Dosimetric effect of set-up error in accelerator-based boron neutron capture therapy for head and neck cancer

The dosimetric effect of set-up error in boron neutron capture therapy (BNCT) for head and neck cancer remains unclear. In this study, we analyzed the tendency of dose error by treatment location when simulating the set-up error of patients. We also determined the tolerance level of the set-up error in BNCT for head and neck cancer. As a method, the distal direction was shifted with an interval of 2.5 mm, from 0.0 mm to +20.0 mm and compared with the dose at the reference position. Similarly, the horizontal direction and vertical direction were shifted, with an interval of 5.0 mm, from −20.0 mm to +20.0 mm. In addition, cases with 3.0 mm and 5.0 mm simultaneous shifts in all directions were analyzed as the worst-case scenario. The dose metrics of the minimum dose of the tumor and the maximum dose of the mucosa were evaluated. From unidirectional set-up error analysis, in most cases, the set-up errors with dose errors within ±5% were Δdistal < +2.5 mm, Δhorizontal < ±5.0 mm and Δvertical < ±5.0 mm. In the simulation of 3.0 mm shifts in all directions, the errors in the minimum tumor dose and maximum mucosal dose were −3.6% ±1.4% (range, −5.4% to −0.6%) and 2% ±1.4% (range, 0.4% to 4.5%), respectively. From these results, if the set-up error was within ±3.0 mm in each direction, the dose errors of the tumor and mucosa could be suppressed within approximately ±5%, which is suggested as a tolerance level.     

Determining a methodology of dosimetric quality assurance for commercially available accelerator-based boron neutron capture therapy system

The irradiation field of boron neutron capture therapy (BNCT) consists of multiple dose components including thermal, epithermal and fast neutron, and gamma. The objective of this work was to establish a methodology of dosimetric quality assurance (QA), using the most standard and reliable measurement methods, and to determine tolerance level for each QA measurement for a commercially available accelerator-based BNCT system. In order to establish a system of dosimetric QA suitable for BNCT, the following steps were taken. First, standard measurement points based on tissue-administered doses in BNCT for brain tumors were defined, and clinical tolerances of dosimetric QA measurements were derived from the contribution to total tissue relative biological effectiveness factor-weighted dose for each dose component. Next, a QA program was proposed based on TG-142 and TG-198, and confirmed that it could be assessed whether constancy of each dose component was assured within the limits of tolerances or not by measurements of the proposed QA program. Finally, the validity of the BNCT QA program as an evaluation system was confirmed in a demonstration experiment for long-term measurement over 1 year. These results offer an easy, reliable QA method that is clinically applicable with dosimetric validity for the mixed irradiation field of accelerator-based BNCT.     

Nasal septal abscess caused by anaerobic bacteria of oral flora

Although nasal septal abscess (NSA) was formerly common, it has become rare since the development of antibiotics. NSA, if left untreated, can lead to intracranial complications such as meningitis and eventually result in saddle-nose deformity. NSA often occurs after injury, and indigenous skin bacteria such as Staphylococcus aureus are frequently detected. We treated a patient who had injured the upper alveolus in a fall on the stairs and developed NSA two weeks later. Anaerobic bacteria, including Veillonella parvula and Peptostreptococcus sp., were detected. Symptoms were relieved by needle and incisional drainage. Our patient represents a very rare case of NSA in terms of the cause of onset and the detected bacteria. Early drainage can result in good outcomes.     

Clerodane diterpenoids with NGF-potentiating activity from Ptychopetalum olacoides

Four new clerodane-type diterpenoids, ptychonolide (1), 20-O-methylptychonal acetal (2), and an equilibrium mixture of ptychonal hemiacetal (3) and ptychonal (4), were isolated from the MeOH extract of the bark of a Brazilian plant, Ptychopetalum olacoides. The structure of 1 was elucidated as a clerodane-type diterpenoid on the basis of spectroscopic data, whereas 2 was assigned to an acetal derivative of 1. Compounds 3 and 4 existed as an equilibrium mixture. A mixture of compounds 3 and 4 was found to exhibit neurite outgrowth-promoting activities on NGF-mediated PC12 cells at concentrations ranging from 0.1 to 10.0 microM.     

