Development of a New Focal Mouse Model of Bone Metastasis in Renal Cell Carcinoma

BACKGROUND/AIM

Developing animal models of bone metastasis in renal cell carcinoma (RCC) is challenging as immunodeficient mice are required. The aim of this study was to develop a simple immune model of RCC bone metastasis.

MATERIALS AND METHODS

RENCA tumor cells were injected into the right femurs of BALB/c mice. Sixty mice were grouped into each twenty-mouse group according to the tumor cell concentration, and the presence or absence and extent of bone metastasis in the total length of the femur were compared using hematoxylin and eosin staining of the excised tissues.

RESULTS

Bone metastasis was significantly higher in the high concentration group than in the other groups (p<0.05), with 10 mice developing bone metastasis at two weeks and nine mice developing bone metastasis at three weeks. The extent of bone metastasis was significantly greater in the high concentration group than in the other groups (p<0.05). Multiple logistic regression analysis was performed to examine the factors influencing bone metastasis, and only the high concentration was a significant factor (p<0.05).

CONCLUSION

We developed a normal immunity mouse model of local bone metastasis from RCC. This model could prove valuable for research into the treatment of bone metastases in RCC.

Dysphagia Secondary to Myotonic Dystrophy Unveiled in a Case of Destructive Spondylitis With Synovitis, Acne, Pustulosis, Hyperostosis, Osteitis (SAPHO) Syndrome Presenting As Torticollis

To report an instructive case involving destructive spondylitis and synovitis-acne-pustulosis-hyperostosis-osteitis (SAPHO) syndrome, presenting with torticollis and postoperative dysphagia without hoarseness, attributed to hidden myotonic dystrophy (DM). A 51-year-old male patient with a cervical deformity, who was previously managed conservatively for a metastatic tumor, underwent reconstruction surgery and subsequently experienced postoperative dysphagia. The presence of destructive spondylitis with torticollis, warranting prompt assessment to prevent paralysis, adds complexity to the delayed identification of DM. Given the rarity of DM, peculiar neurological symptoms and other systemic comorbidities did not lead to a preoperative diagnosis without prior knowledge. The patient's dysphagia induced respiratory arrest and required reintubation. Challenges in extubation and ventilator weaning arose due to hypercapnia. Superimposed COVID-19 infection elongated the duration of intubation. Extubation failed due to aspiration pneumonia and required a tracheotomy. Despite laryngeal elevation and preservation of the relaxation of the oesophageal entrance, the sensation and movement of the tracheopharynx were disturbed. The patient exhibited an oropharyngeal propulsive disorder, predominantly indicative of motor neuron disease. The patient's mother stated that his brother had been hospitalized for a long time after abdominal surgery. Finally, the patient was diagnosed with DM, which is known to cause post-anesthetic dysphagia. Recognizing the existence of severe destructive cervical spondylitis associated with SAPHO is crucial. Although DM is not very common, it is not classified as extremely rare. Therefore, surgeons should be mindful of the potential risks associated with general anesthesia in patients with DM. The complexity of preoperative conditions may hinder an accurate diagnosis. Recognizing and establishing preoperative expectations can assist surgeons in preventing complications, even if complex spinal surgery is required for patients with DM.

Teriparatide and etelcalcetide improve bone, fibrosis, and fat parameters in chronic kidney disease model rats

Objectives

Chronic kidney disease (CKD) complicated by secondary hyperparathyroidism (SHPT) is associated with an increased risk of fragility fractures. Etelcalcetide (EC) is a treatment for SHPT that reduces serum parathyroid hormone (PTH) levels. However, the effects of combined treatment with osteoporosis drugs such as teriparatide (TPTD) remain unclear. This study investigates the combined effects of EC and TPTD on bone in CKD model rats.

Methods

The CKD model was established in 8-week-old male Wistar rats by feeding them a 0.75% adenine diet for 4 weeks. At 20 weeks of age, the rats were divided into 4 groups (N = 9-10 in each group): CKD group (vehicle administration), TPTD group (30 μg/kg, 3 times/week), EC group (0.6 mg/kg, daily), and Comb group (TPTD and EC combined). EC was injected for 12 weeks starting at 20 weeks of age, and TPTD was injected for 8 weeks starting at 24 weeks of age. After treatment, the followings were evaluated: bone mineral density, bone strength, biochemical tests, bone and fat histomorphometry, and micro-computed tomography.

Results

In CKD model rats, the combination of EC and TPTD was more effective in increasing cortical bone thickness and bone strength and inhibiting porosity. In addition, the combined treatment decreased bone marrow adiposity and fibrosis, and it increased bone mass and improved bone microstructure in trabecular bone.

Conclusions

With the observed benefits such as improved bone mass, bone strength, structural properties, and bone marrow adiposity, combination therapy may be a potential way to improve bone fragility in CKD.

Effects of bisphosphonates and treadmill exercise on bone and kidney in adenine-induced chronic kidney disease rats

INTRODUCTION

The increasing prevalence of osteoporosis and chronic kidney disease (CKD) due to the aging of society has highlighted the need for development of effective treatments for elderly patients. This study examined whether the combination of treadmill exercise therapy and alendronate (ALN) can improve bone mineral density (BMD) and bone strength without worsening renal function in adenine-induced CKD model rats.

MATERIALS AND METHODS

8-week-old male Wistar rats (n = 70) were divided into experimental groups based on the treatment protocol, i.e., non-CKD (control), vehicle only (CKD), ALN only, exercise only, and combined ALN plus exercise. A 0.75% adenine diet was used to induce CKD. Groups were killed at either 20 or 30 weeks of age. Comprehensive assessments included serum and urine biochemistry tests, renal histology, bone histomorphometry, BMD measurement, micro-computed tomography examinations, and biomechanical testing.

