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Biomedical subjects

I G Vlachonikolis

Publications and source records attributed to I G Vlachonikolis.

At least 19 recordsLinked to original sources
PubMed2001

Anti-Saccharomyces cerevisiae mannan antibodies and antineutrophil cytoplasmic autoantibodies in Greek patients with inflammatory bowel disease.

OBJECTIVES: The combined measurement of perinuclear antineutrophil cytoplasmic autoantibodies (pANCA) and anti-Saccharomyces cerevisiae mannan antibodies (ASCA) has recently been suggested as a valuable diagnostic approach in inflammatory bowel disease (IBD). The aim of this study was to assess the value of detecting pANCA and ASCA in the differentiation between ulcerative colitis (UC) and Crohn's disease (CD) in a Greek population with IBD. METHODS: Sera were collected from 157 patients with IBD (97 with UC, 56 with CD, and four with indeterminate colitis) and 150 healthy controls. Determination of pANCA was performed by a standard indirect immunofluorescence technique on ethanol-fixed granulocytes and ASCA by an ELISA assay. RESULTS: In patients with UC, sensitivity, specificity, positive predictive value, and negative predictive value of the pANCA test was 67%, 84%, 93%, and 46% respectively. These values did not change significantly when the combination of positive pANCA and negative ASCA was used. ASCA test in diagnosing CD yielded a sensitivity, specificity, positive predictive value, and negative predictive value of 39%, 89%, 54%, and 81%. The combination of pANCA negative and ASCA positive increased the positive predictive value to 77% and it was associated with small bowel disease. CONCLUSIONS: A positive pANCA test in Greek patients has a diagnostic value in confirming a diagnosis of UC. Measurement of pANCA and ASCA together has a rather limited value in the differential diagnosis between UC and CD but may be of help in studying disease heterogeneity.

Adult↗
PubMed2000

Aberrant expression of the major sialoglycoprotein (CD43) on the monocytes of patients with myelodysplastic syndromes.

CD43, a sialylated glycoprotein expressed on the surface of most hematopoietic cells, has been implicated in cell adhesion and signaling. The reduced expression of this antigen in patients with Wiscott-Aldrich syndrome, in which progressive immunodeficiency is a major problem, raised the question whether abnormal expression of this molecule could affect the susceptibility to infections in patients with myelodysplastic syndromes (MDS). We studied the expression of this antigen on the monocytes of ten patients with chronic myelomonocytic leukemia (CMML) and compared the results with 67 patients suffering from other MDS syndromes and with 18 healthy individuals. We chose this series as it plays an important role in MDS patients where in most cases the neutrophils are defective. We also examined the following antigens as indicative of activation and adhesion of the monocytes in these patients: CD11b, CD18, CD35, CD38, CD44, CD69. We found decreased expression of CD43 on the monocytes of the RA, RAS, RAEB, and RAEB-t patients compared with the CMML and controls. The other activation molecules studied were found to be upregulated, suggesting the existence of activated monocytes in these patients. The increased levels of soluble vascular cell adhesion molecule in these patients suggest vascular endothelial activation in the absence of infection. Further experiments are needed to investigate the significance of CD43 downregulation in these patients, its role in cell adherence and tissue migration, and the correlation of the phenomenon to the increased susceptibility to infections observed in these patients.

Adult↗
PubMed2000

Hyperhomocysteinemia in Greek patients with inflammatory bowel disease.

In recent years hyperhomocysteinemia has been established as a new risk factor for arterial and venous thrombosis. Since patients with inflammatory bowel disease (IBD) frequently suffer from thromboembolic events, we studied the prevalence and clinical significance of hyperhomocysteinemia in Greek patients with ulcerative colitis (UC) and Crohn's disease (CD). In 108 consecutive fasting IBD patients (53 UC and 55 CD) and 74 healthy controls (HC), a standard record of various clinical thrombotic risk factors was completed by interview, and fasting serum concentrations of total homocysteine (tHcy), folate, cobalamin, creatinine, cholesterol, HDL, LDL, and triglycerides were measured. The concentration (mean +/- SD) of serum tHcy was significantly higher in UC (15.9 +/- 10.3 micromol/liter) and CD patients (13.6 +/- 6.5) than in controls (9.6 +/- 3.4, P < 0.05). Both UC and CD patients had lower levels of folate than HC (P < 0.05). Covariance analysis of age, gender, and all clinical variables indicated that the differences in homocysteine levels between IBD patients and HC remain significant even after adjustment for these covariates. In conclusion, mild hyperhomocysteinemia is common in Greek IBD patients and may account for the increased thrombotic risk of these patients.