Vitamin D Metabolite Ratio in Pregnant Women with Low Blood Vitamin D Concentrations Is Associated with Neonatal Anthropometric Data

Existing evidence on the correlation between maternal vitamin D concentrations and birth outcomes is conflicting. Investigation of these associations requires accurate assessment of vitamin D status, especially in individuals with low 25-hydroxyvitamin D (25(OH)D) concentrations. This study examined the correlations between birth outcomes and the maternal vitamin D metabolite ratio (VMR) 1 (defined as the ratio of 24,25(OH)₂D₃ to 25(OH)D) and VMR2 (defined as the ratio of 3-epi-25(OH)D₃ to 25(OH)D) using data from the Japan Environment and Children’s Study at Chiba Regional Center. A total of 297 mother–neonate pairs were analyzed. Using liquid chromatography–tandem mass spectrometry, we measured 25(OH)D₂, 25(OH)D₃, 24,25(OH)₂D₃, and 3-epi-25(OH)D₃ concentrations in maternal serum samples. These data were analyzed in relation to birth anthropometric data using multivariable linear regression. Of the study participants, 85.2% showed insufficient vitamin D concentrations. VMR1 was strongly correlated with 25(OH)D concentrations, whereas VMR2 showed a weak correlation. Only VMR2 was associated with all anthropometric data. VMR2 in pregnant women with low vitamin D blood concentrations is a useful marker for neonatal anthropometric data and is independent of 25(OH)D. Accurate measurement of vitamin D metabolites could help better understand the effects of vitamin D on birth outcomes.     

Vesicular nucleotide transporter is a molecular target of eicosapentaenoic acid for neuropathic and inflammatory pain treatment

Eicosapentaenoic acid (EPA), an omega-3 (ω-3) polyunsaturated fatty acid, is an essential nutrient that exhibits antiinflammatory, neuroprotective, and cardiovascular-protective activities. Although EPA is used as a nutrient-based pharmaceutical agent or dietary supplement, its molecular target(s) is debatable. Here, we showed that EPA and its metabolites strongly and reversibly inhibit vesicular nucleotide transporter (VNUT), a key molecule for vesicular storage and release of adenosine triphosphate (ATP) in purinergic chemical transmission. In vitro analysis showed that EPA inhibits human VNUT-mediated ATP uptake at a half-maximal inhibitory concentration (IC₅₀) of 67 nM, acting as an allosteric modulator through competition with Cl⁻. EPA impaired vesicular ATP release from neurons without affecting the vesicular release of other neurotransmitters. In vivo, VNUT^−/− mice showed a delay in the onset of neuropathic pain and resistance to both neuropathic and inflammatory pain. EPA potently attenuated neuropathic and inflammatory pain in wild-type mice but not in VNUT^−/− mice without affecting the basal nociception. The analgesic effect of EPA was canceled by the intrathecal injection of purinoceptor agonists and was stronger than that of existing drugs used for neuropathic pain treatment, with few side effects. Neuropathic pain impaired insulin sensitivity in previous studies, which was improved by EPA in the wild-type mice but not in the VNUT^−/− mice. Our results showed that VNUT is a molecular target of EPA that attenuates neuropathic and inflammatory pain and insulin resistance. EPA may represent a unique nutrient-based treatment and prevention strategy for neurological, immunological, and metabolic diseases by targeting purinergic chemical transmission.

