Search Results (28)

Pheochromocytoma, a rare catecholamine-secreting tumor, poses significant perioperative challenges due to its potential for severe hemodynamic instability. Careful management of patients with pheochromocytoma is critical for patient safety and favorable outcomes. The diagnostic workup focuses on biochemical analysis of plasma or urinary metanephrines, followed by imaging for tumor localization and genetic testing to identify hereditary syndromes. Preoperative management emphasizes adequate alpha-adrenergic blockade followed by beta-blockade to stabilize cardiovascular function. Anesthetic planning requires meticulous attention to volume status, cardiovascular optimization, and intraoperative monitoring to mitigate the risks of hypertensive crises and hypotension. Postoperative care must account for ongoing hemodynamic and metabolic fluctuations. A multidisciplinary, protocol-driven approach is essential to improve outcomes in patients undergoing pheochromocytoma resection. This paper provides a comprehensive overview of the genetic, biochemical, clinical, and anesthetic considerations involved in the diagnosis and perioperative management of pheochromocytoma. Full article

Goats raised on pastures are seldom handled except for purposes such as weighing and providing veterinary care. Regular positive interactions with human caretakers have been reported to attenuate fear and stress responses to routine human handling; however, this has not been adequately studied in meat goats. This experiment was conducted to determine the effects of habituation to handling on behavioral, physiological, and metabolomic responses in goats when subjected to routine handling. Seventy-two male (uncastrated) Spanish goats (6 mo; BW = 25.2 ± 0.37 kg) were randomly allocated to one of two treatment (Trt) groups: (i) regularly handled by stroking the back of each goat before feeding time for 90 days (handled: H) or (ii) not subjected to handling during the same period, but all other conditions were the same (non-handled: NH). After the 90-day habituation period, the goats were subjected to an arena test in the presence of an observer. Immediately after the test, the goats were subjected to routine veterinary exams that involved blood sampling (0 min) and measuring heart rate (HR), respiratory rate (RR), rectal temperature (RT), and body weight (BW). Blood samples were also collected after the veterinary exam (20 min) to determine physiological and metabolomic responses. Data from the arena test were analyzed using a Mann–Whitney U Test, and blood physiological responses were analyzed using MIXED procedures in SAS with sampling time (Time) as a repeated measure. Unpaired t-tests showed that the increase in BW was higher in the H goats (p < 0.01) compared to the NH goats over the 90 d habituation period. The approach distance from the observer (p < 0.05) and frequency of urination (p < 0.05) were greater in the NH goats during the arena test. HR (p < 0.01) and RR (p < 0.01) were higher in the NH group compared to the H group. Plasma cortisol concentrations were higher at 20 min than at 0 min (p < 0.05), while epinephrine (p < 0.05), metanephrine, normetanephrine, phenylethylamine, and 5-methoxytryptamine concentrations were higher (p < 0.05) in the NH goats than in the H goats. A targeted metabolomics analysis showed that six of the eight affected amino acids were lower (p < 0.05), and six of the seven affected phosphatidylcholines were higher (p < 0.05) in the NH goats compared to the H goats. The results show that habituation reduces fear and stress responses to routine handling, in addition to increasing BW, which can improve the welfare of meat goats. Full article

Background: Quantifying urinary catecholamines and metanephrines is essential for the clinical screening and diagnosis of neuroendocrine tumours. HPLC with electrochemical detection (HPLC-ECD) is commonly used for this type of analysis but requires extensive sample cleanup. Simple and rapid dilute-and-shoot LC–multiple-reaction monitoring (MRM)-MS assays have been developed for quantitating these analytes in urine but have not yet been validated according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. Methods: A simple dilute-and-shoot sample preparation without derivatization was used. C18 RP-UPLC-MRM-MS and positive-ion ESI were used, usually with two transitions per analyte being monitored. Certified deuterated internal standards were used for each analyte. Results: This assay was validated according to the CLSI C62-A guidelines, including accuracy/trueness, imprecision, sensitivity, specificity, carryover, stability, and linearity. The final MRM-MS method was compared to the established HPLC-ECD clinical chemistry reference method. The run time was reduced from 25 min to 5 min. Conclusions: A simple, robust, rapid, and cost-effective LC-MRM-MS assay for measuring urinary catecholamines and metanephrines was developed and validated according to the CLSI guidelines. This validated method requires minimal sample manipulation before analysis and provides sensitivity, specificity, and improved precision. The implementation of this assay in clinical laboratories will facilitate early and accurate diagnosis. Full article

