Biomedical subjects

F Tanriverdi

Publications and source records attributed to F Tanriverdi.

12 recordsLinked to original sources

PubMed2005

Effects of 18-month of growth hormone (GH) replacement therapy in patients with Sheehan's syndrome.

OBJECTIVE: Growth hormone deficiency (GHD) in adults is associated with abnormal body composition, altered lipid profile, reduced quality of life and osteoporosis. Replacement with recombinant GH results in significant improvements in most of these altered parameters. The most common cause of adult GHD in previous studies was due to pituitary tumors or their treatment. Sheehan's syndrome classically refers to postpartum hypopituitarism due to pituitary necrosis occurring secondary to massive bleeding at or just after delivery. While severe GHD is a well-established feature of Sheehan's syndrome, the effects of Growth hormone replacement therapy (GHRT) in these patients has not been extensively investigated. The present study was therefore designed to investigate the effects of GHD and GHRT in patients with Sheehan's syndrome. DESIGN: The study comprised 14 severely GH-deficient patients with Sheehan's syndrome with a mean age of 49.4+/-7.9 yr. Treatment with GH was started at a dose of 0.15 mg per day in month 1, was increased to 0.30 mg per day in month 2, and was maintained at 0.66 mg per day until the end of month 18. With the similar maintenance dose adequate age adjusted IGF-I levels for each patient has been achieved. Blood pressure, lipid profile, biochemical parameters, anthropometric measurements including body mass index (BMI), waist and waist to hip ratio (W/H), and bone mineral density (BMD) were investigated before and at 3, 6, 12 and 18 months of the GHRT. RESULTS: The duration of GHD from the onset of the disease was 19.4+/-1.6 yr. The majority of the patients (78%) had panhypopituitarism. At baseline mean total cholesterol, LDL-cholesterol and triglyceride levels were higher than the normal reference ranges but HDL-cholesterol levels were within the lower normal range. During the treatment period total cholesterol and LDL-cholesterol levels decreased and HDL-cholesterol levels increased significantly (P < 0.05). Waist circumference and waist to hip ratio were decreased significantly during the GHRT when compared to basal measurements (P < 0.05). There was a significant positive correlation between the basal waist circumference and the duration of GHD (P < 0.05). CONCLUSIONS: This study clearly demonstrates that Sheehan's syndrome is characterized by severe and long-standing GHD. GHRT have beneficial effects in several parameters including lipid profile and waist circumference. But we could not observe any improvement in BMD after 18 months of GHRT. However interpretations of the present results need to be made with caution because of the uncontrolled design. Further placebo controlled studies with high number of patients with Sheehan's syndrome are warranted.

Adult↗

PubMed2005

GnRH-I and GnRH-II have differential modulatory effects on human peripheral blood mononuclear cell proliferation and interleukin-2 receptor gamma-chain mRNA expression in healthy males.

GnRH-I and its receptor (GnRHR-I) have previously been demonstrated and shown to be biologically active in the immune system, notably within peripheral lymphocytes. Recently however, a second form of GnRH (GnRH-II) has been described in the human. The functions of both these neuropeptides in PMBCs have not been understood yet. The present study was therefore designed to investigate the effects of GnRH-I and/or GnRH-II on human PMBC proliferation in males. Secondly, the effects of GnRH-I and GnRH-II on IL-2 dependent lymphocyte proliferation were examined. Finally, we analysed the role of GnRH-I and GnRH-II in IL-2R gamma-chain expression. Peripheral venous blood samples were obtained from six male healthy volunteers (Mean age 27.75 +/- 1.5). Non-radioactive cell proliferation assay was used for proliferation studies and we used quantitative real-time RT-PCR to examine the role of GnRH-I and GnRH-II on IL-2R gamma-chain expression in PMBCs. Treatment of PMBCs with GnRH-I (10(-9) M and 10(-5) M) and with interleukin-2 (IL-2) (50 U/ml) resulted in a significant increase in cell proliferation compared with the untreated control. PMBCs cotreated with IL-2 and GnRH-I demonstrated higher proliferative responses than IL-2 treatment alone, the enhancement of GnRH-I on IL-2 response being significant only at GnRH-I concentration of 10(-5) M. Co-incubation of IL-2+ GnRH 10(-5) M with a GnRH antagonist (Cetrorelix; 10(-6) M) significantly decreased the proliferation. GnRH-II did not affect the proliferation of PMBCs alone, and did not alter the proliferative response to IL-2. The proliferative responses to GnRH-I (alone and with IL-2) were significantly attenuated by GnRH-II coincubation (each in equal molar concentrations; 10(-9) M to 10(-5) M). It was found that GnRH-I increased the expression of IL-2Rgamma mRNA in a dose dependent manner, with a significant increase of percentage 162.3 +/- 14 of control at 10(-5) M. In contrast, IL-2Rgamma expression was significantly decreased in all concentrations of GnRH-II (10(-9) M to10(-5) M), and the maximum decrease was detected at 10(-5) M, with percentage 37.7 +/- 6.6 of control. All these findings strongly suggest that regulation of IL-2R expression may therefore be an important target for GnRH-I and GnRH-II in PMBCs in males. In summary, present study clearly demonstrates the differential effects of GnRH-I and GnRH-II on PMBC proliferation, IL-2 proliferative response, and IL-2Rgamma expression in PMBCs in males. To our knowledge, our observations provide the first evidence for the interactions of these local neuropeptides at lymphocyte level. Further experimental data in human are warranted to explore the clinical implications of these data.

