Pharmacokinetics and Bioavailability of the GnRH Analogs in the Form of Solution and Zn2+-Suspension After Single Subcutaneous Injection in Female Rats.

BACKGROUND AND OBJECTIVES: Although many synthetic gonadoliberin analogs have been developed, only a few of them, including buserelin, were introduced into clinical practice. Dalarelin, which differs from buserelin by just one aminoacid in the position 6 (D-Ala), is not widely used so far. Gonadotropin-releasing hormone (GnRH) analogs are used to treat many different illnesses and are available in different forms like solution for injection, nasal spray, microspheres, etc. Unfortunately, none of the above drug formulations can release the hormones for 24 h. We assumed that classical suspension could solve this problem. METHODS: Two sets of experiments were performed. In the first one, buserelin and dalarelin were injected into mature female rats in two forms: suspension, in which the analogs are bounded by Zn2+ ions and solution. The pharmacokinetic parameters and bioavailability of the analogs were calculated, based on their concentration in the plasma measured by high-performance liquid chromatography method (HPLC). In the second experiment, the hormones in two different forms were injected into superovulated immature female rats and then the concentration of Luteinizing hormone (LH), Follicle-stimulating hormone (FSH) and 17ß-estradiol in the serum was measured by radioimmunological method. RESULTS: The Extent of Biological Availability (EBA), calculated on the base of AUC0-∞, showed that in the form of solution buserelin and dalarelin display, respectively, only 13 and 8 % of biological availability of their suspension counterparts. Comparing both analogs, the EBA of dalarelin was half (53 %) that of buserelin delivered in the form of solution and 83 % when they were delivered in the form of suspension. The injection of buserelin or dalarelin, in the form of solution or suspension, into superovulated female rats increased LH, FSH and estradiol concentration in the serum. However, after injection of the analogs in the form of suspension, the high concentration of LH and FSH in the serum persisted longer. CONCLUSION: Performed studies indicate that GnRH analogs in the form of suspension have higher bioavailability than their solution counterparts. It influences the effects of their action, especially in relation to LH and FSH.

Effect of methylprednisolone pulse therapy with and without alendronate on biochemical markers of bone turnover in patients with Graves' ophthalmopathy.

INTRODUCTION:  Immunosuppression with glucocorticoids is the method of choice in the treatment of active Graves' ophthalmopathy (GO). However, glucocorticoid therapy may have side effects, among others, it affects bone metabolism. OBJECTIVES:  The aim of the study was to compare the effect of methylprednisolone pulse therapy (MPPT) with and without alendronate on bone turnover markers in patients with GO with normal and reduced bone mineral density (BMD). PATIENTS AND METHODS:  The study included 53 patients with GO and 20 sex- and age­matched healthy controls. Twenty patients with normal BMD (17 women, 3 men, aged 45 ±1.0 years) received only MPPT (8 g intravenously during 4 weeks). The remaining patients, with reduced BMD, were randomly assigned either to MPPT without alendronate (10 women, 2 men, aged 47 ±1.0 years) or MPPT with alendronate (18 women, 3 men, aged 47 ±1.0 years). BMD of the lumbar spine and femoral neck was assessed using dual energy X­ray absorptiometry  (DEXA) before treatment. The markers of bone formation (serum osteocalcin, carboxyterminal propeptide of type I collagen [PICP], alkaline phospatase) and the markers of bone resorption (serum carboxyterminal telopeptide of type I collagen [ICTP], cross­linked C­terminal telopeptide of type I collagen [CTX], serum calcium [Ca] and potassium [P], as well as urinary excretion of deoxypyridinoline, Ca, and P) were determined before and after treatment. RESULTS:  MPPT caused a decrease in bone formation markers and an increase in some bone resorption markers. MPPT with alendronate decreased bone formation and bone resorption markers. CONCLUSIONS:  A negative effect of MPPT on bone turnover is observed both in patients with GO with normal and with reduced BMD. Simultaneous use of MPPT and alendronate in patients with GO and reduced BMD suppresses bone resorption caused by methylprednisolone.

