Biomedical subjects

A Pappa

Publications and source records attributed to A Pappa.

18 recordsLinked to original sources

PubMed2005

Preliminary investigation of using volatile organic compounds from human expired air, blood and urine for locating entrapped people in earthquakes.

A preliminary investigation on the possibility of using volatile organic compounds (VOCs) determination of expired air, blood and urine, for the early location of entrapped people in earthquakes, has been carried out. A group of 15 healthy subjects has been sampled. The identification of a common "core" of substances might provide indications of human presence that can be used for the development of a real time field analytical method for the on site detection of entrapped people. Expired air samples have been analyzed by thermal desorption GC/MS and VOCs from blood and urine by headspace SPME-GC/MS. Acetone was the only compound found common in all three matrices. Isoprene was found in both expired air and blood samples. Acetone and isoprene along with a number of saturated hydrocarbons were among the major constituents identified in expired air analysis. Various ketones (2-pentanone, 4-heptanone, 2-butanone) were also determined over urine specimens. Using the techniques and methods of field analytical chemistry and technology appears to be the proper approach for applying the results of the present study in real situations.

Acetone↗

PubMed2003

Enzyme immunoassays for the determination of ovine LH and FSH.

The development of competitive enzyme immunoassays for ovine plasma LH (oLH) and FSH (oFSH) is described. Standards and plasma samples were preincubated with diluted antiserum to oLH or oFSH and the reacted solution (100 micro l per well) was transferred to plates previously coated with oLH or oFSH, respectively. The second antibody used was anti-rabbit IgG horseradish peroxidase. The measuring range was 0.39-50 ng/ml for each hormone and the 50% relative binding sensitivity was 9 ng/ml for oLH. The respective value for oFSH was 3.5 or 34 ng/ml with different hormone and antibody preparations used for the assay. The enzyme immunoassays were used to determine oLH and oFSH levels in plasma from ewes of two breeds during the oestrous cycle. The assays detected the first FSH surge coincident with the LH surge, the second FSH surge about 24 h later and the periodic fluctuations of FSH concentrations during the luteal phase of the oestrous cycle. These enzyme immunoassays are an efficient and economic alternative to the established radioimmunoassays (RIA) for oLH and oFSH.

Animals↗

PubMed2001

Corneal and stomach expression of aldehyde dehydrogenases: from fish to mammals.

We have studied the distribution of the ALDH3A1, ALDH1A1 and ALDH2 proteins in the cornea and stomach of several animal species, including mammals (C57BL/6J and SWR/J mice, rat and pig), birds (chicken and turkey), amphibians (frog) and fish (trout and zebrafish). High ALDH3A1 protein levels and catalytic activities were detected in C57BL/6J mouse, rat and pig. We found complete absence of the ALDH3A1 protein in SWR/J mice, which carry the Aldh3a1(c) allele characterized by four amino acid substitutions (G88R, I154N, H305R and I352V) and lack of enzymatic activity. This indicates that the SWR/J mouse strain is a natural gene knockout model for ALDH3A1. Traces of ALDH3A1 were detected in rabbit, whereas expression was absent from chicken, turkey, frog, trout, and zebrafish. Interestingly, significant levels of the cytosolic ALDH1A1 and mitochondrial ALDH2 proteins were detected by immunoblot analysis in all examined species that are deficient in ALDH3A1 expression. In contrast, no ALDH1A1 or ALDH2 protein was detected in the species expressing ALDH3A1. It can, therefore, be concluded that corneal expression of ALDH3A1 or ALDH1A1/ALDH2 occurs in a taxon-specific manner, supporting the protective role of these ALDHs in cornea against the UV-induced oxidative damage.

Aldehyde Dehydrogenase↗

PubMed2001

Aldehyde dehydrogenase gene superfamily: the 2000 update.

