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Nikolaos Nikolaidis

Publications and source records attributed to Nikolaos Nikolaidis.

At least 19 recordsLinked to original sources
PubMed2006

A new methodology for the comparative study of the root canal instrumentation techniques based on digital radiographic image processing and analysis.

OBJECTIVE: The objective of this study was to evaluate the utility of digital image processing and analysis procedures for the study and comparison of the efficiency of 2 root canal instrumentation techniques. STUDY DESIGN: Forty mandibular incisors with a single canal were randomly divided into 2 groups of 20 teeth. A step-back technique was followed for the instrumentation of the root canals of Group 1 teeth using hand stainless steel Hedström files (Dentsply Maillefer, Switzerland), while a crown-down technique using ProFile engine-driven nickel-titanium instruments (Dentsply Maillefer) was followed for the instrumentation of the Group 2 root canals. Radiographs of each tooth were taken in bucco-lingual and mesio-distal projections, both before and after instrumentation, under constant conditions and by using a direct digital intraoral radiography system. The postoperative radiographs were digitally subtracted from their respective preoperative radiographs. A contrast enhancement process was applied to the resultant digital subtractive images. The enlargement of the root canals created by each instrumentation technique regarding the apical 6 mm was assessed through the application of region segmentation and area measurement processes. RESULTS: Using this methodology no significant difference between the 2 preparation techniques was found in terms of configuration and enlargement of the root canals. CONCLUSIONS: The application of this methodology provided the ability to (1) visualize dentin lost during root canal instrumentation, (2) simultaneously compare root canal morphology before and after instrumentation, and (3) quantitatively evaluate the enlargement of the root canal area induced by each of the instrumentation techniques.

Dental Pulp Cavity↗
PubMed2006

Pegylated IFN-alpha 2b added to ongoing lamivudine therapy in patients with lamivudine-resistant chronic hepatitis B.

AIM: To investigate the role of pegylated-interferon (IFN) alpha-2b in the management of patients with lamivudine-resistant chronic hepatitis B. METHODS: Twenty consecutive anti-HBe positive patients were treated with pegylated IFN alpha-2b (100 mug sc once weekly) for 12 mo. There was no interruption in lamivudine therapy. Hematology, liver biochemistry, serum HBV DNA levels were detected by PCR, and vital signs were also assessed. Liver histology was assessed in some patients at entry and at wk 52 for comparison. RESULTS: Nine patients (45%) had a partial virological end-treatment response; seven patients (35%) showed complete virological end-treatment response. Eight patients (40%) showed biochemical end-treatment response. There was a trend for higher virological response rates in patients who had previously responded to IFN and relapsed compared to IFN non-responders (four out of seven patients vs none out of six patients, respectively; P=0.1). Patients without virological end-treatment response showed significant worsening of fibrosis [median score 2 (range, 1 to 3) vs median score 3 (range, 1 to 4)], in the first and second biopsy respectively (P=0.014), whereas necroinflammatory activity was not significantly affected. Patients with complete or partial virological end-treatment response did not show any significant changes in histological findings, possibly due to the small number of patients with paired biopsies (n=5). Nevertheless, after 12 mo of follow-up, only one patient (5%) showed sustained virological response and only 2 patients (10%) showed sustained biochemical response. Two patients (10%) discontinued pegylated IFN both after 6 mo of treatment due to flu-like symptoms. CONCLUSION: Pegylated IFNalpha-2b, when added to ongoing lamivudine therapy in patients with lamivudine-resistant chronic hepatitis B, induces sustained responses only in a small minority of cases.

Adult↗
PubMed2006

Ductal plate malformation and congenital hepatic fibrosis Clinical and histological findings in four patients.

Congenital hepatic fibrosis belongs to the fibrocystic diseases of the liver and represents ductal plate malformation of interlobular bile ducts, along with a destructive cholangiopathy associated with fibrosis. Four patients with congenital hepatic fibrosis are described. Their median age at presentation was 25 years; none of them had a family history of liver or renal disease. Variceal bleeding was the initial manifestation in three patients. All of them required frequent endoscopic variceal ligation sessions and distal splenorenal shunting was also performed in two, almost obviating the need for further variceal ligation. Variceal bleeding did not recur during follow-up. One of these three patients rarely exhibited acute cholangitis; administration of ursodeoxycholic acid resulted in complete remission. In contrast, the fourth patient showed frequent severe episodes of acute cholangitis but normal cholangiographic findings. He underwent liver transplantation but died 2 months later. Laboratory findings disclosed pancytopenia in all patients whereas hepatic synthetic capacity was well preserved. Renal function was unaffected despite the presence of polycystic kidneys in two patients. In summary, congenital hepatic fibrosis can also be diagnosed in older ages, might have strikingly different manifestations and is associated with prominent portal hypertension necessitating aggressive management in order to prevent variceal bleeding.

