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Biomedical subjects

N Nikolaidis

Publications and source records attributed to N Nikolaidis.

At least 19 recordsLinked to original sources
PubMed2006

Low-molecular-weight heparin (enoxaparin) as adjuvant therapy in the treatment of active ulcerative colitis: a randomized, controlled, comparative study.

BACKGROUND: Heparin could be beneficial to the treatment of active ulcerative colitis because of its anticoagulant, anti-inflammatory and immunomodulatory properties. AIM: To evaluate the tolerability, safety and efficacy of low-molecular-weight heparin as adjuvant therapy in patients with active ulcerative colitis. METHODS: Thirty-four adult patients with active ulcerative colitis were consecutively included in a prospective, randomized, comparative study, and were treated for 12 weeks. Eighteen patients in the 'standard therapy' group were treated with aminosalicylates and weekly tapered corticosteroids. Sixteen patients in the 'heparin therapy' group were treated with standard therapy plus enoxaparin 100 Anti-Xa IU/kg/day subcutaneously. RESULTS: Seventeen patients in the 'standard therapy' group and 15 patients in the 'heparin therapy' group completed the study. Tolerability and compliance to therapy were excellent and no withdrawals were noted because of complications. There was a significant improvement in the disease severity in both groups (P<0.001), without any difference between them (P=not significant). Both treatment groups showed similar proportions of disease improvement (65% and 73%, respectively; P=not significant). There were no significant differences in inflammation (fibrinogen, ESR, CRP) and coagulation (thrombin-antithrombin complex, F1+2, D-dimers) parameters during and at the end of the study between treatment groups. CONCLUSION: Adjuvant administration of low-molecular heparin in patients with active ulcerative colitis is safe and well tolerated, but no additive benefit over standard therapy for ulcerative colitis was noted.

Adjuvants, Pharmaceutic↗
PubMed2005

Adefovir dipivoxil added to ongoing lamivudine therapy in patients with lamivudine-resistant hepatitis B e antigen-negative chronic hepatitis B.

BACKGROUND: Long-term treatment with lamivudine is required to control viral replication in patients with hepatitis B e antigen-negative chronic hepatitis B, but is associated with a high rate of viral resistance. The role of adefovir dipivoxil in these patients has not been definitively evaluated. AIM: To address the role of adefovir in the management of patients with lamivudine-resistant hepatitis B e antigen-negative chronic hepatitis B. METHODS: Patients were assigned to receive adefovir 10 mg once daily plus ongoing lamivudine 100 mg once daily for 52 weeks. The primary end point was reduction in serum hepatitis B virus DNA level (hepatitis B virus DNA response). Secondary end points included the proportion of patients with undetectable hepatitis B virus DNA at week 52 (complete virological response) and the percentage of patients with normalization of alanine transferase level at week 52 (biochemical response). RESULTS: A total of 49 consecutive patients were enrolled in this study. After 52 weeks of treatment, all patients had an hepatitis B virus DNA response and 57.1% had complete virological response. Biochemical response occurred in 75.6% of patients. CONCLUSIONS: Administration of adefovir in patients with lamivudine-resistant chronic hepatitis B results in significant suppression of viral replication. Nevertheless, continuous therapy will probably be needed in order to maintain remission in these patients.

Adenine↗
PubMed2003

Bioequivalence study of two brands of enalapril tablets after single oral administration to healthy volunteers.

