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Biomedical subjects

B Marek

Publications and source records attributed to B Marek.

At least 19 recordsLinked to original sources
PubMed2002

Dynamic pattern of IGF-I and chosen biochemical markers of bone metabolism in a rat model of postmenopausal osteoporosis.

OBJECTIVE: To assess the relationship between the dynamic pattern of IGF-I levels and chosen biochemical markers of bone metabolism in ovariectomized rats - a model of postmenopausal osteoporosis. METHODS: Six-month-old rats were randomized to sham operation (control group) or ovariectomy. Serum levels of insulin-like growth factor (IGF-I) and chosen biochemical markers of bone metabolism (alkaline phosphatase - ALP, carboxyterminal propeptide of type I procollagen - PICP, cross-linked carboxyterminal telopeptide of type I collagen - ICTP in serum as well as urinary excretion of hydroxyproline - HYP and total calcium - Ca) were measured before (group 0) and 1, 2, 3, 4, 6, 8, 12, 16, 20, 24 and 28 weeks after the operation. RESULTS: In a model of experimental osteoporosis induced by ovariectomy in female rats a distinct tendency to decrease the IGF-I concentrations was shown. Differences were significant in relation to the control group in a period from 2 to 28 weeks after operation. Ovariectomy stimulated the values of studied markers of bone metabolism; it was more intensified in regard to resorption markers. Significant ICTP and HYP concentrations' changes, in relation to the control group, were shown in the some period and total calcium - from 2 to 16 weeks after ovariectomy. However, the values of studied markers of bone formation were generally changing to a slight degree. Significant differences of ALP activity, in relation to the control group, were observed only at 8 and 20 weeks, while those of PICP concentrations were found at in 4, 8 and 12 weeks after the operation. The alterations in the levels of IGF-I correlated significantly and negatively with the changes in ALP activity as well as in PICP, ICTP, HYP and Ca concentrations both in ovariectomized and control rats. This relation was more expressed in the ovariectomized group. CONCLUSIONS: Our findings suggest that secondary changes in IGF-I concentration, due to the deficiency of sex hormones, results in altered bone metabolism in ovariectomized rats.

Alkaline Phosphatase↗
PubMed2001

Influence of adjuvant chemotherapy with cyclophosphamide, methotrexate and 5-fluorouracil on plasma melatonin and chosen hormones in breast cancer premenopausal patients.

OBJECTIVE: To investigate the effect of chemotherapy on levels of melatonin in patients with breast cancer. BACKGROUND: In light of reports on the possible oncostatic role of melatonin in breast cancer patients, it is essential to know the influence of adjuvant chemotherapy with cyclophosphamide, methotrexate and 5-fluorouracil (CMF) on plasma melatonin concentration as well as on its contributing factors, e.g. current hormonal state of the organism. The combination therapy is one of the oldest, safest and most commonly prescribed adjuvant treatments. METHOD: Twenty-four breast cancer patients on CMF chemotherapy were studied along with a control group of 16 healthy pre-menopausal women. RESULTS: Plasma melatonin concentration (determined by RIA method) in breast cancer patients prior to treatment did not differ significantly from that of healthy women, but it was significantly increased after the initial cycle of CMF, and significantly increased as compared to a group of healthy women. We did not notice any significant interactions between plasma melatonin and growth hormone, prolactin, estradiol, progesterone, cortisol and met-enkephalin concentrations in all studied groups. CONCLUSION: The possible oncostatic action of melatonin warrants further investigation to elucidate whether the induced increase of blood melatonin concentration is essential to successful CMF chemotherapy.

Adult↗
PubMed2001

Assessment of the relationship between circadian variations of salivary melatonin levels and type I collagen metabolism in postmenopausal obese women.

