UVC-Protective Activity of Lemongrass Among 12 Fat-soluble Herbal Extracts: Rapid Decay Due to Cytotoxicity.

BACKGROUND/AIM: The COVID-19 pandemic led to the rapid spread of the use of ultraviolet C (UVC) sterilizers in many public facilities. Considering the harmful effects of prolonged exposure to UVC, manufacturing of safe skin care products is an important countermeasure. In continuation of our recent study of water-soluble herbal extracts, the present study aimed at searching for anti-UVC components from fat-soluble herbal extracts. MATERIALS AND METHODS: Human dermal fibroblast and melanoma cells were exposed to UVC (1.193 W/m2) for 3 min. Viable cell number was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell-cycle analysis was performed using a cell sorter. UVC-protective activity was quantified by the selective index (SI), i.e., the ratio of the 50% cytotoxic concentration for unirradiated cells to the concentration that restored viability of UVC-treated cells by 50%. RESULTS: Only lemongrass extract, among 12 fat-soluble herbal extracts, showed significant anti-UVC activity, comparable to that of lignified materials and tannins, but exceeding that of N-acetyl-L-cysteine and resveratrol. Lemongrass extract was highly cytotoxic, producing a subG1 cell population. During prolonged incubation in culture medium, the anti-UVC activity of lemongrass extract, sodium ascorbate and vanillic acid declined with an approximate half-life of <0.7, 5.4-21.6, and 27.8-87.0 h, respectively. CONCLUSION: Removal of cytotoxic principle(s) from lemongrass extract is crucial to producing long-lasting UVC-protective effects.

Fundamental research for dose control during supine dental panoramic radiography.

OBJECTIVE: This study aimed to control radiation doses when using a portable supine dental panoramic radiography system by measured the scattered doses. METHOD: The study used LPX7007 (Asahi Roentgen) for the panoramic radiography system. The subjects comprised a cylinder phantom (QualitA) and a RANDO Phantom (Alderson). The semiconductor dosimeter was an X2 survey sensor (RaySafe). The phantom was set at a height of 1 m from the floor, and the sensor was set at 1 m from the floor at the genital level and 1.5 m at the lens level. Measurements were taken at 30°intervals clockwise from 0°at distances of 0.5 m and 1 m in radius around the phantom. The occupational exposure range was defined as 0 ± 30° and the public exposure range was defined as the occupational exposure range and 30° to 150° and 210° to 330° as the public exposure range. RESULT: The highest doses were observed in the 120° and 240° directions, and the lowest in 0° ± 30° range. The lowest limit number of images taken in the occupational exposure range was 130 images at a distance of 0.5 m, 452 images at 1 m at the lens level for the cylinder phantom, and 320 images at 0.5 m and 1098 images at 1 m for the RANDO Phantom. In the public exposure range at the genital level, there was one image at 0.5 m and six images at 1 m for the cylinder phantom, and two images at 0.5 m and eight images at 1 m for the RANDO Phantom. CONCLUSION: We found that radiation exposure can be reduced by keeping a distance from the subject, avoiding working at 120° and 240° and staying within 0° ± 30° behind the panoramic radiography system.

Stray radiation dose reduction using a backscatter shield and a rectangular collimator for a handheld intraoral X-ray unit.

The objective of this study was to study the dose reduction effect on occupational exposure of operators and public exposure other than operators when a backscatter shield and a rectangular collimator are used in conjunction with a handheld intraoral X-ray unit. The occupational exposure was reduced to 40% when the backscatter shield was attached to the cone-tip, to 13% when the rectangular collimator was attached and to 7.7% when the backscatter shield and rectangular collimator were used together. On the other hand, the public exposure was reduced to 20% when the rectangular collimator was attached, but the backscatter shield was not effective in reducing the public exposure. Attaching a backscatter shield is effective in reducing the occupational exposure, and a rectangular aperture is effective in reducing the occupational exposure, as well as the public exposure.

