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A García-Martínez, D A Cano, A Flores-Martínez, J Gil, M Puig-Domingo, S M Webb, A Soto-Moreno and A Picó

Objective

Silent corticotroph tumors are a pituitary neuroendocrine tumor subtype of corticotroph lineage that do not clinically express Cushing’s disease. The silencing of this type of tumor is not fully understood. The aim of the present study was to delve into the lack of secretory activity, studying the post-transcriptional and post-translational regulation of POMC/ACTH in a series of molecularly identified functioning and silent corticotroph tumors.

Design

We analyzed 24 silent corticotroph, 23 functioning corticotroph and 25 silent gonadotroph tumors.

Methods

We used Sanger sequencing, quantitative real-time PCR and Western blot to analyze genetic alterations in POMC, gene expression of TBX19, NEUROD1, POMC, PCSK1, PCSK2, CPE and PAM and protein expression of POMC, PC1/3, PC2, CPE and PAM.

Results

We found different polymorphisms in the POMC gene of corticotroph tumors, some of them related to deficiency of proopiomelanocortin. Silent corticotroph tumors showed lower PC1/3 gene and protein expression than functioning ones, especially compared to micro-functioning corticotroph tumors (all P < 0.05). Moreover, we found a positive correlation between PC2 and CPE gene and protein expression (rho ≥ 0.670, P < 0.009) in silent corticotroph tumors compared with functioning ones.

Conclusions

By studying the post-transcriptional and post-translational processing of POMC and ACTH, respectively, in a large series of silent and functioning corticotroph tumors, we found that the lack of secretory activity of these tumors is related to an impaired processing of POMC and a high degradation of ACTH, with the macro-functioning corticotroph tumor behaving as an intermediate state between micro-functioning and silent corticotroph tumors.

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Olaf M Dekkers

P values should not merely be used to categorize results into significant and non-significant. This practice disregards clinical relevance, confounds non-significance with no effect and underestimates the likelihood of false-positive results. Better than to use the P value as a dichotomizing instrument, the P values and the confidence intervals around effect estimates can be used to put research findings in a context, thereby taking clinical relevance but also uncertainty genuinely into account.

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Steven Wj Lamberts and Leo Hofland

Octreotide remains 40 years after its development a drug, which is commonly used in the treatment of acromegaly and GEP-NETs. Very little innovation that competes with this drug occurred over this period. This review discusses several aspects of 40 years of clinical use of octreotide, including the application of radiolabeled forms of the peptide.

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Ida Kim Wium-Andersen, Merete Osler, Martin Balslev Jørgensen, Jørgen Rungby and Marie Kim Kim Wium-Andersen

Objective: Diabetes is a risk factor for dementia, but whether antidiabetic medication decreases the risk is unclear. We examined the association between antidiabetic medication and dementia.

Design: We performed a nested case-control study within a cohort of all 176,250 patients registered with type 2 diabetes in the Danish National Diabetes Register between 1995-2012. This population was followed for dementia diagnosis or anti-dementia medication use until May 2018. Using risk-set sampling, each dementia case (n=11,619) was matched on followup time and calender year of dementia with four controls randomly selected among cohort members without dementia (n=46,476). Ever use and mean daily defined dose of antidiabetic medication was categorized in types (insulin, metformin, sulfonylurea and glinides combined, glitazone, dipeptidyl peptidase 4 (DPP4) inhibitors, glucagon-like peptide 1 (GLP1) analogs, sodium-glucose transport protein 2 (SGLT2) inhibitors and acarbose).

Methods: Conditional logistic regression models were fitted to calculate odds ratios (ORs) for dementia associated with antidiabetic medication use, adjusting for potential confounders.

Results: Use of metformin, DPP4 inhibitors, GLP1 analogs, and SGLT2 inhibitors were associated with lower odds of dementia after multible adjustments (ORs of 0.94 (95% confidence interval (CI) 0.89-0.99), 0.80 (95%CI 0.74-0.88), 0.58 (95%CI 0.50-0.67), and 0.58 (95%CI 0.42-0.81), respectively), with a gradual decrease in odds of dementia for each increase in daily defined dose. Analyses of the most frequent treatment regimes did not show any synergistic effects of combined treatment.

Conclusion: Use of metformin, DPP4 inhibitors, GLP1 analogs and SGLT2 inhibitors was associated with lower risk of dementia in patients with diabetes.