RESULTS

Blood biochemistry tests, urine analyses and histological evaluations of the kidney demonstrated that ALN treatment did not worsen renal function or kidney fibrosis in moderate-stage CKD model rats. Both ALN and treadmill exercise significantly suppressed bone resorption (p < 0.05-p < 0.01). Moreover, ALN monotherapy and combined ALN and treadmill exercise significantly improved BMD of the lumbar spine and femur, bone microstructure, and trabecular bone strength (p < 0.05-p < 0.01). Treadmill exercise was also shown to decrease cortical porosity at the mid-diaphysis of the femur and improve kidney fibrosis.

CONCLUSION

The combination of ALN and treadmill exercise is effective in improving BMD, the microstructure of trabecular and cortical bone, and bone strength, without compromising renal function in adenine-induced CKD model rats.

Effects of Soft Tissue Sarcoma and Doxorubicin on Bone Metabolism in Mice

BACKGROUND/AIM

This study aimed to evaluate the effects of doxorubicin (Dox) on bone microstructure and metabolism in a mouse model of soft tissue sarcoma.

MATERIALS AND METHODS

CCRF S-180II cells (2-4×10⁵ cells/0.2 ml) were injected subcutaneously into the back of mice. The mice were divided into four groups according to tumor and treatment status and were reared and sacrificed after 2 or 4 weeks. Micro-computed tomography (CT) was performed to calculate the architecture of the femoral bone. The proximal tibia was double stained with tartrate-resistant acid phosphatase (TRACP) and alkaline phosphatase (ALP), and bone morphometry was performed.

RESULTS

Trabecular bone mass was significantly reduced in the Sarcoma and Sarcoma+Dox groups. Cortical bone thickness was reduced in the DOX group, with a stronger effect observed in the Sarcoma+Dox group. In bone morphometry, osteoclast number at the bone surface (Oc.N/BS) was significantly lower in the Dox, Sarcoma, and Sarcoma+Dox groups than in the Control group at 2 weeks. The osteoblast surface at the bone surface (Ob.S/BS) was significantly lower in the Dox and Sarcoma groups than in the Control group at 2 weeks. At 4 weeks, the differences were smaller for both Oc.N/BS and Ob.S/BS.

CONCLUSION

The use of doxorubicin alone worsened the cortical bone structure; however, the presence of both soft-tissue sarcoma and doxorubicin use worsened both cortical and trabecular bone structures from an early stage.

Molten salt synthesis of CrMnFeNi alloy nanopowder passivated by TiOx–ZrOy shell used as a superior catalyst support in liquid-phase hydrogenation†

A molten salt method was used to prepare CrMnFeNi alloy nanopowder passivated by TiO_x–ZrO_y surface shell with a high specific surface area (23 m² g⁻¹) from the oxide precursors. Analyses by scanning electron microscopy/transmission electron microscopy with energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy revealed the formation of an alloyed Cr–Mn–Fe–Ni-rich core surrounded by an oxide surface shell with a Ti/Zr-rich composition, confirming the formation of TiO_x–ZrO_y/CrMnFeNi nanopowder. It was speculated that the CrMnFeNi alloy nanoparticles were preferentially formed from the constituent metals by a faster reduction of any oxides of Cr, Mn, Fe, and Ni and a subsequent alloying with Ti and Zr could hardly occur due to the high thermodynamic stability of CrMnFeNi alloy. A Ni-loaded TiO_x–ZrO_y/CrMnFeNi catalyst exhibited superior catalytic performance to common Ni-loaded TiO₂ and ZrO₂ in the liquid-phase hydrogenation of p-nitrophenol at room temperature. The enhancement could have originated from an excellent electrical property of CrMnFeNi alloy, promoting the formation of active metallic nickel on the surface during the reaction. Leaching amounts of the constituent elements of Ti–Zr–Cr–Mn–Fe–Ni and loaded Ni was very little in the reaction solution after the reaction; the results confirmed that the prepared CrMnFeNi alloy nanopowder was very stable due to the protection of the Ti/Zr-rich oxide shell. Thus, the potential application of the alloyed powder used as catalyst support was demonstrated.

The enhancement of liquid-phase hydrogenation by NaBH₄ over Ni-loaded CrMnFeNi alloy nanoparticles passivated by TiO_x–ZrO_y.

Molten Salt Synthesis of Intermetallic Compound TiNi Nanopowder Passivated by TiOx Shell Prepared from NiTiO3 for Catalytic Hydrogenation

Titanium-nickel alloy is an attractive material due to its unique properties of shape memory effect, superior elasticity, and biocompatibility. Generally, Ti-Ni alloy powders are prepared from pure elemental powders of Ti and Ni as starting materials, but it is an energy-intensive process to obtain pure titanium. In this study, intermetallic compound TiNi powder passivated by TiO_x shell was prepared by directly reducing a commercial NiTiO₃ using CaH₂ reducing agent in a molten LiCl at 650 °C. Analyses by X-ray diffraction, scanning electron microscopy/transmission electron microscopy with energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy revealed that the powder had a core-shell structure, with the core of TiNi and the shell of TiO_x-rich composition with scarce metallic Ni nicely catalyzing hydrogenation reactions with good recyclability and stability.