Adult↗

PubMed2005

The effects of 12 months of growth hormone replacement therapy on cardiac autonomic tone in adults with growth hormone deficiency.

OBJECTIVES: Growth hormone deficiency (GHD) in adults is associated with a cluster of cardiovascular risk factors. Some abnormalities of cardiac structure and function have been reported in adult patients with GHD, but there are few data related to cardiac autonomic tone. Non-invasive assessment of cardiac autonomic status can be achieved by heart rate variability (HRV), which can be measured by using time-domain or frequency-domain variables. To our knowledge, short-term (6 months) effects of GH replacement therapy (GHRT) on HRV in a limited number of patients have been evaluated prospectively in only two previous studies. The present study was therefore designed to investigate the effects of GHD and 12 months of GHRT on cardiac autonomic tone in a larger number of adult patients with severe GHD. PATIENTS AND METHODS: HRV measurement, by using time-domain variables, was performed in 22 patients with GHD (eight men, 14 women; mean age 45.4 +/- 2.4 years) and 22 healthy controls (nine men, 13 women; mean age 40.8 +/- 1.8 years) at baseline. The time-domain variables (sympathetically influenced parameters SDNN and SDANN and parasympathetically influenced parameters RMSSD and PNN50) were derived from 24-h electrocardiogram (ECG) recordings. In the patient group, cardiac autonomic tone was re-evaluated after 6 and 12 months of GHRT. RESULTS: Mean baseline values of SDNN and SDANN were significantly higher (higher values mean lower sympathetic activity) in GHD patients than in healthy controls (P < 0.05), but mean baseline values of RMSSD and PNN50 did not differ significantly in healthy controls and patients. After 6 and 12 months of GHRT, mean SDNN and SDANN were decreased significantly when compared with the baseline values before GHRT (P < 0.05). However, mean RMSSD and PNN50 did not differ significantly from baseline. When SDNN and SDANN measurements were evaluated individually for each patient, after 12 months of GHRT both of the sympathetically influenced parameters decreased in 90% of the patients. CONCLUSIONS: These data indicate that sympathetic tone is decreased in adult patients with severe GHD. Additionally, an increment in sympathetic activity and normalization of sympathovagal balance have been demonstrated after 6 and 12 months of GHRT. This result suggests that, at least at the doses used in this study, GHRT improves sympathetic tone, without an obvious arrhythmogenic effect.

Adult↗

PubMed2004

Boxing as a sport activity associated with isolated GH deficiency.

