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Biomedical subjects

D Vidal

Publications and source records attributed to D Vidal.

At least 19 recordsLinked to original sources

Acantholytic dyskeratotic naevi following Blaschko's lines: a mosaic form of Darier's disease.

Darier's disease (DD) is an autosomal-dominant skin disorder characterized by loss of adhesion between epidermal cells and abnormal keratinization. Several patients with unilateral, linear, 'zosteriform' or localized lesions have been reported. We report three cases of DD in a localized pattern corresponding to mosaicism type 1 according to Happle's classification and review the literature about the genetic cause of DD and DD in a 'zosteriform' pattern.

Acantholysis↗

Insight into some of the signaling pathways triggered by a lipid immunomodulator.

The use of non specific immunomodulatory agents takes an important place in the aspecific host response to invading microorganisms. In this context, antimicrobial properties of royal jelly have been ascribed to organic acids (mainly 10 hydroxy-2-decenoic acid or 10-HDA) and proteins. We synthesized a derivative of 10-HDA, the 1-(2-methoxyethoxymethyl)2,3-(10-hydroxy2-decenoyl)(E) glycerol referred as diHDA-glycerol which was previously found to protect mice against virulent Salmonella typhimurium challenge through more adequate immune regulations. This study was conducted to further investigate some of the signaling pathways followed by diHDA-glycerol in cell transduction. Members of NF-kappaB transcription factors are key regulators of many cytokines acting on immunity and they control genes involved in responses to numerous signals such as bacterial products. Therefore, we investigated some parameters acting on NF-kappaB translocation in U937 cells after diHDA-glycerol treatment. Due to the chemical structure of the molecule we also investigated the sphingomyelinase pathway. Our results showed that diHDA-glycerol induced a rapid NF-kappaB translocation as a consequence of IkappaB-alpha proteolysis. An intracellular production of reactive oxygen species (ROS) may also account for NF-kappaB activation, without de novo protein synthesis. DiHDA-glycerol induced a strong activation of neutral sphingomyelinase, suggesting an important role of sphingolipids in the regulatory responses induced by diHDA-glycerol.

Adjuvants, Immunologic↗

Tuberculous gumma following venepuncture.

An 88-year-old man with a past medical history of pulmonary tuberculosis presented with a 2-year history of an indolent enlarging ulcerated nodule on his left wrist following a venous blood test. Skin biopsy of the ulcer showed granulomas, Ziehl-Neelsen stain was negative, and cultures grew Mycobacterium tuberculosis. Underlying bone and joint disease was excluded, and the lesion healed completely with 6 months of standard antituberculous treatment. We review the literature on tuberculous gumma following an injury.

Aged↗

The selective AMPA receptor antagonist GYKI 53784 blocks action potential generation and excitotoxicity in the guinea pig cochlea.

The role of AMPA receptors in cochlear synaptic transmission and excitotoxicity was investigated by comparing the actions of a selective AMPA antagonist GYKI 53784 (LY303070) with additional AMPA/kainate antagonists, GYKI 52466 and DNQX, and the NMDA antagonist, D-AP5, in several electrophysiological, neurotoxicological and histochemical tests. GYKI 53784 had the same potency as DNQX and was 10 times more potent than GYKI 52466 in reducing auditory nerve activity. The NMDA antagonist D-AP5 had no effect on auditory nerve activity. When single-fiber activity was blocked with GYKI 53784, the effects of AMPA or kainate were also antagonized. GYKI 53784 completely blocked excitotoxicity (i.e. destruction of the afferent nerve endings) induced by AMPA and kainate. The histochemical detection of Co(2+) uptake was used to study Ca(2+) influx within the primary auditory nerve cells. Application of AMPA induced no significant Co(2+) uptake into the cells, suggesting that these receptors normally have a very low permeability to Ca(2+). Application of kainate induced significant Co(2+) uptake that was blocked by the AMPA receptor antagonist GYKI 53784 suggesting that kainate stimulated Ca(2+) entry through AMPA receptor channels. Results suggest that AMPA-preferring receptors are functionally located at the sensory cell-afferent synapse whereas NMDA and kainate receptors are not.

