Josef Marek

Josef Marek
Charles University in Prague | CUNI ·  3rd Department of Medicine - Department of Endocrinology and Metabolism (1. LF)

Prof., MD, PhD

About

274
Publications
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3,558
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Additional affiliations
August 1965 - present
Charles University in Prague
Position
  • Professor (Full)
August 1965 - present
University General Hospital
University General Hospital
Position
  • Professor (Full)

Publications

Publications (274)
Article
Full-text available
Purpose Stereotactic radiosurgery is one of the treatment options for prolactinomas, the most commonly used being Gamma Knife Radiosurgery (GKRS). GKRS is indicated mainly in the treatment of dopamine agonist (DA)-resistant prolactinomas. In our study, we report on our experience in treating prolactinoma patients by GKRS. Methods Twenty-eight pati...
Article
Full-text available
Purpose: Cushing's syndrome is characterized by metabolic disturbances including insulin resistance. Mitochondrial dysfunction is one pathogenic factor in the development of insulin resistance in patients with obesity. We explored whether mitochondrial dysfunction correlates with insulin resistance and other metabolic complications. Patients and...
Article
Hyperprolactinemia is a common laboratory finding, It is found in some physiological states and in endocrinological and nonendocrinologcal diseases. Prolactinomas are the most common cause of pathologic hyperprolactinemia and the most frequent type of pituitary adenoma. Hyperprolactinemia causes infertility, disturbance of the menstrual cycle due t...
Article
Pituitary adenomas are the most common tumours of the sellar region. A combination of neurosurgery, radiation and pharmacological approaches are applied for the treatment of pituitary adenomas. In certain cases, patient observation is another option. Neurosurgery is the first-choice treatment for acromegaly, Cushing's disease and TSH secreting aden...
Article
Adenomas which secrete thyrotropic hormone (thyrotropinomas) are rare and constitute less than 3 % of pituitary adenomas. In laboratory studies there is a typical elevation of thyroid hormones with nonsupressible TSH. In differential diagnostics it is necessary to distinguish above all the syndrome of resistance to thyroid hormones. Clinical sympto...
Article
Background: The effect of intraoperative magnetic resonance imaging (iMRI) on the extent of sellar region tumors treated endonasally has been described in previous research. However, the effects of iMRI on endocrinologic outcome of growth hormone-secreting adenomas have been studied in only a few small cohort studies. Methods: Inclusion criteria...
Article
We explored the effect of chronically elevated circulating levels of growth hormone (GH)/insulin-like-growth-factor-1 (IGF-1) on mRNA expression of GH/IGF-1/insulin axis components and p85alpha subunit of phosphoinositide-3-kinase (p85alpha) in subcutaneous adipose tissue (SCAT) of patients with active acromegaly and compared these findings with he...
Article
Pituitary adenomas are frequently occurring intracranial neoplasms. The aim of the treatment of pituitary adenomas is to normalize hormonal hypersecretion, to preserve the normal pituitary function, to reserve or treat impaired pituitary function and to control tumor growth and its mechanical effects on the surrounding structures. Treatment modalit...
Article
Full-text available
Aims: Pituitary adenomas (PA) are non-invasive benign tumors with a high autopsy prevalence. They are classified according to the type of hormone secreted (prolactin, growth hormone, adrenocorticotropin, thyrotropin, folitropin, or luteinizing hormone). Clinically non-functioning adenomas (CNFA) lacking the typical hypersecretion of hormones make...
Article
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Introduction: In the past 10 years, endoscopic resection of pituitary adenomas has become an alternative to microsurgical resection with the additional advantage of increasing the patient’s postoperative comfort. This analysis explored whether endoscopic resection can reduce the risk of postoperative neurohypophyseal dysfunction. Material and metho...
Article
This study investigated quantitated expression of dopamine 2 receptor (D2R) and somatostatin receptors of the five types (SSTR1-SSTR5) in a large series of clinically non-functioning pituitary adenomas (CNFAs). Co-expression of these receptors in individual adenomas was studied as well as correlation between receptor types. Adenoma tissue from 198...
Article
Full-text available
Our aim was to analyze the correlation of early postoperative cortisol levels in patients after transsphenoidal pituitary adenoma surgery compared to the standard dose ACTH test and Insulin tolerance test (ITT) several months later. We retrospectively reviewed data from 94 patients operated for pituitary adenoma in years 2009-2012. The comparison o...