Effects of teriparatide and low-intensity aerobic exercise on osteopenia in type 2 diabetes mellitus rats

INTRODUCTION

In patients with type 2 diabetes mellitus (T2DM), bone fragility increases fracture risk. Teriparatide (TPTD) improves bone strength, and exercise therapy suppresses blood glucose levels in T2DM. In this study, the combined effects of TPTD and exercise therapy on trabecular and cortical bone were examined in advanced T2DM model rats.

MATERIALS AND METHODS

Thirty-week-old Otsuka Long-Evans Tokushima Fatty rats were divided into four groups (n = 9-10 in each group at two time points): Cont group (vehicle-treated control), TPTD group (TPTD 30 μg/kg injected subcutaneously, 3 times/week), Exe group (treadmill exercise, 10 m/min, 60 min/day, 5 times/week), and Comb group (TPTD-treated and treadmill exercise combined). Five and 10 weeks after treatment, bone mineral density (BMD), bone strength, and bone micro-architecture were measured.

RESULTS

TPTD and combined treatment significantly increased BMDs of the lumbar spine and femur compared to the Cont group (p < 0.05 to p < 0.01). In the three-point bending test of the femur, only combined treatment increased the maximum load at 5 weeks compared with the Cont and Exe groups (p < 0.01). In the compression test of the distal femoral metaphysis, both TPTD and combined treatment increased the trabecular bone strength compared with the Cont and Exe groups (p < 0.05 to p < 0.01). Although TPTD and combined treatment improved the micro-architecture of trabecular bone (p < 0.05 to p < 0.01), only combined treatment improved the micro-structures of cortical bone from 5 weeks of treatment (p < 0.05 to p < 0.01).

CONCLUSION

The combination of TPTD and treadmill exercise increased BMD and trabecular and cortical bone strength of the femur with improved micro-architecture in T2DM model rats.

Development of New Mouse Breast Cancer Model of Local Bone Metastasis and Verification Using Bisphosphonates

BACKGROUND/AIM

Local tumor injection models require complicated procedures. The purpose was to establish a simple local bone metastasis model using normal mice, and to study the usefulness of the model with bisphosphonates (BP).

MATERIALS AND METHODS

This study used a versatile C57BL/6 mouse model and E0771 cells. Tumor cells were injected into the right femur. Mice were divided into groups depending on the concentration of cells injected and the use of BP or not. The degree of bone destruction between the different conditions was compared using micro-computed tomography (μCT).

RESULTS

Bone destruction was confirmed in four mice in the high-concentration group at 3 weeks, and in all other mice at 4 and 6 weeks. At 6 weeks post-injection, bone destruction was significantly suppressed in the BP group (p<0.05).

CONCLUSION

We created a breast cancer mouse model of local bone metastasis. Zoledronate showed the same usefulness as in previous models. It may be an effective model for evaluating treatments for bone metastasis.

Analysis of bone in adenine-induced chronic kidney disease model rats

Objectives

The purpose of this study is to investigate the stage of chronic kidney disease (CKD) in adenine-induced CKD model rats by serum analyses, and to examine bone mineral density (BMD), bone strength, and microstructure of trabecular and cortical bone in these rats.

Methods

Eight-week-old, male Wistar rats (n = 42) were divided into 2 groups: those fed a 0.75% adenine diet for 4 weeks until 12 weeks of age to generate CKD model rats (CKD group); and sham rats. The CKD and sham groups were sacrificed at 12, 16, and 20 weeks of age (n = 7 in each group and at 12, 16, and 20 weeks), and various parameters were evaluated, including body weight, renal wet weight, muscle wet weight, renal histology, biochemical tests, BMD, biomechanical testing, and micro-computed tomography (CT). The parameters were compared between the 2 groups at the various time points.

Results

In the CKD model rats, at 20 weeks of age, serum creatinine, phosphorus, and intact-PTH levels were elevated, and serum calcium levels were normal, indicating that the CKD was stage IV and associated with secondary hyperparathyroidism. Decreased BMDs of the whole body and the femur were observed as bone changes, and micro-CT analysis showed deterioration of bone microstructure of the cortical bone that resulted in decreased bone strength in the cortical and trabecular bone.

Conclusions

These CKD model rats showed stage IV CKD and appear appropriate for evaluating the effects of several treatments for CKD-related osteoporosis and mineral bone disorder.

Teriparatide and exercise improve bone, skeletal muscle, and fat parameters in ovariectomized and tail-suspended rats

INTRODUCTION

Although teriparatide (TPTD) and exercise may improve osteoporosis, muscle atrophy, and fat metabolism during ageing, the effects of treatment with a combination of TPTD and exercise on these factors remain unclear. Therefore, this study examined the effects of TPTD and exercise on bone, skeletal muscle, and fat in ovariectomized and tail-suspended rats.

MATERIALS AND METHODS

Seven-month-old female Wistar rats were ovariectomized and subjected to tail suspension. The rats were then randomized into one of the following four groups (n = 20/group) after 4 weeks: control group, treated with TPTD vehicle and no exercise; TPTD group (30 µg/kg TPTD, 3 days/week); Exercise group (treadmill at 12 m/min, 60 min/day, 5 days/week); and Combined group treated with TPTD and treadmill exercise. After 1 and 8 weeks of treatment, bone, skeletal muscle, and fat tissue parameters were evaluated.

RESULTS

TPTD improved bone mineral density (BMD), bone structure, bone strength at the femoral metaphysis, and the percentage of skeletal muscle mass, and decreased the percentage of fat mass and the adipose volume in the bone marrow. Treadmill exercise increased BMD, bone strength of cancellous bone, and the percentage of skeletal muscle mass, and decreased the percentage of fat mass as seen on dual-energy X-ray absorptiometry. Furthermore, combined treatment significantly affected BMD, bone structure, and bone strength of cortical bone at the femoral diaphysis.

