Effects of pentobarbital, isoflurane, or medetomidine-midazolam-butorphanol anesthesia on bronchoalveolar lavage fluid and blood chemistry in rats

Bronchoalveolar lavage fluid (BALF) is commonly examined for pulmonary toxicity in animal studies. Two common means of anesthesia before euthanasia and bronchoalveolar lavage in rats are intraperitoneal injection of pentobarbital and inhalation of isoflurane. Medetomidine-midazolam-butorphanol is an alternative anesthesia to pentobarbital for animal welfare; however, the effect of this combination on BALF and blood chemistry is unknown. Here, we compared the effects of anesthesia by intraperitoneal injection of pentobarbital or one of two combinations of medetomidine-midazolam-butorphanol (dose, 0.375-2.0-2.5 or 0.15-2.0-2.5 mg/kg) or by inhalation of isoflurane on BALF and blood chemistry in rats with or without pulmonary inflammation. In BALF, we determined total protein, albumin, lactate dehydrogenase, total cell count and neutrophil count. In serum, we conducted a general chemistry screen. After anesthesia with pentobarbital or isoflurane, there were no significant differences between any of the BALF or blood chemistry parameters with or without inflammation. After anesthesia with either of the combinations of medetomidine-midazolam-butorphanol, lactate dehydrogenase, total cell count, neutrophil count, and almost all of the blood chemistry parameters were comparable with those observed after pentobarbital or isoflurane; however, BALF albumin and serum glucose were significantly increased in rats without inflammation. After the combination of low-dose medetomidine in rats with inflammation, BALF parameters were comparable with those observed after pentobarbital or isoflurane. Our results show that, of the anesthetics examined, inhalation of isoflurane is the most appropriate means of anesthesia when examining BALF or serum for toxicity studies in rats.

[Descending Necrotizing Mediastinitis Survived by Two Operations;Report of a Case]

The patient, a 65-year-old woman, visited at her local doctor's office with the chief complaint of pharyngeal pain. After being administered antibacterial drugs, hyperthermia persisted and the pharyngeal pain became exacerbated. She was referred to our hospital and diagnosed as a retropharyngeal abscess and descending necrotizing mediastinitis (DNM). She was urgently hospitalized and surgery was performed. The mediastinal pleura was incised with thoracoscopic guidance and curettage, irrigation, and drainage were performed. Additional drainage was determined to be necessary based on findings from subsequent chest computed tomography and a prolonged inflammatory reaction. Therefore, on hospital day 7, 2nd surgery were performed, and tracheotomy was additionally performed with curettage of the neck abscess. The patient was taken off mechanical ventilation on hospital day 18, and discharged on hospital day 55.

Combined repeated-dose and reproductive/developmental toxicity screening test of 1-tert-butoxy-4-chlorobenzene in rats

We have carried out animal toxicity tests of chemicals for a chemical safety program implemented by the Ministry of Economy, Trade, and Industry of Japan. Here, we tested 1-tert-butoxy-4-chlorobenzene in a combined repeat-dose and developmental and reproductive toxicity test. The test chemical was administered daily by gavage to 9-week-old Crl:CD (SD) rats at doses of 0, 20, 100, and 500  mg/kg/d. Males were treated for 42 d beginning 14 d before mating. Females were treated from 14 d before mating to day 4 of lactation. Decreased spontaneous locomotion, decreased respiratory rate, and incomplete eyelid opening were observed at 500 mg/kg/d (both sexes), but resolved within 30 min of administration, suggesting central nervous system depression. No notable changes were observed in body weight, food consumption, functional battery tests, or blood test. Increased liver weight with centrilobular or diffuse hepatocyte hypertrophy was observed at 100 and 500 mg/kg/d (both sexes). There were no biochemical or histopathological changes related to hepatotoxicity. Increased kidney weight with basophilic tubules, tubule dilatation, and increased hyaline droplets were observed in males dosed at 100 and 500 mg/kg/d. Immunohistochemical staining indicated α_2u-globulin nephropathy, a male rat-specific toxicity. Although kidney weight was also increased in females dosed at 500 mg/kg/d, it was not considered to be an adverse effect because there were no histopathological changes. Pup weights on postnatal day 0 were decreased at 500 mg/kg/d and still decreased on postnatal day 4. Our data indicated the no-observed-adverse-effect-level for repeated-dose and reproductive/developmental toxicity for 1-tert-butoxy-4-chlorobenzene was 100 mg/kg/d.