Phaeochromocytomas (PC) and sympathetic paragangliomas (PGL) are potentially malignant tumours arising from the adrenal medulla (PC) or elsewhere in the sympathetic nervous system (PGL). These tumours usually secrete catecholamines and are associated with significant morbidity and mortality, so accurate and timely diagnosis is essential. The initial diagnosis of phaeochromocytoma/paraganglioma (PPGL) is often dependent on biochemical testing. There is a range of pre-analytical, analytical and post-analytical factors influencing the analytical and diagnostic performance of biochemical tests for PPGL. Pre-analytical factors include patient preparation, sample handling and choice of test. Analytical factors include choice of methodology and the potential for analytical interference from medications and other compounds. Important factors in the post-analytical phase include provision of appropriate reference ranges, an understanding of the potential effects of various medications on metanephrine concentrations in urine and plasma and a consideration of PPGL prevalence in the patient population being tested. This article reviews these pre-analytical, analytical and post-analytical factors that must be understood in order to provide effective laboratory services for biochemical testing in the diagnosis of PPGL. Full article

Purpose: Residual adrenocortical function, RAF, has recently been demonstrated in one-third of patients with autoimmune Addison’s disease (AAD). Here, we set out to explore any influence of RAF on the levels of plasma metanephrines and any changes following stimulation with cosyntropin. Methods: We included 50 patients with verified RAF and 20 patients without RAF who served as controls upon cosyntropin stimulation testing. The patients had abstained from glucocorticoid and fludrocortisone replacement > 18 and 24 h, respectively, prior to morning blood sampling. The samples were obtained before and 30 and 60 min after cosyntropin stimulation and analyzed for serum cortisol, plasma metanephrine (MN), and normetanephrine (NMN) by liquid-chromatography tandem-mass pectrometry (LC-MS/MS). Results: Among the 70 patients with AAD, MN was detectable in 33%, 25%, and 26% at baseline, 30 min, and 60 min after cosyntropin stimulation, respectively. Patients with RAF were more likely to have detectable MN at baseline (p = 0.035) and at the time of 60 min (p = 0.048) compared to patients without RAF. There was a positive correlation between detectable MN and the level of cortisol at all time points (p = 0.02, p = 0.04, p < 0.001). No difference was noted for NMN levels, which remained within the normal reference ranges. Conclusion: Even very small amounts of endogenous cortisol production affect MN levels in patients with AAD. Full article

This experiment was conducted to determine the effects of habituation to livestock trailers on stress responses in goats transported for long periods. Intact male Spanish goats (12-month old; BW = 31.6 ± 0.34 kg; N = 168) were separated into two treatment (TRT) groups and maintained on two different paddocks. Concentrate supplement was fed to one group inside two livestock trailers (5.0 × 2.3 m each; habituated group, H), while the other group received the concentrate supplement, but not inside the trailers (non-habituated, NH). After 4 weeks of habituation period, goats were subjected to a 10-h transportation stress in four replicates (n = 21 goats/replicate/TRT). Blood samples were collected by a trained individual by jugular venipuncture into vacutainer tubes before loading (Preload), 20 min after loading (0 h), and at 2-h intervals thereafter (Time) for analysis of stress responses. There was a tendency for a TRT effect (p < 0.1) on tyramine and metanephrine concentrations. Phenylethylamine and 5-methoxytryptamine concentrations were significantly greater (p < 0.05) in the H group compared to the NH group. Both dopamine and 5-methoxytryptamine concentrations decreased (p < 0.05) with transportation time; however, TRT × Time interaction effects were not significant. Habituation to trailers may be beneficial in mood and energy stabilization in goats during long-distance transportation. Full article