Aldehyde dehydrogenase (ALDH) superfamily represents a group of NAD(P)(+)-dependent enzymes that catalyze the oxidation of a wide spectrum of endogenous and exogenous aldehydes. With the advent of megabase genome sequencing, the ALDH superfamily is expanding rapidly on many fronts. As expected, ALDH genes are found in virtually all genomes analyzed to date, indicating the importance of these enzymes in biological functions. Complete genome sequences of various species have revealed additional ALDH genes. As of July 2000, the ALDH superfamily consists of 331 distinct genes, of which eight are found in archaea, 165 in eubacteria, and 158 in eukaryota. The number of ALDH genes in some species with their genomes completely sequenced and annotated, Escherichia coli and Caenorhabditis elegans, ranges from 10 to 17. In the human genome, 17 functional genes and three pseudogenes have been identified to date. Divergent evolution, based on multiple alignment analysis of 86 eukaryotic ALDH amino-acid sequences, was the basis of the standardized ALDH gene nomenclature system (Pharmacogenetics 9: 421-434, 1999). Thus far, the eukaryotic ALDHs comprise 20 gene families. A complete list of all ALDH sequences known to date is presented here along with the evolution analysis of the eukaryotic ALDHs.

Aldehyde Dehydrogenase↗

PubMed2000

Role of aldehyde dehydrogenases in endogenous and xenobiotic metabolism.

Aldehydes are highly reactive molecules that are intermediates or products involved in a broad spectrum of physiologic, biologic and pharmacologic processes. Aldehydes are generated from chemically diverse endogenous and exogenous precursors and aldehyde-mediated effects vary from homeostatic and therapeutic to cytotoxic, and genotoxic. One of the most important pathways for aldehyde metabolism is their oxidation to carboxylic acids by aldehyde dehydrogenases (ALDHs). Oxidation of the carbonyl functional group is considered a general detoxification process in that polymorphisms of several human ALDHs are associated a disease phenotypes or pathophysiologies. However, a number of ALDH-mediated oxidation form products that are known to possess significant biologic, therapeutic and/or toxic activities. These include the retinoic acid, an important element for vertebrate development, gamma-aminobutyric acid (GABA), an important neurotransmitter, and trichloroacetic acid, a potential toxicant. This review summarizes the ALDHs with an emphasis on catalytic properties and xenobiotic substrates of these enzymes.

Aldehyde Dehydrogenase↗

PubMed2000

Involvement of p65 in the regulation of NF-kappaB in rat hepatic stellate cells during cirrhosis.

We have examined the NF-kappaB binding and functional activities in two stellate cell lines derived from normal (NFSC) and cirrhotic (CFSC) rat liver. Gel mobility shift assays revealed two bands in NFSC nuclear extracts that correspond to p65/p50 heterodimers and p50/p50 homodimers. In contrast, a single and more intense band that migrates faster was detected in CFSC nuclear extracts. This band supershifts with either p65 or p50 antibody. The differential NF-kappaB binding observed in these two cell lines appears to depend on the phosphorylation of the p65 subunit rather than the expression levels of either p65 or p50. The nonphosphorylated NF-kappaB form, present in CFSC cells, possesses significantly lower transcriptional activity compared to phosphorylated NF-kappaB, found in NFSC cells. To our knowledge, this is the first report on the NF-kappaB regulation at the p65 protein in hepatic stellate cells. It is likely that this regulation affects IL-6 expression and may represent a mechanism regulating hepatocyte death during fibrogenesis.

Animals↗

PubMed2000

T cells and fibroblasts in affected extraocular muscles in early and late thyroid associated ophthalmopathy.

AIM: To determine whether there are differences in the lymphocytic cell infiltrate present in affected extraocular muscles (EOM) during early and late stages of thyroid associated ophthalmopathy (TAO). METHODS: 17 biopsies of affected EOMs were collected from two groups of TAO patients (n=14): the first of five patients with early, active TAO, and the second of nine patients with late, inactive TAO. The control group was of EOM biopsies taken from 14 non-TAO patients undergoing squint surgery. Immunohistochemical analysis was undertaken using the relevant monoclonal antibodies and an avidin-biotin system and the three groups compared. RESULTS: Both CD4+ and CD8+ T cells were found in the cellular infiltrate in early, active TAO specimens which were much less evident either in late, inactive stage disease or in control tissue. There was also a significant increase in both CD45RO+ and CD45RB+ cells and macrophages in early TAO compared with the others. Increased expression of HLA-DR antigen by interstitial cells including fibroblasts was detected in both early and late disease but the EOM fibres remained morphologically intact and did not express MHC class II antigens at any time. CONCLUSION: These results demonstrate that T cells are only significantly present in early disease but increased HLA-DR antigen expression on fibroblasts is observed at all stages. This suggests that T cells are much more involved in the early than the later stages of the disease process and that early activation of fibroblasts occurs. Early intervention with immunosuppressive therapy to downregulate cytokine production by T cells may significantly influence the sequelae caused by EOM fibrosis.

