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Biomedical subjects

A Castell

Publications and source records attributed to A Castell.

8 recordsLinked to original sources
PubMed2004

Morphometric analysis of mice uteri treated with the preservatives methyl, ethyl, propyl, and butylparaben.

The alkyl esters of p-hydroxybenzoic acid (PHBA) known as parabens (Pbens) are widely used as preservatives in food, pharmaceuticals, and cosmetics. Several in vivo and in vitro studies have shown these compounds to be estrogenic. Here, for the first time, we present evidence of their estrogenicity using a morphometric analysis of uteri from mice treated with the preservatives methylparaben (MePben), ethylparaben (EtPben), propylparaben (PrPben), and butylparaben (BuPben) compared with estradiol (E2). Different groups of adult ovariectomized (Ovx) CD1 mice were subcutaneously (sc) treated daily for three days with two different equimolar doses (362 and 1086 micromol/kg) of the Pbens: MePben (55 and 165 mg/kg), EtPben (60 and 180 mg/kg), PrPben (65 and 195 mg/kg), BuPben (70 and 210 mg/kg), E2 (10 microg/kg; 0.036 micromol/kg), and vehicle (propyleneglycol; V, 10 mL/kg). On the fourth day, uteri were dissected, blotted, weighed, and placed in a fixative solution for 24 h. The paraffin embeded uteri were cut to obtain 7 microm thick transversal sections. Luminal epithelium heights (LEH), glandular epithelium heights (GEH), and myometrium widths (MW) were measured. The highest Pbens dose was able to produce uterotrophic effects (38 to 76%) compared to E2 efects (100%). The relative uterotrophic potency to E2 (100) was from 0.02 to 0.009. Significant increases (P < 0.05) in LEH, GEH, and MW as compared with V were obtained: LEH from 87 to 113% (E2 153%), GEH from 10 to 40% (E2 60%), and MW from 35 to 43% (E2 88%). These results confirm that Pbens at the doses assayed here induce estrogenic histological changes in the uteri of Ovx mice.

Animals↗
PubMed2000

L-DOPA-induced neurotoxic and apoptotic changes on cultured chromaffin cells.

Adrenal chromaffin cell (ACC) transplantation has been considered as one of the therapeutic strategies for Parkinson disease (PD). This strategy involves the administration of L-DOPA, although in reduced doses, to ACC-transplanted patients. Using cytochemical and morphological methods, we examined the effects of clinically applicable concentrations of L-DOPA on cultured chromaffin cells. We found an increase of cell death in both necrotic and apoptotic patterns. These data suggest that therapeutic preventive measures during ACC transplantation processes for PD should be taken.

Animals↗
PubMed2000

Immunocytochemical, ultrastructural and neurochemical evidences on synaptogenesis and dopamine release of rat chromaffin cells co-cultured with striatal neurons.

The results reported herein address the question of synaptogenesis between adrenal chromaffin cells and striatal neurons. The release of dopamine from chromaffin cells in the presence of striatal neurons was also examined. Co-culture of newborn rat chromaffin cells and striatal neurons at 1:1 ratio was made. Cultures were examined morphologically using immunocytochemistry and ultrastructural techniques (transmission electron microscopy), while quantitation of dopamine in the culture media by HPLC-ECD was also determined. Neurite outgrowth from chromaffin cells was enhanced in the presence of striatal neurons and numerous synaptic-like contacts between these two cell types were observed. Higher concentration of dopamine was also present in the co-culture medium as compared with those containing only chromaffin cells. The development of synapses between these two types of cells may give support to the functionality of transplants in human cases of Parkinson disease (PD).

Animals↗
PubMed1997

Characterization of melittin effects in synaptosomes.

The effects of melittin at increasing concentrations on: [3H]GABA release from mouse brain synaptosomes; on the radioactivity released from [3H]arachidonic acid labeled synaptosomal membranes; on synaptosomes ultrastructure and on the leakage of the cytoplasmic marker, lactate-dehydrogenase (LDH) was investigated. Melittin 0.3, 1, 3, 7, and 10 microM progressively increases [3H]GABA release, but the efficacy of melittin is decreased when the amount of tissue exposed to a constant concentration of the toxin increases. The release of [3H]GABA induced by melittin below 3 microM is Ca2+ dependent, but not that induced by the higher concentrations. The Ca2+ dependent fraction of the [3H]GABA released by 0.3 microM melittin is selectively inhibited by 10 microM quinacrine and 1 microM nordihydroguaiaretic acid (NDGA) and facilitated by 3 microM indomethacin, whereas the Ca2+ independent fraction of the [3H]GABA released by melittin is not. In the presence of Ca2+, melittin 0.3, 1 and 10 microM progressively increases [3H]arachidonic acid release over control release, but the effectiveness of melittin is also decreased as the amount of tissue increases. No apparent changes in synaptosomes ultrastructure are observed in 0.3 microM treated synaptosomes, but a noticeable disorganization is produced in 10 microM melittin-treated synaptosomes, independently on the presence of external Ca2+. LDH activity only increases over control activity in the supernatant solutions of 10 microM melittin treated synaptosomes, also in a Ca2+ independent manner. Our interpretation of these results is that the Ca2+-dependent, pharmacologic sensitive component of melittin-induced release of [3H]GABA, unmasked when 0.3 microM melittin was used, involves the activation of a Ca2+-dependent type of membrane PLA2. The Ca2+-independent release of [3H]GABA is in contrast, highly probable to be due to the membrane perturbation produced by complex melittin/lipid interactions.

Animals↗
PubMed1993

Using mathematical morphology to determine left ventricular contours.

The aim of this study is to investigate the use of mathematical morphology for the determination of left ventricular contours in scintigraphic images using multigated radionuclide angiography. We have developed a completely automatic method that first restores the image with a Wiener filter, then finds the region where the left ventricle is contained, and finally segments the left ventricle contour and a background zone. The contours depend on the values of the parameters that appear in the mathematical morphology method, which are related to the height and the slope of the count distribution. Results obtained with this method are compared with the contours and the background zones outlined by experts on the basis of the number of counts. We study the values of the parameters with which the optimum correlation is obtained.

Humans↗
PubMed1990

Langerhans-like cells in amphibian epidermis.

Langerhans cells have been described in epidermis and other stratified epithelia of mammals. In other vertebrates equivalent cells have not been found. Amphibians show skin graft rejection, so it is possible that these animals have epidermal cells homologous to Langerhans cells. In this work we demonstrate the existence of ATPase-positive dendritic cells in frog epidermis that are similar ultrastructurally to mammalian Langerhans cells, except for the absence of Birbeck granules.

Adenosine Triphosphatases↗
PubMed1986

Comparison of agar dilution, microdilution, and disk elution methods for measuring the synergy of cefotaxime and its metabolite against anaerobes.

The activities of cefotaxime (CTX) and desacetyl cefotaxime (des-CTX) were tested both singly and in combination against 173 anaerobic clinical isolates. The MIC of CTX for 50% of 60 Bacteroides fragilis isolates was 22.4 micrograms/ml in broth, compared with 47.4 micrograms/ml in agar. This reduced efficacy in agar was seen with all species tested and is in apparent conflict with reported clinical efficacy of the drug. Synergy between CTX and des-CTX was observed with 70 to 100% of the isolates, including 60% of all Bacteroides spp. tested. The susceptibility results in a synergy system correlated well with those noted in a broth-disk elution method incorporating 32 micrograms of CTX and 8 micrograms of des-CTX per ml. The correlation was poorer when the broth-disk method contained 16 micrograms of CTX and 8 micrograms of des-CTX per ml.

Bacteria, Anaerobic↗