Publications by authors named "Heerden M"

Purpose: The current study aimed to investigate the use of surrogate immunohistochemical (IHC) markers of proliferation and stem cells to distinguish ameloblastoma (AB) from ameloblastic carcinoma (AC).

Methods: The study assessed a total of 29 ACs, 6 ABs that transformed into ACs, and a control cohort of 20 ABs. The demographics and clinicopathologic details of the included cases of AC were recorded.

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This study presents the first clinical implementation of an efficient online daily adaptive proton therapy workflow (DAPT).The DAPT workflow includes awhere aand aare optimized on the planning computed tomography (CT). In the, theis re-optimized on daily images from an in-room CT.

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Background And Purpose: Rare but severe toxicities of the optic apparatus have been observed after treatment of intracranial tumours with proton therapy. Some adverse events have occurred at unusually low dose levels and are thus difficult to understand considering dose metrics only. When transitioning from double scattering to pencil beam scanning, little consideration was given to increased dose rates observed with the latter delivery paradigm.

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Objectives: This study aimed to analyze the clinicoradiologic features and Ki-67 proliferation indices between the histopathologic variants of ameloblastomas (ABs) for possible associations.

Study Design: The diagnosis and histopathologic variant were confirmed for all cases by experienced Oral and Maxillofacial Pathologists. Immunohistochemistry for Ki-67 was performed on the most representative formalin-fixed paraffin-embedded tissue block.

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Ad26.COV2.S vaccination can lead to vaccine-induced immune thrombotic thrombocytopenia (VITT), a rare but severe adverse effect, characterized by thrombocytopenia and thrombosis.

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Radiotherapy developed empirically through experience balancing tumour control and normal tissue toxicities. Early simple mathematical models formalized this practical knowledge and enabled effective cancer treatment to date. Remarkable advances in technology, computing, and experimental biology now create opportunities to incorporate this knowledge into enhanced computational models.

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Background: The anti-cancer agent 2-methoxyestradiol (2-ME) has been shown to have anti-proliferative and anti-angiogenic properties. Previously, the effect of 2-ME on early- and late-stage breast cancer (BC) was investigated in vivo using a transgenic mouse model (FVB/N-Tg(MMTV-PyVT)) of spontaneous mammary carcinoma. Anti-tumor effects were observed in late-stage BC with no effect on early-stage BC.

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Purpose: The purpose of this study was to report the clinical and patient-reported outcomes of children and adolescents with intracranial meningioma treated with pencil beam scanning proton therapy (PBS-PT).

Material And Methods: Out of a total cohort of 207 intracranial meningioma patients treated with PBS-PT between 1999 and 2022, 10 (4.8%) were children or adolescents aged < 18 years.

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The prevalence of breast cancer (BC) continues to increase and is the leading cause of cancer deaths in many countries. Numerous in vitro and in vivo studies have demonstrated that 2-methoxyestradiol (2-ME) has antiproliferative and antiangiogenic effects in BC, thereby inhibiting tumour growth and metastasis. We compared the effect of 2-ME in early- and late-stage BC using a transgenic mouse model-FVB/N-Tg(MMTV-PyVT)-of spontaneously development of aggressive mammary carcinoma with lung metastasis.

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Intestinal organoids derived from LGR5 adult stem cells allow for long-term culturing, more closely resemble human physiology than traditional intestinal models, like Caco-2, and have been established for several species. Here we evaluated intestinal organoids for drug disposition, metabolism, and safety applications. Enterocyte-enriched human duodenal organoids were cultured as monolayers to enable bidirectional transport studies.

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Turbulence in stirred tank flotation tanks impacts the bulk transport of particles and has an important role in particle-bubble collisions. These collisions are necessary for attachment, which is the main physicochemical mechanism enabling the separation of valuable minerals from ore in froth flotation. Modifications to the turbulence profile in a flotation tank, therefore, can result in improvements in flotation performance.

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Since the original outbreak of the SARS-CoV-2 virus, several rapidly spreading SARS-CoV-2 variants of concern (VOC) have emerged. Here, we show that a single dose of Ad26.COV2.

