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Biomedical subjects

E Montesinos

Publications and source records attributed to E Montesinos.

At least 19 recordsLinked to original sources
PubMed2002

Plant-microbe interactions and the new biotechnological methods of plant disease control.

Plants constitute an excellent ecosystem for microorganisms. The environmental conditions offered differ considerably between the highly variable aerial plant part and the more stable root system. Microbes interact with plant tissues and cells with different degrees of dependence. The most interesting from the microbial ecology point of view, however, are specific interactions developed by plant-beneficial (either non-symbiotic or symbiotic) and pathogenic microorganisms. Plants, like humans and other animals, also become sick, but they have evolved a sophisticated defense response against microbes, based on a combination of constitutive and inducible responses which can be localized or spread throughout plant organs and tissues. The response is mediated by several messenger molecules that activate pathogen-responsive genes coding for enzymes or antimicrobial compounds, and produces less sophisticated and specific compounds than immunoglobulins in animals. However, the response specifically detects intracellularly a type of protein of the pathogen based on a gene-for-gene interaction recognition system, triggering a biochemical attack and programmed cell death. Several implications for the management of plant diseases are derived from knowledge of the basis of the specificity of plant-bacteria interactions. New biotechnological products are currently being developed based on stimulation of the plant defense response, and on the use of plant-beneficial bacteria for biological control of plant diseases (biopesticides) and for plant growth promotion (biofertilizers).

Bacteria↗
PubMed2000

Clear cell syringoid carcinoma: an ultrastructural and immunohistochemical study.

Syringoid carcinoma (syringoid "eccrine" carcinoma or eccrine epithelioma) is a rare cutaneous tumor with some controversy regarding its correct definition. It may also be difficult to differentiate from its benign counterpart (syringoma), other adnexal carcinomas, and cutaneous metastasis from adenocarcinomas. We present a case of a syringoid carcinoma of the clear cell variant complemented with an immunohistochemical and ultrastructural study, the latter revealing cytoplasmic accumulation of glycogen and presence of intercellular and intracellular lumina in clear tumor cells, as well as diverse hallmarks of malignancy (i.e., perineural invasion, tumor necrosis, and deep invasion). Clear tumor cells showed cytoplasmic and membranous immunoreactivity to epithelial membrane antigen, carcinoembryonic antigen, keratins, and S-100. Our ultrastructural and immunohistochemical results support the ductal differentiation of the glycogen-filled clear cell tumor population.

Aged↗
PubMed2000

Generalized cutaneous depigmentation following sulfamide-induced drug eruption.

A 41-year-old male developed a generalized drug eruption following sulfamide therapy, with progressive albino-like generalized cutaneous depigmentation. Electron microscopy showed the absence of melanocytes, and clear cells with Langerhans cell characteristics were seen along the basal layer. The present case constitutes a unique reaction to sulfamides not previously reported in the literature.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Aluminium allergy in patients hyposensitized with aluminium-precipitated antigen extracts.

During hyposensitization therapy with aluminium-precipitated antigen solutions, a small % of patients develop persistent subcutaneous nodules at the injection site; the existence of delayed sensitivity to aluminium has been implicated in the pathogenesis of these nodules. We studied the prevalence of aluminium sensitivity (using patch, prick and intradermal tests) and common contact allergens (TRUE Test) in 20 healthy subjects, and in 40 patients treated with aluminium-containing extracts, 20 of whom had persistent subcutaneous nodules that remained for more than 2 months, the other half having no nodular reactions or nodules that remained for less than 2 months. Aluminium sensitivity was found only in those patients of the treated group who had persistent nodular reactions, 4 cases of positivity to an aluminium chloride patch test being found. All 4 cases were women, nodules remained for more than 6 months, and intracutaneous tests were negative. 3 of them also had contact sensitivity to nickel. In 2 cases, nodules were removed for histological and histochemical examination, showing non-specific inflammatory granulomas, and aluminium crystals being found in only 1 case. It is concluded that delayed sensitivity to aluminium appears to be implicated in the pathogenesis of persistent nodular reactions, but sensitivity to aluminium was not found in patients treated with aluminium-precipitated extracts without persistent nodular reactions.