[Pharmacokinetics of digoxin in hyperthyroidism. Effect of methimazole]. / Farmakokinetyka digoksyny u chorych z nadczynnoscia tarczycy. Wplyw metimazolu.

INTRODUCTION: Cardiovascular abnormalities may be the only manifestations of overt hyperthyroidism. In patients with heart failure and atrial fibrillation digoxin can be beneficial in controlling the symptoms and signs, but hyperthyroid patients show an impaired response or even resistance to digoxin treatment. The aim of the study is to establish: 1. Are there any differences in the pharmacokinetics of a single oral dose of digoxin between hypertyroid and euthyroid patients? 2. Does simultaneous administration of digoxin and methimazole affect the pharmacokinetics of a single oral dose of dogoxin? 3. Does methimazole-induced euthyroidism change the pharmacokinetics of a single oral dose of digoxin? MATERIAL AND METHODS: The subject of the study were 28 patients with hyperthyroidism and 15 healthy persons. We evaluated the pharmacokinetics of a single oral dose of digoxin. Moreover we evaluated pharmacokinetics of a single dose of digoxin after simultaneous administration of digoxin and methimazole in 12 patients and 12 methimazole treated patients werere-assessed once they had become euthyroid. RESULTS: Hyperthyroid patients showed significantly lower serum digoxin concentrations, shorter T1/2 beta and a significantly smaller area under the concentration curve (AUC) that the control group. Administration of methimazole did not affect digoxin pharmacokinetics. CONCLUSIONS: In hyperthyroid patients: 1. the pharmacokinetics of a single oral dose of digoxin does differ from that observed in healthy subjects. 2.methimazole do not alter digoxin pharmacokinetics.

Melatonin and childhood refractory epilepsy--a pilot study.

BACKGROUND: The aim of the study was to assess diurnal melatonin secretion in children with refractory epilepsy (N=74) as compared to children without epileptic seizures (N=37) and to compare melatonin secretion in children with focal and generalized refractory epilepsy. MATERIAL/METHODS: In the study group 4 subgroups were defined: children with focal symptomatic epilepsy, focal cryptogenic epilepsy, generalized symptomatic epilepsy, and generalized cryptogenic epilepsy. Melatonin level was measured every 3 hours using the RIA method. RESULTS: Analysis of diurnal melatonin secretion indicated a lower level of the hormone in patients with refractory epilepsy. The daily rhythm of melatonin secretion in the study group was maintained, with a peak shift of melatonin secretion especially visible in the subgroup with generalized symptomatic refractory epilepsy in the age group between 6 months and 3 years of age. CONCLUSIONS: The hypothesis may be formed that a lowered level of melatonin in the study group in relation to the comparison group is the consequence of the natural course of epilepsy or is influenced by antiepileptic drugs.

Factors determining changes in concentrations of pro-inflammatory markers in blood serum in the initial period after kidney transplantation from dead donor.

BACKGROUND: The main aim of this paper is to determine scope of changes in concentration of selected pro-inflammatory factors in blood serum in the initial period after the kidney transplantation from the brain death donor and attempt of establishing which of them are connected with delayed function of the organ, initial condition of both the donor and the recipient. MATERIAL/METHODS: The prospective examination carried out in group of 20 patients that underwent kidney transplantation from 10 donors diagnosed brain death. Blood samples were drawn before the transplantation procedure, 4 hours after procedure and in 4(th) day after the procedure. The blood serum analysis included: interleukin-6 (IL-6), tumor necrosis factor-alpha, interleukin-1beta (IL-1b) and C-reactive protein (CRP). RESULTS: In perioperative period the dynamic changes of all observed markers were noticed, especially in 4 th hour after the transplantation procedure. Generally, apart from TNFalpha, their concentration in blood serum was raising (the most significantly for IL-6) and then in 4(th) day reached the level equal to or lower than before transplantation. CONCLUSIONS: The delayed graft function is accompanied by high CRP level in donors before grafting and sustaining rise of IL-1b content in blood serum in 4(th) day after the transplantation procedure. The IL-6 content in this period revealed similar tendency in recipients' pairs that have been given the kidney from one donor, reflecting the condition of an organ that has been transplanted.