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Susan Kralisch, Annett Hoffmann, Nora Klöting, Armin Frille, Hartmut Kuhn, Marcin Nowicki, Sabine Paeschke, Anette Bachmann, Matthias Blüher, Ming-Zhi Zhang, Raymond C Harris, Michael Stumvoll, Mathias Fasshauer and Thomas Ebert

Objective

Neuregulin 4 (NRG4) has recently been introduced as a novel brown adipose tissue (BAT)-secreted adipokine with beneficial metabolic effects in mice. However, regulation of Nrg4 in end-stage kidney disease (ESKD) and type 2 diabetes mellitus (T2DM) has not been elucidated, so far.

Design/methods

Serum NRG4 levels were quantified by ELISA in 60 subjects with ESKD on chronic hemodialysis as compared to 60 subjects with an estimated glomerular filtration rate >50 mL/min/1.73 m2 in a cross-sectional cohort. Within both groups, about half of the patients had a T2DM. Furthermore, mRNA expression of Nrg4 was determined in two mouse models of diabetic kidney disease (DKD) as compared to two different groups of non-diabetic control mice. Moreover, mRNA expression of Nrg4 was investigated in cultured, differentiated mouse brown and white adipocytes, as well as hepatocytes, after treatment with the uremic toxin indoxyl sulfate.

Results

Median serum NRG4 was significantly lower in patients with ESKD compared to controls and the adipokine was independently associated with a beneficial renal, glucose and lipid profile. In mice with DKD, Nrg4 mRNA expression was decreased in all adipose tissue depots compared to control mice. The uremic toxin indoxyl sulfate did not significantly alter Nrg4 mRNA expression in adipocytes and hepatocytes, in vitro.

Conclusions

Circulating NRG4 is independently associated with a preserved renal function and mRNA expression of -Nrg4 is reduced in adipose tissue depots of mice with DKD. The BAT-secreted adipokine is further associated with a beneficial glucose and lipid profile supporting NRG4 as potential treatment target in metabolic and renal disease states.

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Julie Refardt, Clara Odilia Sailer, Irina Chifu, Bettina Winzeler, Ingeborg Schnyder, Martin Fassnacht, Wiebke Fenske, Mirjam Christ-Crain and the CODDI-Investigators

Background

Diagnosis and treatment of dysnatremia is challenging and further complicated by the pitfalls of different sodium measurement methods. Routinely used sodium measurements are the indirect (plasma/serum) and direct (whole blood) ion-selective electrode (ISE) method, showing discrepant results especially in the setting of acute illness. Few clinicians are aware of the differences between the methods in clinically stable patients or healthy volunteers.

Methods

Data of 140 patients and 91 healthy volunteers undergoing osmotic stimulation with hypertonic saline infusion were analyzed. Sodium levels were measured simultaneously by indirect and direct ISE method before and at different time points during osmotic stimulation up to a sodium threshold of ≥150 mmol/L. The primary outcome was the difference in sodium levels between the indirect and direct ISE method.

Results

878 sodium measurements were analyzed. Mean (s.d.) sodium levels ranged from 141 mmol/L (2.9) to 151 mmol/L (2.1) by the indirect ISE compared to 140 mmol/L (3) to 149 mmol/L (2.8) by the direct ISE method. The interclass correlation coefficient between the two methods was 0.844 (95% CI: 0.823–0.863). On average, measurements by the indirect ISE were 1.9 mmol/L (95% CI limits: −3.2 to 6.9) higher than those by the direct ISE method (P < 0.001). The tendency of the indirect ISE method resulting in higher levels increased with increasing sodium levels.

Conclusion

Intra-individual sodium levels differ significantly between the indirect and direct ISE method also in the absence of acute illness. It is therefore crucial to adhere to the same method in critical situations to avoid false decisions due to measurement differences.

