Publications by authors named "Olli Tynninen"

Article Synopsis
  • Aggressive pituitary neuroendocrine tumors (PitNETs) often grow despite treatment and can metastasize, making them particularly challenging to manage.
  • This study analyzed tumor samples from 64 patients to investigate genetic markers, finding distinct patterns between aggressive/metastatic tumors and benign ones through genome-wide methylation and chromosomal analyses.
  • The results indicate potential biomarkers that could help in identifying high-risk patients earlier, refining treatment protocols, and improving outcomes for those with aggressive pituitary tumors.
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Myopathy is a common manifestation in mitochondrial disorders, but the pathomechanisms are still insufficiently studied in children. Here, we report a severe, progressive mitochondrial myopathy in a four-year-old child, who died at eight years. He developed progressive loss of muscle strength with nocturnal hypoventilation and dilated cardiomyopathy.

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Background: Tenofovir disoproxil fumarate (TDF) compared to tenofovir alafenamide (TAF) leads to lower body weight and plasma lipids by an unknown mechanism. We hypothesize that TDF, when absorbed, may damage enterocytes of the proximal duodenum, leading to reduced absorption of nutrients.

Methods: People living with HIV, without significant gastrointestinal symptoms, receiving TDF (n=12) or TAF (n=12) containing regimen underwent esophagogastroduodenoscopies with duodenal biopsies.

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Fatty acid binding protein 3 (FABP3) is expressed both in tumor cells and in the tumor vasculature, making it a potential target for medical imaging and therapy. In this study, we aimed to radiolabel a CooP peptide with a free amino and thiol group, and evaluate the radiolabeled product [F]FNA--CooP for imaging FABP3 expression in breast cancer brain metastases by positron emission tomography. [F]FNA--CooP was prepared by highly chemoselective -acylation and characterized using different chemical approaches.

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Background: Necrotizing myopathies and muscle necrosis can be caused by immune-mediated mechanisms, drugs, ischemia, and infections, and differential diagnosis may be challenging.

Case Presentation: We describe a case of diabetic myonecrosis complicated by pyomyositis and abscess caused by Escherichia coli. A white woman in her late forties was admitted to the hospital with a 1.

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Background: Fatty acid binding protein 3 (FABP3) is a target with clinical relevance and the peptide ligand ACooP has been identified for FABP3 targeting. ACooP is a linear decapeptide containing a free amino and thiol group, which provides opportunities for conjugation. This work is to develop methods for radiolabeling of ACooP with fluorine-18 (F) for positron emission tomography (PET) applications, and evaluate the binding of the radiolabeled ACooP in human tumor tissue sections with high FABP3 expression.

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Article Synopsis
  • Progressive multifocal leukoencephalopathy (PML) is a rare neurological disorder caused by the reactivation of the JC polyomavirus (JCPyV).
  • The study focused on analyzing gene expression and viral changes in PML-affected brain tissue, highlighting how the virus infects specific brain cells like astrocytes and oligodendrocytes.
  • Findings indicated significant changes in human genes linked to neuroinflammation and neurodegenerative diseases, suggesting a strong immune response in the brains of PML patients.
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Background: JC polyomavirus (JCPyV) persists asymptomatic in more than half of the human population. Immunocompromising conditions may cause reactivation and acquisition of neurotropic rearrangements in the viral genome, especially in the non-coding control region (NCCR). Such rearranged JCPyV strains are strongly associated with the development of progressive multifocal leukoencephalopathy (PML).

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Patients with myopathies caused by pathogenic variants in tropomyosin genes TPM2 and TPM3 usually have muscle hypotonia and weakness, their muscle biopsies often showing fibre size disproportion and nemaline bodies. Here, we describe a series of patients with hypercontractile molecular phenotypes, high muscle tone, and mostly non-specific myopathic biopsy findings without nemaline bodies. Three of the patients had trismus, whilst in one patient, the distal joints of her fingers flexed on extension of the wrists.

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Purpose: To evaluate the incidence, clinical features, diagnostic challenges, management and prognosis of cutaneous squamous cell carcinoma of the eyelid (ecSCC) in southern Finland, northern Europe, latitude 62° N.

Methods: Patients were identified from the Finnish Cancer Registry and the Helsinki University Hospital databases during a 25-year period (1998-2022). Age, sex, location, clinical and histopathological diagnosis, treatment and outcome were retrieved.

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IgG4-related disease (IgG4-RD) is an emerging immune-mediated chronic fibrotic disease characterized by tumour-like mass formation. Reports of brain parenchymal involvement in IgG4-RD are rare and complete treatment-related remission of lesions has never been reported. Here, we present a woman in her mid-50s who developed headache and seizures.