Comparison of the local pulmonary distribution of nanoparticles administered intratracheally to rats via gavage needle or microsprayer delivery devices

Intratracheal administration methods are used to conduct toxicological assessments of inhaled nanoparticles (NPs), and gavage needles or microsprayers are common intratracheal delivery devices. The NP suspension is delivered in a liquid state via gavage needle and as a liquid aerosol via microsprayer. The differences in local pulmonary NP distribution (called the microdistribution) arising from the different states of the NP suspension cause differential pulmonary responses; however, this has yet to be investigated. Herein, using microbeam X-ray fluorescence microscopy, we quantitatively evaluated the TiO₂ pulmonary microdistribution (per mesh: 100 μm × 100 μm) in lung sections from rats administered an intratracheal dose of TiO₂ NPs (6 mg kg^-1 ) via gavage needle or microsprayer. The results revealed that: (i) using a microsprayer appears to reduce the variations in TiO₂ content (ng mesh^-1 ) among rats (e.g., coefficients of variation, n = 3, microsprayer vs gavage needle: 13% vs 30%, for the entire lungs); (ii) TiO₂ appears to be deposited less in the right middle lobes than in the rest of the lung lobes, irrespective of the chosen intratracheal delivery device; and (iii) similar TiO₂ contents (ng mesh^-1 ) and frequencies are deposited in the lung lobes of rats administered TiO₂ NPs via gavage needle or microsprayer. This suggests that the physical state of the administered NP suspension does not markedly alter TiO₂ pulmonary microdistribution. The results of this investigation are important for the standardization of intratracheal administration methods. Copyright © 2016 John Wiley & Sons, Ltd.

Effects of dose volume and delivery device on bronchoalveolar lavage parameters of intratracheally administered nano-sized TiO2 in rats

The intratracheal (IT) test is useful for screening the pulmonary toxicity of inhaled materials, including nanomaterials. However, a standard procedure has not yet been authorized internationally, and the effects of different test parameters are unknown. To determine appropriate experimental conditions for the IT test, we intratracheally administered nano-sized TiO₂ to male F344 rats at 3.0 mg/kg body weight by using two delivery devices (gavage needle or microaerosolizer) and dose volumes of 0.5-3.0 mL/kg (gavage needle) or 0.5-2.0 mL/kg (microaerosolizer). We evaluated the pulmonary deposition and interlobar distribution of TiO₂ at both 30 min and 3 days after administration. In addition, the inflammatory components in bronchoalveolar lavage (BAL) fluid were measured 3 days after administration of TiO₂. At dose volumes of 0.5-2.0 mL/kg, the BAL values were comparable regardless of the device used. In addition, pulmonary TiO₂ burden and lobar concentration patterns were equivalent at all combinations of dose volume and delivery device. In conclusion, the acute pulmonary toxicity of nanomaterials can be assessed effectively by using an IT test in which the test agent is provided to rats at a dose volume of 0.5-2.0 mL/kg with either a gavage needle or microaerosolizer.

Carpal Tunnel Syndrome Accompanying Radial Dysplasia Due to Thalidomide Embryopathy

We performed endoscopic carpal tunnel release in four hands in three patients suffering from radial dysplasia due to thalidomide embryopathy. Carpal canal pressure measurements results confirmed the diagnoses. All operations were successfully performed and resulted in no complications. Tingling sensation and sensory disturbances of the hands subsided.

Categorization of nano-structured titanium dioxide according to physicochemical characteristics and pulmonary toxicity

