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Biomedical subjects

A Papadopoulos

Publications and source records attributed to A Papadopoulos.

At least 73 records · Page 4Linked to original sources
PubMed1988

Secreted phosphoproteins associated with neoplastic transformation: close homology with plasma proteins cleaved during blood coagulation.

We have previously demonstrated that a wide variety of rodent and human tumor cells secrete markedly elevated levels of a transformation-related phosphoprotein with a molecular weight (depending on animal species) of 58,000 to 69,000. With antibody raised to the tumor-secreted phosphoprotein (rat), we have now identified an antigenically related protein in normal rat and human plasma. The rat plasma protein and the rat tumor-secreted phosphoproteins comigrated on polyacrylamide gels and were identically cleaved during blood coagulation as well as by purified thrombin. Mouse macrophages expressed a similar or identical phosphoprotein suggesting that monocytic cells may be a source of the normal plasma protein. Consistent with elevated secretion of this protein by tumor cells, plasma and sera from cancer patients contained elevated levels of this protein, raising the possibility that this circulating marker may prove useful for monitoring tumor burden. Amino acid sequence derived from the amino terminus of the rat tumor phosphoprotein indicates that it is distinct from previously sequenced proteins, but that it may be related to protein-tyrosine kinases encoded by viral and proto-onc genes.

Amino Acid Sequence↗
PubMed1985

A study of the extent and pathology of experimental avulsion injury in rabbit arteries and veins.

A comparison was made between operating microscope observations and histopathological examination of the ruptured ends of experimentally avulsed rabbit femoral arteries and veins. Under the operating microscope no damage was evident in arteries or veins more than 0.8 cm (on average) from the rupture site, the common lesions being tears, holes, bruising, sleeving and dilatations. In light microscope and electron microscope studies arterial and venous lesions were often noted up to 4 cm from the rupture site both proximally and distally. Severe circumferential skip lesions involving the tunica intima and media in the arteries were noted, and commonly deep clefts also extended through all three tunicae at arterial bifurcations. In avulsed veins complete tears through all tunicae or partial loss of intima and media were observed. The extensive nature of these lesions is the most likely reason for the lower success rate of avulsed digits in replantation surgery.

Animals↗
PubMed1985

The ratio MDA/MDAa as a new index of platelet hyperactivity.

Since 1979, malonyldialdehyde (MDA) is considered a sensitive index of platelet hyperactivity. Stimulators of phospholipase A2 are used in the procedure of MDA production in order to obtain the final quantity (MDAa) which corresponds to the total amount of arachidonic acid present; without stimulation the production of MDA is minimal in non-activated platelets (MDA non-activated). Therefore, the more the MDA/MDAa ratio approaches unity, the more activated are the thrombocytes. We utilized for the first time this new index for the investigation of hyperactive platelets, and we studied 56 persons (17 patients with thrombophilic disease as group A, 17 normals as group B and 22 diabetics without ketoacidosis as group C). We proved that the new index (MDA/MDAa) can be used to detect persons with functionally hyperactive platelets because large differences are found between the mean values of normals and the values of patients with established thrombotic disease, at a high confidence limit (means +/- 3 SD covering 99% of the samples). Comparing the sensitivity of this new index with the other three methods used for the detection of hyperactive platelets [ratio of circulating platelet aggregates (CPA), aggregation with ADP, spontaneous aggregation] in groups B and C we found that only the ratio MDA/MDAa was able to reveal that (a) the two groups B and C are not identical (a statistical conclusion after comparison with the other methods) and (b) there were 5 diabetics in group C who had more hyperactive platelets than the others (these patients were not detected by any other method).

Adenosine Diphosphate↗
PubMed1982

Sexual differentiation of arachidonate toxicity in mice.

Mature male and female mice 50 days of age were challenged with i.v. sodium arachidonate at doses of 12.5, 25, 50 and 100 mg/kg. A dose-dependent response in terms of mortality was observed. Males were significantly more susceptible to arachidonate-induced mortality than females at the 25 and 50 mg/kg doses (P less than .05). The 100 mg/kg dose produced 100% mortality in both sexes. When mice aged 23, 29, 35 and 50 days were challenged with 50 mg/kg of arachidonate, no gender difference was observed until mice were 35 days of age, at which time the male mortality was 80%, compared to 57% for female mice (P less than .05). Mice gonadectomized at 23 days and intact mice 23 days of age were treated with s.c. estradiol, testosterone or vehicle for 7 days before arachidonate challenge. Among these groups, the gonadectomized females and intact males were significantly protected by estradiol when compared to the appropriate controls (P less than .05). In contrast, testosterone pretreatment had no significant effect on mortality. These results demonstrate that the development of the gender difference in arachidonate-induced mortality in mice is dependent upon the presence of gonadal hormones in the immature stages.

Adrenal Glands↗
PubMed1977

Rocking motion of the right cardiac cavities in Ebstein's anomaly. A specific cineangiographic sign.