Adult↗

PubMed2000

Polymorphisms of human aldehyde dehydrogenases. Consequences for drug metabolism and disease.

Aldehyde dehydrogenases (ALDHs), a superfamily of NAD(P)(+)-dependent enzymes with similar primary structures, catalyze the oxidation of a wide spectrum of endogenous and exogenous aliphatic and aromatic aldehydes. Thus far, 16 ALDH genes with distinct chromosomal locations have been identified in the human genome. Polymorphism in ALDH2 is associated with altered acetaldehyde metabolism, decreased risk of alcoholism and increased risk of ethanol-induced cancers. Polymorphisms in ALDH3A2, ALDH4A1, ALDH5A1 and ALDH6A1 are associated with metabolic diseases generally characterized by neurologic complications. Mutations in ALDH3A2 cause loss of enzymatic activity and are the molecular basis of Sjögren-Larsson syndrome. Mutations in ALDH4A1 are associated with type II hyperprolinemia. Deficiency in ALDH5A1 causes 4-hydroxybutyric aciduria. Lack of ALDH6A1 appears to be associated with developmental delay. Allelic variants of the ALDH1A1, ALDH1B1, ALDH3A1 and ALDH9A1 genes have also been observed but not yet characterized. This review describes consequences of ALDH polymorphisms with respect to drug metabolism and disease.

Alcoholism↗

PubMed1999

Development and application of competitive ELISA assays for rat LH and FSH.

Rat LH (rLH) and FSH (rFSH) were measured by sensitive and specific competition ELISAs. The rat LH ELISA used rLH-I-9 coated plates, an antiserum against rLH and an antibody against rabbit IgG labeled with peroxidase. Using rLH-RP-3 as a standard, rat LH was determined by binding of the anti-LH antibody to rLH-I-9 coated plates. The sensitivity of the assay was 0.8 ng/mL. Similarly, the rat FSH-ELISA used rFSH-I-8 coated plates, an antiserum against rFSH and an antibody against rabbit IgG labeled with peroxidase. Using rFSH-RP-3 as a standard, the FSH-ELISA was also determined by binding of the anti-FSH antibody to rFSH-I-8 coated plates. The sensitivity of this assay was 1.25 ng/mL. Both rat LH and FSH ELISA assays are highly specific and provide accurate determination of gonadotrophins in buffers, sera, cell culture media, and anterior pituitary extracts. These assays were used for monitoring the gonadotrophin surge-attenuating factor (GnSAF) and inhibin activities present in human follicular fluid (hFF). The 2 new ELISA procedures have practical advantages (safety, convenience, economy) over the RIA methods, and they perform as well as the RIA techniques at the same range of concentrations.

Animals↗

PubMed1999

Purification of a candidate gonadotrophin surge attenuating factor from human follicular fluid.

Gonadotrophin surge attenuating factor (GnSAF) is a new non-steroidal ovarian substance, different from inhibin, which attenuates the pre-ovulatory luteinizing hormone (LH) surge in superovulated women. Human follicular fluid (FF) was used as a source for the isolation of GnSAF, the activity of which was monitored in an in-vitro pituitary bioassay. Primary rat pituitary cells were incubated with test substances for 48 h and subsequently washed and incubated with 0.1 micromol/l gonadotrophin releasing hormone (GnRH) plus test substances for 4 h. GnSAF activity was expressed as the reduction of GnRH-induced LH secretion in the 4 h incubation. GnSAF was purified from 250 ml of FF which was heat-treated at 80 degrees C for 5 min. Heparin-sepharose chromatography, Con-A sepharose chromatography, reversed-phase high-performance liquid chromatography (HPLC) and preparative native gel electrophoresis were used for GnSAF fractionation. Using these purification steps, we have obtained an apparently homogeneous preparation that stains as a single band on sodium dodecyl sulphate (SDS)-polyacrylamide gel electrophoresis. GnSAF has an apparent molecular weight of 12.5 kDa and was identified by amino acid sequence (mass spectrometry) to be the C-terminal fragment of human serum albumin.