BACKGROUND: Few experimental and clinical studies show that melatonin (MEL) can play a significant part to modulate circadian bone metabolism. On this basis it was suggested that MEL secretion which altered during 24-h in obese women could be of importance to regulate bony mass defect after menopause. OBJECTIVE: The aim of the study was to prove if there were any connection between changes in 24-h profile of serum MEL levels and circadian metabolism of type I collagen in postmenopausal women with visceral obesity. METHODS: The relationship of 24-h profile of salivary MEL and circadian metabolism of type I collagen (as assessed by measuring saliva concentrations of carboxyterminal propeptide of type I procollagen--PICP and cross-linked carboxyterminal telopeptide of type I collagen--ICTP) was investigated in 26 women with visceral obesity (33.5 < BMI < 42.1 kg/m(2)) and 18 healthy volunteers with correct body mass (21 < BMI < 24.5 kg/m(2); 0.73 < WHR < 0.76). The specimens were collected at subjects' home at 3 h intervals during a 24 h span. The age range of all subjects was 52-60 years. RESULTS: In all the obese women studied a tendency to suppress circadian levels of tested biochemical markers of bone metabolism was observed (especially regarding ICTP); those alterations were accompanied by substantial increment in MEL concentrations during the day. Significant and negative correlation was found between values of acrophase MEL and PICP rhythms and both amplitude and acrophase of MEL and ICTP rhythms. CONCLUSION: Our results confirm hypothesis that alterations in MEL concentrations might have a protective effect against postmenopausal loss of bone mass.

Body Constitution↗
PubMed2001

Assessment of the relationship between dynamic pattern of nighttime levels of melatonin and chosen biochemical markers of bone metabolism in a rat model of postmenopausal osteoporosis.

BACKGROUND: Lately, there have been suggestions that bone mass changes occurring in postmenopausal women may remain related to melatonin. OBJECTIVE: To assess the relationship between the dynamic pattern of nighttime levels of melatonin and chosen biochemical markers of bone metabolism in ovariectomized rats--a model of postmenopausal osteoporosis. METHODS: Mature Wistar female rats were either ovariectomozed or underwent a sham operation. Following this they were killed at 02:00AM at weekly intervals for 8 weeks after surgery. Serum levels of MEL at death related to the chosen biochemical markers of bone formation (alkaline phosphatase--ALP; carboxyterminal propeptide of type I procollagen--PICP, both in serum) and resorption (cross-linked carboxyterminal telopeptide of type I collagen--ICTP in serum; hydroxyproline--HYP and total calcium--Ca, both excreted in urine). RESULTS: In all ovariectomized rats changes of examined indices of bone tissue metabolism were found to be dynamic and statistically significant relative to the control group; however the changes were more pronounced regarding resorption markers. Following ovariectomy, the increase in ALP and PICP values was found to begin at the 4th and the 1st week, while that in ICTP, HYP and Ca at the 2nd, the 1st and the 1st week, respectively. The ALP and PICP values remained at a similar level until the end of observation, whereas ICTP, HYP and Ca gradually decreased. MEL levels were decreased during the 2nd week following surgery and slightly increased 2 weeks later. The serum MEL levels in the ovariectomized group were significantly and negatively correlated with serum ICTP and both urinary HYP and Ca levels. CONCLUSION: Our findings in rats seem to corroborate the concept of secondary changes in MEL levels co-participating in the development of bone mass changes characteristic for postmenopausal osteoporosis.

Alkaline Phosphatase↗
PubMed2001

[Function of the growth hormone axis--insulin-like growth factors--insulin-like growth factor binding proteins in patients with chronic liver diseases].

Up to date have demonstrated that more and more young people are affected by chronic liver diseased. There is a close relationship between the liver and endocrine system as far as hormone inactivation, synthesis of growth factors, proteins binding hormones and proteins binding growth factors in the liver are related. Impairment of the hepatocyte function may lead to disturbed homeostasis of the endocrine system. Current opinions on growth hormone (GH)--insulin-like growth factors (IGFs)--insulin-like growth factors binding proteins (IGFBPs) axis activity in men with chronic liver diseases are presented.

Chronic Disease↗
PubMed2001

Influence of pinealectomy and long-term melatonin administration on GH-IGF-I axis function in male rats.