Action Potentials↗

Effect of a synthetic lipid immunomodulator on the regulation of the transcription factor NF-kappaB.

Macrophage activation plays a central role in host defense against a variety of pathogens via inducible messengers. The transcription factor NF-kappaB controls the synthesis of cytokines involved in immune responses. In quiescent cells, NF-kappaB is located in the cytosol bound to an inhibitor IkappaB. Upon appropriate signal, NF-KB translocates to the nucleus and binds to DNA. The present study investigated the involvement of an immunomodulator, (diHDA-glycerol) on the NF-kappaB/IkappaB complex. Results were compared to those obtained with lipopolysaccharide (LPS) as a major virulence factor in bacterial sepsis. Data showed that exposure of J774.1 cells either to LPS or diHDA-glycerol substantially increased with time the nuclear levels of NF-kappaB complexes. Antibodies to various NF-kappaB proteins supershifted p50, p65 and to a lesser extent c-rel. Western blot analyses showed a rapid cytosolic IkappaB-alpha turn over following LPS exposure in contrast to diHDA-glycerol treatment. Further experiments investigated the involvement of protein kinase C (PKC) by using two inhibitors, staurosporine and H7. Pretreatment of J774.1 with either inhibitor prior to diHDA-glycerol or LPS exposure decreased NF-kappaB activation. Our results indicate that diHDA-glycerol was acting on NF-kappaB through IkappaB regulative mechanisms differing from those used by LPS. DiHDA-glycerol is likely acting on many other transcription factors targeting distinct genes implied in up regulation of the immune system.

Adjuvants, Immunologic↗

Cytological and bacteriological findings in guttural pouch lavages of clinically normal horses.

Percutaneous washes of the guttural pouches were obtained from two groups of 15 clinically normal horses, one lightly exercised and the other heavily exercised. Microbiological and cytological studies showed a wide variation in the differential cell counts. The cytological pattern of the normal lavages (< 5 per cent neutrophils) was characterised by a large proportion of ciliated columnar epithelial cells, a few non-ciliated cuboidal epithelial cells, and less than 1 per cent monocytes, lymphocytes, and eosinophils. Abnormal lavages (with more than 5 per cent neutrophils) had higher levels of bacterial growth than normal lavages. There were significant differences between the bacterial growth and total cell count, and also between the neutrophil contents of the lavages from the two groups of horses.

Animals↗

Emergence and dissemination of quinolone-resistant Escherichia coli in the community.

We studied the evolution of resistance to quinolones in Escherichia coli from 1992 to 1997 in Barcelona, Spain. An increasing proportion of quinolone-resistant E. coli (QREC) infections was observed. QREC strains were more common in patients with nosocomial infections but also increased in patients with community-acquired infections (9% in 1992 to 17% in 1996). Seventy (12%) of 572 episodes of E. coli bacteremia were due to QREC. Factors significantly associated with QREC bacteremia were the presence of underlying disease, recent exposure to antibiotics, and bacteremia of unknown origin. In the multivariate analysis, only prior exposure to antimicrobial agents (P < 0.001; odds ratio [OR] = 2), specifically, to quinolones (P < 0. 001; OR = 14), and the presence of a urinary catheter (P < 0.001; OR = 2) were significantly associated with QREC bacteremia. Among 16 QREC isolates from cultures of blood of community origin selected at random, 13 different pulsed-field gel electrophoresis patterns were recognized, showing the genetic diversity of these isolates and in turn indicating the independent emergence of QREC in the community. The prevalence of QREC in the feces of healthy people was unexpectedly high (24% in adults and 26% in children). A survey of the prevalence of QREC of avian and porcine origin revealed a very high proportion of QREC in animal feces (up to 90% of chickens harbored QREC). The high prevalence of QREC in the stools of healthy humans in our area could be linked to the high prevalence of resistant isolates in poultry and pork.