A potentially useful means of predicting the pulmonary risk posed by new forms of nano-structured titanium dioxide (nano-TiO2) is to use the associations between the physicochemical properties and pulmonary toxicity of characterized forms of TiO2. In the present study, we conducted intratracheal administration studies in rats to clarify the associations between the physicochemical characteristics of seven characterized forms of TiO2 and their acute or subacute pulmonary inflammatory toxicity. Examination of the associations between the physicochemical characteristics of the TiO2 and the pulmonary inflammatory responses they induced revealed (1) that differences in the crystallinity or shape of the TiO2 particles were not associated with the acute pulmonary inflammatory response; (2) that particle size was associated with the acute pulmonary inflammatory response; and (3) that TiO2 particles coated with Al(OH)3 induced a greater pulmonary inflammatory response than did non-coated particles. We separated the seven TiO2 into two groups: a group containing the six TiO2 with no surface coating and a group containing the one TiO2 with a surface coating. Intratracheal administration to rats of TiO2 from the first group (i.e., non-coated TiO2) induced only acute pulmonary inflammatory responses, and within this group, the acute pulmonary inflammatory response was equivalent when the particle size was the same, regardless of crystallinity or shape. In contrast, intratracheal administration to rats of the TiO2 from the second group (i.e., the coated TiO2) induced a more severe, subacute pulmonary inflammatory response compared with that produced by the non-coated TiO2. Since alteration of the pulmonary inflammatory response by surface treatment may depend on the coating material used, the pulmonary toxicities of coated TiO2 need to be further evaluated. Overall, the present results demonstrate that physicochemical properties may be useful for predicting the pulmonary risk posed by new nano-TiO2 materials.

Spontaneous regression of bronchogenic cyst accompanied by pneumonia

Bronchogenic cysts arise from abnormal budding of the ventral diverticulum of the foregut or tracheobronchial tree during embryogenesis, are the most common cystic masses in the mediastinum, and are generally asymptomatic. A spontaneous regression in a mediastinal bronchogenic cyst (MBC) with pneumonia is rare. A 30-year-old male had a tumor shadow in the middle mediastinum. When he visited our hospital, he had a mild fever with coughing and sputum. A chest computed tomography (CT) scan showed a decrease in the tumor size and the existence of right pneumonia. MBC may be involved in the etiology of pneumonia; therefore, bronchogenic cysts need to be resected as soon as possible.

Video-assisted thoracic surgery for primary myelolipoma of the posterior mediastinum

BACKGROUND

Myelolipoma is an uncommon tumor comprising adipose tissue and normal hematopoietic cells and mainly occurs in the adrenal cortex. Mediastinal myelolipoma is very rare; we report a case of posterior mediastinal myelolipoma that required surgical resection.

CASE PRESENTATION

A 56-year-old male was diagnosed with a posterior mediastinal tumor by computed tomography. The tumor was originally noted in 2005, and during follow-up in March 2014, it was found to have increased in size. During consultation at our hospital, on magnetic resonance imaging (MRI), we considered the possibility that the tumor was malignant. Consequently, we resected the tumor by video-assisted thoracic surgery (VATS). The histopathological findings revealed that the tumor had undergone intrathoracic extramedullary hematopoiesis. However, after considering the patient's background and histopathological findings, we diagnosed the tumor as a thoracic extra-adrenal myelolipoma.

CONCLUSIONS

Pathological analysis was instrumental in clarifying the diagnosis. We recommend surgery as a treatment option for posterior mediastinal tumors.

Characterization and evolutionary analysis of tributyltin-binding protein and pufferfish saxitoxin and tetrodotoxin-binding protein genes in toxic and nontoxic pufferfishes

Understanding the evolutionary mechanisms of toxin accumulation in pufferfishes has been long-standing problem in toxicology and evolutionary biology. Pufferfish saxitoxin and tetrodotoxin-binding protein (PSTBP) is involved in the transport and accumulation of tetrodotoxin and is one of the most intriguing proteins related to the toxicity of pufferfishes. PSTBPs are fusion proteins consisting of two tandem repeated tributyltin-binding protein type 2 (TBT-bp2) domains. In this study, we examined the evolutionary dynamics of TBT-bp2 and PSTBP genes to understand the evolution of toxin accumulation in pufferfishes. Database searches and/or PCR-based cDNA cloning in nine pufferfish species (6 toxic and 3 nontoxic) revealed that all species possessed one or more TBT-bp2 genes, but PSTBP genes were found only in 5 toxic species belonging to genus Takifugu. These toxic Takifugu species possessed two or three copies of PSTBP genes. Phylogenetic analysis of TBT-bp2 and PSTBP genes suggested that PSTBPs evolved in the common ancestor of Takifugu species by repeated duplications and fusions of TBT-bp2 genes. In addition, a detailed comparison of Takifugu TBT-bp2 and PSTBP gene sequences detected a signature of positive selection under the pressure of gene conversion. The complicated evolutionary dynamics of TBT-bp2 and PSTBP genes may reflect the diversity of toxicity in pufferfishes.