Article
Purpose: This paper presents our 18 years of experience in treating ACTH secreting adenomas (Cushing's disease and Nelson's syndrome) using the Leksell gamma knife (LGK) irradiation. Methods: Twenty-six patients with Cushing's disease were followed-up after LGK irradiation for 48-216 months (median 78 months). Seventeen patients had undergone pr...
Article
Acromegaly, if untreated, leads to numerous complications and premature death of patients. In recent years, significant changes in the treatment of acromegaly were achieved. The surgical approach was innovated, what allows completely selective removal of most microadenomas without any damage of the pituitary and safe debulking of the tumor mass in...
Article
Acromegaly is usually diagnosed after several years of duration. The multimodal therapy - surgery, radiotherpy, pharmacotherapy - is necessary to suppress the activity of the disease in the majority of patients. Register of sellar tumors (RESET) collecting data of patients from eight tertiary centers since the year 2000 was established in 2008 to a...
Article
Objectives In the past 10 years, endoscopic resection of pituitary adenomas has become an alternative to microsurgical resection with the additional advantage of increasing the patient's postoperative comfort. This analysis explored whether endoscopic resection can reduce the risk of postoperative neurohypophyseal dysfunction. Design We rated and c...
Article
Prolactinomas account for approximately 40% of all pituitary adenomas. Hyperprolactinemia causes hypogonadism, infertility and galactorrhea. Macroprolactinomas may cause signs of local expansion, such as headache, visual field defects and paresis of oculomotor nerves during suprasellar and parasellar extensions. Compression of healthy pituitary tis...
Article
Full-text available
Salivary cortisol reflects the free fraction of serum cortisol. Monitoring salivary cortisol may be a promising alternative method for assessing serum cortisol in some clinical situations. We aimed to compare the reliability of salivary vs. serum cortisol during ACTH test. 84 subjects (mean age 63.2; 24-89 years; n=66 males) suspected for adrenocor...
Article
The spectrum of pituitary stalk lesions is broad and only partially overlaps with the pathology of the pituitary gland. These lesions can be divided into congenital and developmental, neoplastic and inflammatory. The clinical manifestation of these lesions is diabetes insipidus and varying degrees of hypopituitarism, which is sometimes accompanied...
Article
The goal of pituitary adenoma radiosurgery is to halt tumor growth, normalize hormonal hypersecretion if present, maintain normal pituitary function, and preserve important structures around the sella. The radiation dose necessary to stop tumor growth is lower than the dose necessary to achieve normalization of hormonal hypersecretion. The minimum...
Article
Cushings syndrome is a rare disorder with variable aetiology which is connected with significantly increased morbidity and mortality. Therefore, early determination of correct aetiology and early treatment are essential for a decrease of morbidity and mortality of patients. Present article introduces review and current recommendation of Czech Socie...
Article
In pregnancy, the volume of pituitary increases by multiplication of lactotopic and gonadotropic cells and developing placenta is the source of numerous hormones and enzymes that significantly affect and alter the function of the endocrine system. This naturally has an impact on the course of pituitary disorders and their treatment. The most common...
Article
Introduction: Acromegaly with GH excess affects up to 20% of the patients with McCune–Albright syndrome (MAS). Surgical treatment for acromegaly in MAS is often difficult because of skull-base dysplasia. Somatostatin analogs are frequently only partially effective and GH receptor antagonist – pegvisomant is more potent in normalizing IGFI levels. R...
Article
Introduction: Salivary cortisol measurement, representing free cortisol, seems to be a promissing alternative method to serum cortisol. Besides its use in the diagnostics of hypercortisolism, it could be of help in evaluation of adrenocortical reserve. It might be useful especially in patients on estrogen replacement, which modulates transcortin an...
Article
The patient, born in 1964, has been followed since her youth in endocrinology out-patient department of the 3 Department of Internal Medicine at the 1 Faculty of Medicine in Prague for the first type of multiple endocrine neoplasia (MEN I), where prolactinsecreting pituitary adenoma, parathyroid adenoma and glucagonoma were gradually discovered. Al...
Article
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Our study explored the role of extrapituitary prolactin (PRL) and toll-like receptors (TLR)2 and TLR4 in defense reaction of immune system to bacterial infection. Forty-two patients diagnosed with sepsis were recruited and blood samples were withdrawn after patients' admission to hospital, after the end of acute phase of sepsis and after the sepsis...