Comprehensive Study of Anti-UVC Activity and Cytotoxicity of Hot-water Soluble Herb Extracts.

BACKGROUND/AIM: COVID-19 pandemic caused the rapid dissemination of ultraviolet C (UVC) sterilization apparatuses. Prolonged exposure to UVC, however, may exert harmful effects on the human body. The aim of the present study was to comprehensively investigate the anti-UVC activity of a total of 108 hot-water soluble herb extracts, using human dermal fibroblast and melanoma cell lines, for the future development of skin care products. MATERIALS AND METHODS: Exposure time to UVC was set to 3 min, and cell viability was determined using the MTT assay. Anti-UVC activity was determined using the selective index (SI), a ratio of 50% cytotoxic concentration for unirradiated cells to 50% effective concentration that restored half of the UVC-induced decrease of viability. RESULTS: Dermal fibroblasts at any population doubling level were more resistant to UVC irradiation than melanoma cells. Both 49 herb extracts recommended by Japan Medical Herb Association (JAMHA) and 59 additional herb extracts showed comparable anti-UVC activity. SI values of selected herbs (Butterbur, Cloves, Curry Tree, Evening Primrose, Rooibos, Stevia, Willow) were several-fold lower than those of vitamin C and vanillin. Their potent anti-UVC activity was maintained for at least 6 h post irradiation, but declined thereafter to the basal level, possibly due to cytotoxic ingredients. CONCLUSION: UVC sensitivity may be related to the growth potential of target cells. Removal of cytotoxic ingredients of herb extracts may further potentiate and prolong their anti-UVC activity.

Effect of cranium structure on dose distribution during intraoral radiography.

OBJECTIVES: This study aimed to evaluate, the effect of the cranium structure on dose distribution by measuring the dose using the RANDO phantom for safe use of an X-ray unit during personal identification work at a large-scale disaster site. METHODS: As the subject, the head and neck of the RANDO Phantom (Alderson) containing a dry skull composed of a tissue-equivalent substance and having a shape similar to that of a living body were studied. With the body in the supine position, the air doses per second of irradiation time were measured for a total of six sections of the anterior, premolar, and molar teeth (molar on the left side) at a tube voltage of 60 kV and tube current of 10 mA during maxilla and mandible intraoral radiography. RESULTS: The region having the highest exposure dose was the main X-ray direction in both the mandible and maxilla. Conversely, the dose tended to be low in the range from the temporal region to the occipital region on both sides of the horizontal plane, from the frontal region to the occipital region of the sagittal plane, and in the parietal region of the frontal plane. CONCLUSIONS: It would be preferable to examine from the top of the body where the dose tends to decrease for all imaging sites.

Overview of Radiological Studies on Visualization of Gubernaculum Tracts of Permanent Teeth.

The eruption pathway from the dental follicle to the gingiva for permanent teeth is known as the gubernaculum tract (GT), a physiologic structure thought to play a role in tooth eruption. Cone beam computed tomography and multi-detector computed tomography have recently been used to visualize the GT, with the results indicating that this structure might be related to the normal eruption of teeth. By contrast, curved and/or constricted GTs may lead to abnormal tooth eruption. In addition, complex odontomas have been reported from within the GT or dental sac of unerupted permanent teeth. If an odontoma occurs within the GT, the tooth will not erupt normally. Moreover, the imaging characteristics of the GT from the top of the odontogenic mass to the alveolar crest are extremely useful for making a differential pathological diagnosis and for differentiating between odontogenic and non-odontogenic masses. Therefore, radiological studies on the GT have been attracting increasing attention. Given this background, the present review aims to clarify the imaging characteristics and review recent studies on the GT considering the importance of the research.

Comparison of air dose and operator exposure from portable X-ray units.