Adult↗
PubMed2000

Do undefined sources of hepatitis C transmission exist? The Greek study in General Practice.

A seroepidemiological study was carried out in 15 primary health care (PHC) centres in rural Greece to determine the prevalence of hepatitis C virus (HCV) in the surgeries of Greek General Practitioners (GPs) and to further clarify the transmission of hepatitis C in Greece. Serum samples were obtained from 1961 subjects (1259 females) aged >/= 15 years, who visited GP surgeries between July 1996 and February 1997 in 15 PHC centres located in three large Greek regions (Macedonia, Attika and Crete). Subjects who participated in the study fulfilled the following criteria: history of blood transfusion; hospital admission of > 7 days' duration without surgical or other intervention; use of intravenous drugs (current or previous); or women with a history of medical or paramedical abortion. Nearly 65% (1263 subjects) of the participants in this study reported hospital admission with a length of stay > 7 days. Antibodies to HCV (anti-HCV) were found in 67 participants (3. 5%), 41 of whom were females and 44 of whom were aged >/= 61 years. The highest prevalence (4.8%) of anti-HCV was found in Crete, and differences among the Greek regions were statistically significant (P < 0.05). Multivariate statistical analysis showed that in addition to regional differences, the following variables had a statistically significant effect on the prevalence of anti-HCV: history of dental surgery; use of intravenous drugs; hospital admission for > 7 days; and the high consumption of alcoholic drinks. Hence there is a significant variability in the prevalence of hepatitis C in well-defined PHC areas of Greece. Several risk factors for acquiring HCV infection have been identified. Screening for HCV risk factors may enable Greek GPs to identify HCV-infected patients.

Adolescent↗
PubMed2000

In vitro study of oxytetracycline adsorption on activated charcoal.

In vitro adsorption experiments simulating pH in gastric environment and using Langmuir isotherm, showed that 408 mg of oxytetracycline was adsorbed per gram of activated charcoal. Langmuir isotherm fitted adsorption data better than a Freundlich isotherm. Freundlich isotherm showed a specific adsorption capacity of 518 mg/g for activated charcoal. Both isotherm parameters indicated a strong oxytetracycline adsorption on activated charcoal in terms of quantity and binding strength. The results demonstrate that the concomitant use of oxytetracyline and activated charcoal should be avoided.

Adsorption↗
PubMed2000

Crete, Greece glaucoma study.

PURPOSE: To investigate the prevalence of primary open-angle glaucoma (POAG) in a randomized sample of the inhabitants of the island of Crete. PATIENTS AND METHODS: In 18 different villages in all four prefectures of the island of Crete, patients were randomly selected from 1993 through 1998, and an in situ study was accomplished. The sampling fraction (covered by the 1991 census) in each village was approximately 5%. Patients were considered to have POAG when the morphologic aspect of a glaucomatous optic disc was present, and/or a nerve fiber layer defect and a visual field defect was present. The presence of Pseudoexfoliation syndrome (PEX) and pseudoexfoliative glaucoma (PEXG) was also investigated. RESULTS: The prevalence of glaucoma in Crete was 2.80%. Of those diagnosed with POAG, 9.67% had an intraocular pressure (IOP) under 21 mm Hg, and 25.80% had PEX. The prevalence of simple ocular hypertension without glaucoma was found in 6.58% of the patients. The ratio of subjects with hypertensive glaucoma to those with simple ocular hypertension was 1:2.6. CONCLUSION: The prevalence of POAG and exfoliation glaucoma appears to be quite high in Crete. Further research will be needed to set more accurate criteria for earlier diagnosis and to enable more efficient organization of the health care system.

Adult↗
PubMed2000

Appendectomy and the development of ulcerative colitis: results of a metaanalysis of published case-control studies.

OBJECTIVE: Numerous epidemiological studies have been performed to determine risk factors that might contribute to the development of ulcerative colitis (UC). Recent studies have focused on the role of appendectomy in the disease's pathogenesis. This report aims to review and analyze the degree of evidence from recent published studies. METHODS: Medline and Embase databases were scrutinized for studies published between 1987 and January 1999. Reference lists from published articles, reviews, and abstracts from major gastrointestinal (GI) meetings were also reviewed. All studies specifically designed to evaluate the association between appendectomy and UC were selected. Thirteen studies that satisfied our selection criteria were evaluated by metaanalysis. RESULTS: The 13 case-control studies collectively gathered evidence from 2770 patients with UC and 3352 controls. Combining the results of the individual studies gave an overall odds ratio of 0.307 (95% confidence interval [CI] = 0.249-0.377) in favor of appendectomy (p<0.0001). This suggests that appendectomy gives a 69% reduction in the risk of developing UC (95% CI = 62%-75%). The test for heterogeneity (of all 13 studies) was not significant (chi2 = 16.213, d.f. = 12, p>0.10). The influence of potential confounding factors (mainly smoking) on these results could be excluded. CONCLUSIONS: The review of the literature and the metaanalysis of the selected studies suggest that the inverse association between appendectomy and UC is strong and consistent. Further studies are needed to establish whether a causal relationship exists.