Article
We explored serum concentrations and mRNA expression of insulin-like-growth factor-1 (IGF-1) axis components in subcutaneous adipose tissue (SCAT) and peripheral monocytes (PM) of 18 healthy females, 11 obese non-diabetic females (OB) and 13 obese women with type 2 diabetes (T2DM) examined at baseline and after very-low-calorie diet (VLCD). T2DM wo...
Article
Full-text available
Relatively frequent pituitary hormone deficiencies are observed after traumatic brain injury (TBI) and subarachnoid hemorrhage (SAH) and according to the published studies the neuroendocrine consequenses of traumatic brain injury are underdiagnosed. In a cohort of 59 patients (49 males, mean age 68.3 years, 36-88 years) after evacuation of subdural...
Article
Polycystic ovary syndrome is one of the most common endocrinopathy in women of fertile age. It is commnoly accompanied by an increased occurence of cardiovascular risk factors. This association led to a consensus statement of Androgen Excess Society for screening of cardiovascular risk factors. We present the recommendations of Czech Endocrine and...
Article
In the last decade, view on corticosteroid- binding globulin has been completely changed (CBG). CBG is high affinity glycoprotein for glucocorticoid hormones, especially Cortisol and corticosterone, and facilitates their transport in the blood. Recent studies suggest that CBG may have more important functions than just the role of a transport prote...
Article
In Czech Republic, new somatostatin analog - pasireotide (SOM230, Signifor* Novartis Pharma) will be available to the therapeutic use at the end of this year. The main indication is the central hypercortisolism caused by ACTH secreting pituitary adenomas. When used in monotherapy, in 25% of these patients, the normalization of urinary free Cortisol...
Article
Full-text available
Clinically non-functioning pituitary adenomas account for about one-third of pituitary tumors. The majority of them are pathologically classified as gonadotropinomas or null-cell adenomas without hormonal expression. The rest represent silent corticotroph adenomas and plurihormonal tumors. Conservative therapy with dopamine agonists is effective in...
Article
Full-text available
To evaluate the efficacy and safety of coadministered lanreotide Autogel (LA; 120  mg/month) and pegvisomant (40-120  mg/week) in acromegaly. This is a 28-week, multicenter, open-label, single-arm sequential study. Patients (n=92) biochemically uncontrolled, on somatostatin analogs (SSAs) or using pegvisomant monotherapy entered a 4-month run-in ta...
Article
Full-text available
Serum adipocyte fatty acid-binding protein (FABP-4) concentrations are linked to human obesity and other features of metabolic syndrome. Patients with Cushing´s syndrome (CS) develop numerous features of metabolic syndrome due to chronic cortisol excess. Here we tested the hypothesis that chronically increased cortisol levels in CS patients may alt...
Article
Full-text available
Radiation therapy is one of the treatment options for pituitary adenomas. The most common side effect associated with Leksell gamma knife (LGK) irradiation is the development of hypopituitarism. The aim of this study was to verify that hypopituitarism does not develop if the maximum mean dose to pituitary is kept under 15 Gy and to evaluate the inf...
Article
To treat pituitary adenomas, three modes of treatment are usually combined: neurosurgery, radiation and pharmacological. Prolactinomas are an exception with predominantly pharmacological management. Patients with acromegaly are usually diagnosed late and thus many neurosurgeries fail to completely remove the adenoma. Any residual tumour tissue is u...
Article
Full-text available
The objective of this study was to measure plasma fibroblast growth factor 21 and 19 (FGF21 and FGF19) levels in patients with Cushing's syndrome (CS) and to compare it with those of lean control subjects (C) and patients with obesity (OB). Fourteen untreated patients with CS, 19 patients with OB and 36 controls were included in the study. Plasma F...
Article
Full-text available
The study was designed to evaluate the long-term efficacy and safety of the 28-day prolonged-release Autogel formulation of the somatostatin analogue lanreotide (Lan-Autogel) in unselected patients with acromegaly. The study comprised four phases: washout; a double-blind comparison with placebo, at a single randomized dose (60, 90 or 120 mg) of Lan...
Article
Pharmacological treatment with dopaminergic agonists (DA) is the treatment of choice for prolactinomas. Surgical and radiation treatment is also indicated in certain situations. We describe our 12-year experience in treating prolactinomas with the Leksell gamma knife (LGK). We followed 35 prolactinoma patients (25.7% microprolactinomas, 74.3% macro...
