Search for the Pair Production of Dark Particles X with K_{L}

We present the first search for the pair production of dark particles X via K_{L}^{0}→XX with X decaying into two photons using the data collected by the KOTO experiment. No signal was observed in the mass range of 40-110 MeV/c^{2} and 210-240 MeV/c^{2}. This sets upper limits on the branching fractions as B(K_{L}^{0}→XX)<(1-4)×10^{-7} and B(K_{L}^{0}→XX)<(1-2)×10^{-6} at the 90% confidence level for the two mass regions, respectively.

Scaling of charge-changing interaction cross sections and point-proton radii of neutron-rich carbon isotopes.

Charge-changing cross sections σ(cc) of stable and unstable nuclei ((9-11)Be, (14-16)C, and (16-18)O) on a carbon target were investigated at 300 MeV/nucleon. A phenomenological analysis based on the Glauber theory indicates an approximate, but universal, scaling of σ(cc) over a wide range of A/Z. This allows the determination of the density distributions of protons tightly bound in the nuclei. An application to (16)C, which is considered to be an anomalously deformed nucleus, indicates a systematic evolution of proton root-mean-square radii and has revealed for the first time a neutron skin effect in carbon isotopes. Being complementary to isotope-shift and electron-scattering experiments, the present method can open up a new approach to explore the structure of exotic nuclei.

Factors affecting prosthetic rehabilitation outcomes in amputees of age 60 years and over.

This retrospective, observational study was designed to investigate factors affecting successful prosthetic ambulation in elderly amputees aged > or = 60 years. The study included 64 unilateral transfemoral or hip disarticulation amputees. Patients who were able to walk > or = 100 m with prosthesis were classified as successful and those who could walk < 100 m as failures. Age, comorbidities, cause of amputation, ability to stand on one leg, patient's motivation for walking and maximum oxygen uptake as a proportion of predicted maximum oxygen uptake (%VO(2max)) during an exercise load test were examined as indicators of physical fitness. Significant differences were noted between the two groups in the number of comorbidities, ability to stand on one leg, patient's motivation for walking and mean %VO(2max). A low number of comorbidities, the ability to stand on one leg, motivation for walking and adequate physical fitness allowing an exercise intensity of > or = 50% VO(2max) were considered to be predictive factors for successful prosthetic rehabilitation.

Multiply charged carbon-ion production for medical application.

Over 3000 cancer patients have already been treated by the heavy-ion medical accelerator in Chiba at the National Institute of Radiological Sciences since 1994. The clinical results have clearly verified the effectiveness and safety of heavy-ion radiotherapy. The most important result has been to establish that the carbon ion is one of the most effective radiations for radiotherapy. The ion source is required to realize a stable beam with the same conditions for daily operation. However, the deposition of carbon ions on the wall of the plasma chamber is normally unavoidable. This causes an "anti-wall-coating effect," i.e., a decreasing of the beam, especially for the higher charge-state ions due to the surface material of the wall. The ion source must be required to produce a sufficiently intense beam under the bad condition. Other problems were solved by improvements and maintenance, and thus we obtained enough reproducibility and stability along with decreased failures. We summarize our over 13 years of experience, and show the scope for further developments.

Application of compact electron cyclotron resonance ion source.

The compact electron cyclotron resonance (ECR) ion source with a permanent magnet configuration (Kei2 source) has been developed at National Institute of Radiological Sciences for a new carbon therapy facility. The Kei2 source was designed for production of C(4+) ions; its performance such as beam intensity and stability has already reached the medical requirements. Therefore, the prototype development of the source for medical use is essentially finished. Recently, we have started a few studies on other applications of the source. One is the production of fullerenes in the ECR plasma and modified fullerenes with various atoms for new materials. A second application is the production of multiply charged ions (not only carbon) for ion implantation. In this paper, some basic experiments for these applications are reported.

Administration of optimum sustained-insulin release PLGA microcapsules to spontaneous diabetes-prone BB/Wor//Tky rats.

To show the possibility of sustained-release insulin formulation composed of PLGA, the optimum one was administered to BioBreeding rat, a model of spontaneous type I diabetes mellitus (IDDM). Every 2 weeks subcutaneous administration made their blood glucose level depend on the insulin release and food intake. However, all of them kept alive with little change or rather a little gain in body weight. Furthermore, some of pregnant rats with intermittent treatment bore fetuses, although additional insulin therapy seemed necessary. Therefore, the formulation could become a new tool as a provider of basal insulin for IDDM patients.