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Iulia Potorac, Ashutosh Trehan, Kamila Szymańska, Julie Fudvoye, Albert Thiry, Ilpo Huhtaniemi, Adrian F Daly, Albert Beckers, Anne-Simone Parent and Adolfo Rivero-Müller

Testosterone production by the fetal testis depends on a functional relationship between hCG and the LH/chorionic gonadotropin receptor (LHCGR). Failure of the receptor to correctly respond to its ligand leads to impaired sexual differentiation in males. A phenotypically female patient with pubertal delay had a 46,XY karyotype and was diagnosed with 46,XY disorder of sex development (DSD). Novel compound heterozygous LHCGR mutations were found in the signal peptide: a duplication p.L10_Q17dup of maternal origin, and a deletion (p.K12_L15del) and a p.L16Q missense mutation of paternal origin. cAMP production was very low for both the deletion and duplication mutations and was halved for the missense mutant. The duplication and missense mutations were both expressed intracellularly, but at very low levels at the cell membrane; they were most likely retained in the endoplasmic reticulum. The deletion mutant had a very limited intracellular expression, indicating impaired biosynthesis. There was reduced expression of all three mutants, which was most marked for the deletion mutation. There was also decreased protein expression of all three mutant receptors. In the deletion mutation, the presence of a lower-molecular-weight band corresponding to LHCGR monomer, probably due to lack of glycosylation, and a lack of bands corresponding to dimers/oligomers suggests absent ER entry. This novel case of 46,XY DSD illustrates how different LHCGR signal peptide mutations led to complete receptor inactivation by separate mechanisms. The study underlines the importance of specific regions of signal peptides and expands the spectrum of LHCGR mutations.

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Gerald Raverot, Alexandre Vasiljevic, Emmanuel Jouanneau and Hélène Lasolle

Recent publications suggested that pasireotide could be a good therapeutic option in some dopamine-resistant or aggressive prolactinomas. We discussed the two published cases and describe another case of poorly differentiated plurihormonal PIT-1-positive adenoma with moderate SSTR2 expression and intense STTR5 expression successfully treated with PAS-LAR 40 mg/month.

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Didier Dewailly and Joop Laven

In women, the anti-Müllerian Hormone (AMH) is secreted by the granulosa cells of growing follicles. Its measurement is strongly correlated with antral follicle count and represents a reliable marker of ovarian reserve. It also has the advantage of being highly reproducible since it has little variation within and between cycles. However, although it seems to be a good quantitative reflection of the ovarian reserve, it does not assess oocyte or embryo quality. This drawback precludes any good prediction of female fertility in the general population as well as in specific subgroups of patients. However, the AMH assay can become an indirect marker of the remaining female fertile years in some cases such as those women that are at risk for premature ovarian failure or in those suffering from polycystic ovary syndrome. Its interest is no more to be proven in assisted reproductive technology where it is a valuable aid to the choice of the proposed techniques, ovarian stimulation protocols and gonadotropin dosage. AMH is finally very informative in monitoring cancer patients having received gonadotoxic drugs or having undergone mutilating ovarian surgeries. In conclusion, although it cannot be considered as itself as a reliable predictor of pregnancy in women, AMH is now a useful tool in the management and treatment of female infertility.

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Selvetta S van Santen, Daniel S Olsson, Casper Hammarstrand, Mark Wijnen, Marry M van den Heuvel-Eibrink, Aart J van der Lely, Gudmundur Johannsson, Joseph A M J L Janssen and Sebastian J C M M Neggers

Objective

Craniopharyngioma patients often have poor metabolic profiles due to hypothalamic–pituitary damage. Previously, using BMI as obesity marker, the occurrence of the metabolic syndrome in these patients was estimated at 46%. Our aim was to determine if dual X-ray absorptiometry (DXA) scan in evaluation of obesity and metabolic syndrome would be superior.

Design

Retrospective study of craniopharyngioma patients for whom DXA scan results were available.

Methods

BMI, fat percentage and fat mass index were used to evaluate obesity and as components for obesity in metabolic syndrome.

Results

Ninety-five craniopharyngioma patients were included (51% female, 49% childhood-onset disease). Metabolic syndrome occurred in 34–53 (45–51%) subjects (depending on the definition of obesity, although all definitions occurred in higher frequency than in the general population). Metabolic syndrome frequency was higher if obesity was defined by fat percentage (52 vs 42%) or fat mass index (51 vs 43%) compared to BMI. Misclassification appeared in 9% (fat percentage vs BMI) and 7% (fat mass index vs BMI) for metabolic syndrome and 29 and 13% for obesity itself, respectively. For metabolic syndrome, almost perfect agreement was found for BMI compared with fat percentage or fat mass index. For obesity, agreement was fair to moderate (BMI vs fat percentage).

Conclusion

Using BMI to evaluate obesity underestimates the true prevalence of metabolic syndrome in patients with craniopharyngioma. Furthermore, fat percentage contributes to a better evaluation of obesity than BMI. The contribution of DXA scan might be limited for identification of the metabolic syndrome.