Glycemic alterations are frequent in patients with pheochromocytoma and paraganglioma (PPGL), but the real incidence of secondary diabetes mellitus (DM) is uncertain, because prospective multicenter studies on this topic are lacking in the literature. The main pathophysiological mechanisms of glucose homeostasis alterations in PPGL, related to catecholamine hypersecretion, are impaired insulin and glucagon-like peptide type 1 (GLP-1) secretion and increased insulin resistance. Moreover, it has been reported that different pathways leading to glucose intolerance may be related to the secretory phenotype of the chromaffin tumor. Predictive factors for the development of glucose intolerance in PPGL patients are a higher age at diagnosis, the need for a higher number of anti-hypertensive drugs, and the presence of secreting neoplasms. Tumor resection is strongly related to the resolution of DM in PPGL patients, with a significant improvement of glycemic control in most cases. We can hypothesize a different personalized therapeutic approach based on the secretory phenotype. The adrenergic phenotype is more closely related to reduced insulin secretion, so insulin therapy may be required. On the other hand, the noradrenergic phenotype mainly acts by increasing insulin resistance and, therefore, insulin-sensitizing antidiabetic agents can find a greater application. Regarding GLP-1 receptor agonists, the data suggest a possible promising therapeutic effect, based on the assumption that GLP-1 secretion is impaired in patients with PPGL. The principal predictors of remission of glycemic alterations after surgery for PPGL are a lower preoperative body mass index (BMI), a larger tumor, higher preoperative catecholamine levels, and a shorter duration of the disease (under three years). Otherwise, after resection of PPGL, hypoglycemia can occur as the result of an excessive rebound of preoperative hyperinsulinemia. It is a rare, but potentially severe complication reported in a lot of case reports and a few small retrospective studies. Higher 24-h urinary metanephrine levels, longer operative times and larger tumors are predictive factors for hypoglycemia in this setting. In conclusion, alterations of carbohydrate metabolism are clinically relevant manifestations of PPGL before and after surgery, but there is the need to conduct multicenter prospective studies to obtain an adequate sample size, and to allow the creation of shared strategies for the clinical management of these potentially severe manifestations of PPGL. Full article

Ionic liquids (ILs), such as imidazoles, can be used to prevent the sorption of analytes onto the walls of the capillary. Prior works have confirmed that coating the capillary wall with a cationic layer can increase its surface stability, thereby improving the repeatability of the separation process. In this study, micellar electrokinetic chromatography (MEKC) is employed to evaluate how two ILs with different anions—namely, 1-hexyl-3-methylimidazolium chloride [HMIM⁺Cl⁻] and 1-hexyl-3-methylimidazolium tetrafluoroborate [HMIM⁺BF₄⁻]—affect the separation efficiency for biogenic amines (BAs) such as metanephrine (M), normetanephrine (NM), vanilmandelic acid (VMA), and homovanillic acid (HVA) in urine samples. To this end, solid-phase extraction (SPE) is employed using different sample pH values, with the results demonstrating that HVA and VMA is easily extracted at a sample pH of 5.5, while a sample pH of 9.0 facilitated the extraction of M and NM. In the applied SPE protocol, selected analytes were isolated from urine samples using hydrophilic–lipophilic-balanced (HLB) columns and eluted with methanol (MeOH). The validation data confirmed the method’s linearity (R² > 0.996) for all analytes within the range of 0.25–10 µg/mL. The applicability of the optimized SPE-MEKC-UV method was confirmed by employing it to quantify clinically relevant BAs in real urine samples from pediatric neuroblastoma (NBL) patients. Full article

Catechol-O-methyltransferase (COMT) has been involved in a number of medical conditions including catechol-estrogen-induced cancers and a great range of cardiovascular and neurodegenerative diseases such as Parkinson’s disease. Currently, Parkinson’s disease treatment relies on a triple prophylaxis, involving dopamine replacement by levodopa, the use of aromatic L-amino acid decarboxylase inhibitors, and the use of COMT inhibitors. Typically, COMT is highly thermolabile, and its soluble isoform (SCOMT) loses biological activity within a short time span preventing further structural and functional trials. Herein, we characterized the thermal stability profile of lysate cells from Komagataella pastoris containing human recombinant SCOMT (hSCOMT) and enzyme-purified fractions (by Immobilized Metal Affinity Chromatography—IMAC) upon interaction with several buffers and additives by Thermal Shift Assay (TSA) and a biological activity assessment. Based on the obtained results, potential conditions able to increase the thermal stability of hSCOMT have been found through the analysis of melting temperature (T_m) variations. Moreover, the use of the ionic liquid 1-butyl-3-methylimidazolium chloride [C₄mim]Cl (along with cysteine, trehalose, and glycerol) ensures complete protein solubilization as well as an increment in the protein Tm of approximately 10 °C. Thus, the developed formulation enhances hSCOMT stability with an increment in the percentage of activity recovery of 200% and 70% when the protein was stored at 4 °C and −80 °C, respectively, for 12 h. The formation of metanephrine over time confirmed that the enzyme showed twice the productivity in the presence of the additive. These outstanding achievements might pave the way for the development of future hSCOMT structural and biophysical studies, which are fundamental for the design of novel therapeutic molecules. Full article