New nanotechnology for the guided tissue regeneration of skin--potential of lyotropic liquid crystals.

Tissue in body must quickly recognize injury to response to the rapid pace of epidermal growth. In skin, the epidermal cells must also react to danger signals from the surrounding extracellular lipid of the stratum corneum spaces and immediately participate by initiating the wound repair process. The topical administration of the lyotropic liquid crystal nanocube to stratum corneum rapidly broke down the lipid lamella structure which would be recognized as a wound without organ-change. This can activate a variety of biological processes. This study set out to determine whether the phase transition of the lipid to a neighbouring different physicochemical structure can stimulate keratinocyte cells and what mechanism is responsible for this response. Using small angle x-ray scattering (SAXS) analysis, a response to the transient structural change of lipid was detected which might result from the diffusion of oil and/or water from nanocube liquid crystal towards the lipid lamella phase. Simultaneously, a significant increase in growth factors and inflammatory cytokines was detected after administration of nanocube. Not only the excess expression of cytokines but also the extent of TEWL as a barrier marker of skin increased. These observations suggest that a structural change in lipid can stimulate and trigger recognition of a slight injury in the wound defence and a repair response as homeostasis. This method actually succeeded in improving photo-induced hyperpigmentation on a human face.

Enhanced skin regeneration by nanoegg formulation of all-trans retinoic acid.

All-trans retinoic acid (atRA) which could smooth wrinkles and produce less pigmented skin after a few months of treatment has been studied in research into topical treatments for a potent inhibitor of new melanin production. However, the clinical responses of commercial atRA cream predominantly comprise severe inflammation. We report a novel nanotechnology "nanoegg" system giving improved effects of atRA self-assembly which were coated by CaCO3. Dorsal areas of hairless mouse and porcine skin were employed for administration of nanoegg ointment and commercial products. The mRNA for heparin-binding epidermal growth factor-like growth factor (HB-EGF) from tissues was measured by a real-time PCR method. All tissues were stained for detection of hyaluronate and the thickness of the epidermis. A clinical trial in humans was carried out at St. Marianna University in Japan. As a result, the irritation and inflammation associated with atRA molecules were substantially reduced. The physicochemical instability of atRA was also dramatically improved. Furthermore, nanoegg enhanced marked expression of mRNA for HB-EGF from keratinocytes, which is known as one of the markers of keratinocyte turnover. Also, production of hyaluronate was surprisingly in the intercellular spaces of the basal and spinous cell layers 2 days after treatment. Even at the low concentration of atRA in the nanoegg system, the proliferation and differentiation of keratinocyte was somewhat enhanced. A nanoegg may thus not only prevent adverse effects, but also markedly enhance the main effect.

Adaptation of the microdosimetric kinetic model to hypoxia.

Ion beams present a potential advantage in terms of treatment of lesions with hypoxic regions. In order to use this potential, it is important to accurately model the cell survival of oxic as well as hypoxic cells. In this work, an adaptation of the microdosimetric kinetic (MK) model making it possible to account for cell hypoxia is presented. The adaptation relies on the modification of damage quantity (double strand breaks and more complex lesions) due to the radiation. Model parameters such as domain size and nucleus size are then adapted through a fitting procedure. We applied this approach to two cell lines, HSG and V79 for helium, carbon and neon ions. A similar behaviour of the parameters was found for the two cell lines, namely a reduction of the domain size and an increase in the sensitive nuclear volume of hypoxic cells compared to those of oxic cells. In terms of oxygen enhancement ratio (OER), the experimental data behaviour can be reproduced, including dependence on particle type at the same linear energy transfer (LET). Errors on the cell survival prediction are of the same order of magnitude than for the original MK model. Our adaptation makes it possible to account for hypoxia without modelling the OER as a function of the LET of the particles, but directly accounting for hypoxic cell survival data.

Two-chamber configuration of Bio-Nano electron cyclotron resonance ion source for fullerene modification.

We report on the modification of fullerenes with iron and chlorine using two individually controllable plasmas in the Bio-Nano electron cyclotron resonance ion source (ECRIS). One of the plasmas is composed of fullerene and the other one is composed of iron and chlorine. The online ion beam analysis allows one to investigate the rate of the vapor-phase collisional modification process in the ECRIS, while the offline analyses (e.g., liquid chromatography-mass spectrometry) of the materials deposited on the plasma chamber can give information on the surface-type process. Both analytical methods show the presence of modified fullerenes such as fullerene-chlorine, fullerene-iron, and fullerene-chlorine-iron.