Adolescent↗
PubMed1992

Changes in cholesterol levels after coronary artery bypass surgery.

To determine the factors responsible for the dramatic fall in cholesterol levels after coronary artery bypass surgery (CABG), the authors reviewed, in a retrospective study, the cholesterol levels of 36 patients who underwent CABG surgery during 1987 and compared their levels with those of a control group of 30 patients who underwent cholecystectomies during the same time. In a prospective study, the authors measured the lipids and the hematocrit levels of 15 patients undergoing CABG surgery before the initiation of cardiopulmonary bypass, after 5 minutes of extracorporeal circulation (ECC), and at the end of ECC. In the CABG group, the plasma cholesterol level fell from 211 +/- 63 mg/dl (mean +/- SE) to 70 +/- 48 mg/dl (p less than 0.01), a 77% decrease within 24 hours of surgery. In the cholecystectomy group, the plasma cholesterol fell from 192.3 +/- 8.9 mg/dl to 158 +/- 76 mg/dl (p less than 0.01), an 18% decrease within 24 hours of surgery. To estimate the contribution of hemodilution or blood loss to the fall in cholesterol, changes in hematocrit were recorded. In the CABG group, hematocrit fell from 39.5 +/- 0.7% to 23.5 +/- 0.7% 24 hours after surgery (41% decrease) (p less than 0.01), whereas in the cholecystectomy group hematocrit fell from 39.4 +/- 0.8% to 37.1 +/- 0.9% on the first postoperative day (6% decrease). There was a positive correlation between the fall in cholesterol and the fall in hematocrit in the CABG group (correlation coefficient 0.472), suggesting that hemodilution was a major factor in the decrease in cholesterol levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Detection of early cytomegalovirus antigen in cell culture].

The reference technique for the diagnosis of active cytomegalovirus infection is the isolation in cellular culture. Its major drawback is the interval between the inoculation of the sample and the development of the characteristic cytopathic effect. Occasionally, this delay may be longer than four weeks. The centrifugation of the sample on the cell monolayer at the time of inoculation and the use of a fluorescein-labeled monoclonal antibody for the detection of the early antigen in cells may considerable reduce the time required for the diagnosis of cytomegalovirus infection. In the present study the technique of detection of the early antigen by immunofluorescence was compared with conventional cell culture in 258 clinical samples referred to the laboratory for study. Fifty-one of them were positive: 28 with both techniques, 12 only with cell culture and 11 only with immunofluorescence. The mean time to obtain positive results was 25 hours for immunofluorescence and 13 days for culture.

Antigens, Viral↗
PubMed1987

Change in Size of Chromatium minus Cells in Relation to Growth Rate, Sulfur Content, and Photosynthetic Activity: A Comparison of Pure Cultures and Field Populations.

The size frequency distribution of planktonic cells of purple sulfur phototrophic bacteria was measured at several depths in a bacterial layer of Lake Cisó (Spain). The bacterioplankton was dominated by Chromatium minus (87 to 94% of the total biomass). The largest cells of C. minus were found in the top part of the bacterial layer. In addition, the in situ and potential specific photosynthetic activity (CO(2) fixation and acetate uptake) and specific pigment content were measured in relation to several key environmental parameters that determine the activity of cells. Potential growth rates were estimated from production rates and biomass. A maximal specific growth rate of 0.074 h was found for the top part of the bacterial layer. Photosynthesis versus light and versus sulfide curves among field samples indicated that light was the main limiting factor controlling the activity of C. minus in Lake Cisó. The specific bacteriochlorophyll a content was very high in all samples (0.27 to 0.36 mug mug of C). Results of laboratory experiments performed with pure cultures indicated that the average cell volume changes from 5.9 to 20.0 mum and that differences in growth rate, breakdown, or synthesis of sulfur and glycogen and degradation of the photosynthetic apparatus are the main factors accounting for the observed changes in cell volume across the bacterial layer.