Omega-3 (ω-3) polyunsaturated fatty acids (PUFAs) are essential nutrients that contain multiple double bonds. PUFAs can be classified into ω-3 and ω-6 depending on the position of the bonds. As humans cannot produce PUFAs, they must be acquired from the diet to maintain homeostasis. Omega-3 PUFAs, such as eicosapentaenoic acid (EPA), are abundantly present in fish and linseed oil and exhibit antiinflammatory, neuroprotective, and cardiovascular-protective activities via the competitive inhibition of cyclooxygenase (COX)-2 in eicosanoid production (1–3). Danish and Greenland Inuit epidemiological studies have reported that EPA reduces the risk of death after myocardial infarction (4, 5), and other studies have reported its influence on analgesia, neuroinflammatory disease (Parkinson’s disease, Alzheimer’s disease, and depression) improvement, platelet aggregation inhibition, decrease in blood triglyceride and glucose levels, and improved insulin resistance (1, 6–11). Omega-3 fatty acid supplementation in COVID-19 patients showed a beneficial effect in managing the cytokine storm (12). Conversely, omega-6 fatty acids, such as arachidonic acid, produce inflammatory eicosanoids and play central roles in the initial stage of inflammatory responses (13). Although arachidonic acid has also been reported to produce antiinflammatory metabolites, omega-6 PUFA-derived linoleate diols have a harmful effect and are biomarkers for severe COVID-19 infection (14). An omega-6 PUFA-enriched Western-style diet, which abundantly contains linoleate, causes neuropathy and chronic pain, but an omega-3 PUFA-enriched diet attenuates these pathological conditions (15).All therapeutic effects of EPA cannot be explained by COX-2 inhibition alone (16). Typically, COX-2 inhibitors (nonsteroidal antiinflammatory druga [NSAIDs]) are effective for inflammatory pain but ineffective for neuropathic pain (16). However, EPA significantly attenuates both inflammatory and neuropathic pain, which strongly suggests another important molecular target of EPA related to neuropathy (7, 8). Although chronic pain is coincidentally caused by inflammation and neuropathy, there is no therapeutic drug with few side effects to attenuate both inflammatory and neuropathic pain (17–20). In this situation, EPA may affect the key signaling molecule(s) in neurological, metabolic, and immunological functions.Purinergic chemical transmission is involved in neurological, metabolic, and immunological disruptions and functions, including neuropathic and inflammatory pain, depression, inflammation, increase in blood triglyceride and glucose levels, insulin resistance, and blood coagulation (21, 22). The released adenosine triphosphate (ATP) and degraded adenosine diphosphate (ADP) or adenosine binds to many types of purinoceptors that are intricately involved in biological and pathological processes. In pain perception, ATP and ADP bind to P2X and P2Y receptors and thereby exacerbate neuropathic and inflammatory pain (23). Adenosine binds to P1 receptors and thereby attenuates neuropathic and inflammatory pain (24). However, a vesicular nucleotide transporter (VNUT/SLC17A9) is localized in the secretory vesicles of neuronal, endocrine, and immune cells. It plays an essential role in vesicular ATP storage in a Δψ- and Cl^–-dependent manner in the purinergic chemical transmission, which leads to vesicular ATP release (25, 26). Thus, VNUT is a key molecule in the initiation of purinergic signaling for neurological, metabolic, and immunological disruptions and functions. Interestingly, the observed effects of the VNUT inhibitor and phenotypes of VNUT^−/− mice were consistent with the above-mentioned therapeutic effects of EPA (27–31). Therefore, we hypothesized that VNUT serves as a molecular target of EPA to attenuate neuropathic and inflammatory pain.Here, we demonstrated that a low concentration of EPA and its metabolites, but not docosahexaenoic acid (DHA), are potent and selective physiological inhibitors of vesicular ATP release via the blockade of purinergic chemical transmission, which improved neuropathic and inflammatory pain and insulin resistance. Furthermore, EPA is more effective for neuropathic and inflammatory pain and has fewer side effects than existing drugs.     

A Rare Case of Rheumatoid Arthritis with Tocilizumab-induced Intestinal Mucosal Injury

Intestinal mucosal injury that develops as a complication of tocilizumab (TCZ) is usually associated with diverticulosis. We herein report a rare case of TCZ-induced intestinal mucosal injury in the absence of diverticulosis. A 74-year-old woman suffering from rheumatoid arthritis started taking TCZ. Six months later, she complained of hematochezia and abdominal pain. Colonoscopy revealed multiple ulcers spreading from the cecum to the transverse colon but no diverticulosis. These lesions were cured at three months after the discontinuation of TCZ. We should consider TCZ as a risk factor for intestinal mucosal injury, even if patients have no history of intestinal disease associated with diverticulosis.