Recent developments of ion sources for life-science studies at the Heavy Ion Medical Accelerator in Chiba (invited).

With about 1000-h of relativistic high-energy ion beams provided by Heavy Ion Medical Accelerator in Chiba, about 70 users are performing various biology experiments every year. A rich variety of ion species from hydrogen to xenon ions with a dose rate of several Gy/min is available. Carbon, iron, silicon, helium, neon, argon, hydrogen, and oxygen ions were utilized between 2012 and 2014. Presently, three electron cyclotron resonance ion sources (ECRISs) and one Penning ion source are available. Especially, the two frequency heating techniques have improved the performance of an 18 GHz ECRIS. The results have satisfied most requirements for life-science studies. In addition, this improved performance has realized a feasible solution for similar biology experiments with a hospital-specified accelerator complex.

Development of a compact ECR ion source for various ion production.

There is a desire that a carbon-ion radiotherapy facility will produce various ion species for fundamental research. Although the present Kei2-type ion sources are dedicated for the carbon-ion production, a future ion source is expected that could provide: (1) carbon-ion production for medical use, (2) various ions with a charge-to-mass ratio of 1/3 for the existing Linac injector, and (3) low cost for modification. A prototype compact electron cyclotron resonance (ECR) ion source, named Kei3, based on the Kei series has been developed to correspond to the Kei2 type and to produce these various ions at the National Institute of Radiological Sciences (NIRS). The Kei3 has an outer diameter of 280 mm and a length of 1120 mm. The magnetic field is formed by the same permanent magnet as Kei2. The movable extraction electrode has been installed in order to optimize the beam extraction with various current densities. The gas-injection side of the vacuum chamber has enough space for an oven system. We measured dependence of microwave frequency, extraction voltage, and puller position. Charge state distributions of helium, carbon, nitrogen, oxygen, and neon were also measured.

Does the use of a cleanser on skin surrounding pressure ulcers in older people promote healing?

OBJECTIVE: To determine whether the use of a skin cleanser on the skin surrounding pressure ulcers helps to promote healing. METHOD: The study was conducted over a two-year period in patients with stage II or more pressure ulcers. All subjects were at least 65 years of age and resident in a long-term care hospital. During the first year, skin was cleansed with normal saline. In year two, a pH-balanced cleanser was used. The healing times for the two methods were then compared. RESULTS: Healing time was shorter in the group using the cleanser for every stage of ulcer, with an especially significant difference for stage II ulcers (p=0.002). Analysis using the Cox proportional hazards model found a 1.79-fold improvement in the healing rate of stage II ulcers when the surrounding skin was washed with the cleanser. CONCLUSION: Cleaning the surrounding skin with a cleanser rather than normal saline promotes the healing of pressure ulcers.

Immunohistochemical localization of kallikrein within the prolactin-producing cells of the rat anterior pituitary gland.

The localization of tissue kallikrein in the pituitary gland of rats was investigated by an immunohistochemical technique using antiserum against rat urinary kallikrein. Kallikrein-positive cells were detected in the anterior lobe of the pituitary of both male and female rats, but were not observed in the posterior lobe of the pituitary in either sex. The kallikrein-positive cells in the anterior pituitary of female rats in oestrus were found to correspond to the prolactin-producing cells, whereas the cells producing GH, LH and ACTH were negative for kallikrein. It is possible, therefore, that the tissue kallikrein may be involved in the production of prolactin and not that of the other anterior pituitary hormones, such as GH, LH, FSH, ACTH and TSH.

Kallikrein- and prolactin-producing cells in the rat anterior pituitary are the same.

Kallikrein-positive cells in the anterior pituitary of female rats were identified to be the same as prolactin-producing cells by using an immunoelectron microscopic method. The kallikrein immunoreactivity was localized at the Golgi apparatus, the rough endoplasmic reticulum, and secretory granules, suggesting that kallikrein is synthesized in the prolactin-producing cells and also may be secreted into the blood vessels.

Multiple lipomas of the ileum with volvulus.

We describe a patient with symptomatic multiple lipomas with volvulus. He complained of gradually increased abdominal pain and distention. Preoperative roentgenograms showed many rounded filling defects of the small intestine. Operation was performed to reduce intestinal obstruction and ileal resection was performed. The dilated ileum was rotated 720 degree clockwise and it contained 115 submucosal and 26 subserosal lipomas. Histologically, the lipomas were benign and consisted of well-developed fat tissue. The patient's postoperative course was satisfactory, and neither residual lipoma nor recurrence were found at barium enema examination two years after operation.