Journal Article↗
PubMed1983

Comparison between direct methods for determination of microbial cell volume: electron microscopy and electronic particle sizing.

Size frequency distributions of different phototrophic and heterotrophic microorganisms were determined by means of scanning and transmission electron microscopy and electronic particle sizing. Statistically significant differences existed among the three techniques used in this study. Cells processed for electron microscopy showed lower mean cellular volumes than those processed for electronic particle sizing, reflecting a shrinkage by factors ranging from 1.1 to 6.2 (mean, 2.3). Processing of cells for scanning electron microscopy caused higher shrinkage than processing for transmission electron microscopy. Shrinkage was dependent neither on the size nor on the cell wall type of the microorganism. When processed for scanning electron microscopy, phototrophic bacteria were strongly shrunken, whereas heterotrophic microorganisms were less affected. A direct relationship existed among phototrophic bacteria between percentage of shrinkage and specific pigment content. This was probably a consequence of the pigment extraction by organic solvents during the dehydration process, previous to the critical point drying, necessary to examine the specimens under the scanning electron microscope.

Bacteria↗
PubMed1983

Ecology and Physiology of the Competition for Light Between Chlorobium limicola and Chlorobium phaeobacteroides in Natural Habitats.

Accurate studies of the pigment composition and isolation in pure cultures of Chlorobiaceae from samples of eight Spanish lakes show that there are two main coexisting groups of green and brown Chlorobium spp. represented respectively by Chlorobium limicola and Chlorobium phaeobacteroides. Laboratory experiments with pure and mixed cultures of the isolated strains show that light quality plays a selective role on the species composition among Chlorobiaceae. This selection depends on the pigment composition which determines the in vivo absorption spectrum of the cells as well as on their ability to adjust the intracellular concentration of light-harvesting pigments to the spectral distribution and energy of light. Correlation analysis performed with field data resulted in significant, but low, correlation coefficients. Nevertheless, they were consistent with laboratory data showing that brown Chlorobiaceae were dominant in deep layers in meromictic lakes, whereas green Chlorobiaceae dominated in layers nearer the surface or underneath plates of Chromatiaceae. The combination of laboratory and field observations stress the role of biological light filtering in determining the species composition among Chlorobiaceae in lakes.

Journal Article↗
PubMed1983

Factors determining annual changes in bacterial photosynthetic pigments in holomictic lake cisó, Spain.

The pigments and biomass of anoxygenic phototrophic bacteria were measured during a year cycle in Lake Cisó (Girona, Spain). Two genera, Chromatium and Chlorobium, accounted for most of the bacterial population. The bacteria were present throughout the year despite complete mixing of the lake during fall and winter. This was possible because the sulfide production in the sediment was high enough to make the lake anaerobic to the very surface. Solar radiation, temperature, and biomass of Chromatium sp. were found to be important in determining pigment concentrations by correlation analysis. Sulfide concentration and biomass of Chlorobium spp. were found to be unimportant. A path analysis was performed to determine what percentage of the variability of pigments could be explained by the variables studied. Since a high percentage could be explained, it was possible to conclude that solar radiation, temperature, and biomass of Chromatium sp. were the main variables.

Journal Article↗
PubMedDate not supplied

Eccrine angiomatous hamartoma: report of three patients.

Eccrine angiomatous hamartoma is a rare, benign entity. The histologic features include proliferation of eccrine sweat glands and angiomatous capillary channels. We report three children who each had a single lesion on a limb. These lesions were clinically angiomatous, and we obtained the diagnosis by histologic and immunohistochemical studies.

Capillaries↗