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Dive into the research topics where George Katzos is active.

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Featured researches published by George Katzos.


Ultrasound in Obstetrics & Gynecology | 2008

Evaluation of pelvic ultrasonography in the diagnosis and differentiation of various forms of sexual precocity in girls

M. Badouraki; Athanasios Christoforidis; I. Economou; Athanasios Dimitriadis; George Katzos

This study was conducted to assess the role of pelvic ultrasound variables in discriminating between normal girls and girls with different forms of sexual precocity, and to establish reliable cut‐off limits of pelvic ultrasound measurements for differentiating between these conditions.


Journal of Clinical Ultrasound | 2008

Sonographic assessment of uterine and ovarian development in normal girls aged 1 to 12 years

Maria Badouraki; Athanasios Christoforidis; Ippoliti Economou; Athanassios S. Dimitriadis; George Katzos

To provide normal references of sonographic uterine and ovarian size in girls aged 1–12 years.


Brain & Development | 1997

Early infantile Krabbe disease: deceptively normal magnetic resonance imaging and serial neurophysiological studies

Dimitrios I. Zafeiriou; Athanasia Anastasiou; Eleni Michelakaki; Persa Augoustidou-Savvopoulou; George Katzos; Eleftherios E. Kontopoulos

Early infantile Krabbe disease is a progressive neurodegenerative disease caused by deficiency of lysosomal enzyme galactocerebroside beta-galactosidase, with onset before the age of 6 months. We present serial clinical, radiological and neurophysiological findings of a patient with early infantile Krabbe disease, presenting at the third day of life with hypotonia, macrocephaly and neonatal seizures. The patient had a deceptively normal initial magnetic resonance imaging examination at the age of 3 months, with progression of the white matter disease over the following 9 months, showing a clinical picture of profound hypotonia with pyramidal and pseudobulbar signs, as well as mild optic atrophy. Assay of galactocerebroside beta-galactosidase activity in leukocyte culture disclosed a marked deficiency of the enzyme (0.00 nmol/mg protein per h with normal values > 0.7 nmol/mg protein per h), thus confirming the diagnosis of Krabbe disease. Nerve conduction velocity and evoked potential studies, as well as the electroencephalogram, were abnormal at the age of 6 months, while serial neurophysiological studies at the age of 12 and 18 months demonstrated the progressive nature of the disease.


Brain & Development | 1997

Single dose immunoglobulin therapy for childhood Guillain-Barrésyndrome

Dimitrios I. Zafeiriou; E. Kontopoulos; George Katzos; Nikos Gombakis; Florence G. Kanakoudi

To establish the efficacy of intravenous immunoglobulins (IVIG) in the treatment of acute Guillain-Barré syndrome (GBS), we treated nine consecutive pediatric cases (age 2.5-13.5 years) fulfilling the criteria for GBS with a single dose of IVIG (Sandoglobulin; 2 g/kg/BW). None of the patients experienced any IVIG related side-effects. The mean time required to improve by at least one grade on the functional GBS scale after IVIG treatment was 3.5 days, while the mean period to regain ambulation was 11.2 days. Full mobilization without evidence of relapse in the follow-up period (mean 14.5 months) was noted in all but one patient who relapsed after 5 months. We conclude that the early use of a single IVIG dose may prevent further progression of the disease, thus shortening the clinical course of childhood GBS. The most beneficial IVIG dose regimen remains to be determined by controlled trials.


European Journal of Haematology | 2010

Elevated serum parathormone levels are associated with myocardial iron overload in patients with β-thalassaemia major

Meropi Dimitriadou; Athanasios Christoforidis; Marina Economou; Efthimia Vlachaki; Liana Fidani; George Katzos; Miranda Athanassiou-Metaxa

Objectives:  Despite advances in conventional treatment, iron‐induced cardiomyopathy is still the most frequent cause of death among patients with β‐thalassaemia major. Recent studies have correlated increased myocardial iron content to decreased levels of vitamin D in thalassaemic patients. The aim of this study was to measure parathormone (PTH) and metabolites of vitamin D and consequently to investigate whether these parameters predispose to myocardial iron overload in patients with β‐thalassaemia major.


Brain & Development | 2003

Familial moyamoya disease in a Greek family.

Dimitrios I. Zafeiriou; Hidetoshi Ikeda; Anastasia L. Anastasiou; Efi Vargiami; Nikos Vougiouklis; George Katzos; Nikos Gombakis; Georgia Gioula; Yoshiharu Matsushima; Fenella J. Kirkham

Moyamoya disease (M-M) is characterized by progressive obstruction of the supraclinoid portion of internal carotid arteries and the proximal middle, anterior and posterior cerebral arteries, associated with the formation of a characteristic net of collateral vessels in the basal ganglia region. Clinical manifestations in childhood include transient ischaemic attacks, seizures and multiple infarcts. Approximately 7% of M-M cases are familial. We report two affected Greek siblings with typical clinical and neuroradiological findings of M-M. Linkage analysis of the whole family was consistent with linkage to the region 3p24-26, as previously reported in other familial Japanese M-M cases.