Selection of peptides that bind to the core oligosaccharide of R-form LPS from a phage-displayed heptapeptide library.

To characterize common sites within the core oligosaccharide of the R-form lipopolysaccharide (LPS), we screened peptides from a phage-displayed heptapeptide library by using the most truncated form of R-LPS, Re-LPS (S. Typhimurium SL1165) as a ligand. After three rounds of biopanning/amplification and subsequent screening by phagemid enzyme-linked immunosorbent assay (ELISA), we selected three distinct clones that bind to the ligand LPS. We characterized the binding sites of the three clones by ELISA and thin-layer chromatography immunostaining and found that the three clones bind the two Re-LPSs (SL1165 and S. Minnesota Re595) and Rb2-LPS. In addition, one of the clones also bound to S-form LPS (S. Enteritidis). Current data show that those clones bind to common carbohydrate structure(s) expressed in the core oligosaccharides of those LPS samples.

Insulin-loaded biodegradable PLGA microcapsules: initial burst release controlled by hydrophilic additives.

We investigated the controlled release of human insulin at an initial stage from poly(DL-lactic-co-glycolic acid) (PLGA, M(w) 6600) spherical matrices. PLGA microcapsules were prepared by the novel solvent evaporation multiple emulsion process. When the crystalline insulin was dispersed in dichloromethane as solid-in-oil (S/O) dispersion, it was found that most of insulin molecules were inlaid on the surface of PLGA microcapsules. Consequently, insulin-loaded PLGA microcapsules exhibited marked rapid release of insulin within several hours in both in vivo and in vitro experiments. On the other hand, the addition of glycerol or water in the primary dichloromethane dispersion results in drastically suppressed initial release. It was found by SEM observation that water- or glycerol-in-oil (W/O or G/O) type mini-emulsion droplets with a mean diameter of 300-500 nm were formed in this primary solution. This phenomenon can be theoretically presumed to occur because insulin and PLGA molecules, having amphiphilic properties, converge on the interface between the hydrophilic additive and dichloromethane. Hence, insulin molecules heterogeneously located in the inside of PLGA microcapsules, not on the surface, would be gradually released with PLGA hydrolytic decomposition. As an additional effect of glycerol, the initial burst was further suppressed due to the decrease of the glass transition temperature of PLGA from 42.5 to 36.7 degrees C. Since the annealing of PLGA molecules took place at around 37 degrees C, the porous structure of microspheres immediately disappeared after immersion in PBS or subcutaneous administration. The insulin diffusion through the water-filled pores would be effectively prevented. The strict controlled initial release of insulin from the PLGA microsphere suggested the possibility of utilization in insulin therapy for type I diabetic patients who need construction of a basal insulin profile.

Marked hypotensive and blood flow-increasing effects of a new lipo-PGE(1) (lipo-AS013) due to vascular wall targeting.

Lipo-AS013 is being developed as an improved formulation of lipo-PGE(1), which is widely used in clinical practice in Japan and some Asian countries. We have previously reported that lipo-AS013, which is a lipid microsphere (LM) preparation of a chemically stable and lipophilic PGE(1) prodrug (AS013, Fig. 1), slowly releases small amounts of the active ingredient (AS013) in human plasma. In the present study, to estimate the vascular wall targeting ability and efficacy of lipo-AS013, we determined the hypotensive and blood flow-increasing effects of lipo-AS013, lipo-PGE(1), PGE(1)CD, and AS013. Lipo-AS013 was found to have longer-lasting hypotensive and blood flow-increasing effects than the other agents. The two LM preparations, lipo-PGE(1) and lipo-AS013, had a markedly stronger effect than PGE(1)CD and AS013 alone, demonstrating the benefit of drug delivery using LM. In spontaneously hypertensive rats (SHR), lipo-AS013 also had a significant hypotensive effect. To confirm vascular wall targeting by lipo-AS013, the localization of PGE(1) in the aorta and neovascular capillaries of rat was investigated by immunostaining. The results indicated that lipo-AS013 was more efficient at delivering the active ingredient (AS013) to the vessel wall. In conclusion, lipo-AS013 could supersede lipo-PGE(1) and PGE(1)CD in clinical use.