[Thymoma with extensive coagulative necrosis and high serum level of CYFRA 21-1; report of a case]

A 73-year-old woman complained of right chest discomfort. Chest X-ray during the follow-up for rheumatoid arthritis showed a mediastinal tumor. Chest computed tomography (CT) and magnetic resonance imaging (MRI) showed a 65-mm tumor in the right anterior mediastinum. A blood test showed high serum levels of CYFRA 21-1(29.8 ng/ml), white blood cells( WBC 10,800/µl), and C-reactive protein(CRP 16.1 mg/dl). Subsequently, inflammatory reactions improved, and the thymic tumor was resected. Histopathologically, the tumor was a type B2 thymoma with extensive coagulative necrosis. After resection, the serum CYFRA 21-1 level returned to the normal range.

Combined repeated dose and reproductive/developmental toxicity screening test of 4-methoxy-2-nitroaniline in rats

4-Methoxy-2-nitroaniline (4M2NA) is widely used as an intermediate for the synthesis of dyes, pigments and other chemical compounds. Since 4M2NA has amino-group and nitro-group on the benzene ring, it was expected that it induced obvious hemolytic anemia. We conducted a combined repeated dose and reproductive/developmental toxicity screening test according to Organisation for Economic Co-operation and Development (OECD) Test Guideline No. 422 (OECD TG 422) to enrich the toxic information and ensure the safety of 4M2NA. 4M2NA was administered to Crl:CD(SD) male and female rats by gavage at 0, 12.5, 75 or 450 mg/kg/day for 42 to maximum of 54 days through pre-mating, mating, pregnancy and lactation periods. An extramedullary hematopoiesis and congestion in spleen, and higher reticulocyte ratio were noted in only females at 450 mg/kg/day without decreased anemic parameters in the hematological examination. Hypertrophy of centrilobular hepatocytes in both sexes was observed with increased relative liver weight at 450 mg/kg/day. Furthermore, the diffuse follicular cell hypertrophy of the thyroid was observed in females at 450 mg/kg/day. No abnormalities were detected in the reproductive indices of copulation, delivery or fetal viability. We concluded the no-observed-adverse-effect level (NOAEL) for repeated-dose toxicity was 75 mg/kg/day based on the trace evidences of hemolytic anemia, and the NOAEL for reproductive/developmental toxicity as 450 mg/kg/day based on no toxicological concerns for reproductive endpoints. The hemolytic anemia was much milder than expected. Thus, we discussed the reason of this much less hemolytic effect from the point of view of the structural characteristics of 4M2NA.

Dose-dependent clearance kinetics of intratracheally administered titanium dioxide nanoparticles in rat lung

AEROSIL(®) P25 titanium dioxide (TiO2) nanoparticles dispersed in 0.2% disodium phosphate solution were intratracheally administered to male F344 rats at doses of 0 (control), 0.375, 0.75, 1.5, 3.0, and 6.0 mg/kg. The rats were sacrificed under anesthesia at 1 day, 3 days, 7 days, 4 weeks, 13 weeks, and 26 weeks after administration. Ti levels in various pulmonary and extrapulmonary organs were determined using sensitive inductively coupled plasma sector field mass spectrometry. One day after administration, the lungs contained 62-83% of TiO2 administered dose. Twenty-six weeks after administration, the lungs retained 6.6-8.9% of the TiO2 administered at the 0.375, 0.75, and 1.5 mg/kg doses, and 13% and 31% of the TiO2 administered at the 3.0 and 6.0 mg/kg doses, respectively. The pulmonary clearance rate constants from compartment 1, k1, were estimated using a 2-compartment model and were found to be higher for the 0.375 and 0.75 mg/kg doses of TiO2 (0.030/day for both) than for TiO2 doses of 1.5-6.0 mg/kg (0.014-0.022/day). The translocation rate constants from compartment 1 to 2, k12, were estimated to be 0.015 and 0.018/day for the 0.375 and 0.75 mg/kg doses, and 0.0025-0.0092/day for doses of 1.5-6.0mg/kg. The pulmonary clearance rate constants from compartment 2, k2, were estimated to be 0.0086 and 0.0093/day for doses of 0.375 and 0.75 mg/kg, and 0-0.00082/day for 1.5-6.0 mg/kg doses. Translocation of TiO2 from the lungs to the thoracic lymph nodes increased in a time- and dose-dependent manner, accounting for 0.10-3.4% of the administered dose at 26 weeks. The measured thoracic lymph node burdens were a much better fit to the thoracic lymph node burdens estimated assuming translocation from compartment 1 to the thoracic lymph nodes, rather than those estimated assuming translocation from compartment 2 to the thoracic lymph nodes. The translocation rate constants from the lungs to the thoracic lymph nodes, kLung→Lym, were 0.000037-0.00081/day, and these also increased with increasing doses of TiO2. Although a small amount of TiO2 had translocated to the liver by 3 days after the administration (0.0023-0.012% of the highest dose administered, 6.0 mg/kg), translocation to the other extrapulmonary organs was not detected.