OBJECTIVE: To compare the relative bioavailability and bioequivalence of 2 enalapril tablet formulations in healthy volunteers under fasting conditions. METHODS: An open-label, single-dose, randomized, two-period, crossover trial with a 1-week washout period in 24 healthy volunteers. The 2 enalapril 20 mg tablet formulations used were Antiprex (Elpen, Greece) as test and Renitec (Vianex, Greece) as reference preparation. Serial blood samples were collected at 19 points for 36 h. Plasma samples were analyzed for enalaprilat, the pharmacologically active metabolite of enalapril, by a validated GC/MS assay. Pharmacokinetic parameters, such as AUC(0-infinity), AUC(0-t), C(max) T(max), t1/2 and MRT were calculated from plasma concentrations for both formulations. Statistical comparisons (ANOVA and 90% confidence intervals) of AUC(0-infinity), AUC(0-t) and C(max) data were evaluated after logarithmic transformation, and differences of T(max) were tested non-parametrically. RESULTS: The parametric 90% confidence intervals of the geometric mean values of the test/reference ratios were 88.0 - 117.6% (point estimate: 101.8%) for AUC(0-infinity), 88.7 - 118.9% (point estimate: 102.7%) for AUC(0-t), and 91.0% - 123.4% (point estimate: 106.0%) for C(max) No statistically significant differences were found between the 2 preparations for T(max) t1/2 and MRT values. CONCLUSIONS: From the results of the present study, it is concluded that the test and reference tablet formulations of enalapril are bioequivalent for both the extent and the rate of absorption and therefore the 2 products can be considered to be interchangeable in clinical practice.

Administration, Oral↗
PubMed2001

Endoscopic band ligation of Dieulafoy-like lesions in the upper gastrointestinal tract.

BACKGROUND AND STUDY AIMS: Endoscopic band ligation (EBL) is currently considered to be the treatment of choice for esophageal variceal bleeding. This study reports on the efficacy and safety of EBL in patients with Dieulafoy-like bleeding lesions in the upper gastrointestinal tract. PATIENTS AND METHODS: Between December 1994 and February 2000, 23 patients with upper gastrointestinal tract hemorrhage (median age 58, range 28-75) were treated using EBL. EBL was used as a rescue therapy in four patients and as the initial treatment in 19 patients. RESULTS: The site of bleeding was the stomach in 10 patients, Billroth II anastomosis in 10, the first part of the duodenum in one, the second part of the duodenum in one, and the jejunum in one patient. Endoscopic band ligation was successful in 22 of the 23 patients. The remaining patient, a young man with a Dieulafoy-like lesion in the jejunum, had recurrent bleeding on day 5 after EBL and underwent elective surgery. CONCLUSIONS: Endoscopic band ligation is an effective and safe endoscopic treatment for Dieulafoy-like lesions. It is easy to use and relatively inexpensive.

Adult↗
PubMed2001

Treatment of complications of hepatic hydatid disease by ERCP.

BACKGROUND: The aim of this study was to evaluate the effectiveness of endoscopic sphincterotomy for preoperative and postoperative complications of hepatic hydatid disease. METHODS: Nineteen patients underwent endoscopic treatment for complications of hepatic hydatid disease. Indications for ERCP in 5 patients treated before surgery (Group A) were obstructive jaundice in 1 and acute cholangitis in 4. In 14 patients treated after surgery (Group B), the indication was acute cholangitis in 6, obstructive jaundice 2, and persistent external drainage in 6 patients. OBSERVATIONS: In group A, ERCP detected hydatid vesicles within the bile duct. All patients underwent endoscopic sphincterotomy and clearance of the duct with no complications. The 6 patients in Group B with persistent external drainage had biliary fistulas that resolved after endoscopic treatment within 10 to 20 days. Among the 8 patients with postoperative obstructive jaundice or acute cholangitis, 7 had cyst remnants obstructing the bile duct and 1 had findings of sclerosing cholangitis. All underwent endoscopic sphincterotomy and clearance of the bile duct without complications. After treatment, all patients, with the exception of the one with sclerosing cholangitis, remained asymptomatic. CONCLUSION: Endoscopic sphincterotomy is a safe and effective treatment for biliary complications of hepatic hydatid disease.

Biliary Fistula↗
PubMed2001

Relative bioavailability of two isosorbide dinitrate sublingual tablet formulations administered as single doses in healthy subjects.