This study was aimed at investigating and comparing exposure dose of workers and the surrounding workers. In addition, worker's exposure was also measure about lens and finger. Four intraoral portable X-ray units were evaluated. The stray radiations were measured using Pitman 37D and ionization chamber (Pitman). MyDosemini (ALOKA) was used for measurement of the finger exposure dose. Without the shield became high in anterior 0.5 m. Comparing the air dose for the four models used in this study showed a high tendency for the two NOMAD models. And using the shields, the images could be taken 4.6 times of the baseline at a maximum and 3.6 times on average. The finger radiation exposure dose was low with both of the NOMAD models, with no significant difference found. By setting the baseline value without a shield, finger radiation exposure when using a shield was lower than the detection limit for the D3000, and was reduced by approximately 94-96% for other three models. All models can photograph around 100 bodies, so it is considered that it is not necessary to switch out the operator considering the operation limit. But even if it does not reach the operation limit, the stochastic effects of radiation exposure can be increased as well as the deterministic effects of the operation limit. The operator and the surrounding workers seek to protect themselves. It is important to perform exposure management that takes into account the stochastic effects to the operator and the surrounding workers.

Reduction of operator exposure by rectangular collimation in portable intraoral radiography.

Portable intraoral X-ray units are frequently used for home-visit dental treatment and personal dental identification. Therefore, the reduction of operator exposure is crucial. Rectangular collimation is effective at reducing patient exposure and operator exposure; however, its effects are not known. We investigated the reduction of operator exposure through rectangular collimation by measuring the backscattered dose in relation to the operator exposure dose. Using a portable intraoral X-ray unit, a head phantom for CT dose measurement as the object, a dosimeter, and stainless-steel rectangular collimator, a 1-cm ambient dose equivalent was measured in intervals of 15° in horizontal and vertical planes with the radii of 50 and 100 cm. The backscattered dose decreased to approximately one-third when a rectangular collimator was attached to the cone tip. This may have been due to the reduction of the volume of scattered X-rays generated in the phantom by rectangular collimation. We clarified that rectangular collimation is effective at reducing the operator exposure and is useful for protecting the operators of portable intraoral X-ray units during home-visit dental treatment and personal dental identification.

Augmentation of Neurotoxicity of Anticancer Drugs by X-Ray Irradiation.

BACKGROUND: In order to investigate the combination effect of anticancer drugs and X-ray irradiation on neurotoxic side-effects (neurotoxicity), a method that provides homogeneously X-ray-irradiated cells was newly established. MATERIALS AND METHODS: PC12 cell suspension was irradiated by X-ray (0.5 Gy) in serum-supplemented medium, immediately inoculated into 96-microwell plates and incubated overnight. The medium was replaced with fresh serum-depleted medium containing 50 ng/ml nerve growth factor to induce differentiation toward nerve-like cells with characteristic neurites according to the overlay method without changing the medium. The differentiated cells were treated by anticancer drugs as well as antioxidants, oxaliplatin or bortezomib, and the viable cell number was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. RESULTS: Antioxidants and anticancer drugs were cytotoxic to differentiating PC12 cells. Combination of anticancer drugs and X-ray irradiation slightly reduced cell viability. CONCLUSION: The present 'population irradiation method' may be useful for the investigation of the combination effect of X-ray irradiation and any pharmaceutical drug.

Can the lower rate of CT- or MRI-related adverse drug reactions to contrast media due to stricter limitations on patients undergoing contrast-enhanced CT or MRI?