Article
Full-text available
Excess GH and IGF-I in acromegaly are associated with reduced life expectancy due to cardiovascular complications. The objective of the study was to investigate the prevalence, incidence, and severity of cardiac valve regurgitation before and after somatostatin-analog treatment in acromegaly. This was a prospective, observer-blinded, multicenter, 1...
Article
Full-text available
The aim of the study was to evaluate skin microvascular reactivity (MVR) and possible influencing factors (fibrinolysis, oxidative stress, and endothelial function) in patients with Cushing's syndrome. Twenty-nine patients with active Cushing's syndrome (ten of them also examined after a successful operation) and 16 control subjects were studied. S...
Article
Prolactin is a one of the stress hormones, like the growth hormone, ACTH, cortisol and catecholamins. Among its wide range of functions is the important role of controlling the immune response which is, unlike in the case of cortisol, of stimulatory nature. For this activity, it is monitored as a factor influencing the progress and course of autoim...
Article
Full-text available
Previous studies revealed altered levels of the circulating insulin-like growth factor-I (IGF-I) and of its binding protein-3 (IGFBP-3) in subjects with coronary atherosclerosis, metabolic syndrome and premature atherosclerosis. Hyperlipidemia is a powerful risk factor of atherosclerosis. We expected IGF-I and IGFBP-3 alterations in subjects with m...
Article
The goal of nonsecreting pituitary adenoma radiosurgery is to halt tumour growth and to maintain normal performance of the hypophysis and the functionally important structures around the sella. The effectiveness of gamma knife radiosurgery was evaluated. Over a period of 10 years (1993-2003), 140 patients with nonsecreting pituitary adenoma were tr...
Article
Knowledge of hypophysis could hardly stagnate in a context of general progress in medical science as such. New knowledge in physiology, pathology and treatment of hypophysis diseases is vast and only some of it could be included in the article. New regulators of hypophysial secretion have been discovered. Among them are hypothalamic chemokines and...
Article
Computer tomography (CT) and magnetic resonance imaging (MRI) quite often detect unexpected cases of enlargement in the hypothalamus-hypophysial region, without the above methods being indicated for clinical manifested symptomatology provoked by the tumour. This is not surprising if we consider that autopsies show the presence of hypophysial adenom...
Article
The hormones with a strong influence on the lipid spectrum and the development of atherosclerosis include cortisol, growth hormone and oestrogens. Cortisol accelerates atherosclerosis both through dyslipidemia and through an increase in visceral fat, hypertension, increased insulin resistance and the development of reduced glucose tolerance which m...
Article
There had been treated 277 patients with pituitary adenoma in period from 1999 to 2003 at Department of Neurosurgery, Central Military Hospital, Prague. Altogether there had been treated 108 patients with hormone-secreting adenomas. Normalization or sufficient hormone level decrease was observed in 61 patients after the first surgery. Hormone level...
Article
In June 2005, an ad hoc Expert Committee formed by the Pituitary Society convened during the 9th International Pituitary Congress in San Diego, California. Members of this committee consisted of invited international experts in the field, and included endocrinologists and neurosurgeons with recognized expertise in the management of prolactinomas. D...
Article
Atherosclerosis is considered a chronic inflammatory condition. The importance of immunopathological mechanisms in these processes has been recognized. Several autoantibodies seem to be implicated in atherogenesis, and anti-endothelial cell antibodies (AECA) are among them. The influence of AECA on endothelial cell function may include endothelial...
Article
Full-text available
The Leksell gamma knife (LGK) is one of the treatment options for pituitary adenomas. We report on our long-term experience treating acromegaly using LGK. Since 1993 we have followed 96 acromegaly patients through periods of from 12 to 120 months. The mean follow-up period was 53.7 +/- 26.8 months. Seventy-two patients were treated with neurosurger...
Article
Full-text available
Cushing's syndrome is associated with typical central redistribution of adipose tissue. The aim of the study was to assess lipolysis and catecholamines and their metabolites in subcutaneous abdominal adipose tissue using an in-vivo microdialysis technique. Nine patients with Cushing's syndrome and nine age-, gender- and body mass index (BMI)-matche...