OBJECTIVE: The purpose of this study was to evaluate the relative bioavailability and bioequivalence of a test and a reference sublingual tablet each containing 5 mg of isosorbide dinitrate in healthy volunteers. METHODS: The study was conducted as an open-label, randomized, single-dose, two-period crossover design in 20 healthy volunteers with a washout period of 7 days, under fasting conditions. Plasma concentrations of the major active metabolite isosorbide 5-mononitrate were quantified, using a validated capillary gas chromatographic assay, with electron-capture detection. The pharmacokinetic parameters used to assess the bioequivalence of the two preparations were AUC(0-infinity) and AUC(0-infinity) for the extent of absorption and Cmax and tmax for the rate of absorption. RESULTS: The calculated 90% confidence intervals of the geometric mean values of the test/reference ratios were 98.2% to 103.2% (point estimate; 100.7%) for AUC(0-infinity) 96.9% to 103.8% (point estimate; 100.3%) for AUC(0-infinity), and 87.9% to 98.2% (point estimate; 92.9%) for Cmax. No statistically significant difference was found for tmax and elimination half-life (t 1/2) values. CONCLUSION: From the results of the present study, it is concluded that the test and reference isosorbide dinitrate sublingual preparations are bioequivalent in both extent and rate of absorption and it can be assumed that they are therapeutically equivalent and exchangeable in clinical practice.

Administration, Sublingual↗
PubMed2000

Sensitivity and tolerance to ethanol in mouse lines selected for ethanol-induced hypothermia.

Within-family selective breeding techniques have been used to create two lines of mice to be insensitive (HOT) and two lines to be sensitive (COLD) to the hypothermic effects of an acute 3.0-g/kg ethanol (EtOH) injection. Previous studies have found HOT mice to be relatively resistant to the development of tolerance to this effect, whereas COLD mice readily develop tolerance. The breeding program is currently in selected Generation 52, and the HOT and COLD mice differ by about 10 degrees C (average of both replicates) in their selected hypothermic response. Starting with selection Generation 20, separate lines of mice were inbred from the HOT-2 and COLD-2 selected lines, while selection continued for the original two replicate lines of HOT and COLD mice. To assess whether different dose treatments would produce differential tolerance development in the HOT and COLD selected lines, we administered different dose regimens across 5 days to HOT and COLD mice. The COLD mice developed tolerance while the HOT mice did not, regardless of total EtOH administered. In a separate study, we administered EtOH (3.0 g/kg) to mice for 3 days to assess a shorter tolerance paradigm. We also present here responses to the selection dose of 3.0-g/kg EtOH in the inbred HOT (IHOT-2) and COLD (ICOLD-2) mice tested after 41 generations of brother-sister mating. In addition, we report recent attempts to find doses of EtOH that would produce an equivalent initial hypothermic response in each of the six lines (HOT-1, COLD-1, HOT-2, COLD-2, ICOLD-2, and IHOT-2). When doses were selected to produce similar initial hypothermic sensitivity, tolerance was tested by giving three daily doses and examining the attenuation of the hypothermic response on the third day. All three COLD lines developed significant tolerance, while the HOT lines did not. The HOT and COLD mice provide a genetic model to study mechanisms mediating acute EtOH-induced hypothermia as well as tolerance development.

Animals↗
PubMed2000

Bioequivalence of two tablet formulations of atenolol after single oral administration in healthy volunteers.

The pharmacokinetic parameters of two oral formulations of 100 mg tablets of atenolol (CAS 29122-68-7; Azectol as test and another commercially available preparation as reference) were compared in an open-label, randomized, single oral dose, two-period cross-over design to 17 healthy volunteers under fasting conditions. Serial blood samples were collected prior to each administration and at 17 points within 36 h after dosing. Plasma concentrations of atenolol were measured by a validated HPLC assay with fluorometric detection. The parametric 90% confidence intervals of the geometric mean values of the test/reference ratios were 94.4% to 112.9% (point estimate: 103%) for AUC0-infinity, 93.7% to 112.8% (point estimate: 103%) for AUC0-36, and 88.3% to 112.1% (point estimate: 100%) for Cmax, within the acceptance criteria for bioequivalence (80%-125%). Tmax values were analyzed by the nonparametric Wilcoxon test and the difference was not statistically significant. Therefore, it is concluded that the test and reference atenolol formulations are bioequivalent for both the extent and the rate of absorption.