Amino Acid Sequence↗

PubMed1998

Stability and safety of traditional Greek salami -- a microbiological ecology study.

The microbiological and physicochemical changes which occurred during the industrial fermentation and ripening of four batches of Greek dry salami manufactured without starter cultures were followed. Moderated dehydration rates, monitored by slowly decreasing relative humidity from 94 to 90% during fermentation, prevented the production of insufficiently acidified batches by maintaining microbial activity for longer when the natural inoculum was low. The terminal pH values (5.0-5.2) and water contents (27.7-30.3%) of the sausages were narrowly ranged. Fermentation was governed by an active (> 10(8) cfu g(-1)) lactic flora, consisting of 'wild' strains of Lactobacillus sake. Gram-negative bacteria and aerobic sporeformers decreased below 10(2) and l0(3) cfu g(-1), respectively, while yeasts did not significantly increase during ripening and were below 10(5) cfu g(-1) in the ripened product. Sausages were substantially free of sulfite-reducing clostridia and coagulase-positive staphylococci during the whole process. Listeria spp., occurred in the fresh sausage mix, but disappeared from all batches at the latest by the end of fermentation. Enterococci exceeded 10(5) cfu g(-1) during the first days and remained at this level during ripening. Novobiocin-resistant staphylococci matching Staphylococcus saprophyticus (mainly) and S. xylosus dominated Micrococcaceae populations, ranged between 10(5) and 10(6) cfu g(-1). This is the first report of such a large contribution from S. saprophyticus to the production of dry salami of good quality. It is concluded that to keep or improve the traditional 'sensory type' of Greek salamis, suitable strains of L. sake, S. xylosus and possibly nitrate-reducing S. saprophyticus should be selected and validated as starter cultures in experimentally inoculated salamis.

Bacteria↗

PubMed1998

An ultrastructural and systemic analysis of glycosaminoglycans in thyroid-associated ophthalmopathy.

PURPOSE: To determine the ultrastructural localisation of glycosaminoglycans (GAGs) in the extraocular muscles (EOMs) of patients with thyroid-associated ophthalmopathy (TAO) and to see whether the quantity and type of GAGs present in blood and urine are markers of the disease. METHODS: Biopsies of affected EOMs were taken and studied by transmission electron microscopy (TEM). These were either fixed conventional for TEM, or in 0.5% tannic acid and others for immunogold staining. Serum hyaluronan (HA) was measured using a radioimmunoassay in patients with TAO as well as control subjects, and urinary GAG levels assessed by photometric quantitation of hexuronic acid after reaction with carbazole. The excretion pattern of the urinary GAGs was determined by discontinuous electrophoresis. RESULTS: TEM showed that there is a marked expansion of the endomysial space in TAO EOM biopsies as compared with non-TAO strabismus specimens. This is caused by an increased number of collagen fibres, interspersed with a granular amorphous material surrounding striated collagen fibres shown to be hyaluronan by immunogold staining. In contrast, serum hyaluronan concentrations were similar in TAO and control patients, although there was a statistically significant difference in the urinary GAG excretion between the two groups of patients examined. By discontinuous electrophoresis, chondroitin sulphate and heparan sulphate were present in both patients and controls. CONCLUSION: GAGs and in particularly HA are present at the EOM level in patients with recently inactive TAO. However, serum levels of HA and urinary GAGs are not sensitive indicators for their presence within the EOMs.

Adult↗

PubMed1997

Adhesion molecule expression in vivo on extraocular muscles (EOM) in thyroid-associated ophthalmopathy (TAO).

