Biomedical subjects

F Poron

Publications and source records attributed to F Poron.

23 records · Page 2Linked to original sources

PubMed1995

Detection of Aspergillus species DNA in bronchoalveolar lavage samples by competitive PCR.

A competitive PCR assay involving the use of bronchoalveolar lavage (BAL) samples for the diagnosis of invasive pulmonary aspergillosis (IPA) was developed. For this purpose, a 1-kb mitochondrial DNA fragment of Aspergillus fumigatus was sequenced. The primers used allowed amplification of A. fumigatus, A. flavus, A. terreus, and A. niger DNAs but not DNAs of other fungi and yeasts. BAL samples from 55 consecutively enrolled patients were tested. Three samples were excluded because of failure of correct amplification of the internal competitive control. Of 28 immunocompromised patients, 6 were PCR positive; 3 died of IPA and their BAL cultures yielded A. fumigatus; and 3 were culture negative and did not develop IPA. Of 15 human immunodeficiency virus-positive patients and 9 immunocompetent patients, 5 and 4, respectively, were both PCR positive and culture negative, and none developed aspergillosis. Thus, PCR confirmed IPA in three patients but gave positive results for 25% (12 of 49) of the patients who did not develop aspergillosis. The predictive value of PCR-positive results seems low for patients at risk for aspergillosis. Moreover, the risk of contamination of reaction buffers or biological samples with Aspergillus conidia seems high and has to be weighed in regard to the potential diagnostic benefit of PCR testing as a routine procedure.

AIDS-Related Opportunistic Infections↗

PubMed1995

Quantitative competitive PCR with bronchoalveolar lavage fluid for diagnosis of toxoplasmosis in AIDS patients.

Of 121 AIDS patients, 12 (10%) had Toxoplasma gondii DNA detected by competitive PCR in their bronchoalveolar lavage samples. Quantitation of the PCR results showed a correlation between the parasite burden and the serum lactic dehydrogenase titer. Quantitative competitive PCR could be useful to assess the diagnosis and the severity of pulmonary toxoplasmosis.

AIDS-Related Opportunistic Infections↗

PubMed1994

Cytokine expression in the muscle of HIV-infected patients: evidence for interleukin-1 alpha accumulation in mitochondria of AZT fibers.

To evaluate the possible role of cytokines in human immunodeficiency virus (HIV)-associated muscular disorders, we performed immunocytochemistry for interleukin-1 alpha, -1 beta, and -6 and tumor necrosis factor-alpha on frozen muscle biopsy specimens from HIV-infected patients with various myopathies (HIV polymyositis in 5, HIV-wasting syndrome in 5, zidovudine myopathy in 10) and from seronegative individuals (normal muscle in 2, mitochondrial cytopathies in 10). The HIV-infected patients showed positive reactivities in vessels (interleukin-1) and in inflammatory cells (mainly interleukin-1 and tumor necrosis factor-alpha), including perivascular hemosiderin-laden macrophages in 5 patients. In zidovudine myopathy, a majority of AZT fibers (i.e., ragged-red fibers with marked myofibrillar changes) showed mild to marked expression of interleukin-1. Expression of interleukin-1 in the other mitochondrial myopathies was much weaker. Interleukin-1 beta messenger RNA was demonstrated in muscle fibers by in situ hybridization, implying that interleukin-1 was produced in muscle cells. Immunoelectron microscopy showed that interleukin-1 alpha was mainly bound to mitochondrial membranes in AZT fibers. Proinflammatory and destructive effects of the studied cytokines might be responsible for several myopathological changes observed in HIV-infected patients, including inflammation and hemosiderin deposits in muscle tissue, and prominent myofibrillar breakdown in AZT fibers.

HIV Infections↗

PubMed1994

Changes in chromogranin A-immunoreactive guinea-pig pulmonary neuroendocrine cells after sensitization and challenge with ovalbumin.

Immunohistochemical study with antisera to chromogranin A and neuron-specific enolase, a general marker for nerves and endocrine cells, was used to quantify changes in bronchial neuroendocrine cells in guinea-pigs sensitized and challenged with ovalbumin. Actively sensitized animals were killed 2, 6, 24, 48, 72, and more than 144 hours after being challenged by an aerosolized solution of ovalbumin. The number of chromogranin A-immunoreactive cells was significantly greater in sensitized but unchallenged animals and in sensitized animals killed 2 and 6 h after challenge when compared to controls; it decreased significantly in animals killed more than 24 h after challenge when compared to sensitized, unchallenged animals. The number of neuron-specific-enolase-immunoreactive cells did not change. We conclude that the peptide content of bronchial neuroendocrine cells increases during sensitization and in the early phase of a hypersensitivity reaction, and that the cells release their granule contents in the late phase of such a reaction. They may therefore play a role in immunoallergic events in the lung.

Animals↗

PubMed1994

Cell localization and regulation of expression of cytochrome P450 1A1 and 2B1 in rat lung after induction with 3-methylcholanthrene using mRNA hybridization and immunohistochemistry.

In order to characterize the response of various pulmonary cell types to polycyclic aromatic hydrocarbons, the expression of cytochrome P450 (CYP) 1A1 and 2B1 mRNA in the lung of rats, with or without induction by 3-methylcholanthrene (3MC), was analyzed by in situ hybridization using appropriate 35S-labeled riboprobes. The expression of the corresponding proteins was investigated immunohistochemically. Following induction with 3MC, the kinetics of mRNA expression differed considerably between Clara cells and type II pneumocytes and venous endothelial cells. In Clara cells, mRNA expression was detected as early as 1 h after induction, peaked between 2 and 4 h, and was completely undetectable at 14 h. In contrast, venous endothelial cells and type II pneumocytes exhibited permanent mRNA expression of CYP 1A1 in 3MC-pretreated rats. These kinetic results explain the striking absence of correlation between mRNA and protein expression observed in Clara cells 24 h after the end of the induction protocol, as these cells exhibited intense protein expression with no mRNA. In contrast, a good correlation was observed for mRNA and protein expression of CYP 2B1, with similar expressions for Clara cells and type II pneumocytes, but no expression in endothelial cells. This study clearly distinguished the regulation of CYP 1A1 expression in the rat lung from that described in the liver. The differences observed in the various lung cell types, whatever the post-transcriptional mechanisms involved, emphasize that studies must be performed at the cellular level in order to understand the specific response to xenobiotics, not only of this organ as a whole but also of its various anatomic structures.

Amino Acid Sequence↗