CONCLUSION

TPTD or treadmill exercise improved bone, skeletal muscle, and fat mass. Combination therapy with TPTD and exercise had synergistic effects on BMD, structure, and bone strength in ovariectomized, tail-suspended rats.

Pediatric spinal infection with epidural abscess: A report of two cases

Background

Pediatric spinal infections are rare and often accompanied by abscesses. Delayed diagnosis commonly leads to a poor neurological prognosis, emphasizing the need for early diagnosis and treatment.

Case Description

We report on two cases of spinal infection; one in a 5-year-old boy with a T8-11 epidural abscess and one in a 10-year-old boy with an L5-S1 epidural abscess. Both cases improved with conservative therapy.

Conclusion

Early magnetic resonance imaging diagnosis and systemic treatment in collaboration with pediatricians are key factors in the successful management of children with spinal infections.

Toxicological effects of chlorophenols to green algae observed at various pH and concentration of humic acid

Humic acid (HA) is ubiquitous organic matter derived by microbial metabolisms. This polymeric substance has both hydrophilic and hydrophobic moieties, and it is known that they affect to bioavailability of environmental pollutants. Objective of this study is to investigate the toxicological effects of chlorophenols to green algae observed at various pH and concentration of HA. Toxicity was determined by algal growth inhibition rate and EC₅₀ of green algae Chlorella vulgaris. As a result, toxicity of 2,4-dichlorophenol was mitigated with increase of the coexisting amount of HA and solution pH. In the case of coexisting 2.5 ppm HA, EC₅₀ of 2,4-dichlorophenol was 12.2 ppm and approximately three times higher than the case of absence of HA at pH 7.5. Meanwhile, Toxicity of 2,4,6-trichlorophenol was enhanced with increase of the coexisting amount of HA. In the case of absence of HA, EC₅₀ of 2,4,6-trichlorophenol was 13.1 ppm and approximately two times higher than the case of coexisting 2.5 ppm HA at pH 7.5. Results suggested that toxicity of chlorophenols is influenced by the electrostatic and hydrophobic interaction between HA and chlorophenols. The hypothesis of toxicity enhancement pathway was proposed in the case of equilibrium-state 2,4,6-trichlorophenol between anionic and nonionic states.

Falls from heights while clearing snow in Akita prefecture: Re-evaluation after preventive countermeasures and public service

BACKGROUND

This study was performed to re-examine the incidence of falls from heights while clearing snow in Akita prefecture after implementation of preventive countermeasures and a public service campaign.

METHODS

This was a retrospective analysis of registration data from the section regarding prevention against natural disasters in the Akita prefectural office. The study population comprised all patients who fell from heights while clearing snow and were transported to the emergency department from December 2015 to March 2018.

RESULTS

In total, 168 individuals (159 male, 9 female) fell from heights while clearing snow. Their mean age was 65.7 years (range, 19-92 years). The largest proportion of falls occurred in January (54.2%; 91 patients). The most common region in which the falls occurred was the inland part of the southern district of Akita prefecture, which accounted for 73.8% of the falls (124 patients). Individuals aged ≥65 years constituted 52.9% of the patients (n = 89). The most common mechanism of injury was a fall from a rooftop, which accounted for 62.5% of the falls (105 patients), followed by a fall from a ladder (31.0%; 52 patients). The most common sites of injury were the upper and lower extremities (39.2%; 66 patients), followed by the spine (36.3%; 61 patients). Seven of the patients died.

CONCLUSIONS

Compared with a previous study by Hatakeyama et al. (Falls from heights while clearing snow in Akita Prefecture. Rinsyou Seikeigeka Clin Orthop Surg 2013 Nov; 48(11): 1091-4 [in Japanese]), the total number of patients who fell from heights while clearing snow decreased by one-half. However, the number of persons aged ≥65 years increased and constituted 52.9% of the patients, reflecting the rapidly expanding older population in Akita prefecture.

Foix-Chavany-Marie Syndrome Induced by a Unilateral Brain Abscess

Foix-Chavany-Marie syndrome (FCMS) is a rare cortical type of pseudobulbar palsy characterized by the loss of voluntary control of the facial, pharyngeal, lingual, and masticatory muscles with preserved reflexive and autonomic functions. FCMS is generally associated with cerebrovascular diseases affecting the bilateral opercular regions. We herein report the clinical features of an 84-year-old right-handed Japanese man with FCMS due to a unilateral brain abscess. The patient's symptoms were resolved after treating the brain abscess. The present clinical results suggest that a unilateral brain abscess in the temporal operculum with a persistent old lesion in the contralateral insular cortex can induce FCMS.

A case of combined laparoscopic reduction and open preperitoneal mesh repair for incarcerated small bowel in a retroperitoneal hernia between the external and internal iliac vessels

We report a rare case of an incarcerated retroperitoneal hernia with or involving the small bowel through the orifice between the right external and internal iliac vessels. A 39-year-old woman was admitted to our hospital because of vomiting and abdominal pain. She had a history of right oophorocystectomy and appendectomy. Abdominal computed tomography revealed small bowel obstruction resulting from an incarcerated retroperitoneal hernia. The small bowel herniated into the retroperitoneal fossa through the orifice between the right external and internal iliac vessels. Laparoscopic reduction of the small bowel was performed, followed by ligation of the sac and placement of a mesh prosthesis through the preperitoneal approach, using a lower midline incision along the previous laparotomy scar. Her postoperative course was uneventful and no recurrence has been observed after surgery.