OBJECTIVE: The aim of this study was to examine whether a decreased occurrence rate of adverse drug reactions (ADRs) to contrast media in contrast-enhanced CT and MRI was attributable to appropriate criteria for patients with some diseases. A secondary aim was to elucidate safety profiles for contrast media and factors influencing the occurrence of ADRs. METHODS: Clinical data of patients who underwent contrast-enhanced CT (5576 cases) or MRI (3357 cases) were retrospectively analyzed to evaluate rates of ADRs to contrast media, symptoms of ADRs, treatments for ADRs, and differences in medical history, blood test results, and other factors between patients with and without ADRs in a dental hospital. RESULTS: The rate of ADRs to contrast media was 0.54% for CT and 0.09% for MRI. The most frequent ADRs in contrast-enhanced CT or MRI were nausea and vomiting as physiologic reactions. Two serious reactions were seen for CT, but none for MRI. Significant differences between patients with and without ADRs were seen in liver function according to blood tests for CT, and in digestive disorders elicited from medical interviews for MRI. CONCLUSION: The lower occurrence rate of ADRs to contrast media in dental hospitals could be due to the adoption of appropriate criteria for patients with some diseases undergoing enhanced CT or MRI. Complete suppression of ADRs to contrast media for CT or MRI is unrealistic, so attention is warranted for patients with decreased liver function when performing enhanced CT, and for patients with digestive disorders when performing enhanced MRI.

Characteristics of diffusion-weighted images and apparent diffusion coefficients of ranulas and other masses in and around the floor of the mouth.

OBJECTIVE: The aim of this study was to evaluate the characteristics of diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) values of ranulas. In addition, to elucidate DWI findings and ADC values of other representative masses in and around the floor of the mouth. STUDY DESIGN: DWI findings and ADC values in 35 patients with ranulas and 33 patients with other masses were retrospectively reviewed with a central focus on cystic masses or lesions that may have cyst-like components in and around the floor of the mouth based on the diagnosis of each respective disease. RESULTS: Ranulas were all well-defined, homogeneous masses with high signal intensity on DWI. The mean ± standard deviation ADC value of the 35 ranulas was 2.59 ± 0.31 × 10-3 mm2/s. There was a significant difference in ADC values between simple and plunging ranulas. On DWI, most other masses were heterogeneous, and most ADC values, except those for thyroglossal duct cysts, hemangiomas, and pleomorphic adenomas, were significantly lower than those for ranulas. CONCLUSIONS: The characteristic DWI and ADC findings of ranulas can be determined accurately, and these data can be significantly useful in the differential diagnosis of many kinds of diseases in and around the oral floor.

Multiple mandibular static bone depressions attached to the three major salivary glands.

A Stafne bone defect is a static bone depression in the mandible that is commonly observed in cortical bone near the mandibular angle. We herein present a rare case in which static bone depressions attached to the three major salivary glands were observed on panoramic radiography and computed tomography (CT). The three static bone depressions in the mandible were visualized on a panoramic radiograph and CT as oval radiolucent masses in a 68-year-old man. The CT numbers in the bone depressions ranged from 10 to 50 HU, and they were close to those of the respective salivary glands. Based on the CT numbers, the areas in the bone depressions were determined to be a normal parotid gland, sublingual gland, and submandibular gland. The patient underwent a follow-up examination and did not request further consultation.

Significance and usefulness of imaging characteristics of gubernaculum tracts for the diagnosis of odontogenic tumors or cysts.

We aimed to determine the significance and usefulness of imaging characteristics of gubernaculum tracts (GT) for the diagnosis of odontogenic tumors or cysts. This was a retrospective analysis of relationships between odontogenic or non-odontogenic tumors or cysts and the GT that were visualized using multi-detector computed tomography (MDCT). The relationship between the size of a mass and expansion of the GT in all odontogenic tumors or cysts to which GTs were contiguous on MDCT, was statistically analyzed. Intact or expanded GTs were detected in MDCT images on the top of almost all odontogenic tumors or cysts, but not on non-odontogenic tumors or cysts. Characteristic image findings regarding the relationship between the GT and the odontogenic mass were detected for the respective odontogenic tumors or cysts in which the GTs were contiguous to the mass on MDCT. In ameloblastomas, expansion of the GTs significantly and very strongly correlated with tumor size (r = 0.741, p = 0.0001), but this correlation was very weak in dentigerous cysts (r = 0.167, p = 0.028) and there was no correlation between these parameters in odontogenic keratocysts (r = -0.089, p = 0.557). The imaging characteristics of GTs at the top of masses should be very useful for both the differential diagnosis of the pathological diagnosis of odontogenic masses and for differentiation between odontogenic and non-odontogenic masses.