Appendectomy↗
PubMed2000

Significance of alpha-2-macroglobulin, alpha-1-acid glycoprotein, and C-reactive protein in pleural effusion differentiation.

BACKGROUND: The differentiation between exudates and transudates is fundamental when investigating the cause of pleural effusions. Acute-phase proteins could be potentially useful markers in this discrimination. OBJECTIVE: The present study was designed to evaluate whether the acute-phase proteins: alpha(2)-macroglobulin (AMG), alpha(1)-acid glycoprotein (AAG) and C-reactive protein (CRP) are useful in investigating the pleural effusions. METHODS: We prospectively measured the concentrations of the above proteins in the serum and pleural fluid of 84 consecutive patients with various diseases using a nephelometric assay. RESULTS: Pleural effusion AMG, AAG and CRP were all significantly elevated in the group of patients with exudates compared to patients with transudates (p < 0.001, p < 0.001 and p < 0.01, respectively). An AAG value >63 mg/dl in a pleural effusion is predictive of an exudate with a sensitivity of 90% and a specificity 85%. Similarly, an AMG value >44 mg/dl in a pleural effusion is predictive of an exudate with a sensitivity and a specificity of 90% and 60%, respectively. Moreover, pleural AAG was significantly higher in cancerous exudates than in exudates and transudates of all other cause taken together (p < 0.001). Finally, to differentiate the same pleural effusion, the cut-off value of 1.0 mg/dl of pleural CRP has a sensitivity and a specificity of 74% and 74%, respectively. CONCLUSIONS: We conclude that both AAG and AMG concentrations in pleural effusions have a high sensitivity and are therefore useful parameters in distinguishing exudates from transudates, but the latter is inferior due to its unacceptably low specificity.

Adult↗
PubMed1999

Correlation between age-related macular degeneration and pseudoexfoliation syndrome in the population of Crete (Greece).

OBJECTIVE: To evaluate the epidemiological correlation between age-related macular degeneration and pseudoexfoliation syndrome in the inhabitants of the island of Crete (Greece). SUBJECTS AND METHODS: A total of 777 persons (315 men and 462 women, aged 40-99 years), representing a randomized sample (1.43%) of the Cretan population, underwent slitlamp and fundus examinations according to protocol. The results were statistically analyzed. RESULTS: The prevalence of pseudoexfoliation was 16.1% (21.3% in men and 12.6% in women) and that of maculopathy, 7.9% (11.7% in men and 5.2% in women). The conditions were significantly correlated with each other (P = .002). Also, both displayed a significant direct correlation with age and altitude (for pseudoexfoliation, P<.001 and P = .002 for age and altitude, respectively; for age-related macular degeneration, P<.001 for age and for altitude) and an increase in bilateral incidence with progressing age. CONCLUSIONS: The observed prevalences of pseudoexfoliation and maculopathy were lower than those reported in the mainland of Greece and other Mediterranean regions. The correlation between age-related macular degeneration and pseudoexfoliation syndrome may be explained by the relationship of each disease with age and altitude.

Adult↗
PubMed1999

Appendectomy, tonsillectomy, and risk of inflammatory bowel disease: case-controlled study in Crete.