Journal Article↗
PubMed2006

A case of successful management with splenectomy of intractable ascites due to congenital dyserythropoietic anemia type II-induced cirrhosis.

The congenital dyserythropoietic anemias comprise a group of rare hereditary disorders of erythropoiesis, characterized by ineffective erythropoiesis as the predominant mechanism of anemia and by characteristic morphological aberrations of the majority of erythroblasts in the bone marrow. Congenital dyserythropoietic anemia type II is the most frequent type. All types of congenital dyserythropoietic anemias distinctly share a high incidence of iron loading. Iron accumulation occurs even in untransfused patients and can result in heart failure and liver cirrhosis. We have reported about a patient who presented with liver cirrhosis and intractable ascites caused by congenital dyserythropoietic anemia type II. Her clinical course was further complicated by the development of autoimmune hemolytic anemia. Splenectomy was eventually performed which achieved complete resolution of ascites, increase of hemoglobin concentration and abrogation of transfusion requirements.

Anemia, Dyserythropoietic, Congenital↗
PubMed2005

Elevated plasma von Willebrand factor levels in patients with active ulcerative colitis reflect endothelial perturbation due to systemic inflammation.

AIM: To evaluate the plasma von Willebrand factor (vWF) levels in patients with ulcerative colitis (UC) and to investigate their relationship with disease activity, systemic inflammation and coagulation activation. METHODS: In 46 patients with ulcerative colitis (active in 34 patients), clinical data were gathered and plasma vWF levels, markers of inflammation (ESR, CRP, and fibrinogen) and thrombin generation (TAT, F1+2, and D-dimers) were measured at baseline and after 12 wk of treatment. Plasma vWF levels were also determined in 52 healthy controls (HC). The relationship of plasma vWF levels with disease activity, disease extent, response to therapy, acute-phase reactants (APRs) and coagulation markers (COAGs) was assessed. RESULTS: The mean plasma vWF concentrations were significantly higher in active UC patients (143.38+/-63.73%) than in HC (100.75+/-29.65%, P = 0.001) and inactive UC patients (98.92+/-43.6%, P = 0.031). ESR, CRP and fibrinogen mean levels were significantly higher in active UC patients than in inactive UC patients, whereas there were no significant differences in plasma levels of D-dimers, F1+2, and TAT. UC patients with raised APRs had significantly higher mean plasma vWF levels than those with normal APRs (144.3% vs 96.2%, P = 0.019), regardless of disease activity. Although the mean plasma vWF levels were higher in UC patients with raised COAGs than in those with normal COAGs, irrespective of disease activity, the difference was not significant (141.3% vs 118.2%, P = 0.216). No correlation was noted between plasma vWF levels and disease extent. After 12 wk of treatment, significant decreases of fibrinogen, ESR, F1+2, D-dimers and vWF levels were noted only in UC patients with clinical and endoscopic improvement. CONCLUSION: Our data indicate that increased plasma vWF levels correlate with active ulcerative colitis and increased acute-phase proteins. Elevated plasma vWF levels in ulcerative colitis possibly reflect an acute-phase response of the perturbed endothelium due to inflammation. In UC patients, plasma vWF levels may be another useful marker of disease activity or response to therapy.

Acute-Phase Proteins↗
PubMed2005

Hyperhomocysteinemia in ulcerative colitis is related to folate levels.

AIM: To study the prevalence and clinical significance of hyperhomocysteinemia (hHcys), an independent factor for arterial and venous thrombosis, in a group of patients with ulcerative colitis (UC). METHODS: Fasting homocysteine (Hcys), folate, and vitamin B(12) serum levels were measured in 40 UC patients and 50 healthy controls. Clinical data regarding UC were gathered. RESULTS: Median serum Hcys levels in UC patients were similar to controls (12.26 micromol/L vs 12.32 micromol/L), but the prevalence of hHcys was higher in UC patients than in controls (30% vs 10%, P = 0.028). UC significantly increased the risk of hHcys (adjusted odds ratio: 4.125; 95%CI: 1.26-13.44). Multivariate regression analysis showed that male sex, folate and vitamin B(12) deficiency or lower serum values were significant independent predictors of higher Hcys levels in UC patients (r(2) = 0.4; P<0.001). CONCLUSION: HHcys is common in UC patients and it is related to folate and vitamin B(12) deficiency or lower serum values. It would be reasonable for patients with UC to receive folate and vitamin B complex supplements as a prophylactic measure.