TAO is an autoimmune condition characterized by mononuclear cell infiltration of the extraocular muscles (EOM) and/or the orbital fat/connective tissue with associated deposition of glycosaminoglycans (GAG) in the interstitial spaces. In this study, the presence and distribution of the vascular adhesion molecules intercellular adhesion molecule-1 (ICAM-1), endothelial-leucocyte adhesion molecule-1 (ELAM-1), vascular cell adhesion molecule-1 (VCAM-1) and the leucocyte integrins CD11a/CD18, CD11b/CD18, CD11c/CD18 were investigated. Nineteen EOM biopsies were collected from 17 patients with early (n = 6) and late (n = 13) TAO as well as from 12 non-TAO control patients. Consecutive cryostat sections of these biopsies were immunostained with MoAbs to the above-mentioned molecules and haematoxylin and eosin. Primary antibody binding was visualized using an avidin-biotin system. In early untreated TAO specimens, the interstitial and perimysial connective tissue surrounding EOM fibres and numerous mononuclear cells stained strongly for ICAM-1. In contrast, the vascular endothelial cells (ulex lectin-positive) stained strongly for ELAM-1 (E-selectin), VCAM-1 as well as ICAM-1. In late disease, the same distribution of immunoreactivity for ICAM-1, ELAM-1 and VCAM-1 was observed, but with significantly lower staining. The leucocyte integrins (CD11a, CD11b, CD11c) were again expressed at significantly higher levels in early TAO specimens compared with late TAO specimens and were minimal or absent in the EOM biopsies harvested from control patients. In conclusion, increased expression of adhesion molecules studied correlated with early active disease and was reduced in later stages.

Adult↗

PubMed1997

Analysis of extraocular muscle-infiltrating T cells in thyroid-associated ophthalmopathy (TAO).

TAO is characterized by an autoimmune process affecting the orbital contents. T cells have been suggested to have a major role in pathogenesis, but so far only limited data are available to clarify the extraocular muscle (EOM)-infiltrating T cell phenotype, antigenic reactivity and cytokine profile in TAO patients. In the present study, biopsies of affected EOM were taken and the infiltrating T cells isolated and expanded in vitro with mitogen. Their phenotype was determined by flow cytometric (FACS) analysis and compared with peripheral blood-derived T cell lines, treated in the same way from the same patient. Cytokines present in the supernatant after mitogen stimulation of the T cell lines were assayed by ELISA. In addition, cytokine mRNA present at the time of biopsy was determined by rapid RNA extraction from EOM and reverse transcription-amplification with specific cytokine oligonucleotide probes (IL-1alpha, IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-13, IL- 15, interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha)). In the T cell lines from two patients, proliferation assays were carried out with antigens derived from thyroid gland, EOM and a thyrotropin (TSH) receptor preparation. Most T cell lines were CD4+, CD45RO+, and TCR alpha/beta+, both from the EOM and the peripheral blood. A wide variety of cytokines was detected by analysis of supernatants or mRNA, but the profiles were not identical comparing the two approaches. However, IL-4 was detected by both. Dose-dependent proliferation was observed in response to thyroid extract in a biopsy-derived T cell line. In conclusion, EOM-infiltrating T cells from patients with TAO, expanded in vitro, were chiefly CD4+ and produced a mixture of cytokines, including IL-4. The proliferation data suggest that there are thyroid-reactive T cells in EOM.

Adult↗

PubMed1996

Seminal volume and total sperm number trends in men attending subfertility clinics in the greater Athens area during the period 1977-1993.

The trends for such important parameters of male fertility as seminal volume and total sperm number were assessed in men living permanently in the Greater Athens area over a prolonged period of time. To this end, the records of three andrological laboratories employing the same method for semen evaluation were analysed retrospectively. Out of 23,850 men examined from 1977 to 1993 (17 years) for couple subfertility, a total of 2385 (10%) were selected for evaluation by a randomization procedure. Analysis of the data included (i) estimation of mean seminal volume and total sperm number per year, (ii) assessment of percentage frequency distribution of each seminal parameter and (iii) evaluation of seminal volume and total sperm number changes in relation to the year of observation and age of the subjects. A significant decrease (P < 0.01) of total sperm number was observed over the years with a mean (+/-SEM) of 154.3 +/- 19.2 x 10(6) at the beginning (1977), dropping to 130.1 +/- 13.3 x 10(6) in the final year (1993). Mean seminal volume was lower in the final year of observation, but its difference from the initial year value was not significant. Frequency distribution analysis showed a marked decline in the 240-400 x 10(6) sub-set of the range of sperm number values from 16.9 +/- 4.5% (1977) to 10.6 +/- 1.6% in the final year (P < 0.01). Multiple regression analysis of seminal volume, total sperm number, age and year of assessment revealed a significant decline of the two seminal parameters along the years of observation (P < 0.05 and P < 0.0001 respectively). Over the same period, a marked deterioration of some air pollution indices was observed in that area. It is concluded that in this racially and ethnically homogeneous sample of men, living under the same environmental conditions, a significant decline in seminal volume and total sperm number occurred over the 17 years of observation.