In 7 cases of Ebstein's anomaly the right cineangiogram disclosed a big right atrium, the tricuspid valve positioned to the left of the spine and tricuspid regurgitation. The right atrial appendage was nearing the outflow tract of the right ventricle and the pulmonary artery so as the normal U appearance of the right aniograms was abolished. In addition to these signs a very characteristics and almost pathognomonic rocking motion of the radiopaque material, moving from the right atrium towards the right ventricle during ventricular diastole and backwards to the atrium during the next ventricular systole was observed. This sequence of motion gives the impression of a rocking hammock or pendulum.

Angiocardiography↗
PubMed1976

The contribution of right ventricular angiocardiography to the diagnosis of tricuspid valvular stenosis (Observations made on 3 patients).

The right ventricular angiocardiographic findings, in the anterioposterior projection, are described on three patients with tricuspid valvular stenosis. During diastole, the tricuspid valve was delineated as an arcline contour, placed between the non opacified right atrium and the opacified right ventricle, and it was displaced to the left of the spine. Its mobility was diminished. Right ventricular angiocardiography seems to be a useful method for the diagnosis of the tricuspid valvular stenosis and the estimation of the pathology and the functional condition of the tricuspid valve. The method is recommended for further evaluation.

Adult↗
PubMedDate not supplied

MRI of abdominal hydatid disease.

Seventy hydatid cysts in 30 patients were studied with magnetic resonance imaging (MRI) and computed tomography (CT); all cases were confirmed surgically. MRI detected all cysts when confined to solid organs, whereas small-sized cysts (< or = 2 cm) may be missed when located in the peritoneal cavity. Hydatid cysts of less than 3 cm (noncomplicated) present no specific findings of hydatid disease. MRI findings suggesting hydatid disease demonstrate a relatively thick hydatid cyst wall, daughter cysts, and germinal membrane detachment. T2-weighted images proved to be superior to T1- or PD-weighted images in demonstrating hydatid cyst wall thickness, germinal membrane detachment, and daughter cysts. In all spin-echo sequences, the maternal cystic content presented much higher signal intensities than that of daughter cysts. This difference in signal intensity is more obvious in T2-weighted images, except in complicated, infected cases. CT proved to be superior to MRI in demonstrating wall calcifications.

Abdomen↗
PubMedDate not supplied

Perforation of the alimentary tract: evaluation with computed tomography.

BACKGROUND: To assess the value of computed tomography (CT) in the diagnosis of perforation of the alimentary tract (AT). METHODS: During a 4-year period 76 patients with proven AT perforation underwent CT within 1 week before surgery or endoscopy. We retrospectively reviewed these CT scans to determine the signs of AT perforation. There were 41 men and 35 women (28-90 years old). Our goal was to establish the diagnosis of AT perforation and, if this was possible, to identify the site and cause of the AT wall rupture. The CT diagnosis of perforation was based on (a) direct findings of extraluminar air or gastrografin and (b) indirect findings of an abscess or an inflammatory mass surrounding an enterolith in the region of appendix or a bowel wall-related phlegmon or abscess with fluid in the mesentery or surrounding radiopaque foreign body. RESULTS: There were 65 true-positive and 11 false-negative cases. Levels of perforation were the esophagus (two), stomach (five), duodenum (12), small bowel (15), appendix (six), and colon (36). Causes were peptic ulcer (11), foreign body (five), trauma (seven), iatrogenic (nine), appendicitis (six), diverticulitis (21), Crohn disease (five), AT carcinoma (eight), and ischemia (four). Level and cause were correctly predicted in 55 and 51 instances, respectively. The sensitivity was estimated to 85.5%. CONCLUSION: CT is a valuable method in the diagnosis of AT perforation. The diagnosis can be established rapidly, without patient preparation and with a high sensitivity.

Adult↗
PubMedDate not supplied

Operational monitoring and forecasting in the Aegean Sea: system limitations and forecasting skill evaluation.

The POSEIDON system, based on a network of 11 oceanographic buoys and a system of atmospheric/oceanic models, provides real-time observations and forecasts of the marine environmental conditions in the Aegean Sea. The buoy network collects meteorological, sea state and upper-ocean physical and biochemical data. The efficiency and functionality of the various system components are being evaluated during the present pre-operational phase and discussed in this paper. The problem of bio-fouling on optical and chemical sensors is found to be a main limitation factor on the quality of data. Possible solutions to this problem as well as quality control methods that are being developed are also described. Finally, an evaluation of the numerical models is presented through the estimation of their forecasting skill for selected periods.

Animals↗
PubMedDate not supplied

Long-term follow-up of patients with adult-onset Still's disease.

OBJECTIVE: To evaluate the long-term outcome of patients with adult-onset Still's disease (AOSD). METHODS: Eleven patients with AOSD who were regularly followed-up during the past 13 years, even after discontinuation of treatment, were evaluated for the long-term prognosis of the disease and its possible complications. RESULTS: No exacerbation of the symptoms was noted during therapy. Only two of the 11 patients exhibited relapse of the systemic disease after discontinuation of treatment. Both patients had previously been on corticosteroids and responded well to reinitiation of therapy. Progressive deforming arthritis was not noted in any patient. Hepatic failure, central nervous system involvement, renal involvement or systematic amyloidosis did not complicate the course of any of the patients. CONCLUSIONS: Long-term prognosis of AOSD may be benign in a significant subset of patients. Further studies should clarify characteristics of the subset of patients for whom disease-modifying therapy is warranted.