PURPOSE: Appendectomy has been suggested as a possible protective factor in ulcerative colitis and as a risk factor in Crohn's disease. Tonsillectomy has also been associated with Crohn's disease. We performed a case-controlled study to investigate these associations in a homogeneous Greek population. METHODS: One hundred thirty-four consecutive cases of ulcerative colitis and 76 cases of Crohn's disease were included in the study. For each inflammatory bowel disease patient and a corresponding healthy control subject, matched for gender, age, and educational level, a standard record on various risk factors was completed by interview. The association between disease status and risk factors was assessed by Pearson's chi-squared test and the independent contribution of each risk factor was analyzed by means of logistic regression analysis. RESULTS: Appendectomy had been performed in 11 (8.2 percent) patients with ulcerative colitis, in 18 (13.4 percent) of their matched healthy control cases, in 19 (25.0 percent) patients with Crohn's disease, and in 10 (13.2 percent) of their matched healthy control cases. Odds ratio for development of ulcerative colitis after appendectomy was 0.6 (95 percent confidence interval, 0.26-1.27). Odds ratio for Crohn's disease was 2.2 (95 percent confidence interval, 0.94-5.12). Odds ratio for development of ulcerative colitis or Crohn's disease after tonsillectomy was 0.95 (95 percent confidence interval, 0.49-1.82) and 3.29 (95 percent confidence interval, 1.29-8.37), respectively. The logistic regression analysis showed that appendectomy and tonsillectomy have no independent association with the risk of developing ulcerative colitis, whereas in Crohn's disease both appendectomy and tonsillectomy have positive associations. Well-established risk factors, such as family history and smoking status, were also verified in this study. CONCLUSIONS: This case-control study, using multivariate logistic regression analysis, showed a less pronounced association between ulcerative colitis and appendectomy than previous reports. Our data also support the conclusion that tonsillectomy is a risk factor for developing Crohn's disease.

Adult↗
PubMed1999

Deactivation of mycotoxins. I. An in vitro study of zearalenone adsorption on new polymeric adsorbents.

This study describes the elimination of zearalenone concentrations in vitro using two new polymeric forms of cross-linked polyvinylpyrrolidone (cryogels of cross-linked PVP). Adsorption of zearalenone was studied under isothermal conditions and simulating pH of intestinal environment. A Freundlich isotherm was used to describe the adsorption data obtained. The results showed significant decrease of zearalenone concentrations, ranging from 33.5-66.2% per 25 mg of polymer. Adsorption capacity (k) was estimated to be higher than that of previously tested adsorbents, including crospovidone. The data indicate the need to investigate structure peculiarities in order to improve mycotoxin deactivation procedures using PVP derivatives.

Adsorption↗
PubMed1999

Interactions between physical and psychosocial risk factors at work increase the risk of back disorders: an epidemiological approach.

OBJECTIVES: To investigate the possible interactions between physical and psychosocial risk factors at work that may be associated with self reported back disorders. METHODS: 891 of 1514 manual workers, delivery drivers, technicians, customer services computer operators, and general office staff reported risk factors at work and back disorders with a self administered questionnaire (59% return rate). Of the 869 respondents with a valid questionnaire, 638 workers were classified in to one of four exposure groups: high physical and high psychosocial; high physical and low psychosocial; low physical and high psychosocial; and low physical and low psychosocial. Low physical and low psychosocial was used as an internal reference group. The exposure criteria were derived from existing epidemiological publications and models for physical and psychosocial work factors. The frequency and amplitude of lifting and the duration spent sitting while experiencing vibration were used as physical exposure criteria. Ordinal values of mental demands, job control, and social support from managers and coworkers were used as psychosocial exposure criteria. RESULTS: The highest increase in risk was found in the high physical and high psychosocial exposure group for symptoms of back disorders. In the crude and multivariate analyses, a departure from an additive risk model was found for the 7 day prevalence of symptoms of a low back disorder and also for a recurrent back disorder not present before the current job but also experienced in the past 7 days. CONCLUSION: This study suggests that an interaction between physical and psychosocial risk factors at work may exist to increase the risk of self reported back disorders. Ergonomic prevention strategies that aim to minimise the risks of symptoms of work related back disorders should not only focus on physical but also on psychosocial risk factors at work. The greatest benefits are likely to be realised when both physical and psychosocial factors are put right.

Adult↗
PubMed1998

Nuclear morphometry of the myocardial cells as a diagnostic tool in cases of sudden death due to coronary thrombosis.

Sudden cardiac death due to underlying coronary artery thrombosis is one of the leading causes of death. However, in a significant percentage of individuals who died suddenly, no indication of myocardial infarction is found during post-mortem examination, especially when the time interval between appearance of symptoms and death is short. In the present study, we have evaluated certain nuclear morphometric parameters, such as, minimum, maximum, mean and standard deviation of perimeter and area in 20 individuals who died of coronary artery thrombosis, within 1 h from symptoms onset. Furthermore, the above parameters were compared with those of a control population of 20 individuals whose sudden death was caused by traffic accidents. Statistical elaboration of the results by means of t-test, Mann-Whitney (U-test) and analysis of covariance (adjusting for age), showed a statistically significant difference for all variables except for the minimum area. With stepwise discriminant analysis method, the mean perimeter was selected as the best predictor of cardiac death. Mean perimeter achieved a correct reclassification percentage (based on Fisher's linear discriminant function) of 92.5% (85% and 100% for cases and controls, respectively). Moreover, by applying the cut-off of 172 microns, we could identify the individuals who died suddenly because of coronary artery thrombosis with a specificity of 100% (sensitivity 85%, P < 0.001). Our results show that nuclear morphometry of the myocardial cells is a reliable diagnostic tool for the diagnosis of coronary thrombosis based lesion in cases of sudden death, even when methods trying to verify the presence of infarction fail to do so.