BACKGROUND: A relationship between circadian GH-IGF-I axis activity and pineal gland function in rats is not sufficiently elucidated, particularly in the aspect of melatonin (MEL) participation with relation to a possible mechanism of these dependencies. OBJECTIVE: Influence of pinealectomy and long-term MEL administration on circadian GH-IGF-I axis function in male rats was evaluated. An attempt was also made to determine whether the effect of exogenous MEL is dependent on the pineal gland presence. METHODS: Studies were performed in 192 sexually mature male Wistar rats, which were subjected to pinealectomy or sham operation. In half of the animals from each group MEL (Sigma, USA) in dose of 50 microg/ 100g b.m. was administrated intraperitoneally (daily between 5 and 6 pm during a 4-week period). Blood for RIA assays of MEL, GH and IGF-I concentrations was collected every 3 hours during a day-beginning at 8 am (rats killed by decapitation). RESULTS: Significant influence of pinealectomy and exogenous MEL on a daily profile of endogenous MEL in rats was confirmed. Distinct, dependent on the time of the day anomalies in circadian oscillations of GH and IGF-I showing positive correlation with changes in endogenous MEL concentrations were also shown. GH rhythm was suppressed in a group of rats with removed pineal gland; after pinealectomy distinct decrease and after MEL use - distinct increase of GH and IGF-I concentrations during the day were observed. It had influenced mean daily concentrations and values of amplitude of circadian GH and IGF-I oscillations in all studied groups of animals. In rats with preserved pineal gland the effect of exogenous MEL action was more intensified. CONCLUSIONS: Pineal gland can influence circadian function of GH-IGF-I axis, and in mechanism of this dependence, changes in endogenous MEL concentrations seem to play an important role. Administration of MEL in rats after pinealectomy only partly prevents changes of GH-IGF-I axis function caused by gland removal, which can indicate participation of other pineal gland substances in generating disturbances. Influence of exogenous MEL on GH-IGF-I axis function during the day is dependent on the presence of pineal gland, which can be connected with indirect and/or direct influence of administrated hormone on this gland.

Animals↗
PubMed2001

Effects of hormone replacement therapy on endocrine and spirometric parameters in asthmatic postmenopausal women.

The aim of the study was to see if there are any correlations between changes in the endocrine system and clinical condition of asthmatic patients, in particular their lung function, caused by hormone replacement therapy (HRT). Fifty-five asthmatic and 20 healthy postmenopausal women (aged 48-60) were studied before HRT and after 6 months of cyclical transdermal 17 beta-estradiol and medroxyprogesterone acetate treatment. Serum estradiol, cortisol and dehydroepiandrosterone sulfate (DHEAS) concentrations were assessed with the use of RIA, and spirometry parameters were measured. Statistically significant diminution of asthma exacerbations, reduced consumption of inhaled glucocorticosteroids and improvement in all investigated spirometry parameters was shown in patients treated with glucocorticosteroids during HRT. A reduction in mean 24-hour serum estradiol levels in asthmatic women was noted, whereas cortisol and DHEAS serum concentrations were decreased in asthmatic patients treated with glucocorticosteroids compared with the control group, before HRT. HRT produced increases in the concentrations of estradiol, cortisol and DHEAS in serum. Significant positive correlations were noted between estradiol concentrations and small and medium bronchi tests. In conclusion, HRT in postmenopausal asthmatic women has a favorable influence on the course of asthma, reduces daily use of glucocorticosteroids and frequency of asthma exacerbations and normalizes serum concentrations of estradiol, cortisol and DHEAS, which were decreased before HRT.

Administration, Cutaneous↗
PubMed2001

Circadian serum levels of dehydroepiandrosterone sulphate in postmenopausal asthmatic women before and after long-term hormone replacement.

OBJECTIVE: To assess mean 24-h serum concentrations of dehydroepianrosterone (DHEAS) in postmenopausal women with asthma before and after hormone replacement therapy (HRT). METHODS: Studies were performed in 55 asthmatic and 20 healthy postmenopausal women aged 48-60 before HRT and after 6 months of transdermal 17b-estradiol (E2) and medroxyprogesterone acetate treatment (cyclical method). Serum DHEAS concentrations were assessed with the use of RIA method. RESULTS: In the group of postmenopausal asthmatic women treated with glucocorticoids the mean 24 h DHEAS serum levels were lower than in a similar group not treated with glucocorticoids and a control group of healthy postmenopausal women. However, in both groups of asthmatic women (e.g. glucocorticoid treated and untreated) a significant increase of mean daily DHEAS levels after 6 months of HRT was observed. The hormone concentrations did not change in control group. CONCLUSIONS: Postmenopausal asthmatic women show diminished circadian dehydroepiandrosterone sulphate serum concentrations irrespective whether they were treated with glucocorticoids or not. However, after 6 months of hormonal replacement therapy in these groups increased levels of DHEA were found.

