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Biomedical subjects

K Papadopoulou

Publications and source records attributed to K Papadopoulou.

13 recordsLinked to original sources
PubMed2006

Bioremediation of a soil contaminated by lindane utilizing the fungus Ganoderma australe via response surface methodology.

Mixtures of a sandy soil and wheat straw were doped with the organochlorine insecticide lindane in glass tubes and were inoculated with the polypore fungus, Ganoderma australe. An evaluation of bioremediation process effectiveness was searched and five parameters identified for the solid-state system. Fungi growth is a function of temperature and requires moisture for a proper colonization. These microorganisms need inorganic nutrients such nitrogen and phosphorus to support cell growth and it is also appropriate to know the range of concentration and toxicity of the used insecticide. Thus, an orthogonal central composite design (CCD) of experiments was used to construct second order response surfaces. Five design factors, namely temperature, moisture, straw, lindane content and nitrogen content and seven optimization parameters (responses), namely lag time, propagation velocity, biomass growth rate, biodegradation rate, biodegradation/biomass, biomass/propagation and biomass content were analyzed. The optima of the responses of the adequate models were found to be the following: propagation velocity 4.25mm/day, biomass growth rate 408mg/day, biodegradation/biomass 56.9microg/g, biomass/propagation 250mg/mm and fungal biomass content in solid mixture 260mg/cm(3). The most important response for bioremediation purposes is biodegradation/biomass which is maximized at the factors levels: temperature 17.3 degrees C, moisture 58%, straw content 45%, lindane content 13ppm and nitrogen content 8.2ppm.

Biomass↗
PubMed2006

Structural brain correlates of IQ changes in bipolar disorder.

BACKGROUND: There is increasing evidence that cognitive deficits are present in bipolar disorder (BP), but their neural correlates have not been fully explored. The aim of this study is to correlate structural brain abnormalities with cognitive performance in BP and to explore differences between clinical subtypes. METHOD: Thirty-six BP patients (13 men, 23 women) with a mean age of 39 years (range 21-63 years) underwent neuropsychological testing and imaging. Twenty-five patients had bipolar disorder I (BP I) and 11 had bipolar disorder II (BP II). Patients with co-morbid psychiatric diagnosis, drug and alcohol abuse or systemic illness were excluded. Correlations between cognitive performance and structural brain changes were explored using high-resolution anatomical imaging and magnetization transfer imaging (MTI). RESULTS: In the whole BP group the difference between estimated pre-morbid IQ and current IQ was significantly correlated with left-sided reduction of the magnetization transfer ratio (MTR) in the superior temporal gyrus, uncus and para-hippocampal gyrus. In BP II patients the areas where these correlations were significant extended to the right superior and middle temporal gyri, cingulate gyrus, pre-cuneus and adjacent frontal and parietal white matter. The volume of superior temporal white matter was also correlated with IQ difference in this subgroup. CONCLUSIONS: The study highlights the association between fronto-temporal abnormalities and decline in IQ in BP. The more extensive abnormalities present in BP II patients suggest that persistent depression, rather than mania, may be a key pathophysiological factor or that BP II represents a clinical phenotype with a higher risk of developing cognitive abnormalities.

Adult↗
PubMed2005

Biodegradation of lindane by Pleurotus ostreatus via central composite design.

The degradation of lindane was studied in liquid-agitated cultures using a commercial strain of the fungus Pleurotus ostreatus as the biodegrading organism. The biodegradation was accomplished with the action of extracellular oxidative enzymes, produced by the fungus to decompose woody substrates. Enzyme activities of manganese peroxidase and laccase were measured in a liquid mineral medium. An orthogonal Central Composite Design of experiments was used to construct second-order response surfaces with the fungus growth, final pH and the lindane biodegradation as optimization parameters. The initial lindane concentration, the nitrogen content, the incubation time and the temperature were used as design factors. Optimal conditions found for all these parameters will be used for the continuation of this project aiming at the bioremediation of contaminated sites with persistent organic pollutants such as lindane.

Biodegradation, Environmental↗
PubMed2005

Memory function after resolution of post-traumatic amnesia.

PRIMARY OBJECTIVES: The aims of this pilot study were (1) to examine neuropsychological, particularly memory functions immediately after post-traumatic amnesia (PTA) resolution according to the Galveston Orientation and Amnesia Test (GOAT), and (2) to provide a preliminary exploration of pattern of performance on GOAT items across PTA duration. METHODS AND PROCEDURES: Thirty-seven head injured patients were administered the Recognition Memory Tests on the day that PTA resolved. Formal neuropsychological assessment was conducted on average 10 days after PTA resolution. MAIN OUTCOMES AND RESULTS: All the patients in the series showed memory impairment which varied in severity but was typically characterized as global and severe. Deficits in executive and speed and attention functions were common. GOAT items relating to orientation were typically passed, while items concerning anterograde and retrograde recall were most commonly failed across all stages of PTA duration. CONCLUSIONS: These findings suggest that reliance on memory performance as a measure of PTA is not ideal and highlight the need for further research of this issue.