Adolescent↗
PubMed2000

Relative bioavailability study of two nifedipine tablet formulations in healthy male volunteers.

OBJECTIVE: To assess the bioequivalence of two oral formulations containing 10 mg of nifedipine. The test preparation were Macorel tablets, the reference preparation were Adalat tablets. SUBJECTS, MATERIAL AND METHODS: The study was designed as a single-dose, three-period crossover randomized design to 18 non-smoker, healthy male volunteers under fasting conditions. Seventeen volunteers completed the study. Plasma samples were analyzed for nifedipine by HPLC after solid-phase extraction. The pharmacokinetic parameters used to assess the bioequivalence of the two formulations were AUC(0-infinite) and AUC(0-t) for the extent of absorption and Cmax and Tmax for the rate of absorption. Statistical comparisons of AUC(0-infinite) AUC(0-t), and Cmax data were evaluated after logarithmic transformation by two-way analysis of variance (ANOVA), and differences of Tmax were tested non-parametricaly. RESULTS: Point estimates (90% confidence intervals) of the test/reference ratios were 97.4% (87.6%-108.3%) for AUC(0-infinite) 97.0% (85.6%-110.1%) for AUC0-t, and 107.7% (89.1%-130.7%) for Cmax. No statistically significant difference was found for Tmax and elimination half-life values. CONCLUSION: Therefore, in accordance with the European Union bioequivalence requirements, the test and reference nifedipine preparations are bioequivalent for both the extent and the rate of absorption.

Adult↗
PubMed1998

The hsp70 locus of Drosophila auraria (montium subgroup) is single and contains copies in a conserved arrangement.

The restriction endonuclease pattern of a number of hsp70-homologous clones isolated from a library of heat shock cDNA from Drosophila auraria, a species belonging to the montium subgroup of the melanogaster species group, reveals two types of clones, A and B, differing in a single restriction site. Both types, as well as hsp70-specific probes derived from both hsp70 loci of Drosophila melanogaster, hybridize in situ with a single band at region 32 A of the 2L polytene arm, indicating a clustered organization of the hsp70 gene copies in D. auraria. The longest type B clone was sequenced and it was found that one strand contains an open reading frame (ORF) exhibiting great identity with a previously described hsp70 gene of D. auraria (now denoted as type A) and with its counterparts of D. melanogaster, while its second strand, unlike the type A clone, does not contain a long antiparallel coupled ORF (LAC ORF) because of a base substitution resulting in a premature stop codon. After additional data had been derived from isolation and characterization of hsp70-homologous genomic clones, together with Southern analysis of genomic DNA, we found that two hsp70 gene copies are present at the above locus of D. auraria with an inverted tandem repeat organization, while the presence of a third hsp70 gene is not clearly evident. The above results are compared with those observed at the homologous loci of some melanogaster subgroup species (D. melanogaster and its sibling species), in which, however, the hsp70 locus is duplicated, and with the more distantly related Dipteran Anopheles albimanus.

Animals↗
PubMed1997

Heat shock gene expression during recovery after transient cold shock in Drosophila auraria (Diptera: Drosophilidae).

Newly synthesized polypeptides during recovery from prolonged cold treatment (0 degree to -1 degree C) of Drosophila auraria, a montium subgroup species, of the melanogaster species group, were analysed in denaturing polyacrylamide gels. In addition, during the cold shock recovery period, Northern analysis of the hsp83 mRNA was performed. A significant induction of two polypeptides, which exhibited electrophoretic mobilities, with the heat inducible 83 and 70 kD hsp83 and hsp70 was detected, but no such induction was evident in the so-called 'small' hsp genes. These results are compared and discussed with those observed in D. melanogaster.

Animals↗
PubMed1996

Non-linear algorithms for processing biological signals.