Administration, Cutaneous↗
PubMed2000

Is positive correlation between cortisol and met-enkephalin concentration in blood of women with breast cancer a reaction to stress before chemotherapy administration?

The role of stress in the course of neoplastic diseases has been emphasised over the past few years. Organism defence in form of increased release of hormones, corticosteroids and endogenous opioids should be assessed as a particular form of adaptation. Interactions between stress hormones and others which may influence the growth of breast cancer cells are possible. In this study, the concentration of cortisol and met-enkephalin vis-à-vis growth hormone, insulin-like growth factor-I, prolactin, estradiol, progesterone and melatonin in blood of women with breast cancer before the first cycle of supplementary chemotherapy was compared to that of healthy women. In a group of patients with breast cancer, before the first cycle of chemotherapy, high hypercortisolemia and positive correlation between cortisol and met-enkephalin was observed which may be a result of stress at the beginning of such treatment. A negative correlation between prolactin and met-enkephalin in this group can indirectly testify to essential participation of endogenous opioids in hormonal regulation and can be a response to stress caused by beginning chemotherapy.

Journal Article↗
PubMed2000

Influence of adjuvant chemotherapy with cyclophosphamide, methotrexate and 5-fluorouracil on plasma insulin-like growth factor-I and chosen hormones in breast cancer pre-menopausal patients.

OBJECTIVE: : To investigate the effect of chemotherapy on levels of IGF-I in patients with breast cancer. BACKGROUND: The latest reports on the role of the insulin-like growth factor (IGF)-I in breast cancer pathogenesis emphasize the importance of the effect of therapy on plasma IGF-I concentration and more generally on the hormonal state of the patient. METHOD: Twenty-four breast cancer patients on adjuvant chemotherapy with cyclophosphamide, methotrexate and 5-fluorouracil (CMF) were studied along with 16 healthy pre-menopausal women. RESULTS: Plasma IGF-I concentration (determined by RIA method) in breast cancer patients prior to treatment did not differ significantly from that of healthy women, but it was significantly decreased after the first cycle of CMF, and significantly lowered as compared to a group of healthy women. CONCLUSION: Further research into the significance of these findings is necessary. No interaction was found between mean IGF-I and growth hormone, prolactin, estradiol, progesterone, cortisol, met-enkephalin or melatonin concentrations.

Adult↗
PubMed2000

Plasma transforming growth factor beta1 in breast cancer patients treated with CMF chemotherapy.

BACKGROUND: In early breast cancer patients the transformed epithelial cells are thought to be sensitive to transforming growth factor beta1 (TGFbeta1)-mediated growth arrest. TGFbeta1 may therefore act as an anti-tumour promoter. However, in advanced breast cancer resistance to such TGFbeta1 action develops. Neoplastic cells produce TGFbeta1, which may enhance tumour invasion and metastasis, mainly by intensifying angiogenesis, which is an immunosuppressive action. In the light of the potential role of TGFbeta1 in breast cancer pathogenesis, an understanding of the effect of applied therapeutic methods on plasma TGFbeta1 concentration is essential. OBJECTIVE: To investigate the effect of adjuvant chemotherapy on plasma transforming growth factor beta1 (TGFbeta1) concentration in breast cancer patients with metastases to axillary lymph nodes. METHOD: Fifteen stage II breast cancer patients on adjuvant chemotherapy with cyclophosphamide, methotrexate and 5-fluorouracil (CMF) were studied along with 15 healthy premenopausal women. RESULTS: Plasma TGFbeta1 concentration (determined by the ELISA method) in the breast cancer patients did not differ significantly from that of the healthy women. Adjuvant CMF chemotherapy significantly decreased plasma TGFbeta1 concentration in those pre-menopausal breast cancer women with metastases to axillary lymph nodes. CONCLUSION: The possible pathogenic action of this growth factor in stage II breast cancer disease warrants further investigation to elucidate whether the induced decrease of blood TGFbeta1 concentration is essential to successful chemotherapy.

Adult↗
PubMed2000

Hormone replacement therapy in postmenopausal asthmatic women.

