and 75 per cent, respectively, in response to these doses. Production of prostacyclin in saphenous-vein tissue (not tested after 40 mg of aspirin) fell only slightly and not significantly after 80 mg but was reduced by 85 per cent after 325 mg. These findings indicate that a low dose of aspirin (40 to 80 mg) can largely inhibit platelet aggregation and thromboxane synthesis but has much less effect on prostacyclin production in arterial and venous endothelium.

Administration, Oral↗