Article
Full-text available
Ghrelin is an endogenous growth hormone (GH) secretagogue recently isolated from the stomach. Although it possesses a strong GH releasing activity in vitro and in vivo, its physiological significance in endogenous GH secretion remains unclear. The aim of this study was to characterize plasma ghrelin levels in acromegaly and growth hormone deficienc...
Article
Ghrelin was originally isolated from the rat stomach and significant amounts were found also in the kidney. Present study was designed to examine changes in ghrelin levels in renal failure and their relationship to the GH/IGF-I axis. Fourty patients with mild-to-severe CRF (19 men, 21 women, aged 62.5 +/- 2.2 years, BMI 27.57 +/- 0.73 kg/m(2)) and...
Article
Vascular growth factors are important not only in angiogenesis but also for the maintenance of normal endothelial integrity and function. Elevated levels of vascular endothelial growth factor (VEGF), angiopoietin-2, hepatocyte growth factor (HGF), endostatin and angiogenin have been associated with endothelial dysfunction and atherosclerosis. Both...
Article
Full-text available
Ghrelin is an acylated peptide stimulating secretion of the growth hormone (GH). It was originally isolated from the rat stomach as an endogenous ligand for the growth hormone secretagogue receptor. Although being predominantly produced by endocrine cells of the gastric fundus, its secretion has been found in various tissues including the kidney. T...
Article
Twenty six patients with macroprolactinomas treated with D2 receptor agonists were examined, 4 patients were later excluded from the group since their treatment was initiated before MRI examination of the brain. Intratumoral hemorrhage during treatment with D2 receptor agonists was observed in 3 (14 %) cases before treatment onset and in 12 (55 %)...
Article
Full-text available
Ghrelin is a member of the group of growth hormone secretagogues (GHSs). It is a peptide hormone, recently isolated from stomach as an endogenous ligand for the growth hormone secretagogue receptor (GHS-R). Ghrelin is mostly produced by the stomach, although its production has been proved in various tissues. It is a potent releaser of growth hormon...
Article
Cushing's syndrome (CS) is associated with central adiposity, insulin resistance and impaired glucose homeostasis. Adipose tissue is thought to regulates glucose homeostasis via circulating adipokines, such as resistin, leptin and adiponectin, although their role in the insulin resistance associated with CS has not been established. We examined the...
Article
The goal of pituitary adenoma radiosurgery is to halt tumor growth, to normalize hormonal hypersecretion if present, and to maintain the performance of a normal hypophysis and functionally important structures around the sella, namely the optic nerve. The minimum distance required between the irradiated target and the optic pathway should be reasse...
Article
The aim of the study was to investigate the mechanism of action of somatostatin analogues (SSA), ionizing radiation, and their combination on pituitary adenoma cells with special emphasis on proliferative and apoptotic activity. In the 14 GH-secreting adenomas pretreated with SSA before surgery, more prominent regressive changes were found accompan...
Article
The goal of pituitary adenoma radiosurgery is to halt tumor growth, to normalize hormonal hypersecretion if present, and to maintain the performance of normal hypophysis and functionally important structures around the sella-namely, the optic nerve. The minimum distance required between the irradiated target and the optic pathway should be reassess...
Article
Effect of growth hormone (GH) on the growth and development of children is generally known. Effects of GH in adults are favorable, though. The aim of the work was to verify effects of GH administration on body composition in adult patients with GH deficit (GHD). The authors examined 15 adult patients with GHD originated in 13 of them in adulthood a...
Article
Unlabelled: Hypercortisolism is associated with a high risk of sickness rate and death rate particularly in view of facilitated arteriosclerotic processes. It is most frequently induced by drug therapy, but endogenous hypercortisolism (Cushing's syndrome) may serve as a suitable model of the effect of hypercortisolism on vascular wall. Our cohort...
Article
Insulin resistance, impaired glucose tolerance and type 2 diabetes are common in acromegalic subjects. The mechanism underlying this insulin resistance is unclear. We investigated the levels of the adipocytokines, resistin, adiponectin and leptin in a group of 18 acromegalic subjects and 18 control subjects matched for age, gender and body mass ind...
Article
Full-text available
The aim of the study was to determine the inhibitory effects of somatostatin analogues with relative specificity to somatostatin receptor subtype 2 (SSTR2) (BIM-23197), subtype 5 (SSTR5) (BIM-23268), and their combination on GH and PRL secretion in acromegalic adenomas in vitro. Three types of answer were observed: 1. In one resistant adenoma no in...