Adolescent↗
PubMed2005

Removal of methylated arsenic in groundwater with iron filings.

Field and laboratory experiments were conducted to study the potential use of Fe filings to remove monomethyl arsenate (MMA) and dimethyl arsenate (DMA) from contaminated waters. Batch experiments show that the affinity of MMAfor Fe filings is comparable to that of inorganic arsenate, but lower than that for arsenite. In contrast, very little DMA was retained by Fe filings or their corrosion products. The wide range of affinities of different As species for Fe filings was confirmed by a series of retention and selective-leaching experiments using small columns and As-spiked groundwater. The effectiveness of Fe filings was also demonstrated with a field deployment at a U.S. Superfund site where groundwater is highly contaminated with both organic and inorganic As species. Over the course of 4 months, a 3 L cartridge of Fe filings removed > 85% of As contained in 16000 L of groundwater containing 1-1.5 mg/L total dissolved As, approximately 30% of which was organic As. The results indicate that Fe filings could be used to treat groundwater contaminated with MMA, which is the main organic form of As at most contaminated sites. Indications of partial demethylation in the column of Fe filings suggest conditions might be optimized further to enhance the removal of DMA.

Arsenates↗
PubMed2005

Effect of lamivudine treatment in patients with decompensated cirrhosis due to anti-HBe positive/HBeAg-negative chronic hepatitis B.

Lamivudine has been shown to improve liver function and reduce the need for liver transplantation (LT) in patients with decompensated HBeAg-positive cirrhosis. Nevertheless, there is only limited experience with lamivudine in patients with anti-HBe-positive/HBeAg-negative cirrhosis. The primary aim of this study was to determine whether lamivudine treatment improves liver function and subsequently pre-LT survival or delays or obviates the need for LT in patients with anti-HBe-positive/HBeAg-negative cirrhosis. Between July 1998 and June 2003, 20 consecutive patients awaiting LT were enrolled in the study. All patients showed active viral replication and were treated with lamivudine 100 mg daily. Significant clinical improvement, defined as a decrease in the Child-Pugh-Turcotte score by >or=2 points, was observed in 11 (55%) patients. The median change in the Child-Pugh-Turcotte score was -2 (range -5 to +2). The median time required to achieve a 2-point or greater reduction in Child-Pugh-Turcotte score was 6 months (range 3-12 months). In nine patients (45%), the Child-Pugh-Turcotte score decreased to <or=6 (Child's class A cirrhosis). At last follow-up, 14 (70%) patients were alive and waiting for LT, with a median LT-free survival of 36 months (range 12-63 months). One patient (5%) developed resistance to lamivudine with reappearance of HBV DNA after 48 months of treatment. In conclusion, our results provide further evidence to the notion that lamivudine is beneficial in patients with decompensated anti-HBe-positive/HBeAg-negative cirrhosis caused by actively replicating chronic hepatitis B.

Antiviral Agents↗
PubMed2005

Protein-losing enteropathy as the principal manifestation of constrictive pericarditis.

Constrictive pericarditis represents a rare cause of protein-losing enteropathy due to intestinal lymphangiectasia. We report the case of a patient with an atypical clinical presentation of constrictive pericarditis and protein-losing enteropathy as its principal manifestation; he was successfully treated with pericardiectomy. We conclude that, constrictive pericarditis should be considered in the presence of protein losing enteropathy and also, protein-losing enteropathy should be considered in the differential diagnosis of hypoalbuminemia.

Aged↗
PubMed2004

Digital radiograph registration and subtraction: a useful tool for the evaluation of the progress of chronic apical periodontitis.

The purpose of this study was to evaluate the suitability of a digital radiograph registration and subtraction software for a sensitive and reliable assessment of the progress of chronic apical periodontitis. Ninety cases of teeth with chronic apical periodontitis have been studied. In each case, a preoperative radiograph was taken, root canals were prepared, and a Ca(OH)2 paste was placed in the root canals. Radiographic control and replacement of Ca(OH)2 paste took place at 15-day intervals. The root canals were obturated 1.5 months after the first appointment. Recall radiographs were taken 0.5, 1.5, 3, 6, and 12 months after the obturation. All radiographs were taken for each case under constant conditions by using a direct digital radiography system. In each case, the preoperative, postoperative, and control and recall radiographs were digitally registered and pairwise subtracted. The resulting images were further processed by using contrast enhancement and pseudocoloring methods. Changes to the periapical tissue structure were easily detectable by using the above-mentioned methodology, even during short time intervals.