Traumatic brain injury (TBI) has long been known as a cause of hypopituitarism, and it is characterized by a high prevalence of neuroendocrine abnormalities. Boxing, one of the most common combative sports, may also result in TBI. As far as we know, pituitary functions including GH status have not been investigated in boxers. Therefore, in this preliminary study, we have assessed the pituitary functions in boxers. Eleven actively competing or retired male boxers with a mean age of 38.0 +/- 3.6 yr and 7 age-, sex- and BMI-matched healthy non-boxing controls were included in the study. Biochemical and basal hormonal parameters including IGF-I levels were measured. To assess GH secretory status in boxers and healthy controls, GHRH (1 microg/kg)+GHRP-6 (1 microg/kg) test was performed. After GHRH+GHRP-6 test, mean peak GH level in boxers and in controls were 10.9 +/- 1.7 and 41.4 +/- 6.7 microg/l, respectively (p < 0.05). Peak GH levels in 5 (45%) boxers were found to be lower than 10 microg/l and considered as severe GH deficient. In the control group, mean IGF-1 levels (367 +/- 18.8 ng/ml) were significantly higher than that obtained in boxers (237 +/- 23.3 ng/dl) (p < 0.01). All the other pituitary hormones were normal including ADH as no signs and symptoms of diabetes insipidus. There was a significant negative correlation between peak GH levels and boxing duration, and between peak GH levels and number of bouts. In conclusion, we think that boxing is a cause of TBI, and GH deficiency is very common among boxers. Further studies including large number of boxers, both professional and amateur, are needed to clarify pituitary dysfunction in boxers.

Adult↗

PubMed2004

Expression of gonadotropin-releasing hormone type-I (GnRH-I) and type-II (GnRH-II) in human peripheral blood mononuclear cells (PMBCs) and regulation of B-lymphoblastoid cell proliferation by GnRH-I and GnRH-II.

GnRH-I and its receptor (GnRHR-I) have previously been demonstrated and shown to be biologically active in the immune system, notably within T cells. Recently however a second form of GnRH (GnRH-II) has been described in the human. The function of both these neuropeptides in B lymphocytes has not previously been explored. The present study investigates GnRH-I and GnRH-II expression in human peripheral mononuclear blood cells (PMBCs) and B lymphoblastoid cells (B-LCLs), as well as their action in regulating B-LCL proliferation in the presence and absence of interleukin-2 (IL-2), both in GnRHR-I mutated lymphocytes and in a normal control. RT-PCR and immunocytochemistry identified locally produced GnRH-I and GnRH-II in all cell groups. Treatment of normal B-LCLs with GnRH-I (10 (-9) M and 10 (-5) M) or with interleukin-2 (IL-2) (50 IU/ml) resulted in a significant increase in cell proliferation compared with the untreated control. IL-2 and GnRH-I (10 (-7) M, 10 (-6) M, 10 (-5) M) induced greater proliferation in normal B-LCLs than IL-2 treatment alone. No significant proliferation occurred in GnRHR-I defective B-LCLs, in response to either GnRH-I (10 (-9) and 10 (-5) M) or IL-2 treatment, nor to IL-2 and GnRH-I (10 (-10) to 10 (-5) M) co-treatment when compared to controls. Co-incubation of IL-2 and IL-2 + GnRH 10 (-5) M with a GnRH antagonist (Cetrorelix; 10 (-6) M) significantly attenuated the proliferation in normal B-LCLs. GnRH-II did not affect proliferation of normal B-LCLs alone, and did not alter the proliferative response to IL-2. Further investigation is required to clarify the physiological relevance of local GnRH-I/GnRH-II in immune system responsiveness.

Adult↗

PubMed2004

Utility of P300 auditory event related potential latency in detecting cognitive dysfunction in growth hormone (GH) deficient patients with Sheehan's syndrome and effects of GH replacement therapy.