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Background: Pathogenic variants in the TPM3 gene, encoding slow skeletal muscle α-tropomyosin account for less than 5% of nemaline myopathy cases. Dominantly inherited or de novo missense variants in TPM3 are more common than recessive loss-of-function variants. The recessive variants reported to date seem to affect either the 5' or the 3' end of the skeletal muscle-specific TPM3 transcript.

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We report a case of pyruvate dehydrogenase E1 alpha subunit deficiency associated with a novel hemizygous PDHA1 variant presenting prenatally as multiple structural brain abnormalities in a male fetus. A healthy Finnish couple was initially referred to the Fetomaternal Medical Center because of suspected fetal choroid plexus cyst at 11 + 2 weeks of pregnancy. At 20 + 0 weeks, multiple abnormalities were observed with ultrasound including narrow thorax, slightly enlarged heart, hypoplastic cerebellum, absent cerebellar vermis and ventriculomegaly.

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Progressive multifocal leukoencephalopathy (PML) is a severe neurological condition caused by reactivation of JC polyomavirus (JCPyV) in immunosuppression. Asymptomatic JCPyV persists in peripheral tissues. Upon reactivation, neurotropic rearrangements may emerge, and the virus gains access to the brain.

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Pediatric neoplasms in the central nervous system (CNS) show extensive clinical and molecular heterogeneity and are fundamentally different from those occurring in adults. Molecular genetic testing contributes to accurate diagnosis and enables an optimal clinical management of affected children. Here, we investigated a rare, molecularly distinct type of pediatric high-grade neuroepithelial tumor (n = 18), that was identified through unsupervised visualization of genome-wide DNA methylation array data, together with copy number profiling, targeted next-generation DNA sequencing, and RNA transcriptome sequencing.

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Gastrointestinal stromal tumour (GIST), the most common sarcoma of the gastrointestinal tract, can be treated effectively with tyrosine kinase inhibitors, such as imatinib. Cancer immune therapy has limited efficacy, and little is known about the immune suppressive factors in GISTs. Fibrinogen-like protein 2 (FGL2) is expressed either as a membrane-associated protein or as a secreted soluble protein that has immune suppressive functions.

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P-cadherin (CDH3) is a cell-to-cell adhesion molecule that regulates several cellular homeostatic processes in normal tissues. Lack of CDH3 expression is associated with aggressive behavior in oral squamous cell carcinoma (OSCC). Previous studies have shown that CDH3 is downregulated in high-grade OSCC and its reduced expression is predictive for poorer survival.

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Purpose: To evaluate the clinical features, diagnostic challenges, management, and prognosis of sebaceous carcinoma (SC) of the eyelids and periocular region in a Nordic country.

Methods: Patients were identified from the Finnish Cancer Registry and the Helsinki University Hospital databases during the 21-year period 1998-2018. Age, sex, location, clinical and histopathologic diagnosis, treatment and outcome were registered.

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Background: Medulloblastomas (MBs) are a heterogeneous group of childhood brain tumors with four consensus subgroups, namely MB , MB , MB , and MB , representing the second most common type of pediatric brain cancer after high-grade gliomas. They suffer from a high prevalence of genetic predisposition with up to 20% of MB caused by germline mutations in only six genes. However, the spectrum of germline mutations in MB remains incomplete.

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Context: Mutations to isocitrate dehydrogenase (IDH) appear to play a prognostic or predictive role in several neoplasias. Immunohistochemical staining designed to detect a specific R132H mutation to IDH1 showed expression in the normal adrenal cortex, raising interest to study the potential role of IDH1 in the pathogenesis of adrenocortical tumors.

Objective: The objective of this work is to study the role of IDH1 and its mutations in adrenocortical tumors.

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Background: Microsurgical resection represents a well-accepted management option for symptomatic benign pineal cysts. Symptoms such as a headache, hydrocephalus, and visual deficiency are typically associated with pineal cysts. However, more recent studies reported over the past years have characterized additional symptoms as a part of the clinical manifestation of this disease and represent additional indications for intervention.

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Background: Pineal region tumors represent challenging surgical lesions with wide ranges of survival reported in different surgical series. In this article, we emphasize the role of complete microsurgical resection (CMR) to obtain a favorable long-term outcome of pineal region tumors.

Methods: We report a retrospective study of pineal region tumors operated on in Helsinki Neurosurgery between 1997 and 2015.

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The current clinical care of glioblastomas leaves behind invasive, radio- and chemo-resistant cells. We recently identified mammary-derived growth inhibitor (MDGI/) as a biomarker for invasive gliomas. Here, we demonstrate a novel function for MDGI in the maintenance of lysosomal membrane integrity, thus rendering invasive glioma cells unexpectedly vulnerable to lysosomal membrane destabilization.

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