Aged↗

[Pulmonary melioidosis].

Melioidosis is most frequently encountered in pulmonary localization. Melioidosis is an infectious disease caused by Burkholderia pseudomallei first described by Whitmore in 1912 in Burma. B. pseudomallei is a Gram negative rod belonging to the Pseudomonadaceae family. Soil and water are the natural reservoirs for the germ which is a specific pathogen for several mammal species. Long endemic in Southeast Asia and several tropical zones, B. pseudomallei has recently been found in temperate zones, including France. Human contamination occurs via the transcutaneous route and often leads to dormant inapparent infection. Many conditions, such as diabetes, renal lithiasis, various circumstances of immunodepression or stress, facilitate clinical manifestations which vary greatly. Pulmonary manifestations may be acute and extensive, producing a torpid pseudo-tuberculous condition or a variety of clinical and radiological features mimicking other diseases. Bacteriological and serological tests may be negative. Exposure in an endemic zone, the notion of a favorable context, weight loss, cavitary images on successive chest x-rays and the presence of extra-pulmonary localizations may be suggestive. Ceftazidime or the amoxicillin-clavulanic acid combination are indicated, but mortality in acute forms still reaches 40%. Relapse can be expected if the treatment duration is too short.

Amoxicillin↗

[Pulmonary anthrax].

Anthrax is a zoonotic disease caused by Bacillus anthracis. Skin disease is the most common form in humans. Pulmonary anthrax related to the inhalation of airborne germs develops after a silent incubation period of several days and followed by acute respiratory distress. Diagnosis is a difficult task and generally based on demonstration of Bacillus anthracis on direct examination. Despite the sensitivity of B. anthracis to penicillin, treatment is rarely successful.

Anthrax↗

The insertion element IS 6110 is a useful tool for DNA fingerprinting of Mycobacterium bovis isolates from cattle and goats in Spain.

A total of 129 Mycobacterium bovis strains from 5 different Spanish locations were fingerprinted using the IS6110 repetitive element. We demonstrated the presence of multiple copies (from 2 to 13) of IS6110 in a large proportion (47.4%) of the M.bovis strains isolated from cattle and we showed that these strains can be successfully differentiated by means of the RFLP with IS6110. All of the M. bovis strains isolated from goats had multiple copies of IS6110 and 4 bands of 2, 1.7, 1.4 and 1.3 kb were common in all the caprine RFLP patterns. The caprine strains formed a clearly separate cluster from the bovine strains.

Animals↗

Monitoring eustachian tube opening: preliminary results in normal subjects.

Sonometry studies the changes of sound intensities induced by the eustachian tube opening in the external meatus when a constant sound is applied in the nasal cavity. The function of the eustachian tube is not disturbed by the test procedure. An original portable device with a high signal-to-noise ratio has been developed in our lab. This device was able to detect a 6-dB sound pressure level (SPL) signal in a 100-dB SPL noise. Long-duration recordings of auditory tubal openings could be performed. This work presents the data found in normal subjects. One hundred twenty healthy ears were recorded. Eustachian tube openings were detected in 62.5% of the cases. Of the 1777 openings recorded, the average opening duration was 430 ms +/- 183 ms. The average number of eustachian tube openings was 21.7+/-16.4 (for 15 minutes). All swallowing did not necessary open the eustachian tube. This work shows that this new device allows long-duration recording of eustachian tube function in everyday life conditions.

Acoustic Stimulation↗

Spacer oligonucleotide typing of Mycobacterium bovis strains from cattle and other animals: a tool for studying epidemiology of tuberculosis.