Adult↗
PubMed2005

An increase in creatine kinase secondary to acute pancreatitis: a case report.

Creatine kinase (CK) activity is found in high concentrations in skeletal muscle, cardiac muscle and brain. Here, we describe a 64-year-old woman with acute pancreatitis and elevated serum CK activity. This association is extraordinarily rare. In particular, laboratory findings which were found to be abnormal were serum CK 4.150 U/l (peaked 1 day after admission) with the CK-MB fraction being less than 5%, lactate dehydrogenase (LDH) 424 U/l, serum lipase 1.265 U/I and serum amylase 1.105 U/l. Some data regarding the phenomenon of acute pancreatitis and elevated serum CK activity are given.

Acute Disease↗
PubMed2001

A new class of oxidosqualene cyclases directs synthesis of antimicrobial phytoprotectants in monocots.

Many plants synthesize antimicrobial secondary metabolites as part of their normal program of growth and development, often sequestering them in tissues where they may protect against microbial attack. These include glycosylated triterpenoids (saponins), natural products that are exploited by man for a variety of purposes including use as drugs [Hostettmann, K. & Marston, A. (1995) Saponins (Cambridge Univ. Press, Cambridge, U.K.)]. Very little is known about the genes required for the synthesis of this important family of secondary metabolites in plants. Here we show the novel oxidosqualene cyclase AsbAS1 catalyzes the first committed step in the synthesis of antifungal triterpenoid saponins that accumulate in oat roots. We also demonstrate that two sodium azide-generated saponin-deficient mutants of oat, which define the Sad1 genetic complementation group, are defective in the gene encoding this enzyme and provide molecular genetic evidence indicating a direct link between AsbAS1, triterpenoid saponin biosynthesis, and disease resistance. Orthologs of AsbAS1 are absent from modern cereals and may have been lost during selection, raising the possibility that this gene could be exploited to enhance disease resistance in crop plants.

Amino Acid Sequence↗
PubMed2001

Genetic polymorphism and taxonomic infrastructure of the Pleurotus eryngii species-complex as determined by RAPD analysis, isozyme profiles and ecomorphological characters.

The Pleurotus eryngii species-complex includes populations of choice edible mushrooms, growing in the greater Mediterranean area in close association with different genera of plants of the family Apiaceae. Their distinct host-specialization served as the principal criterion for the discrimination of several taxa; however, the genetic relationships among the various P. eryngii ecotypes remain ambiguous. In the present study, 46 Pleurotus strains with a wide range of geographical origins were isolated from Eryngium spp., Ferula communis, Cachrys ferulacea, Thapsia garganica and Elaeoselinum asclepium subsp. asclepium, and were subjected to isozyme and random amplified polymorphic DNA-PCR (RAPD) analysis. The 16 enzyme activities tested were controlled by 28 loci, 11 of which were monomorphic. Host-exclusive zymograms for the Aph (acid phosphatase) and Phe-1 (dopa-phenoloxidase) loci were obtained from Pleurotus strains associated with C. ferulacea. Allele frequencies, genetic diversity and mean diversity were high for isolates from Eryngium spp. and Ferula communis. In RAPD analysis, the use of five primers allowed the production of 45 (out of 48) polymorphic bands, while four molecular markers specific for the identification of Pleurotus strains growing on E. asclepium subsp. asclepium and C. ferulacea were obtained. The Pleurotus strains produced 35 distinct electrophoretic types and 42 RAPD patterns, which independently permitted the separation of the fungal populations into five clusters in accordance with their host-specificity. In addition, the evaluation of the principal ecological and morphological characters provided further evidence for discriminating between P. nebrodensis growing on C. ferulacea and the rest of the host-associated populations. The latter represent taxa at the varietal level: P. eryngii var. eryngii, P. eryngii var. ferulae and P. eryngii var. elaeoselini. The position of taxa of dubious validity, such as P. hadamardii and P. fossulatus, is discussed in relation to the new findings. All Mediterranean Pleurotus populations growing on umbellifers seem to have recently diverged through a sympatric speciation process, that is based on both intrinsic reproductive barriers and extrinsic ecogeographical factors.

Apiaceae↗
PubMed1999

Adaptation and population dynamics of Azotobacter vinelandii during aerobic biological treatment of olive-mill wastewater.

Olive-mill wastewater (OMW) has a high organic and polyphenol content and is resistant to biodegradation. Its disposal leads to a major environmental pollution problem in the Mediterranean basin. The detoxification of OMW following inoculation with Azotobacter vinelandii (strain A) was performed for two successive 5-day-period cycles in an aerobic, biowheel-type reactor, under non-sterile conditions. The phytotoxicity of the processed product was reduced by over 90% at the end of both cycles. To exclusively monitor the A. vinelandii population in the reactor a most probable number-PCR approach was employed and applied daily to serial dilutions of total DNA extracted from reactor samples. PCR sensitivity was independent of the presence of OMW or non-target DNA. The A. vinelandii population dynamics were successfully monitored, showing an initial adaptation period, followed by a sharp population maximum on the fourth day of both cycles (1.6x10(8) and 9.6x10(7) cells ml(-1) respectively), after a major phytotoxicity decline. N(2) fixation rates were estimated using the acetylene reduction assay and reached a peak during the first 1-2 days of each cycle (36 and 29 nmol C(2)H(2) ml(-1) h(-1) respectively). The data are consistent with an initial physiological adaptation phase, where the presence of phenolic compounds limits A. vinelandii growth but stimulates N(2) fixation, followed by a rapid growth phase as phytotoxicity declines.