Brain & Development | 2001

L-2-Hydroxyglutaric aciduria presenting as status epilepticus

Dimitrios I. Zafeiriou; Adrian C. Sewell; Persephone Savvopoulou-Augoustidou; Nikos Gombakis; George Katzos

L-2-Hydroxyglutaric aciduria (L-2-HGA) is a rare organic aciduria with a slowly progressive course regarding CNS involvement. We present a 13.5-year-old female patient who presented at the Emergency Department with a generalized status epilepticus, which promptly responded to intravenous phenytoin. CT and MRI demonstrated subcortical white matter alterations. The neurological examination revealed mild mental retardation, macrocephaly and ataxic gait with cerebellar signs. Repeated urinary organic acid analysis demonstrated increased excretion of 2-hydroxyglutaric acid which was of the L-configuration. The constellation of macrocephaly in a patient with mental retardation, cerebellar tract involvement and subcortical white matter signal alterations on MRI should alert the physician to the possibility of L-2-HGA. Although rare, epileptic seizures or even status epilepticus can be among the presenting symptoms in organic acidurias with a slow course, such as L-2-HGA.


Brain & Development | 2004

Thelarche variant in a girl with Angelman syndrome

George Katzos; Panagiota Triantafyllou; Nikolaos Gombakis; Christalena Sofocleous; Dimitrios I. Zafeiriou

A case of Angelman syndrome (AS) with thelarche variant in a 4.5-year-old girl is presented. Clinical suspicion of AS was raised at the age of 15 months when she presented with mental retardation and epilepsy, absence of speech, ataxic gait with jerky movements, hyperactivity and paroxysmal episodes of laughter. Moreover, she had facial dysmorphic features such as microbrachycephaly, mid-facial hypoplasia, macrostomia and prominent mandible. Dinucleotide repeat polymorphism (DNRP) analysis, identified absence of maternal alleles at D15S543, D15S113 and GABRB3 loci, findings consistent with AS. Studies on CYP19 locus (outside the 15q11-13 region) revealed the presence of two different alleles, thus excluding the possibility of paternal isodisomy of chromosome 15 in this patient. Breast development at the age of 4.5 years, accompanied by accelerated growth velocity and bone age suggested the diagnosis of variant thelarche. This is the second case of AS with sexual precocity reported and whether this combination is a coincidence or not remains to be clarified.


Hematology | 2011

Fok‐I gene polymorphism of vitamin D receptor in patients with beta‐thalassemia major and its effect on vitamin D status

Meropi Dimitriadou; Athanasios Christoforidis; Liana Fidani; Marina Economou; Vassilios Perifanis; George Katzos; Miranda Athanassiou-Metaxa

Abstract Most of the biological actions of vitamin D are mediated by an intracellular receptor (VDR) in which several single nucleotide gene polymorphisms have been identified. Vitamin D deficiency is increasingly identified among thalassemic patients and recent evidence links it with myocardial iron accumulation. The aim of this work was to assess the distribution of the Fok‐I polymorphism of the VDR gene among Greek children and young adults with beta‐thalassemia major and to investigate its association with 25(OH)D3 and 1,25(OH)2D3 serum levels. Sixty‐nine thalassemic patients (35 females and 34 males), with a mean age of 23·05±6·07 years, participated in the study. Genotype frequencies of Fok‐I were similar to those previously reported for other populations; 44·9% of the patients were homozygotes for F allele, 43·5% were heterozygotes and 11·6% were homozygotes for the f allele. Low levels of serum 25(OH)D3 were recorded, as 41 patients (59·4%) were below the cut‐off limit of 50 nmol/l that determines deficiency, whereas, levels of 1,25(OH)2D3 showed wide variability ranging from deficiency (⩽50 pmol/l) in 34 patients (49·3%) to excess (⩾125 pmol/l) in 13 patients (18·8%). When stratifying patients according to serum 1,25(OH)2 D3 concentrations, a higher prevalence of the f allele was observed in the deficiency group (P = 0·03). A comparison of the serum concentrations of the two vitamin D metabolites produced a trend towards a negative correlation (r = −0·204, P = 0·09). Further studies are required to assess the genetic contribution to the regulation of vitamin D metabolites in the serum of patients with beta‐thalassemia major.


European Journal of Clinical Investigation | 2015

Transient generalized glucocorticoid hypersensitivity.

Nicolas C. Nicolaides; Agaristi Lamprokostopoulou; Alexandros Polyzos; Tomoshige Kino; Eleni Katsantoni; Panagiota Triantafyllou; Athanasios Christophoridis; George Katzos; Maria Dracopoulou; Amalia Sertedaki; George P. Chrousos; Evangelia Charmandari

Transient generalized glucocorticoid hypersensitivity is a rare disorder characterized by increased tissue sensitivity to glucocorticoids and compensatory hypo‐activation of the hypothalamic–pituitary–adrenal axis. The condition itself and the underlying molecular mechanisms have not been elucidated.

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Dive into the George Katzos's collaboration.

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Dimitrios I. Zafeiriou

Aristotle University of Thessaloniki

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Athanasios Christoforidis

Aristotle University of Thessaloniki

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Miranda Athanassiou-Metaxa

Aristotle University of Thessaloniki

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Nikos Gombakis

Aristotle University of Thessaloniki

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Marina Economou

Aristotle University of Thessaloniki

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Meropi Dimitriadou

Aristotle University of Thessaloniki

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Panagiota Triantafyllou

Aristotle University of Thessaloniki

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Eleftherios E. Kontopoulos

Aristotle University of Thessaloniki

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Emmanouil Hatzipantelis

Aristotle University of Thessaloniki

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Liana Fidani

Aristotle University of Thessaloniki

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