The spacer oligonucleotide typing (spoligotyping) method was evaluated for its ability to differentiate Mycobacterium bovis strains. This method detects the presence or absence of spacers of the direct repeat locus of the M. bovis genome. The spacers in the direct repeat locus are amplified by PCR and are detected by hybridization of the biotin-labelled PCR product with a membrane containing oligonucleotides derived from spacer sequences that have previously been bound to a membrane. One hundred eighty-two M. bovis isolates from domestic animals (cattle, goat, sheep, and cats) and wild animals (deer and wild boar) were spoligotyped, and the results were compared with those obtained by IS6110 restriction fragment length polymorphism analysis. Two rather homogeneous clusters of isolates containing 20 and 4 types, respectively, were identified by spoligotyping. The first cluster included isolates from cattle, cats, and feral animals. By spoligotyping, isolates from the Spanish wild boar and deer had the same pattern as some bovine isolates, suggesting transmission between these animals and cattle and highlighting the importance of the study of these reservoirs. The second cluster included all the caprine and ovine isolates. Within each cluster, the patterns of the different strains differed only slightly, suggesting that the spoligotypes may be characteristic of strains from particular animal species. Spoligotyping proved to be useful for studying the epidemiology of bovine M. bovis isolates, especially of those isolates containing only a single copy of IS6110. In view of our results, we suggest fingerprinting all M. bovis strains by the spoligotyping method initially and then by IS6110 restriction fragment length polymorphism typing of the strains belonging to the most common spoligotypes.

Animals↗

[Biocontamination, European standardization and pharmaceutical industry].

The coming to light of new concepts in environmental microbiology, particularly the notions of bacterial adhesion and of biofilm or of cells in starvation, conducted to an evolution of the standardization of the controlled contamination area. It is necessary to match to the biocontamination of hazard area the principles governing the quality insurance used in alimentary industry named HACCP (hazard analysis of control critical point). This method will have to be applied wilfully to all the fields where a patient or a product risk a biocontamination.

Chemistry, Pharmaceutical↗

In vitro biological activities of arglabin, a sesquiterpene lactone from the Chinese herb Artemisia myriantha Wall. (Asteraceae).

The immunomodulating properties of arglabin, a sesquiterpene lactone isolated from Artemisia myriantha Wall. (Asteraceae) were investigated using the murine macrophage tumor line J774.1. Arglabin-stimulated macrophages displayed a strong cytotoxic activity and the lowest doses (1.25 micrograms/mL and 0.125 micrograms/mL) induced a significant stimulation of cell mitochondrial metabolism, which correlated with [3H]TdR uptake by J774.1 cells under the same experimental conditions. In addition, the secretion of cytokines involved in host defence mechanisms--IL-1, TNF-alpha, and IL-2--was investigated upon incubation of J774-1 cells with arglabin. Arglabin triggered the production of the three cytokines from J774-1 cells. However, the pattern of cytokine secretion differed to some extent, according to the methodology used for cytokine measurement: either traditional bioassay or specific immunoassay (ELISA). Our data emphasize a possible proliferative effect of arglabin in the traditional bioassays, at least for the highest concentrations used. The results were verified with specific ELISA immunoassays. Using either method, lower concentrations of arglabin (ranging from 12.5 micrograms/mL to 0.125 micrograms/mL) were the most effective in inducing IL-1, TNF-alpha, or IL-2 secretion. In addition, preliminary data on phagocytosis showed that arglabin enhanced the uptake of fluorescent latex beads by J774.1 cells.

Animals↗

Effects of taxol on the macrophage function. Interactions with some immunological parameters.

The effects of Taxol on some immunological parameters were investigated, in vitro, in the murine macrophage cell line J774.1. Mitochondrial dehydrogenase activity and (3H) TdR incorporation were shown to be increased in Taxol treated cells. Likewise, Taxol induced TNF alpha secretion. But Taxol seemed to be a weak inducer of the two interleukins IL-1 and IL-2, since their detection occurred late in the cell culture supernatants.

Alkaloids↗