Journal Article↗
PubMed1999

Compromised disease resistance in saponin-deficient plants.

Saponins are glycosylated plant secondary metabolites found in many major food crops [Price, K. R., Johnson, I. T. & Fenwick, G. R. (1987) CRC Crit. Rev. Food Sci. Nutr. 26, 27-133]. Because many saponins have potent antifungal properties and are present in healthy plants in high concentrations, these molecules may act as preformed chemical barriers to fungal attack. The isolation of plant mutants defective in saponin biosynthesis represents a powerful strategy for evaluating the importance of these compounds in plant defense. The oat root saponin avenacin A-1 fluoresces under ultraviolet illumination [Crombie, L., Crombie, W. M. L. & Whiting, D. A. (1986) J. Chem. Soc. Perkins 1, 1917-1922], a property that is extremely rare among saponins. Here we have exploited this fluorescence to isolate saponin-deficient (sad) mutants of a diploid oat species, Avena strigosa. These sad mutants are compromised in their resistance to a variety of fungal pathogens, and a number of lines of evidence suggest that this compromised disease resistance is a direct consequence of saponin deficiency. Because saponins are widespread throughout the plant kingdom, this group of secondary metabolites may have general significance as antimicrobial phytoprotectants.

Journal Article↗
PubMed1998

Detection of human papillomaviruses in squamous cell carcinomas of the lung.

The aim of this study was to evaluate the possible association of human papillomaviruses (HPV) with the development of squamous cell lung carcinomas (SqCLCs). Tissue material from 52 cases of SqCLCs were studied, and the data were evaluated according to the degree of differentiation, HPV presence and type. Analysis was performed by polymerase chain reaction (PCR) method using consensus primers, and the results were confirmed by subsequent Southern blot hybridization. Overall, the results showed 69% positivity (n=32). Forty-one cases were examined for the presence of specific HPV types (6/11 and 16/18) by hybridization of the PCR products with 32P-labelled probes. HPV 6/11 types were detected in 6 of the 29 positive cases (20.6%). HPV 16/18 types were the most prevalent types, and were detected in 11/29 cases (37.9%: 4/10 of well-differentiated cases, 6/25 of moderately and 1/6 of poorly differentiated carcinomas). Our results confirm the possibility that HPV might play a role in the development of SqCLCs and suggest a possible relation of high-risk HPV16/18 types to tumour differentiation.

Carcinoma, Squamous Cell↗
PubMed1996

Phaseolus ENOD40 is involved in symbiotic and non-symbiotic organogenetic processes: expression during nodule and lateral root development.

ENOD40 is an early nodulin gene, recently isolated from legume species forming nodules either after Rhizobium infection or spontaneously. ENOD40 cDNAs from Phaseolus plants were isolated and nucleotide sequence determination revealed 85% and 88.5% homology with the reported soybean cDNA clones. The putative polypeptide deduced coincides with the soybean one but a stop codon, almost in the middle of the respective ORF, renders it much shorter. This polypeptide was overexpressed as a fusion protein in Escherichia coli. Although the spatial expression pattern of the gene in the root pericycle and nodule primordium at early stages of development as well as in the pericycle of the vascular bundles and uninfected cells in mature nodules is comparable to the gene's expression pattern in soybean, differences in developmental regulation are evident. We have shown that ENOD40 transcripts are also detected at very early stages of lateral root development, in the dividing pericycle cells of the root stele that give rise to the lateral root primordia. The presence of Rhizobium causes an enhancement of the gene's expression and also induction of the gene in the vascular tissues of developed lateral roots. Interestingly, a discrimination on the gene's expression level in adventious and acropetal incipient lateral root primordia, emerging in infected and uninfected roots, is observed. This indicates that the gene's product may be involved in the hormonal status of the plant and that ENOD40 may be used as a molecular marker in lateral root initiation.

Amino Acid Sequence↗
PubMed1995

Expression pattern of uricase II gene during root nodule development in Phaseolus vulgaris.

A Phaseolus vulgaris uricase II cDNA clone has been isolated and sequenced. Comparison on the nucleotide level between this clone and the soybean uricase II clone revealed 88.8% identity. The in situ hybridization technique was used to follow the expression pattern in developing root nodules of Phaseolus vulgaris. The uricase II transcripts were localized only in the uninfected cells of the central tissue and mainly in the periphery of the cell. Uricase II mRNA is first detected in nodules 12 days after infection. A maximum level of transcripts is reached in 21-day-old nodules, followed by a considerable reduction in 28-day-old nodules.

Amino Acid Sequence↗