Publications by authors named "Osinga T"

Article Synopsis
  • This study investigates the effectiveness and safety of a combination therapy using immune checkpoint inhibitors (ICIs) for certain subgroups of metastatic castration-resistant prostate cancer (mCRPC) patients who show an immunogenic profile.
  • The trial involved 69 patients with specific genetic markers and assessed the disease control rate after treatment, aiming to exceed 22%.
  • Results showed that 38% of patients achieved disease control beyond 6 months, with the highest success in patients with mismatch repair deficiency, but treatment led to significant side effects in some cases, with 20% permanently discontinuing therapy.
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Immune checkpoint inhibitors (ICIs) are increasingly recognised to effectuate long-lasting therapeutic responses in solid tumours. However, ICI therapy can also result in various immune-related adverse events, such as ICI-associated myocarditis, a rare but serious complication. The clinical spectrum is wide and includes asymptomatic patients and patients with fulminant heart failure, making it challenging to diagnose this condition.

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Article Synopsis
  • The study evaluates the use of salivary metanephrines for diagnosing pheochromocytomas and paragangliomas (PPGL), highlighting its noninvasive collection method compared to plasma or urine samples.
  • Results show that salivary metanephrines in patients with PPGL are significantly higher than in healthy participants, with a diagnostic sensitivity of 89% and specificity of 87%.
  • Despite promising results indicating a correlation between salivary and plasma metanephrines, salivary testing is not yet a replacement for traditional plasma measurements in diagnosing PPGL.
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Article Synopsis
  • A study was conducted to evaluate the effectiveness of two α-adrenergic receptor blockers, phenoxybenzamine and doxazosin, in preventing hemodynamic instability during surgery for pheochromocytoma or sympathetic paraganglioma.
  • The results showed no significant difference in the time patients spent outside the target blood pressure range when treated with either medication, but phenoxybenzamine was linked to better management of intraoperative hemodynamic stability.
  • Overall, both drugs were safe with no mortality reported, and the complication rates were similar, highlighting the importance of individualized patient care in surgical settings.
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Succinate dehydrogenase (SDH) mutations lead to the accumulation of succinate, which acts as an oncometabolite. Germline SDHx mutations predispose to paraganglioma (PGL) and pheochromocytoma (PCC), as well as to renal cell carcinoma and gastro-intestinal stromal tumors. The SDHx genes were the first tumor suppressor genes discovered which encode for a mitochondrial enzyme, thereby supporting Otto Warburg's hypothesis in 1926 that a direct link existed between mitochondrial dysfunction and cancer.

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Dopamine is a catecholamine that acts both as a neurotransmitter and as a hormone, exerting its functions dopamine (DA) receptors that are present in a broad variety of organs and cells throughout the body. In the circulation, DA is primarily stored in and transported by blood platelets. Recently, the important contribution of DA in the regulation of angiogenesis has been recognized.

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Germline mutations of the gene encoding succinate dehydrogenase subunit B (SDHB) predispose to head-and-neck-paraganglioma (HNPGL), sympathetic PGL, pheochromocytoma and renal cell carcinoma for which regular surveillance is required. SDHB-associated tumors harbor germline and somatic mutations, consistent with Knudson's two-hit hypothesis. To assess the penetrance and optimal surveillance for different manifestations of SDHB mutation carriers.

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Background: Hypertension can be the predominant sign of pheochromocytoma (PCC) and sympathetic paraganglioma (sPGL) and screening for PCC/sPGL is often performed in patients who are already being treated with antihypertensive agents. There is very little information about the influence of antihypertensive drugs on plasma free metanephrines. The aim of this study was to determine whether commonly prescribed antihypertensive drugs can falsely elevate plasma free metanephrines concentrations measured by LC-MS/MS analysis.

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Germline mutations occur in up to 30-40% of pheochromocytoma/paraganglioma, with mutations in the succinate dehydrogenase (SDH) subunits B (SDHB) and D (SDHD) being the most common. Blood samples are favored for obtaining high quality DNA, however, leukocytes can also be obtained by collecting saliva. The aim of this study was to determine whether SDHB and SDHD gene mutations in patients with pheochromocytoma/paraganglioma could be determined using a salivary sample.

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Background: Determination of metanephrine (MN), normetanephrine (NMN), and 3-methoxytyramine (3-MT) in saliva may offer potential diagnostic advantages in diagnosing pheochromocytoma.

Methods: In this preliminary study, we determined metanephrine concentrations in saliva of healthy subjects and the relationship with simultaneously measured plasma metanephrines. We also studied the possible influence of pre-analytical conditions such as a collection device, awakening, posture, and eating on the salivary metanephrine levels.

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Background: Plasma 3-methoxytyramine (3-MT), a metabolite of dopamine, is elevated in up to 28% of patients with head and neck paragangliomas (HNPGLs). As free dopamine is incorporated in circulating platelets, we determined dopamine concentration in platelets in patients with a HNPGL.

Methods: A single center cohort study was performed between 2012 and 2014.

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Background/aim: Increased dopamine production may be a feature of head and neck paraganglioma (HNPGL). 18F-fluorodihydroxyphenylalanine positron emission tomography scintigraphy has a high sensitivity for detecting HNPGLs. These observations strongly suggest that HNPGLs have the capacity for L-3,4-dihydroxyphenylalanine uptake and conversion towards dopamine.

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Intestinal pseudo-obstruction is a rare and relatively unknown complication of phaeochromocytoma÷ paraganglioma (PCC÷PGL). Its pathophysiology can be explained by the hypersecretion of catecholamines, which may reduce the peristaltic activity of the gastrointestinal tract. Clinically, this can result in chronic constipation, intestinal pseudo-obstruction or even intestinal perforation.

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Context: Follow-up after adrenalectomy for pheochromocytoma is recommended because of a recurrence risk. During follow-up, plasma and/or urinary metanephrine (MN) and normetanephrine (NMN) are interpreted using reference ranges obtained in healthy subjects.

Objective: Because adrenalectomy may decrease epinephrine production, we compared MN and NMN concentrations in patients after adrenalectomy to concentrations in a healthy reference population.

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Aim: This study aimed to determine the prevalence of excess dopamine in relation to clinical symptoms and nuclear imaging in head and neck paraganglioma (PGL) patients.

Patients And Methods: Thirty-six consecutive patients with head and neck PGLs, evaluated between 1993 and 2009, were included. Clinical symptoms, dopamine excess (urinary 3-methoxytyramine (3-MT) or dopamine and/or plasma dopamine or 3-MT) and (nor)epinephrine excess (urinary (nor)metanephrine) as well as (111)In-octreotide and (123)I-metaiodobenzylguanide (MIBG) scintigraphy were documented.

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