This paper illustrates different approaches to the analysis of biological signals based on non-linear methods. The performance of such approaches, despite the greater methodological and computational complexity is, in many instances, more successful compared to linear approaches, in enhancing important parameters for both physiological studies and clinical protocols. The methods introduced employ median filters for pattern recognition, adaptive segmentation, data compression, prediction and data modelling as well as multivariate estimators in data clustering through median learning vector quantizers. Another approach described uses Wiener-Volterra kernel technique to obtain a satisfactory estimation and causality test among EEG recordings. Finally, methods for the assessment of non-linear dynamic behaviour are discussed and applied to the analysis of heart rate variability signal. In this way invariant parameters are studied which describe non-linear phenomena in the modelling of the physiological systems under investigation.

Algorithms↗
PubMed1996

The Drosophila montium subgroup species. Phylogenetic relationships based on mitochondrial DNA analysis.

Mitochondrial DNA (mtDNA) restriction site maps for three Drosophila montium subgroup species of the melanogaster species group, inhabiting Indian and Afrotropical montium subgroup territories, were established. Taking into account previous mtDNA data concerning six oriental montium species, a phylogeny was established using distance-matrix and parsimony methods. Both genetic diversity and mtDNA size variations were found to be very narrow, suggesting close phylogenetic relationships among all montium species studied. The phylogenetic trees that were constructed revealed three main lineages for the montium subgroup species studied: one consisting of the Afrotropical species Drosophila seguyi, which is placed distantly from the other species, one comprising the north-oriental (Palearctic) species, and one comprising the southwestern (south-oriental, Australasian, Indian, and Afrotropical) species. The combination of the mtDNA data presented here with data from other species belonging to the melanogaster and obscura subgroups revealed two major clusters: melanogaster and obscura. The melanogaster cluster is further divided into two compact lineages, comprising the montium subgroup species and the melanogaster complex species; the species of the other complex of the melanogaster subgroup, yakuba, disperse among the obscura species. The above grouping is in agreement with the mtDNA size variations of the species. Overall, among all subgroups studied, the species of the montium subgroup seem to be the most closely related.

Animals↗
PubMed1995

Three computer methods to reconstruct pulpal blood vessels and nerves.

This study describes three methods of computerized three-dimensional reconstruction of the main neurovascular pulpal bundle of human teeth, using serial cross-paraffin sections, digital image processing, and three-dimensional computer graphics. These methods are surface representation, representation by means of a stack of slices, and volume representation.

Adolescent↗
PubMed1995

Computerized reconstruction of TEM examined pulpal blood vessels and nerves.

Five healthy premolars were used for transmission electron microscopy examination and three-dimensional (3D) reconstruction of pulpal blood vessels and their surrounding nerves. Serial Epon thin sections were taken from specimens. After a series of preprocessing steps that included digitization, contrast enhancement, slice alignment, segmentation and interpolation, three dimensional surface representation was performed using the triangulation method. The findings showed that vessels were usually accompanied by a number of myelinated and unmyelinated nerves. The nerves shared a more or less common course with the vessels. Small arteries presented greater number of nerves in their vicinity, compared to small veins. In the sections examined, no direct contact between the nerve trunks and the wall of the vessels was found; the closest distance measured was approximately 67 microns. The common course of vessels and nerves suggested autonomic innervation on part of the myelinated axons.

Adult↗
PubMed1993

[Trichobezoar as a rare cause of ileus of the small intestine].

For several weeks a 15-year-old girl had complained of increasing abdominal pain with vomiting. On admission to hospital the bloated abdomen was diffusely sensitive to pressure and the bowel sounds were high pitched and loud. Erythrocyte sedimentation rate was increased to 23/40 mm and the white cell count to 12,000/microliters. Ultrasound examination revealed an echo-dense area with dorsal echo loss at the gastric side of the pylorus. X-ray films of the stomach showed fluid levels and a soft-tissue mass in the left upper abdomen. At laparotomy a large (12 x 6 cm) trichobezoar was found in the middle of the small intestine and two smaller ones at the pylorus. Subsequently the patient admitted to trichophagia but refused any psychological treatment.

Adolescent↗