Adult↗

PubMed1994

Extraocular muscle problems in thyroid eye disease.

In this paper methods of visualisation of the extraocular muscle changes in thyroid eye disease are discussed. The histopathology of extraocular muscle biopsies has been studied by both light and electron microscopy to show the type of cellular infiltration and the amorphous material in the extracellular matrix. A series of questions to which answers have not yet been found concerning thyroid eye disease are posed which may help to direct new research projects. Finally, in the last part of the paper, the surgical results in a series of 41 patients having ocular muscle surgery for diplopia and/or compensatory head postures due to thyroid eye disease are described. The conclusions drawn from these results are that one should maintain the patient euthyroid, establish by orthoptic measurements that the ocular movements have been stable for at least 6 months, treat by recessing tight muscles using adjustable sutures, and aim to undercorrect the vertical deviation at the time of adjustment.

Diplopia↗

PubMed1993

Variability of peritoneal protein loss in diabetic and nondiabetic patients on continuous ambulatory peritoneal dialysis.

In order to evaluate the influence of diabetes mellitus on peritoneal membrane permeability, we studied the peritoneal protein loss in two groups of patients. Group A consisted of 16 patients (9 nondiabetics and 7 diabetics) who were in the first month of treatment on continuous ambulatory peritoneal dialysis (CAPD). Group B consisted of 13 patients (7 nondiabetics and 6 diabetics) who had been on CAPD for approximately 15 months. In both groups we measured the body weight, serum total protein, albumin, and total protein, urea, and glucose in the peritoneal fluid. We did not find any difference in groups A and B between diabetics and nondiabetics as far as the estimated parameters were concerned. Age, body weight, serum biochemistry, and protein and urea content in peritoneal fluid were similar, when group A was compared to group B. Patients of group B had on average higher protein losses than those who had been on the method for a short period (mean 7.9 g/dL, vs 6.09 g/dL). Six patients were followed for over 15 months and were found to have significantly increased protein losses (p = 0.02). Glucose levels in peritoneal fluid were significantly lower in patients in group B, p < 0.05 (mean 51.8 g/dL vs 37.1 g/dL). Peritoneal protein loss does not seem to differ between diabetic and nondiabetic patients with end-stage renal disease treated with CAPD, at any given time of the treatment. We observed an increase in protein loss in some patients and a tendency to increase the protein loss in others.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMedDate not supplied

A comparison of the Api-10M commercial microdilution system with the tube dilution and standard microdilution methods.

The susceptibilities of urinary isolates of Escherichia coli (50 strains), Klebsiella pneumoniae (15 strains) and Proteus mirabilis (15 strains) to gentamicin and ampicillin were determined and compared using the following methods: standard tube dilution, standard microdilution, commercial microdilution and disk diffusion susceptibility tests. Results of susceptibility testing performed with the Api- 10M commercial microdilution method agreed with those of the tube dilution method in 93% of the tests, but in only 70% of those obtained with the standard microdilution method; tube dilution and standard microdilution agreed in 85.6% of the cases. All three methods of MIC susceptibility testing agreed with the disk diffusion method in 100% of the tests. There was a definite tendency for the Api- 10M system to give higher MICs than the tube dilution method; the standard microdilution method tended to give lower MICs than those obtained by tube dilution and the commercial microdilution system. The Api- 10M system is a reliable, simple and accurate method since it correlates very will with the tube dilution method.

Ampicillin↗