Analysis of ammonia toxicity in landfill leachates

Toxicity identification evaluation (TIE) phase I manipulations and toxicity test with D. magna were conducted on leachates from an industrial waste landfill site in Japan. Physicochemical analysis detected heavy metals at concentrations insufficient to account for the observed acute toxicity. The graduated pH and aeration manipulations identified the prominent toxicity of ammonia. Based on joint toxicity with additive effects of unionized ammonia and ammonium ions, the unionized ammonia toxicity (LC50,NH3(aq)) was calculated as 3.3 ppm, and the toxicity of ammonium ions (LC50,NH4 (+) ) was calculated as 222 ppm. Then, the contribution of ammonia toxicity in the landfill leachate toxicity was calculated as 58.7 vol% of the total toxicity in the landfill leachate. Other specific toxicants masked by ammonia's toxicity were detected. Contribution rate of the toxicants other than by ammonia was 41.3 vol% of the total toxicity of the landfill leachate.

Preservation of microplate-attached human hepatoma cells and their use in cytotoxicity tests

We investigated the feasibility of hypothermic- orcryogenically-preserved human hepatoma Hep G2 cell preculturedin 96-well plates in cytotoxicity testings. First, we observedthat microplates precoated with both collagen (CN) and pronectin (PN) showed significantly improved living cell adhesion (71.0 +/- 5.5%) after 48 hr of cryopreservation with 10%-DMSO containing culture medium, whereas non-coated surfaces gave very low living cell adhesion (33.5 +/- 2.1%). Hypothermic preservation was most suitable for short-term storage, and cryogenic preservation at -20 degrees C allowed cells to be used within a week of the storage period. Only cryopreservation in a deep freezer (-85 degrees C) gave satisfactory results in much longer period of storage. Second, we evaluated the cytotoxicity of ten chemicals during 48 hr of exposure using hypothermically - (4 degrees C for 2 days) or cryogenically - (-85 degrees C for 7 days) preserved cells cultured inCN/PN-precoated microplates in comparison with results fromfreshly inoculated cells. Although almost the same LD(50)values were obtained, LD(10) values of relatively hydrophilic chemicals obtained with cryopreserved cell were significantly lowered. These results shown that CN/PN-precoating is effective in keeping cells attached even in recultivation of preserved cells and that the toxicities of relatively hydrophilic chemicals tend to be overestimated when we use preserved cells in that manner.

A new model for predicting time course toxicity of heavy metals based on Biotic Ligand Model (BLM)

A new model for predicting time course toxicity of heavy metals was developed by extending the effective ratio of biotic ligand binding with toxic heavy metals to the total biotic ligand for 50% of test organisms (f(50)) derived by the Biotic Ligand Model (BLM). BLM has been well-known as a useful model for prediction of heavy metal toxicity. BLM can consider the effect of exposure conditions such as pH and Ca(2+) on heavy metal toxicity. In addition to the exposure conditions, heavy metal toxicity is strongly dependent on exposure time. In this study, BLM is extended to predict time dependency of heavy metal toxicity by connecting with the concept of primary reaction. The model developed in this study also generates the estimation of the 50% effect concentration (EC(50)) for toxicologically unknown organisms and heavy metals. Two toxicological and kinetic constants, f(50,0) and k, were derived from the initial value of f(50) (f(50,0)) and a time constant (k) independent of time. The model developed in this study enables us to acquire information on the toxicity of heavy metals such as Cu, Cd and Co easily.

Evaluation of the ecotoxicity of solid wastes using rapid leaching test and bioassays

A rapid leaching test (RLT) involving the use of ultrasonic irradiation was developed. The applicability and suitability of different leaching procedures for solid wastes were evaluated in terms of the leached concentration of heavy metals and total organic carbon and the ecotoxicity potential of the solid wastes. Solid wastes, including incineration ash and sludge, were used. We performed the RLT and the Japanese standard leaching test (JLT-13) to evaluate the ecotoxicity of the solid wastes. The leaching test samples were analyzed using 3 different bioassays. A higher concentration of heavy metals was obtained by the RLT than by JLT-13. The concentrations of organic compounds leached by the RLT correlated well with those of the organic compounds leached by JLT-13. These results indicate that the RLT developed in this study is a useful method to estimate the leachability of heavy metals and organic compounds in solid waste samples. Although the 50% effective concentration (EC(50)) values of the RLT and JLT-13 solid waste eluates derived by a human cell-based bioassay were slightly different, the EC(50) values of these eluates derived by 2 other ecotoxicity tests correlated well.

Ecotoxicity assessment of sludge and leaching test eluates of sludge

Sludge mainly collected from wastewater treatment plants were subjected to chemical and ecotoxicological characterization to provide a preliminary assessment of their suitability for land application. We examined the leachability and toxicity of organic compounds in several industrial wastes and recovered materials such as dewatered sludge through standard leaching tests. Several toxicity tests were performed under standard laboratory conditions using a freshwater alga, a crustacean, and some terrestrial plants. Some eluates showed high toxicity. No correlation was found between the ecotoxicological and chemical characteristics or the sum parameters (TOC, total organic carbon concentration). Further, bioassays are extended to exhibit the toxicity, which can be explained by the presence of organic compounds. In general, the eluates differed in their toxicity profiles and their organic chemical composition. Therefore, chemical analyses are unreliable for quantifying biological effects. The samples can be classified as ecotoxic/hazardous based on the LC/EC(50) (lethal concentration/effective concentration reducing 50% of survival or biological activity) values. It is necessary to know the relative ecotoxicity of the potential leachate from organic sludge waste before landfill in order to predict the environmental impact in the event of leakage from the landfill.