Increased dietary phosphate intake has been associated with severity of coronary artery disease, increased carotid intima–media thickness, left ventricular hypertrophy (LVH), and increased cardiovascular mortality and morbidity in individuals with normal renal function as well as in patients suffering from chronic kidney disease. However, the underlying mechanisms are still unclear. To further elucidate the cardiovascular sequelae of long-term elevated phosphate intake, we maintained male C57BL/6 mice on a calcium, phosphate, and lactose-enriched diet (CPD, 2% Ca, 1.25% P, 20% lactose) after weaning them for 14 months and compared them with age-matched male mice fed a normal mouse diet (ND, 1.0% Ca, 0.7% P). Notably, the CPD has a balanced calcium/phosphate ratio, allowing the effects of elevated dietary phosphate intake largely independent of changes in parathyroid hormone (PTH) to be investigated. In agreement with the rationale of this experiment, mice maintained on CPD for 14 months were characterized by unchanged serum PTH but showed elevated concentrations of circulating intact fibroblast growth factor-23 (FGF23) compared with mice on ND. Cardiovascular phenotyping did not provide evidence for LVH, as evidenced by unchanged LV chamber size, normal cardiomyocyte area, lack of fibrosis, and unchanged molecular markers of hypertrophy (Bnp) between the two groups. However, intra-arterial catheterization revealed increases in systolic pressure, mean arterial pressure, and pulse pressure in mice fed the CPD. Interestingly, chronically elevated dietary phosphate intake stimulated the renin–angiotensin–aldosterone system (RAAS) as evidenced by increased urinary aldosterone in animals fed the CPD, relative to the ND controls. Furthermore, the catecholamines epinephrine, norepinephrine, and dopamine as well as the catecholamine metabolites metanephrine. normetanephrine and methoxytyramine as measured by mass spectrometry were elevated in the urine of mice on CPD, relative to mice on the ND. These changes were partially reversed by switching 14-month-old mice on CPD back to ND for 2 weeks. In conclusion, our data suggest that excess dietary phosphate induces a rise in blood pressure independent of secondary hyperparathyroidism, and that this effect may be mediated through activation of the RAAS and stimulation of the sympathetic tone. Full article

The overproduction of catecholamines in pheochromocytoma/paraganglioma (PPGL) induces a hypermetabolic state. The aim of this study was to evaluate the incidence of a hypermetabolic state and differences in substrate metabolism in consecutive PPGL patients divided by catecholamine phenotype. Resting energy expenditure (REE) and respiratory quotient (RQ) were measured in 108 consecutive PPGL patients and 70 controls by indirect calorimetry. Hypermetabolic state was defined according to the Mifflin St. Jeor Equation as a ratio above 110%. Hypermetabolic state was confirmed in 70% of PPGL patients, regardless of phenotype. Older age, prevalence of diabetes mellitus and arterial hypertension were correlated with hypermetabolic PPGL as compared to normometabolic form. Analysis according to overproduced catecholamine showed differences in VCO₂ (p < 0.05) and RQ (p < 0.01) and thus different substate metabolism between phenotypes in hypermetabolic form of PPGL. Lipid utilization was higher in the adrenergic phenotype (p = 0.001) and positively associated with the percentage of REE ratio (R = 0.48, p < 0.001), whereas the noradrenergic phenotype preferentially oxidizes carbohydrates (P = 0.001) and is correlated with the percentage of REE ratio (R = 0.60, p < 0.001). Hypermetabolic state in PPGL is a common finding in both catecholamine phenotypes. Hypermetabolic PPGL patients are older and suffer more from diabetes mellitus and arterial hypertension. Under basal conditions, the noradrenergic type preferentially metabolizes carbohydrates, whereas the adrenergic phenotype preferentially metabolizes lipids. Full article

