Biomedical subjects

G Skodras

Publications and source records attributed to G Skodras.

9 recordsLinked to original sources

PubMed2007

Cleaner co-combustion of lignite-biomass-waste blends by utilising inhibiting compounds of toxic emissions.

In this paper, the co-combustion behaviour of coal with wastes and biomass and the related toxic gaseous emissions were investigated. The objective of this work is to add on towards a cleaner co-combustion of lignite-waste-biomass blends by utilizing compounds that could inhibit the formation of toxic pollutants. A series of co-combustion tests was performed in a pilot scale incinerator, and the emissions of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were measured. The co-combustion behaviour of lignite with olive kernels, MDF and sawdust was studied and the ability of additives such as urea, almond shells and municipal sewage sludge to reduce the PCDD/F emissions was examined. All blends were proven good fuels and reproducible combustion conditions were achieved. The addition of inhibitors prior to combustion showed in some cases, relatively high PCDD/F emissions reduction. Among the inhibitors tested, urea seems to achieve a reduction of PCDD/F emissions for all fuel blends, while an unstable behaviour was observed for the others.

Air Pollutants↗

PubMed2006

Pyrolysis and combustion behaviour of coal-MBM blends.

In the present work, thermogravimetric analysis was employed in order to investigate the behaviour of MBM and their blends with Greek brown coal, under pyrolysis and combustion conditions. MBM presented enhanced pyrolysis rates reflecting its high volatile and low ash contents compared to Greek brown coal. Increased conversion rates were observed when MBM was added in the brown coal sample. Significant interactions were detected between the two fuel blend components leading to significant deviations from the expected behaviour. The catalytic effect of mineral matter on the pyrolysis of MBM resulted in reaction rate decrease and DTG curve shift to lower temperatures for the demineralised MBM. Alterations in the combustion process due to the mineral matter were minimal when testing the blends. Interactions maintained during combustion and lower reactivity of MBM was achieved due to the reduced oxygen content.

Biological Products↗

PubMed2006

Leaching and toxicity behavior of coal-biomass waste cocombustion ashes.

Land disposal of ash residues, obtained from the cocombustion of Greek lignite with biomass wastes, is known to create problems due to the harmful constituents present. In this regard, the leachability of trace elements from lignite, biomass, and blends cocombustion ashes was investigated by using the Toxicity Characteristic Leaching Procedure (TCLP) of the US Environmental Protection Agency (US EPA). In this work, the toxicity of the aqueous leachates and the concentrations of the metals obtained from the leaching procedure were measured using the Microtox test (Vibrio fischeri) and inductive coupled plasma-atomic emission spectrometer (ICP-AES), respectively. The toxic effects of most leachates on Vibrio fischeri were found to be significantly low in both 45% and 82% screening test protocols. However, the liquid sample originating from olive kernels fly ash (FA4) caused the highest toxic effect in both protocols, which can be attributed to its relatively high concentrations of As, Cd, Co, Cu, Mn, Ni, and Zn.

Aliivibrio fischeri↗

PubMed1999

Prevalence of enteric pathogens in HIV-related diarrhea in the midwest.

HIV disease is often associated with the condition of diarrhea, which may be accompanied by enteric infection or gastrointestinal tumor. This study prospectively investigated 27 episodes of chronic diarrhea in 24 patients with HIV infection. Upper endoscopy and sigmoidoscopy with biopsies at three sites (distal duodenum, sigmoid colon, and rectum) and viral and mycobacterial blood cultures were performed. Stool specimens were sent for standard tests. A primary infectious diagnosis was found in 10 (37%) of 27 episodes: cytomegalovirus (CMV) colitis (n = 4), 3 microsporidiosis (n = 3), cryptosporidiosis (n = 2), and colonic histoplasmosis (n = 1). Patients with CD4 counts of less than 50 cells/mm3 and with lower albumin levels were more likely to have a primary infectious diagnosis. Adenovirus was found in 7 cases but was often associated with another organism; these were not considered to be primary diagnoses. Blood cultures for viruses were not useful, and all mycobacterial cultures were negative. A flexible sigmoidoscopy with histologic examination and culture of biopsy samples were the diagnostic tools that yielded most infectious diagnoses. Follow-up showed that two thirds of patients improved with nonspecific antidiarrheal medications regardless of diagnosis. The study supports a minimalistic approach to the problem of diarrhea in patients with HIV infection. Upper and lower endoscopy lead to a precise diagnosis in a minority of cases, and the outcome was similar in patients with or without a primary infectious diagnosis.

Adult↗

PubMed1994

Ovarian lymphoma and serous carcinoma of low malignant potential arising in the same ovary. A case report with literature review of 14 primary ovarian lymphomas.