A-type antiferro-orbital ordering with I4(1)/a symmetry and geometrical frustration in the spinel vanadate MgV2O4

We conduct a detailed structural analysis of the S=1 pyrochlore antiferromagnet MgV2O4, which exhibits an antiferromagnetic ordering marginally at TN=40  K, triggered by a structural transition from cubic to tetragonal symmetry at TS=62  K, using high resolution synchrotron x-ray diffraction and convergent beam electron diffraction. We reveal that the tetragonal phase below TS has the symmetry of I4(1)/a and that the distortion pattern of VO6 octahedra is consistent with A-type antiferro-orbital ordering with alternating stacking of layers with yz/xy orbital chains and zx/xy orbital chains along the tetragonal c axis. This implies that an anisotropic coupling of V moments produced by the orbital ordering below TS primarily brings about the antiferromagnetic ordering.

Combined repeated dose and reproductive/developmental toxicity screening test of tert-butylhydrazine monohydrochloride in rats

tert-Butylhydrazine monohydrochloride was daily administered by gavage to groups of Crl:CD (SD)IGS rats at doses of 0 (control), 0.8, 4, or 20 mg/kg/day. Twelve males per group were treated for a total of 42 days from 14 days before mating. Twelve females per group were treated from 14 days before mating to day 4 of lactation throughout the mating and gestation periods. Recovery groups of five males and five non-pregnant females per group were dosed for 42 days followed by a 14-day recovery period. No deaths were observed in any groups of either sex. There were no considerable changes in body weight, food intake, general appearance, functional observations or biochemical analysis. Values of the anemic parameters were decreased in the 20 mg/kg/day males and in all female dose groups. The relative weight of the liver, kidneys and spleen was significantly increased in 20 mg/kg/day females. Histopathological examination showed congestion and hemosiderin deposition in the spleen at 20 mg/kg/day in both sexes, but there were no changes in the liver or kidneys in either sex. Anemic parameters with hemosiderin deposition did not completely recover in the 20 mg/kg/day group in both sexes after the recovery period. As for reproduction, a significant reduction was only observed in the number of corpora lutea at 20 mg/kg/day. It was thus concluded that the LOAEL was 0.8 mg/kg/day based on the decreased values of the anemic parameters of repeated-dose toxicity, and that the NOAEL was 4 mg/kg/day based on the low number of corpora lutea of reproductive/developmental toxicity.

Novel Pauli-paramagnetic quantum phase in a Mott insulator

In Mott insulators, the strong electron-electron Coulomb repulsion localizes electrons. In dimensions greater than one, their spins are usually ordered antiferromagnetically at low temperatures. Geometrical frustrations can destroy this long-range order, leading to exotic quantum spin liquid states. However, their magnetic ground states have been a long-standing mystery. Here we show that a quantum spin liquid state in the organic Mott insulator EtMe(3)Sb[Pd(dmit)(2)](2) (where Et is C(2)H(5)-, Me is CH(3)-, and dmit is 1,3-dithiole-2-thione-4,5-dithiolate) with two-dimensional triangular lattice has Pauli-paramagnetic-like low-energy excitations, which are a hallmark of itinerant fermions. Our torque magnetometry down to low temperatures (30 mK) up to high fields (32 T) reveals distinct residual paramagnetic susceptibility comparable to that in a half-filled two-dimensional metal, demonstrating the magnetically gapless nature of the ground state. Moreover, our results are robust against deuteration, pointing toward the emergence of an extended 'quantum critical phase', in which low-energy spin excitations behave as in paramagnetic metals with Fermi surface, despite the frozen charge degree of freedom.