Toxicity of copper and cadmium in combinations to Duckweed analyzed by the biotic ligand model

The biotic ligand model (BLM) of acute toxicity to aquatic organisms is based on the concept that metals binding onto biotic ligand may cause toxic effect on the organism. The BLM can take into incorporation between metal speciation and the protective effects of competing cations account. The demonstrated BLM can provide a good estimation of the amount of single metal effect under various conditions such as pH, coexistence of other non toxic cations. However, toxic metals are often found as mixture in nature. This study estimated combined toxicity of Cu and Cd examined by growth inhibition of Duckweed (Lemna paucicostata) by using single toxicity data as toxic unit (TU) derived by three types of model, BLM and two conventional models, free ion activity model (FIAM), and total metal concentration model. According to our results, single toxicity data derived by the BLM can estimate combined toxicity described as a function of TU. Particularly under the high level of heavy metals stress, BLM clearly predicted toxicity of heavy metals compared with other two models. According to numeric correlation (R(2), root mean square error), the order is BLM (R=0.83, RMSE=13.5)> total metal concentration model (R=0.41, RMSE=24.9)> FIAM (R=0.36, RMSE=26.1).

Effect of dissolved organic matter source on phytotoxicity to Lemna aequinoctialis

The effect of dissolved organic matter (DOM) on metal toxicity to aquatic organisms has been reported. Biotic ligand model (BLM) can account for this factor to predict metal toxicity. However, few attempts have been made to assess the effect of the DOM on metal phytotoxicity to duckweeds. The objectives of this study were to examine the effect of DOM on copper toxicity to the duckweed Lemna aequinoctialis, and to determine if DOM concentration alone, regardless of DOM source, is an acceptable input parameter for the BLM for copper. Nine different DOM isolates from nine different sites in Japan were used in this study. A significant difference was observed between the lowest and the highest copper binding capacity. Phytotoxicity for copper decreased with increasing DOM concentration. These observations support use of the copper biotic ligand model (BLM) with AFA% (active fulvic acid percent) as a regulatory tool to predict copper phytotoxicity on duckweeds.

Arsenic speciation for the phytoremediation by the Chinese brake fern, Pteris vittata

Arsenic (As) speciation for the phytoremediation by the Chinese brake fern was studied. In particular, the mechanism of how plants induce compounds containing thiol (SH) and proteins by As exposure in terms of the relationship between As and phosphate uptaken into plant cells was examined. Pteris vittata callus could efficiently reduce As(V) to As(III) by the rapid introduction of reductase and synthesize thiols leading to phytochelatins production. Furthermore, Pteris vittata could control phosphate concentration in the cells corresponding to the concentration of arsenite and arsenate. To our best knowledge, this is the first report to show the mechanisms of such high As tolerance of Pteris vittata using their callus in terms of in vitro approach for the analysis of As speciation and metabolism route.

Prediction of genotoxicity of various environmental pollutants by artificial neural network simulation

In order to evaluate human carcinogenic risks, genotoxicity data such as animal cancer bioassay are often not available. In this study, to assess the relevance of indicator of carcinogenic risks, we used the "molecular diversity approach" to estimate the genotoxicity based upon Salmonella genotoxicity test using the umu test and systemic toxicity data of the 82 environmental chemicals predicted by neural network simulation. The 82 environmental chemicals were randomly selected for this study according to the production and usage in Japan. Even in this challenging trial for QSTR (Quantitative Structure Toxicity Relationship) study, approaches using artificial neural networks can account for about 94% of the variation in the genotoxicity results derived by the umu-test.

The Influences of Method of Calcium Correction and the Timing of Blood Collection on Application of The K/DOQI Clinical Practice Guidelines for Bone Metabolism and Disease in Japan

We investigated the treatment of renal osteodystrophy (ROD) in Japan and problems concerning the K/DOQI Guidelines. The subjects were 3698 hemodialysis patients (2328 males and 1370 females) with a mean age of 61.4 years. On average, they had been on hemodialysis for 8.34 years. The serum phosphorus level was <3.5 mg/dL in 5% of the subjects, 3.5-5.5 mg/dL in 49%, 5.6-7.0 mg/dL in 33%, and >7.0 mg/dL in 13%. The serum calcium level was <8.4 mg/dL in 16% of the subjects, 8.4-9.5 mg/dL in 47%, 9.5-10.2 mg/dL in 22%, and >10.2 mg/dL in 15%. The intact PTH level was <150 pg/mL in 57%, 150-300 pg/mL in 27%, and >300 pg/mL in 16% of the patients. The first problem is that correcting Ca is not always performed in clinical fields. The uncorrected calcium level was 9.14+/-0.92 mg/dL, while the corrected calcium level [Ca = Ca + 0.8 x (4-Alb)] was 9.26+/-0.93 mg/dL (P < 0.05). The second problem is that the timing of blood collection is not described in the K/DOQI Guidelines. Subjects with a serum phosphorus level >7.0 mg/dL at 3 days after the previous dialysis were selected for assessment. In these patients, the midweek serum phosphorus level (7.13+/-0.15 mg/dL) at was significantly lower than that (8.11+/-0.15 mg/dL) at the beginning of the next week (P < 0.001). These results suggest that it is necessary to specify the timing of measurement and the method of Ca correction when guidelines for management of ROD are established in the future.