Case-Control Studies↗
PubMed1998

Endothelial corneal damage after neodymium:YAG laser treatment: pupillary membranectomies, iridotomies, capsulotomies.

BACKGROUND AND OBJECTIVES: To evaluate the corneal changes after Nd:YAG laser pupillary membranectomies (group A), iridotomies (group B), and capsulotomies (group C) in a follow-up period of 6 months. PATIENTS AND METHODS: The Nd:YAG laser was applied to 3 different groups of patients. Specular microscopy, including the counting of corneal thickness and cell density, the percentage of hexagonal cells, and the cell area, was performed preoperatively and postoperatively. RESULTS: Some dark areas were recorded in the corneal endothelium in groups A and B. A nonstatistically significant decrease of cell density was recorded by the end of the first month. A significant loss of endothelial cells during the sixth month was recorded in groups A and C. CONCLUSION: The appearance of dark areas in the corneal endothelium is mainly related to the total energy delivered. The YAG laser treatments do not provoke an immediate and conspicuous loss of the endothelial cells, but may act as a stimulus for an accelerated loss of endothelial cells.

Aged↗
PubMed1997

Nd:YAG laser removal of pupillary membranes developed after ECCE with PC-IOL implantation.

PURPOSE: To define the frequency of development of pupillary membranes after ECCE with PC-IOL implantation, and to remove the pupillary membranes using the Nd:YAG laser. METHODS: From 400 patients who had undergone ECCE and were free from local or systemic illness affecting the blood-ocular barrier, 20 eyes developed pupillary membranes Nd:YAG laser was used to remove these pupillary membranes. RESULTS: The frequency of pupillary membranes was found to be 5% (9.8% in pex eyes and 3.3% to the non-pex eyes). Visual acuity improved in 17 eyes by 2 to 5 Snellen lines. No serious complications were observed, endothelium inclusive. CONCLUSION: Pseudoexfoliation might play a significant role in the development of postoperative pupillary membranes which could be successfully treated with the use of Nd:YAG laser. The safety of the procedure has to be evaluated in relation to the corneal endothelium damage in long-term.

Aged↗
PubMed1997

Epidemiology of pseudoexfoliation in the island of Crete (Greece).

PURPOSE: To evaluate the pseudoexfoliation (PEX) prevalence in the island of Crete (Greece). METHOD: Organized visits to various villages, to examine a predetermined number of people born and living in these villages, in collaboration with the local birth register offices. RESULTS: PEX prevalence in Crete, in people aged 40 years and more, was found to be 16.1% (men: 21.3%, women: 12.6% - Prefecture of: Heraklion 11.5%, Chania 13.4%, Lasithi 16.9%, Rethymnon 27%). 28.8% of PEX-patients presented IOP > 21 mmHg. In unilateral PEX-patients, mean IOP of PEX-eyes was found to be 17.82 mmHg versus 15.6 mmHg in fellow eyes. CONCLUSION: PEX prevalence was higher in men than in women and increases with age, as does bilaterality. A correlation between increased PEX prevalence and high altitude may exist. PEX is a risk factor for the development of IOP disturbances which seem to appear earlier in women.

Adult↗
PubMed1996

A prospective epidemiologic study of Crohn's disease in Heraklion, Crete. Incidence over a 5-year period.

BACKGROUND: There has been an impression from published work that Crohn's disease is less common in southern than in northern Europe. A low incidence of Crohn's disease has been observed in Greece, but conclusive data are still lacking. METHOD: A 5-year prospective and population-based epidemiologic study of Crohn's disease was carried out in a well-defined area of Crete. RESULTS: The mean annual incidence of the disease for the years 1990-94 was 3.0 per 10(5) inhabitants. During the study period the incidence increased from 1.9/10(5) in 1990 to 3.8/10(5) in 1994. The male to female ratio was 2.4:1. The age group 25-34 years had the highest age-adjusted incidence (6.3/10(5)). The incidence of Crohn's disease was also found to be higher in smokers, in urban areas, and in people with high educational level. CONCLUSION: Crohn's disease is common in Heraklion, Crete. The findings of the study are discussed in relation to those of other European countries.

Adult↗