OBJECTIVE: Impaired cognitive function has been demonstrated in adults with growth hormone (GH) deficiency (GHD) by using different neuropsychological tests. Despite several studies, present knowledge about the impact of GHD and GH replacement therapy (GHRT) on cognitive function is limited. P300 event-related potential (ERP) application is a well-established neurophysiological approach in the assessment of cognitive functions including the updating of working memory content and the speed of stimulus evaluation. GHD is a well-known feature of Sheehan's syndrome and cognitive changes due to GHD and the effects of GHRT remain to be clarified. The present study was designed to investigate the effects of GHD and 6 months of GHRT on cognitive function in patients with Sheehan's syndrome by using P300 latency. DESIGN AND METHODS: The study comprised 14 patients with Sheehan's syndrome (mean age, 49.5+/-7.8 years) and 10 age-, education- and sex-matched healthy controls. With hormone replacement therapy, basal hormone levels other than GH were stable before enrollment and throughout the GHRT. The diagnosis of GH deficiency was established by insulin-tolerance test (ITT), and mean peak level of GH in response to insulin hypoglycemia was 0.77+/-0.35 mIU/l. Treatment with GH was started at a dose of 0.45 IU (0.15 mg)/day in month 1, was increased to 0.9 IU (0.30 mg)/day in month 2 and was maintained at 2 IU (0.66 mg)/day. Initially baseline auditory ERPs in patients and controls were recorded at frontal (Fz), central (Cz), and parietal (P3 and P4) electrode sites. In the patient group, ERPs were re-evaluated after 6 months of GH replacement therapy. During each session P300 amplitude and latency were measured. RESULTS: Mean serum insulin-like growth factor-I (IGF-I) concentration in the patient group before GHRT was 23+/-13 ng/ml. After 6 months of GH therapy mean IGF-I significantly increased to an acceptable level, 234+/-71 ng/ml (P<0.05). The mean latencies (at all electrode sites) of the patients before GHRT were found to be significantly prolonged when compared with those of normal controls (P<0.05). After 6 months of GHRT mean P300 latencies (at all electrode sites) were decreased significantly when compared with latencies before treatment (P<0.05). CONCLUSIONS: The present study, using P300 ERP latencies, therefore suggests an impairment of cognitive abilities due to severe GHD in patients with Sheehan's syndrome and an improvement of cognitive function after 6 months of physiological GHRT. Moreover, this was a novel application of P300 ERP latencies in cognitive function detection in patients with GHD. Further studies with different patient groups need to be done to assess the clinical use of this electrophysiological method in the diagnosis of cognitive dysfunction due to GHD.

Acoustic Stimulation↗

PubMed2003

The hypothalamic-pituitary-gonadal axis: immune function and autoimmunity.

GnRH and sex steroids play an important role in immune system modulation and development. GnRH and the GnRH receptor are produced locally by immune cells, suggesting an autocrine role for GnRH. Experimental studies show a stimulatory action of exogenous GnRH on the immune response. The immune actions of GnRH in vivo are, however, less well established. Oestrogen and androgen receptors are expressed in primary lymphoid organs and peripheral immune cells. Experimental data have established that oestrogens enhance the humoral immune response and may have an activating role in autoimmune disorders. Testosterone enhances suppressor T cell activity. Although there are some clinical studies consistent with these findings, the impact of sex steroids in autoimmune disease pathogenesis and the risk or benefits of their usage in normal and autoimmune-disordered patients remain to be elucidated. There are neither experimental nor clinical data evaluating functional GnRH-sex steroid interactions within the human immune system, and there is a paucity of data relating to GnRH analogues, hormone replacement therapy and oral contraceptive and androgen action in autoimmune diseases. However, a growing body of experimental evidence suggests that an extra-pituitary GnRH immune mechanism plays a role in the programming of the immune system. The implications of these findings in understanding immune function are discussed.

Androgens↗

PubMed1997

An in vitro test model for investigation of disinfection of dentinal tubules infected with Enterococcus faecalis.

The aim of the present study was to develop an in vitro test model from human teeth to comparatively examine antibacterial effectiveness of calcium hydroxide, parachlorophenol (PCP) and camphorated parachlorophenol (CPCP) against Enterococcus faecalis in infected root canals. Cylindrical dentin specimens were prepared from freshly extracted human maxillary anterior teeth. The specimens were inoculated with E. faecalis and then medicated with either CPCP, PCP or Ca(OH)2. The disinfecting efficacy of these agents was tested by collecting dentin chips from the inner ("canal") walls of the specimens and counting viable E. faecalis. The dentin chips were diluted and a classical bacterial count technique was used for recovery of E. faecalis strains of 5% sheep blood agar. The effectiveness of CPCP and PCP at one day was superior to the effectiveness of Ca(OH)2. In the three-day group, CPCP was the most effective, followed by Ca(OH)2. The experimental model used in this study may be useful for investigation of the effect of intracanal medicaments on microorganisms lodged in the root dentinal tubules.

Calcium Hydroxide↗

PubMed1996

Early tensile bond strength between dentin and composite resin mediated by bonding agents.