Rapid activated sludge respiration inhibition test performed by CO2 producing rate using a carbon dioxide sensor

The rapid activated sludge inhibition test (rapid ASRI) is one of the promising bioassays to evaluate environmental risk to the ecosystem caused by various pollutants. To improve the sensitivity and stability of ASRI, the CO2 producing rate (CPR) using a carbon dioxide gas sensor was employed to examine the respiration activity of activated sludge and to compare it to that by the conventional activated sludge respiration inhibition test using oxygen uptake rate (OUR) by EC50 values derived from dose response curve. Detection of respiratory activity based on CPR has higher reliability and sensitivity than that of OUR. It should be noted that the sensitivity of CPR for evaluating toxicity is sufficiently high in terms of derived dose response curve of some model environmental pollutants and the resultant EC50 values.

Development of new toxicity identification evaluation by assessing toxicity reduction on adsorption and ion-exchange treatments

A new toxicity identification evaluation method for water exhibiting toxicity has been suggested by evaluating toxicity reduction resulting from adsorption and ion-exchange treatments. Adsorption using various adsorbents such as activated carbon, chitosan and zeolite, and ion-exchange using cationic and anionic ion-exchange resins were performed. In addition, toxicity was evaluated by a cell survival test using human liver cancer origin cells (HepG2), and the dose response data was applied to treatment characteristics. The amount of toxicity adsorbed by the various adsorbents was defined based on adsorption isotherm. Parameters of the toxicity adsorption isotherm provided information that allowed us to identify the toxicity-controlling chemicals in environmental water containing various chemicals. The method is promising for water quality management because it can be used to identify toxicity-controlling chemicals among various environmental pollutants.

Estimation of cytotoxicity to HEP-G2 cells of 255 environmental pollutants and water using QSAR (Quantitative Structure-Activity Relationship)

Although bioassays are considered to be a rational method for environmental management, the procedure is generally too complicated to be applied to daily water quality management. In this study, the feasibility of using for application of a conventional QSAR (Quantitative Structure-Activity Relationship) method was examined to estimate the cytotoxicity of various pollutants found in environmental water. logP, pKa, and molecular weight were chosen as the physico/chemical properties of the pollutants, and defined equations for estimating cytotoxicity based on multiple linear regression analysis between these properties and in vitro cytotoxicity data from our previous results. As a result, a method for estimating cytotoxicity of environmental pollutants that had a certain probability (R>0.8) for the 255 chemicals was successfully developed. Considerably high reliability was shown in the leave-one-out prediction of multi-regression analysis. In addition, the cytotoxicity of environmental water samples was estimated based on multi-regression analysis, using as our samples leachates from 25 landfill sites in Japan. The method developed in this study estimated quantitatively the cytotoxicity of the environmental water from chemical analysis data without conducting a cytotoxicity test.

Preservation of human cell bioassay device for the on-site evaluation of environmental waters

We have already developed a novel disposable bioassay device based on the low-density lipoprotein (LDL) uptaking activity of human hepatoblastoma Hep G2 cells in our previous work. However, this device is not readily applicable to evaluate river water toxicity on-site because it cannot be preserved for more than one week. In this work, we developed the method for preservation of the device to enable it to be preserved for at least one month. The device can be supplied to individual environmental sites without any facilities for cell culture. We can evaluate river water toxicity by 2 hours of exposure after thawing. Therefore, this kind of device could be a promising tool for daily water quality management.

Cultured human-cell-based bioassay for environmental risk management

Among bioassays for evaluating various impacts of chemicals on humans and ecosystems, those based on cultured mammalian-cells can best predict acute lethal toxicity to humans. We expect them to be employed in the future in environmental risk management alongside mutagenicity tests and endocrine-disrupting activity tests. We recently developed a disposable bioassay device that immobilizes human hepatocarcinoma cells in a small micropipette tip. This enables very quick (within 2 h) evaluation of acute lethal toxicity to humans. For bioassay-based environmental management, 2 promising approaches have been demonstrated by the US-EPA: toxicity identification evaluation (TIE) and toxicity reduction evaluation (TRE). The Japanese Ministry of Environment has been supporting a multi-center validation project, aimed at assembling a bioassay database. To make full use of these resources, we present a numerical model that describes contribution of individual chemical to observed toxicity. This will allow the selection of the most effective countermeasure to reduce the toxicity. Bioassay-based environmental risk management works retrospectively, whereas impact assessment using substance flow models and toxicity databases works prospective. We expect that these 2 approaches will exchange information, act complementarily, and work effectively in keeping our environment healthy in the 21 st century.

Development of a rapid and sensitive bioassay device using human cells immobilized in macroporous microcarriers for the on-site evaluation of environmental waters

We developed a novel disposable bioassay device based on the fluorescein isothiocyanate-labelled low-density lipoprotein-uptake activity of human hepatoblastoma Hep G2 cells. The cells were cultured in porous microcarriers at a high cell density and packed in a filter tip that has a hydrophobic membrane. Upon evaluation of water samples, the culture medium was decanted by pipetting it down with a micropipet, and the samples were then introduced to the cell-immobilizing part of the tip only by pipetting them up after mixing them with x10 concentrated culture medium. The new device enabled us to detect almost the same toxicity levels of river water within 2 h of exposure as those detected by a conventional 48-h cell-survival assay. This is the first bioassay device for the rapid on-site evaluation of environmental waters using cultured human cells, and therefore promising for water-quality management based on risk to humans.