[The desmopressin test in the diagnosis of Cushing's disease]. / Test z desmopresyna w rozpoznawaniu ACTH-zaleznego zespolu Cushinga pochodzenia przysadkowego.

INTRODUCTION: Early and precise diagnosis is necessary in successful treatment of the patients with Cushing's disease. Transsphenoidal surgery is the first line treatment option in Cushing's disease. In patients in whom magnetic resonance imaging does not visualise pituitary adenoma patient selection for surgical treatment should be based on convincing results of functional tests. OBJECTIVES: The diagnostic accuracy of the desmopressin test was compared with that of the CRH test and the overnight high-dose dexamethasone suppression test in the diagnosis of Cushing's disease. DESIGN AND METHOD: We studied 15 patients with pituitary-dependent Cushing's disease (10 with detected microadenoma and 5 with undetected microadenoma using magnetic resonance imaging). The diagnosis was confirmed during pituitary surgery. The control group included 15 subjects without Cushing's syndrome. Patients underwent tests with desmopressin, CRH and 8 mg overnight dexamethasone. RESULTS: A false negative response to CRH was present in 1 of 15 patients, a false negative response t dexamethasone was present in 1 of 15 patients and a false negative response to desmopressin in 2 of 15 patients. In other patients positive responses to CRH, desmopressin and dexamethasone were found. A positive response to desmopressin was present in 4 of 5 patients with undetected pituitary adenoma. In the control group a positive response to CRH and dexamethazone and a negative response to desmopressin was found in all patients. CONCLUSIONS: 1. The highest diagnostic accuracy in the diagnosis of some patients with Cushing's disease is achieved by using a desmopressin test with high-dose dexamethasone test and CRH-test. 2. The desmopressin test can be used to precisely identify healthy individuals.

[Difficulties in the diagnosis of Cushing's disease--usefulness of desmopressin test]. / Trudnosci w rozpoznaniu ACTH-zaleznego zespolu cushinga pochodzenia przysadkowego -- rola testu z desmopresyna.

A 39-year-old man with occult eutopic corticotropin microadenoma leading to Cushing's syndrome was presented. Magnetic resonance imaging was unable to identify the pituitary microadenoma. In another department bilateral adrenalectomy was justified. In our department to identify or exclude a pituitary source of autonomous corticotropin secretion desmopressin test was performed. Intravenous desmopressin administration enhanced both circulating concentrations ofACTH and cortisol by 217.36% (peak vs. baseline) and 67% respectively. The patient underwent a transsphenoidal adenomectomy. Immunostaining demonstrated ACTH in adenoma cells. After surgery cortisol levels returned to the normal range, moreover no ACTH and cortisol response was elicited by desmopressin administration. This clinical case represents the demonstration of the possibility to unmask an occult eutopic Cushing's syndrome with the desmopressin test.

[Leptin concentration in umbilical cord blood and maternal blood]. / Stezenie leptyny w surowicy krwi pepowinowej noworodków i w surowicy krwi ich matek.

We investigated leptin concentration in umbilical cord blood of 51 newborns (mean 5.71 +/- 3.28 ng/ml) and in maternal blood (mean 22.11 +/- 10.95 ng/ml). Leptin concentration in 20 preterm infants (mean 4.73 +/- 2.15 ng/ml) was significantly lower (p < 0.05) than in full-term newborns (mean 6.34 +/- 2.08 ng/ml) and tended to increase according to gestational age and birth weight. We suggested leptin concentration had a role in intrauterine development.

[Endothelin ET-1 in patients with non-toxic nodular goiter]. / Endotelina ET-1 u chorych z wolem guzkowym obojetnym.