Adult↗
PubMedDate not supplied

Increased salivary cortisol reliably induced by a protein-rich midday meal.

OBJECTIVE: This study was conducted to determine whether an increase in salivary free cortisol would be reliably elicited by a midday meal, thus providing a convenient physiological challenge to the hypothalamic-pituitary-adrenal (HPA) axis, and whether this cortisol release depended on the protein content of the meal. METHOD: In healthy men, free cortisol was measured in saliva samples taken before and after two identical protein-rich midday meals (39% energy as protein) and compared with a day on which no meal was eaten. Next, in healthy women in a nonclinical setting, salivary cortisol was measured before and after a protein-rich meal (32% energy as protein) on one day and a low-protein meal (5% energy as protein) on another day. Measures of mood, appetite, and psychological well-being were also taken. RESULTS: An acute meal-dependent increase in salivary cortisol occurred, which was reliable over 2 test days. This increase in cortisol depended on the proportion of protein in the meal, increasing after the high-protein but not the low-protein meal. The extent of this increase in cortisol correlated significantly with poor psychological well-being in women. Some postmeal improvement of mood (positive affect) was associated with the high- but not the low-protein meal. CONCLUSIONS: The cortisol response to meals may have implications for the effects of meal composition on mood, cognitive function, and food choice. The measurement of free cortisol in saliva provides a psychologically stress-free and reliable technique to assess the cortisol response to a standard protein-rich meal, ie, a physiological challenge to the HPA axis in men and women that could be investigated in naturalistic settings outside the laboratory.

Adolescent↗
PubMedDate not supplied

Diffuse large cell lymphomas: identification of prognostic factors and validation of the International Non-Hodgkin's Lymphoma Prognostic Index. A Hellenic Cooperative Oncology Group Study.

Several clinical prognostic factors have been identified that predict treatment outcome in patients with diffuse large cell lymphomas. An International Non-Hodgkin's Lymphoma Prognostic Index (IPI) has been recently formulated. We tried to identify the clinical prognostic factors that predict treatment outcome in Greek patients with diffuse large cell lymphomas and validated the IPI in these patients. The possible prognostic variables for tumor response, relapse-free (RFS) and overall survival (OS) were analyzed in 239 consecutive patients treated with anthracycline-based chemotherapy regimens. In univariate analysis, factors associated with poor response were stages III-IV, performance status (PS) >/=2, spleen and bone marrow involvement, more than one extranodal site involved, increased lactate dehydrogenase (LDH) value, hemoglobin (Hb) <12 g/dl, albumin <3.5 g/dl, erythrocyte sedimentation rate (ESR) >50 mm/h. Multivariate analysis identified stage, PS, more than one extranodal site involved, increased LDH level, and ESR > 50 mm/h as the factors more predictive of poor response. For RFS, multiple Cox analysis found stages III-IV and bone marrow involvement to be statistically significant. For OS, multiple Cox analysis identified stage III-IV, PS >/=2, bone marrow involvement, more than one extranodal site involved, increased LDH level and ESR > 50 mm/h as negative prognostic factors. Patients stratified in the different risk groups of the IPI had a significantly different outcome regarding complete response (CR) rate, RFS and OS. In conclusion, although age >60 years was not recognized as an adverse factor in this analysis, our patients stratified in the different groups of the IPI had significant differences in CR rate, 2-year RFS and OS verifying the prognostic significance of the index. Bone marrow involvement and ESR > 50 mm/h, parameters that are not included in the IPI, adversely affected survival.

Adult↗
PubMedDate not supplied

Elevated expression of secreted phosphoprotein I (osteopontin, 2ar) as a consequence of neoplastic transformation.

Several lines of evidence have recently been presented indicating that proteins previously referred to as Mr 62,000-67,000 transformation-associated secreted phosphoprotein, 2ar, osteopontin, bone sialoprotein I, and 44K Dal bone phosphoprotein are all very likely encoded by the same gene. We have found that markedly elevated expression of this protein, which henceforth is referred to as secreted phosphoprotein I (Sppl) closely correlates with neoplastic transformation of a variety of cell types and that patients with advanced stage metastatic cancers have elevated levels of Sppl in their blood. Moreover, Sppl expression is induced in mouse epidermal cells in vitro and mouse epidermis in vivo with the tumor promoter TPA (Craig et al, J. Biol. Chem. 264: 9682-9689, 1989). Sppl amino acid sequence deduced from cDNA nucleotide sequence (Oldberg et al, Proc. Natl. Acad Sci. U.S.A. 83: 8819-8823, 1986) contains the GRGDS cell-binding sequence which is known to be important for cell attachment to several adhesive proteins found in extracellular matrices. Because of the presence of the GRGDS cell-binding sequence in Sppl, it is probable that abnormally high expression of this soluble protein by tumor cells has important consequences for interactions between tumor cells and the host tissue matrix.

Amino Acid Sequence↗