Evidence for a mate-attracting chemosignal in the dwarf African clawed frog Hymenochirus

Many male frogs and toads possess sexually dimorphic skin glands (breeding glands). However, in most anuran species, the functional significance of the glands is unknown. Here we show that the breeding glands of male dwarf African clawed frogs (Hymenochirus sp. ) release a mate-attractant chemosignal. The mate-attractant activity was assessed using a two-choice aquatic Y-maze. Female Hymenochirus were allowed to choose between different treatment waters (e.g., plain water and water housing males) in the upstream arms of the maze, and the females' movements were monitored by computer-linked motion sensors. Females showed a positive chemotaxis to water housing males and to water containing homogenized breeding glands. Females showed no reaction to water housing conspecific females or to water housing breeding gland-ablated males. Additional choice tests demonstrated that females were more attracted to water housing males than to water housing females and to water containing homogenized breeding glands than to water housing breeding gland-ablated males. Males in the maze showed no response to water housing either females or other males, indicating that the attractant is specific for females and is therefore neither a species aggregation signal nor a food-related attractant. These results represent the first experimental demonstration of a mate-attractant function for anuran breeding glands. Because many anuran species possess breeding glands, these results suggest that pheromonal communication could be more widespread among frogs and toads than previously believed.

Rapid and sensitive neurotoxicity test based on the morphological changes of PC12 cells with simple computer-assisted image analysis

In order to develop a rapid and sensitive bioassay for the screening of chemicals with possible neurotoxicity, a computer-assisted simple image-analysis system was developed to quantify small changes in the specific morphology of the cultured pheochromocytoma cell line, PC12. This cell forms a neuron-like microfibril network (neurites) in response to a nerve growth factor (NGF) stimulation in vitro. Dichrolvos (DDVP) and methylmercury chloride (MMC) were employed as model neurotoxicants. In DDVP treatment, there was no large difference in the ED50s (effective dose that reduces the morphological index by 50%) among the toxicities determined from various morphological indices, but they were significantly lower than those observed by whole-cell-area-based toxicity assay using the hepatoblastoma cell line, Hep G2. In contrast, in MMC treatment, neurite-length-based toxicity was observed as early as 2 h, and at 48 h this was lower by over three orders of magnitude compared with whole-cell-area-based one (2.06 x 10(-7) mM vs. 6.42 x 10(-4) mM). These results demonstrate that the developed bioassay using image analysis of nerve-tissue-derived cell morphology allows us to screen possible neurotoxic chemicals very rapidly with highly enhanced sensitivity, particularly for some chemicals that preferentially act on nerve fibers.

[Aldehyde dehydrogenase 2(ALDH2) gene polymorphism in NIDDM patients with chronic renal failure]

In order to investigate the influence of aldehyde dehydrogenase 2(ALDH2) genotype in the pathogenesis of nephropathy due to non-insulin dependent diabetes mellitus (NIDDM), genotyping of ALDH2 was measured using the PCR-RFLP method in patients with NIDDM on chronic hemodialysis (HD). The results were as follows; 1) The frequency of active ALDH2 was 63% and that of inactive ALDH2 was 37%. 2) The percentage of active ALDH2 was significantly higher in patients with alcohol tolerance than that in those without it (38%). 3) The estimated amount of alcohol consumption in the past was 506 +/- 720 g/week in the active ALDH2 group, and 156 +/- 288 g/week in the inactive ALDH2 group, showing a significant difference between the two groups. 4) Interdialytic body weight gain was larger in patients with active ALDH2 than in those with inactive ALDH2. Since the frequency of active ALDH2 was similar to that in patients without nephropathy, these results do not support the hypothesis that ALDH2 gene polymorphism is involved in the development and persistence of chronic renal failure due to NIDDM. However, salt and water craving in dialysis patients may be influenced partially by an active ALDH2 gene.

Embryogenesis-promoting factors in rat serum

Regarding whole rat embryo cultures in vitro, rat serum as a culture medium is known to support the normal growth of rat embryos in the organogenesis phase. The purpose of the present study was to isolate the embryogenesis-promoting factors from rat serum as a first step in the development of a defined serum-free medium for a whole embryo culture system. Pooled rat serum after heat inactivation was fractionated into three major peaks (frA, containing a region of void volume, frB, and frC) by gel filtration. The 9.5-day rat embryos that were cultivated for 48 hr in essential salt medium containing frB (with a molecular size range of 100-500 kDa) revealed normal growth. Three proteins (27 kDa, 76 kDa, and 190 kDa) that had the embryogenesis-promoting effects were isolated from 3-hr delayed centrifuged rat serum by the ion exchange chromatography. The 76-kDa protein was found to be rat transferrin by immunoblotting. The 27-kDa protein was identified as apo-AI (the major apoprotein of high-density lipoprotein) by immunoblotting. High-density lipoprotein obtained from pooled rat serum by a NaBr density gradient ultracentrifugation was found to have a positive effect on embryogenesis. The 10-kDa protein was also identified as alpha 1-inhibitor 3 by immunoblotting. In addition, the embryogenesis-promoting effect of the fraction containing 27-kDa and 190-kDa proteins declined within a short period of storage at -20 degrees C. This decrease was countered by supplementing its fraction (D-2) with albumin isolated from rat serum. These results in the present study suggest that transferrin, high-density lipoprotein, and alpha 1-inhibitor 3 in rat serum may be embryogenesis-promoting factors, and that albumin appeared to play a role in the embryogenesis of rat embryos in whole embryo cultures.