The aim of this study was to evaluate, in vitro, the early tensile bond strength values of three dentin bonding agents (Scotchbond, Tenure and Gluma) to dentin. Fifteen non-carious, extracted, human third molars were used in this study. The bond strengths were calculated in an Instron test machine and expressed in MN/m2. The results were evaluated statistically using the Student-test. The in vitro tensile bond strengths of the three bonding agents to dentin showed higher values than the tensile bond strength of composite resin alone and differences among the bond strengths were significant (P < 0.05). Greater bond strength values were obtained with the Gluma bonding system than with Scotchbond or Tenure systems.

Bisphenol A-Glycidyl Methacrylate↗

PubMed1993

Pulp responses to three dentine bonding agents in dogs' teeth.

The purpose of this study was to evaluate pulp reactions to cavities treated with Scotchbond Dual Cure, Gluma and Tenure dentine bonding agents in four adult dogs, at intervals of 7, 30 and 90 days. The reactions were compared with the results from a control group in which the cavities were treated with zinc oxide/eugenol cement. The results indicated that Scotchbond Dual Cure dentine bonding agent caused less pulp reaction than Gluma and Tenure dentine bonding agents. However, long-term (90 days) specimens showed that none of these three bonding agents caused any severe reaction. The recovery of the pulp and a thick layer of reparative dentine formation were found quite significant.

Animals↗

PubMed1992

Streptococcus mutans in plaque from margins of conventional and high copper amalgam restorations.

Levels of Streptococcus mutans in plaque samples from margins of conventional and high copper amalgam restorations were compared in fourteen patients, each having one conventional amalgam filling in each quadrant and one high copper amalgam filling on the contra-lateral side were examined. The percentage of S. mutans of total CFU count in plaque was higher on conventional amalgam than on high copper amalgam. The difference was statistically significant (p < 0.01).

Adolescent↗

PubMedDate not supplied

Evaluation of the hypothalamic-pituitary-adrenal axis in untreated patients with polymyalgia rheumatica and healthy controls.

OBJECTIVE: To explore the hypothalamic-pituitary-adrenal (HPA) axis in polymyalgia rheumatica (PMR). SUBJECTS AND METHODS: This study was carried out on 13 female patients with PMR who were diagnosed according to the criteria of Chuang et al (Ann Intern Med 1982;97:672-80) and 10 healthy female subjects in the Department of Physical Medicine and Rehabilitation, Erciyes University Medical School. In the patient and control groups, basal cortisol, adrenocorticotrophic hormone (ACTH), 17alpha-hydroxyprogesterone (17-OHP), 11-deoxycortisol (11-S), dehydroepiandrosterone sulfate (DHEAS), androstenedione (A), prolactin (PRL), and thyroid stimulating hormone (TSH) levels were measured. Cortisol, 17-OHP, 11-S and A responses after the low-dose (1 microg) ACTH stimulation test and cortisol and DHEAS responses after the dexamethasone suppression test were detected. We also measured acute phase reactants including C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). RESULTS: Age and sex characteristics were similar in both patient and control groups. The levels of basal hormones including cortisol, ACTH, 17-OHP, 11-S, DHEAS, A, prolactin and TSH and cortisol and DHEAS levels after the low-dose dexamethasone suppression test were not significantly different between the patient and control groups. However, cortisol/CRP and ACTH/CRP ratios were significantly lower in the patient group. Cortisol and DHEAS responses after the low-dose dexamethasone suppression test were not significantly different between the patient and control groups. Cortisol response after the 1 microg ACTH stimulation test was significantly lower in the patients than in the control group, but there were no significant differences in 17-OHP, 11-S and A responses between the patients and controls. Correlation analysis showed that there was a negative correlation between peak cortisol levels after the ACTH stimulation test and disease duration, and also a positive correlation between cortisol levels after the low-dose dexamethasone suppression test and acute phase reactants including CRP and ESR. CONCLUSION: A significant low cortisol response to ACTH stimulation was detected in the patients with PMR. In addition, a negative correlation after the 1 microg ACTH stimulation test between peak cortisol levels and disease duration was detected. These findings may indicate hypoactivation in the HPA axis.

Adrenal Cortex Hormones↗