Endothelin ET-1 plays an important, however not entirely identified role in physiology and pathology of thyroid gland. The aim of the study was to determine if in patients with non-toxic nodular goiter there is relationship between size of goiter and ET-1 concentration in plasma of peripheral venous blood and plasma of venous blood taken from thyroid vein in patients undergoing strumectomy. The study included 30 patients with non-toxic nodular goiter (29 women and 1 man, mean age 48 year) and 15 healthy persons of control group. In all ET-1 concentration in plasma of venous peripheral blood and T3, T4, TSH serum concentration were estimated using radioimmunologic methods, as well as size of thyroid gland were evaluated in ultrasonography. Patients with nodular goiter underwent strumectomy. During the operation, before strumectomy, blood from thyroid vein was sampled to estimate plasma ET-1 concentration. Patients were divided into two groups: with adenomatous goiter (14 patients) and colloid goiter (16 patients). The goiter size was similar in each group. In all of the groups there was no relationship between goiter size and ET-1 concentration in plasma of peripheral and thyroid vein. Lack of correlation between ET-1 concentration in plasma and goiter size does not exclude possible ET-1 role in goitrogenesis, it suggests that ET-1 may play a role in control of thyroid gland trophic regulation and vascularity as paracrine or autocrine factor. Significantly higher concentration of ET-1 in plasma of thyroid vein in comparison to plasma of peripheral venous blood and positive correlation between ET-1 concentration in thyroid and peripheral plasma were found in both studied groups of patients with goiter and this may speak for increased ET-1 production within the goiter.

Melatonin secretion profile after experimental pineal gland compression in rats.

OBJECTIVES: Pineal gland hormone, melatonin, is a current issue of interest for accumulating data concerning its diverse physiological functions. The disturbances in melatonin secretion are observed in different pathological conditions involving pineal regions, but it is not ascertained if those disturbances present any clinical implications. The aim of this work was to examine whether pineal gland compression changes melatonin secretion. SETTING AND DESIGN: The experiment was carried out on adult rats, divided into four equal groups: (i) control (no surgery was performed), (ii) sham-operated, (iii) with sham pineal gland compression and (iv) with pineal gland compression performed by cotton piece application. METHODS: The profile of melatonin secretion was assessed in blood samples collected five times daily, every second day, starting from 8 to 14 day following surgery. RESULTS: We found that surgery itself significantly increased night melatonin secretion in comparison to controls. By contrast, in pineal-gland compressed rats, melatonin secretion was lower than in control group, suggesting that the influence of pineal compression overcame that induced by operation stress. CONCLUSIONS: In conclusion, we presume that pineal gland compression (like in case of some tumors) results in decrease of the concentration of blood melatonin, that may possibly result in decreased protective action of the indoleamine.

Melatonin secretion in patients with pineal region tumors-preliminary report.

Tumors of the pineal region, though not very common, are recently more often diagnosed due to the introduction of computer tomography and magnetic resonance examinations into neurosurgical practice. However many controversies about the treatment of them still exist. Some of them need aggressive treatment. The others are benign and asymptomatic. Thus it seems to be important to improve our diagnosis of mass lesion of the pineal region, especially before taking a decision for surgery. The purpose of this study was to find any significant changes in the circadian pattern of melatonin secretion in patients with pineal region tumors. Blood samples were collected preoperatively from 21 patients with diagnosed pineal region tumors. In 13 patients sampling was performed at 08:00, 14:00, 20:00 and 02:00 h during a 24-hour period but in 8 former ones only at 02:00 h at night. The samples were immediately centrifuged and the serum stored at -20 degrees C until analysis. The patients stayed in the darkened room from 23:00 to 05:00 h. Plasma melatonin was measured by direct and specific radioimmunoassay. The following three groups of results were found: (1) eight patients showed normal melatonin secretion profiles, (2) six cases with lack of the night maximum plasma value, and (3) seven cases with nocturnal melatonin concentration higher than in the healthy population (>100pg/ml). We observed no correlation between melatonin secretion and histological type of tumor. In conclusion, we suggest that changes of melatonin secretion could indicate the pineal region pathology. However further studies with a larger group of patients, especially with tumors originating from the pineal gland (pinealocytoma, pinealoblastoma), are necessary.