OBJECTIVES: Assessment of mean 24 h oestradiol (E2) and oestrone (E1) concentration and basic FSH secretion in postmenopausal asthmatic women, before and after HRT use, and to identify any connections between changes in hormone concentrations and patients' clinical state. SUBJECTS: Postmenopausal women (55 asthmatic and 20 healthy, aged 48-60 years). METHOD: Serum hormone concentration was assessed by radioimmunoassay before HRT and after 6 months of transdermal 17beta-E2 and medroxyprogesterone acetate treatment (cyclical method). Intensification of menopausal symptoms was assessed by Kupperman's index. RESULTS: Secretion of oestrogens was lower in postmenopausal women asthmatic women than in postmenopausal healthy women. HRT caused an increase in oestrogen concentration. The 24-h fluctuations of E1 and E2 in all studied groups before and after HRT did not differ significantly. A statistically significant decrease in the number of menopausal symptoms was found during the course of HRT. During the period of HRT, there was a reduction in the number of patients in whom it was necessary to use oral glucocorticoid therapy during exacerbation of asthma. CONCLUSION: A greater reduction in oestrogen secretion was found in postmenopausal asthmatic women than in postmenopausal healthy women. HRT resulted in normalization of serum oestrogen concentration in asthmatic women and diminishing psychosomatic symptoms of the menopause and symptoms of asthma.

Aged↗
PubMed2000

[Growth hormone and its interactions with chosen parameters of hormonal state in pre-menopausal women after mastectomy for breast cancer on adjuvant chemotherapy].

It seems, that quantitative changes of growth hormone (GH) in blood and imbalance between GH and hormones can influence the breast cancer cells proliferation, and can be a favourable element in breast cancer progression. The procedure to normalize hormonal system can have a therapeutic action. The aim of the presented work is to asses the plasma GH levels in 24 pre-menopausal women after mastectomy for breast cancer on adjuvant chemotherapy with cyclophosphamide, methotrexate, 5-fluorouracil (CMF). In this study interactions between GH and insulin like growth factor-I, prolactin, estradiol, progesterone (P), melatonin, cortisol and met-enkephalin were assessed. The control group was consisted of 16 healthy women. Plasma GH concentration and interactions between GH and studied parameters in women with breast cancer did not differ from healthy women. Highly significant positive correlation between GH and P after administration CMF was shown. CMF did not influence the interactions between GH and other studied parameters.

Adult↗
PubMed1999

Effects of hydroxylapatite coating crystallinity on biosolubility, cell attachment efficiency and proliferation in vitro.

A hydroxylapatite (HA) coating with approximately 97% crystalline HA content (MP-1 treated HA coating, MP-HA) was tested in vitro for its biosolubility and cellular biocompatibility. The MP-HA coating was compared with a standard HA coating with approximately 63% crystallinity (SHA) and an amorphous HA coating with approximately 25% crystallinity (AHA), as well as a titanium (Ti) surface without HA coating as a control. The topographic study with scanning electron microscopy indicated that MP-HA appeared more coarse, with projected nodules which altered the shape of cells attached to the substrate. Biosolubility study indicated that MP-HA had the least effect on the culture medium pH, while AHA (P < 0.01) and SHA (P < 0.05) significantly raised the medium pH up to 8.2 and 7.75, respectively. X-ray diffraction (XRD) analysis showed essentially unchanged levels of the total soluble phases of all coatings after incubation with culture medium, except that the CaO phase was rapidly dissolved from AHA coatings and completely eliminated from SHA coatings. Cultures of human gingival fibroblasts on these HA coatings showed that MP-HA and SHA had about the same cell attachment efficiency which was relatively lower than that of AHA coatings. MP-HA generated significant higher cell proliferation rate relative to AHA (P < 0.01) and SHA (P < 0.05). This study indicated that surface chemistry and topography of lower crystallinity might be favorable to cell attachment, but that elevated medium pH might result in a cytotoxic effect that inhibits the proliferation of attached cells on coating surfaces.

Biocompatible Materials↗
PubMed1999

[Insulin-like growth factor-I: pathophysiologic and clinical aspects].

The paper reviews the factors which affect synthesis and metabolic activity of the insulin-like growth factor-I (IGF-I), its receptor and binding proteins as age, nutritional state, hormonal state and liver function. Attention is also focused on the role of IGF-I in pathogenesis of osteoporosis and neoplastic diseases.

Humans↗