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Odontogenic keratocysts (OKCs) are common cysts of odontogenic origin that usually occur as a single nonsyndromic cyst in isolation (sporadic) or as syndromic multiple cysts as a manifestation of naevoid basal cell carcinoma syndrome. Alterations involving the PTCH gene are the most commonly identified factor associated with up to 85% and 84% of naevoid basal cell carcinoma syndrome and sporadic cases, respectively. Other Hedgehog pathway and non-Hedgehog pathway-associated genes have been implicated in the pathogenesis of OKCs.

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Cross-species comparison of drug responses at the organoid level could help to determine the human relevance of findings from animal studies. To this end, we first need to evaluate the in vitro to in vivo translatability of preclinical organoids. Here, we used 5-fluorouracil (5-FU) as an exemplar drug to test whether the in vivo gut response to this cytotoxicant was preserved in murine intestinal organoids.

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Background: Laboratories use quality control processes to monitor and evaluate analytical performance in terms of precision and bias. Sigma metrics provide an objective assessment of laboratory quality using the total allowable error as an additional parameter.

Objective: This study aimed to determine the sigma metrics of analytes when using different total allowable error guidelines.

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Adipogenesis, through adipocyte hyperplasia and/or hypertrophy, leads to increased adiposity, giving rise to obesity. A genome-wide transcriptome analysis of in vitro adipogenesis in human adipose-derived stromal/stem cells identified SLC7A8 (Solute Carrier Family 7 Member 8) as a potential novel mediator. The current study has investigated the role of SLC7A8 in adipose tissue biology using a mouse model of diet-induced obesity.

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Despite obesity being a major health concern, information on the early clinical changes that occur in plasma and tissues during obesity development and the influence of sexual dimorphism is lacking. This study investigated changes in tissue and organ histology, macrophage infiltration, plasma hormones, lipid, and chemokine and cytokine levels in mice fed on a high fat diet for 11-weeks. An increase in adiposity, accompanied by adipocyte hypertrophy and macrophage infiltration, was observed to be significantly greater in males than females.

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We previously reported that a single immunization with an adenovirus serotype 26 (Ad26)-vector-based vaccine expressing an optimized SARS-CoV-2 spike (Ad26.COV2.S) protected rhesus macaques against SARS-CoV-2 challenge.

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Fetal examinations in embryo-fetal developmental (EFD) studies are based on macroscopic and dissecting microscopic evaluations, and histopathology is rarely performed other than to confirm macroscopic findings. Fetal lens examination is therefore generally limited to the presence, size, shape, and color of any abnormality. In a Sprague-Dawley rat EFD study with the fatty acid amide hydrolase (FAAH) inhibitor JNJ-42165279, an unusually high incidence of macroscopic granular foci was noted within the lens of gestation day 21 fetuses across all groups including controls, with higher incidence in the high-dose group.

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Background: Plasmablastic lymphoma (PBL) is an aggressive neoplasm that commonly develops in HIV-positive patients, usually affecting the oral cavity. EBV is present in the majority of cases, therefore, playing an important role in the pathogenesis of this neoplasm.

Methods: PBL diagnosed from 2000 to 2020 were retrieved from the archives of the Department of Oral Pathology and Oral Biology at the University of Pretoria, South Africa.

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Safe and effective coronavirus disease-19 (COVID-19) vaccines are urgently needed to control the ongoing pandemic. While single-dose vaccine regimens would provide multiple advantages, two doses may improve the magnitude and durability of immunity and protective efficacy. We assessed one- and two-dose regimens of the Ad26.

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Previously we have shown that a single dose of recombinant adenovirus serotype 26 (Ad26) vaccine expressing a prefusion stabilized SARS-CoV-2 spike antigen (Ad26.COV2.S) is immunogenic and provides protection in Syrian hamster and non-human primate SARS-CoV-2 infection models.

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Local delivery to the lower gut to treat diseases of the colon has become a topic of special attention. Tissue exposure of locally acting agents is not represented by plasma concentrations. Therefore, reliable methods to measure tissue uptake at the primary site of action (e.

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Galactorrhoea is the presence of breast milk secretion in non-pregnant or non-breastfeeding females. In females with galactorrhoea and amenorrhoea, hyperprolactinaemia is the most likely cause. Chest wall pathology is a known cause of hyperprolactinaemia, however there are few documented reports on galactorrhoea following burn injury to the chest wall.

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