Functional evaluation of swallowing in patients with tongue cancer before and after surgery using high-speed continuous magnetic resonance imaging based on T2-weighted sequences.

OBJECTIVES: The aim of this study was to determine the usefulness of evaluating the function of swallowing before and after surgery in patients with tongue cancer by using T2-weighted sequences of high-speed continuous magnetic resonance imaging (HSCMRI). STUDY DESIGN: The imaging findings and related parameters on HSCMRI along with those on routine MRI examinations before and after surgery were examined in 19 patients with tongue cancer. In addition, changes in various parameters during 1 year after surgery were evaluated in 10 patients. RESULTS: In most patients examined, the direction of flow to the esophagus could be seen on HSCMRI before and after surgery. Significant correlations were observed among 4 parameters and in the responses to a dysphagia questionnaire. CONCLUSIONS: The results of the present study suggest that the dynamics of swallowing can be directly visualized on HSCMRI by using 4 parameters that permit the evaluation of changes before and after surgery, and this enables objective evaluation of patients' swallowing complaints.

Changes in the distributions of fluorine-18-labelled fluoro-2-deoxy-d-glucose accumulation into tongue-related muscles after dissection in patients with tongue cancer.

OBJECTIVES: To elucidate the changes in the distributions of fluorine-18-labelled fluoro-2-deoxy-d-glucose (18F-FDG) accumulation in the tongue muscles of patients following four kinds of surgical operations for tongue cancers. METHODS: The changes in the distributions of 18F-FDG accumulations in the tongue muscles on positron emission tomography (PET)-CT, in association with imaging findings on CT and MRI, were retrospectively analyzed before and after four kinds of surgical operations for 50 patients with tongue cancers. RESULTS: 18F-FDG-PET-positive areas appeared at the back of the intrinsic muscles of the tongue after invasive surgery for tongue cancers despite the absence of abnormal findings on CT and MRI. A correlation between the standardized uptake value maximum of 18F-FDG in the intrinsic muscles and the degree of invasiveness of the surgical procedures for tongue cancers (r = 0.539, p < 0.01) was found. CONCLUSIONS: It is important to pay attention to the changes in 18F-FDG distributions in the intrinsic muscles of the tongue before and after invasive surgery despite the absence of abnormal findings on CT and MRI when evaluating the tongue on 18F-FDG-PET.

Importance of absorbable surgical sutures for the prevention of stitch abscess after surgery in patients with oral squamous cell carcinoma

BACKGROUND: To elucidate the significance of absorbable surgical sutures in the occurrence of stitch abscess after surgery in patients with oral squamous cell carcinoma (SCC). MATERIAL AND METHODS: The subjects were 251 patients who underwent excision and/or reconstruction and/or neck dissection for oral SCC using absorbable surgical sutures. Detection rates and characteristics of patients with stitch abscess were retrospectively evaluated by comparing between our present and previous data. RESULTS: There was only one stitch abscess among the 251 patients. A significant difference in the incidence of stitch abscess was found between the present data and our previous data. Of course, no significant correlations were found between the occurrence of stitch abscess using absorbable surgical sutures and the various factors seen in our previous analysis. CONCLUSIONS: A complete switch of surgical sutures from silk to absorbable surgical sutures is needed for surgery in patients with oral SCC

Characteristics of the gubernaculum tracts in mesiodens and maxillary anterior teeth with delayed eruption on MDCT and CBCT.