Ovarian lymphoma was incidentally identified in the ovary of a 31-year-old patient who underwent surgical exploration for an ovarian mass. The 6-cm mass was a serous carcinoma of low malignant potential and was located in the same ovary with the lymphoma. The lymphomatous nodule measured 1.5 cm and was diagnosed as diffuse, large-cell lymphoma of B-cell phenotype. Careful search during surgery, as well as extensive postoperative workup, showed no evidence of spread of either tumor type beyond the ovary. In a small pilot study, we examined 37 randomly selected oophorectomy specimens to determine the possible occurrence of lymphoid tissue in the ovary that could serve as substrate for development of ovarian lymphoma. Variable numbers of lymphocytes were identified in 34 of 37 ovaries, mainly in association with common ovarian lesions. This finding and the clinicopathologic data of 14 other reported cases of ovarian lymphoma provide evidence that lymphomas can arise primarily in the ovary.

Adult↗

PubMed1993

Primary prostatic signet-ring cell carcinoma.

We report an uncommon case of primary prostatic signet-ring cell carcinoma which meets all criteria that define this clinicopathologic entity. Histologically, the tumor showed three different growth patterns, all of which contained large numbers of signet-ring cells. The predominant pattern, comprising approximately 50 percent of the tumor, was solid sheets of pure signet-ring cells. An intriguing finding was the presence of intestinal metaplasia involving the prostatic urethra and the large periurethral ducts. All mucin stains were intensely positive within the signet-ring cells and in the mucin lakes. Signet-ring cells stained positively for prostatic specific antigen, prostatic acid phosphatase, and carcinoembryonic antigen immunoperoxidase markers. Our patient presented with symptoms of urinary tract obstruction and locally widespread disease, infiltrating the rectum and the bladder, thus demonstrating the aggressive biologic behavior that traditionally has been ascribed to signet-ring cell carcinomas.

Acid Phosphatase↗

PubMed1993

Gastrointestinal endoscopic pathology in patients seropositive for human immunodeficiency virus.

Endoscopic pathological findings in human immunodeficiency virus (HIV)-positive patients have never been reported from the Midwest. We review the endoscopic and histologic findings in HIV-positive patients referred for endoscopy. The major symptoms that prompted referral to the gastroenterology service were: diarrhea (26%), esophageal symptoms (26%), abdominal pain (19%) and hematochezia (12%). One hundred and twenty-nine symptomatic episodes in 90 patients were retrospectively reviewed. Overall, a diagnosis was reached in 57% of the symptomatic episodes, but in only 32% was a specific infection or neoplasm detected. The most common lesions responsible for diarrhea, esophageal symptoms and pain were Histoplasma colitis, Candida esophagitis and cytomegalovirus colitis. The majority (81%) of the lesions were treatable. The diagnostic yield was significantly higher (44%) for evaluations of patients who were CDC class IV (median CD4, 30 cells/mm3), compared with 14% of patients of other classifications (median CD4, 424 cells/mm3). In addition, evaluation of diarrhea, esophageal symptoms and pain yielded a diagnosis in 41% of the episodes, vs. 11% for evaluation of other symptoms. We conclude that gastrointestinal symptoms are common in HIV-positive patients in the Kansas City area, but are often minor, and that specific infections or neoplasms are diagnosed more commonly in CDC class IV patients and in patients with diarrhea, esophageal symptoms and abdominal pain.

AIDS-Related Opportunistic Infections↗

PubMedDate not supplied

Toxic emissions during co-combustion of biomass-waste wood-lignite blends in an industrial boiler.

The objectives of this work were to study the PCDD/F emissions during the co-combustion of waste wood/coal co-combustion in an industrial boiler and to determine the relation of the toxic emissions to the fuel properties. Co-combustion experiments were performed in a 13.8 MWthermal industrial moving grate combustor. The fuels which were examined in this study included Greek lignite, natural uncontaminated wood, power poles and medium density fibers (MDFs) which were by-products of the plant production process. Fuel blends were prepared by mixing single components in various concentrations. PCDD/F emissions were collected during experimental runs and were analyzed according to standard methods. Low PCDD/F emissions were obtained during the co-combustion tests, lower than the limit value of 0.1 ng TEQ/Nm3. The lowest values were observed during the combustion of fuel blends containing MDF, possibly due to the inhibitory action of some of the N-containing MDF ingredients, such as urea. No direct correlation was found between the PCDD/F and the copper emissions, while examination of the PCDD/F homologue patterns revealed the predominance of the lower chlorinated isomers over the higher ones.

Air Pollutants↗

PubMedDate not supplied

Immunohistochemical localization of amyloid beta-protein deposits in extracerebral tissues of patients with Alzheimer's disease.

An autopsy study was conducted on patients with Alzheimer's disease in order to explore the possibility of amyloid beta-protein deposits in tissues other than the brain. Immunoperoxidase staining techniques were employed using an amyloid beta-protein antiserum as primary antibody; paraffin sections of kidney, liver, heart, lung, spleen, bone marrow, colon, stomach, adrenal, thyroid, and brain were examined. Our autopsy cases were divided into two groups. The first group comprised 10 patients with Alzheimer's disease. The second group consisted of eight control cases, of age-matched individuals, that died of unrelated causes and showed no clinicopathologic evidence of Alzheimer's disease. Identification was made of strong, although focal, positive staining in two kidneys and one lung of three different patients with Alzheimer's disease. All other tissues, including the control cases, showed negative staining.

Aged↗