Calcium Hydroxide↗
PubMed2002

Psychiatric education: a survey of Greek trainee psychiatrists.

OBJECTIVE: This survey investigates psychiatric trainees' attitudes regarding specific educational fields, in order to detect possible divergence from the priorities specified by the European Board of Psychiatry (EBP). It also explores certain factors which influence these attitudes. METHOD: A structured questionnaire containing 80 randomized educational objectives, which corresponded to 18 basic areas of psychiatric knowledge and competence, was given to 60 psychiatric trainees in 12 psychiatric training institutions in Greece. For the analysis of data, we used descriptive statistics, correlations, and one-way analysis of variance. RESULTS: Despite the variance which existed, the majority of trainees considered nearly all the fields in question as essential for their training, with great priority given to psychopharmacology and biological psychiatry by 91.7% and 91.4% of the trainees, respectively. On the other hand, we found that stage of training, gender, training centre and medical school of graduation played an important role in the formation of the trainees' priorities. CONCLUSIONS: The investigation of trainees' attitudes towards educational fields in psychiatry can be very useful in the development of a training plan, and at the same time constitute a valuable index for monitoring the responsiveness of training programmes to the European guidelines for psychiatric training.

Adult↗
PubMed2002

Virtual endodontics: three-dimensional tooth volume representations and their pulp cavity access.

The purpose of this study was the application of both digital three-dimensional image processing and virtual reality techniques in endodontics. Three-dimensional volume representations of 2 teeth from each tooth category, 16 teeth in total, have been reconstructed. All teeth were embedded in polyester resin, and serial cross-sections 0.75-mm thick were taken from each tooth by using a special microtome. Each section was studied under a stereoscopic microscope, and its microscopic image was directly digitized using a video-camera. The surfaces of hard dental tissues were segmented from each section. Semiautomatic alignment and frame interpolation were performed on the sequence of tooth sections by using appropriate digital image processing techniques. Three-dimensional volume representations from each tooth were achieved in this project to produce the final three-dimensional teeth models, on which virtual accesses of pulp cavities have been performed. Three-dimensional teeth volume representations and virtual tooth "drilling" could serve as perfect educational tools under certain circumstances.

Anatomy, Cross-Sectional↗
PubMedDate not supplied

Colchicine treatment of liver fibrosis.

BACKGROUND/AIMS: Because of its antifibrotic and anti-inflammatory effects, colchicine has been proposed as a treatment for liver disease. The results from clinical trials have however been inconsistent. The aim of the present study was to evaluate the effect of colchicine in the treatment of patients with hepatic fibrosis of various etiologies. METHODOLOGY: Thirty-eight patients were randomized to receive either colchicine 1 mg per day (n=21, group A) or no antifibrotic agent (n=17, group B). Treatment lasted for at least 12 months. Liver biopsy was performed prior to entry and after 12 months. Liver function tests, serum aminoterminal peptide of procollagen III (PIIINP) levels and CD4:CD8 ratio of peripheral blood T lymphocytes (PBTLs) were performed at baseline and bimonthly or every 4 months post-treatment. RESULTS: Mean albumin serum levels increased 12 months post-treatment period only in group A (p<0.05). Mean serum PIIINP levels did not change significantly after 12 months of treatment in group A; in 7 patients a reduction in mean serum PIIINP levels was noticed during 24-month post-treatment follow-up period (p<0.05). At baseline, a correlation between focal or bridging necrosis and CD4:CD8 ratio of PBTLs was noticed in group A (p < 0.05). The mean serum CD4:CD8 ratio was increased after 12 months of colchicine treatment (p<0.05) associated with abrogation of this correlation; comparison between the two groups revealed increased CD4:CD8 ratio in group A at 12 months (p<0.05). The histological findings according to Knodell criteria in both groups remained unchanged after 12 months follow-up. The treatment was well tolerated in all patients. CONCLUSIONS: Long-term colchicine treatment in patients with hepatic fibrosis appears to exert an anti-inflammatory, anti-fibrotic and immunomodulatory effect.

Adult↗