OBJECTIVES: To elucidate the characteristics of the gubernaculum tracts (GTs) in maxillary anterior teeth with normal or delayed eruption and in mesiodens by using multidetector computed tomography and cone beam computed tomography. STUDY DESIGN: The characteristics of GTs in maxillary anterior teeth of 205 patients with impacted mesiodens were retrospectively analyzed by using multidetector computed tomography and cone beam computed tomography. The GTs of teeth with normal or delayed eruption and the GTs of mesiodens were examined. RESULTS: The detection ratio of GTs in impacted mesiodens and anterior teeth with delayed eruption was significantly lower than in teeth with normal eruption. A significant difference in the angulation was found between normal and delayed eruptions. Almost all detectable GTs in the inverted mesiodens were derived from the incisive canal, while the remaining were from the alveolar crest. The connecting area of major GTs to tooth in inverted mesiodens was the cervical or root area, but in all other anterior teeth, it was the crown area. CONCLUSIONS: GTs of inverted mesiodens may exhibit characteristics that are different from those of normal GTs when the teeth and/or the palate are developing.

Alterations in 18F-FDG accumulation into neck-related muscles after neck dissection for patients with oral cancers

BACKGROUND: 18F-fluoro-2-deoxy-D-glucose (18F-FDG) accumulations are commonly seen in the neck-related muscles of the surgical and non-surgical sides after surgery with neck dissection (ND) for oral cancers, which leads to radiologists having difficulty in diagnosing the lesions. To examine the alterations in 18F-FDG accumulation in neck-related muscles of patients after ND for oral cancer. MATERIAL AND METHODS: 18F-FDG accumulations on positron emission tomography (PET)-computed tomography (CT) in neck-related muscles were retrospectively analyzed after surgical dissection of cervical lymph nodes in oral cancers. RESULTS: According to the extent of ND of cervical lymph nodes, the rate of patients with 18F-FDG-PET-positive areas increased in the trapezius, sternocleidomastoid, and posterior neck muscles of the surgical and/or non-surgical sides. In addition, SUVmax of 18F-FDG-PET-positive areas in the trapezius and sternocleidomastoid muscles were increased according to the extent of the ND. CONCLUSIONS: In evaluating 18F-FDG accumulations after ND for oral cancers, we should pay attention to the 18F-FDG distributions in neck-related muscles including the non-surgical side as false-positive findings

A spatial association between odontomas and the gubernaculum tracts.

OBJECTIVES: The purpose of this study was to identify the spatial relationship and/or association between odontomas and the gubernaculum tract or the dental sac and the characteristic findings for radiographic diagnosis of odontomas. STUDY DESIGN: The visualizations of the odontomas and the gubernaculum tract were retrospectively analyzed using cone beam computed tomography or multidetector computed tomography. RESULTS: Most of odontomas were within the gubernaculum tract or dental sac of unerupted permanent teeth on computed tomography. In some odontomas, the gubernaculum tract existed as a well-defined low density tract extending from the top of odontomas on computed tomography. CONCLUSIONS: A close spatial relationship and/or association between odontomas and the gubernaculum tract or dental sac on computed tomography may be used as one of the criteria for radiographic diagnosis of odontomas. Development of odontomas may be associated with the gubernaculum tract or dental sac of unerupted permanent teeth.

Detection and imaging characteristics of the gubernacular tract in children on cone beam and multidetector computed tomography.

PURPOSE: To elucidate the appearance and imaging characteristics of the gubernacular tract (GT) during the growth stage of children. Furthermore, this study evaluated the significance of the appearance of the GT. STUDY DESIGN: The visualizations of the GT were retrospectively analyzed by using panoramic radiographs and computed tomography (CT) in children. RESULTS: In patients with normal eruption who had unerupted permanent teeth, except maxillary central supernumerary teeth, the GT was clearly visualized as a well-defined low-density tract on CT but not on panoramic radiographs. In patients with obstructive eruption, including impaction, the GT was deformed and not visible on CT. CONCLUSIONS: This paper describes the frequency of detection and appearance of the GT in unerupted teeth. Preliminary data suggest that any alteration to the GT may be used to predict abnormal eruption of permanent teeth.