A novel dual-template magnetic molecularly imprinted polymer (MMIP) was synthesized to extract normetanephrine (NMN), metanephrine (MN) and 3-methoxytyramine (3-MT) from spot urine samples. As the adsorbent of dispersive solid-phase extraction (d-SPE), the MMIP was prepared using dopamine and MN as dual templates, methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the crosslinking reagent and magnetic nanoparticles as the magnetic core. NMN, MN, 3-MT and creatinine (Cr) in spot urine samples were selectively enriched by d-SPE and detected by HPLC-fluorescence detection/ultraviolet detection. The peak area (A) ratios of NMN, MN and 3-MT to Cr were used for the diagnosis of pheochromocytomas and paragangliomas (PPGLs). The results showed that the adsorption efficiencies of MMIP for target analytes were all higher than 89.0%, and the coefficient variation precisions of intra-assay and inter-assay for the analytes were within 4.9% and 6.3%, respectively. The recoveries of the analytes were from 93.2% to 112.8%. The MMIP was still functional within 14 days and could be reused at least seven times. The d-SPE and recommended solid-phase extraction (SPE) were both used to pretreat spot urine samples from 18 PPGLs patients and 22 healthy controls. The correlation coefficients of A_NMN/A_Cr and A_MN/A_Cr between d-SPE and SPE were both higher than 0.95. In addition, the areas under the receiver operator curves for spot urine A_NMN/A_Cr, A_MN/A_Cr and plasma free NMN and MN were 0.975, 0.773 and 0.990, 0.821, respectively, indicating the two methods had the similar performances. The d-SPE method took only 20 min, which was effective in clinical application. Full article

Recently, the genetic background of pheochromocytomas/paragangliomas (PPGLs) has been rapidly revealed. These tumors have been referred to as the “ten percent tumor”; however, the frequency of genetic variants of PPGLs has turned out to be more common than expected. PPGLs are potentially hereditary tumors and appear clinically sporadic. Here, we report a case of bilateral pheochromocytoma (PCC) with a variant in the MYC-associated factor X (MAX) gene (c.295 + 1G > A). A male patient was diagnosed with adrenal pheochromocytoma (PCC) and underwent a left adrenalectomy at the age of 40. A new tumor in the right adrenal gland was detected at the age of 43. Urinary metanephrine and normetanephrine concentrations gradually increased. The size of the right adrenal PCC continued to increase one year after detection. Genetic testing of the peripheral blood revealed the presence of a pathogenic variant in MAX. The natural history of adrenal PCCs with the MAX variant has not yet been clarified, because the number of reported cases is not sufficient. Thus, clinicians should consider a MAX variant when they find bilateral or multiple PCCs. Full article

Success of adrenal vein sampling (AVS) is verified by the selectivity index (SI), i.e., by a step-up of cortisol levels between the adrenal vein and the infrarenal inferior vena cava samples, beyond a given cut-off. We tested the hypothesis that androstenedione, metanephrine, and normetanephrine, which have higher gradients than cortisol, could increase the rate of AVS studies judged to be bilaterally successful and usable for the clinical decision making. We prospectively compared within-patient, head-to-head, the selectivity index of androstenedione (SI_A), metanephrine (SI_M), and normetanephrine (SI_NM), and cortisol (SI_C) in consecutive hypertensive patients with primary aldosteronism submitted to AVS. Main outcome measures were rate of bilateral success, SI values, and identification of unilateral PA. We recruited 136 patients (55 + 10 years, 35% women). Compared to the SI_C, the SI_A values were 3.5-fold higher bilaterally, and the SI_M values were 7-fold and 4.4-fold higher on the right and the left side, respectively. With the SI_A and the SI_M the rate of bilaterally successful AVS increased by 14% and 15%, respectively without impairing the identification of unilateral PA. We concluded that androstenedione and metanephrine outperformed cortisol for ascertaining AVS success, thus increasing the AVS studies useable for the clinical decision making. Full article

Pheochromocytomas/Paragangliomas (PPGLs) and adrenocortical tumors are rare neoplasms with significant heterogeneity in their biologic and clinical behavior. Current diagnostic and predictive biomarkers include hormone secretion, as well as histopathological and genetic features. PPGL diagnosis is based on biochemical measurement of catecholamines/metanephrines, while histopathological scoring systems have been proposed to predict the risk of malignancy. Adrenocortical tumors are mostly benign, but some can be malignant. Currently, the stage of disease at diagnosis and tumor grade, appear to be the most powerful prognostic factors. However, recent genomic and proteomic studies have identified new genetic and circulating biomarkers, including genes, immunohistochemical markers and micro-RNAs that display high specificity and sensitivity as diagnostic or prognostic tools. In addition, new molecular classifications have been proposed that divide adrenal tumors in distinct subgroups with different clinical outcomes. Full article