Magnetically Hidden State on the Ground Floor of the Magnetic Devil's Staircase

We investigated the low-temperature and high-field thermodynamic and ultrasonic properties of SrCu_{2}(BO_{3})_{2}, which exhibits various plateaux in its magnetization curve above 27 T, called a magnetic Devil's staircase. The results of the present study confirm that magnetic crystallization, the first step of the staircase, occurs above 27 T as a first-order transition accompanied by a sharp singularity in heat capacity C_{p} and a kink in the elastic constant. In addition, we observe a thermodynamic anomaly at lower fields around 26 T, which has not been previously detected by any magnetic probes. At low temperatures, this magnetically hidden state has a large entropy and does not exhibit Schottky-type gapped behavior, which suggests the existence of low-energy collective excitations. Based on our observations and theoretical predictions, we propose that magnetic quadrupoles form a spin-nematic state around 26 T as a hidden state on the ground floor of the magnetic Devil's staircase.

First phase 1 clinical study of olaparib in pediatric patients with refractory solid tumors

BACKGROUND

The survival of patients with high-risk, refractory, relapsed, or metastatic solid tumors remains dismal. A poly(ADP-ribose) polymerase (PARP) inhibitor could be effective for the treatment of pediatric solid tumors with defective homologous recombination.

METHODS

This open-label, multicenter phase 1 clinical trial evaluated the safety, tolerability, and efficacy of olaparib, a PARP inhibitor, in pediatric patients with refractory solid tumors to recommend a dose for Phase 2 trials. Olaparib (62.5, 125, and 187.5 mg/m² twice daily) was administered orally every day (1 cycle = 28 days) using a standard 3 + 3 dose-escalation design. Patients aged 3-18 years with recurrent pediatric solid tumors were eligible. Pharmacokinetic and pharmacodynamic analyses were performed.

RESULTS

Fifteen patients were enrolled and received olaparib monotherapy, which was well tolerated. The recommended phase 2 dose for daily administration was 187.5 mg/m² twice daily. Pharmacokinetics were dose proportional. The area under the concentration-time curve from 0 to 12 h and the peak plasma concentration for 187.5 mg/m² twice daily in children were comparable to previous data obtained in a 200-mg, twice-daily cohort and lower than those in the 300-mg twice-daily cohort in adults. Pharmacodynamic studies demonstrated substantial inhibition of PARP activity. Two partial responses were observed in patients with Wilms tumor and neuroblastoma.

CONCLUSIONS

This report is the first clinical trial to describe the use of a PARP inhibitor as monotherapy in children. Olaparib was well tolerated, with preliminary antitumor responses observed in DNA damage response-defective pediatric tumors.

LAY SUMMARY

This Phase 1 trial evaluated the efficacy and safety of olaparib in patients with refractory childhood solid tumors. Olaparib was well tolerated, achieving objective response in 2/15 patients. The DNA damage response was attenuated in nearly one-half of advanced neuroblastoma patients, demonstrating the utility of the PARP inhibitor. The results support further investigation of olaparib as a new treatment for DNA damage-response or repair-defective pediatric cancers.

Randomly Hopping Majorana Fermions in the Diluted Kitaev System α-Ru_{0.8}Ir_{0.2}Cl_{3}

dc and ac magnetic susceptibility, magnetization, specific heat, and Raman scattering measurements are combined to probe low-lying spin excitations in α-Ru_{1-x}Ir_{x}Cl_{3} (x≈0.2), which realizes a disordered spin liquid. At intermediate energies (ℏω>3  meV), Raman spectroscopy evidences linearly ω-dependent Majorana-like excitations, obeying Fermi statistics. This points to robustness of a Kitaev paramagnetic state under spin vacancies. At low energies below 3 meV, we observe power-law dependences and quantum-critical-like scalings of the thermodynamic quantities, implying the presence of a weakly divergent low-energy density of states. This scaling phenomenology is interpreted in terms of the random hoppings of Majorana fermions. Our results demonstrate an emergent hierarchy of spin excitations in a diluted Kitaev honeycomb system subject to spin vacancies and bond randomness.

Phase I clinical study of oral olaparib in pediatric patients with refractory solid tumors: study protocol

Background

There is no established standard chemotherapy for recurrent pediatric solid tumors such as neuroblastoma and sarcoma. Since some of these tumor cells show dysfunctions in homologous recombination repair, the goal is to conduct a phase I study of olaparib, a poly(ADP-ribose) polymerase inhibitor. In this clinical trial, the aims are to evaluate the safety, tolerability, and efficacy of olaparib in pediatric patients with refractory solid tumors and to recommend a dose for phase II trials.

Methods

In this open-label, multicenter study, olaparib tablets (62.5, 125, and 187.5 mg/m² b.i.d.) will be administered orally in a standard 3 + 3 dose escalation design. Patients aged 3 to 18 years with recurrent pediatric solid tumors are eligible. Pharmacokinetic and pharmacodynamic analyses will also be performed.

Discussion

This study aims to extend the indications for olaparib by assessing its safety and efficacy in pediatric refractory solid tumor patients.

Trial registration

UMIN-CTR (UMIN000025521); Registered on January 4, 2017.

Three-dimensional longitudinal changes of maxilla and mandible morphology during the predental period

AIM

The purpose of this study was to longitudinally analyse the morphology of maxilla and mandible over time in infants using a three-dimensional (3D) surface scanner.

MATERIALS AND METHODS

Seventeen Japanese full-term infants participated in the study. Dental plaster models were fabricated every 3 months from 1 month of age to 12 months. The plaster models were scanned using the 3D surface scanner to create 3D models. The arch width, arch length, arch angle, palatal depth and palatal area of the 3D models were analysed.

RESULTS

The arch width and length of maxilla and mandible increased as the arch angle decreased. The arch width and length of the maxilla were greater than those of the mandible. The total alveolar ridge morphology increased in size in the occlusal view, with marked growth in the sagittal direction. The palatal depth remained virtually unchanged although the palatal area increased as a result of buccal growth of the alveolar ridge.

CONCLUSIONS

The morphological growth pattern of the maxilla and mandible in infants can be evaluated quantitatively using 3D analysis. Knowledge about the healthy development of children and their orofacial growth patterns during the predental period can be applied as an index for diagnostic criteria.

Application of three-dimensional digital models for the morphometric analysis of predentition plasters: accuracy and precision

AIM

This study aimed to test the accuracy and precision of measurements of three-dimensional (3D) digital models from the pre-dentition period using a noncontact 3D measurement system (3D scanner) versus the gold standard method of direct measurements using a digital caliper on plaster models.

MATERIALS AND METHODS

Ten pairs of plaster models were obtained from children during the predentition period. Linear measurements were performed using both methods. Three operators were trained in the use of both methods for this study. Measurements were performed with a minimum 2-week interval between measurements in a randomly chosen order.

RESULTS

The mean difference between the measured values using the two methods was <0.2 mm for each measurement. There was no linearity in the measurements using pre-dentition digital models. An ANOVA Gage R&R analysis revealed that there was no significant operator difference (P < 0.307). The rate of variation of the 3D scanner over the total variation was 2.8%. The ICC was 0.982 (P< 0.001), suggesting excellent interoperator agreement.

CONCLUSION

The results suggest that measurements of digital 3D pre-dentition models are highly accurate and precise, and also comparable to measurements using the gold standard method.

Adiabatic measurements of magneto-caloric effects in pulsed high magnetic fields up to 55 T

Magneto-caloric effects (MCEs) measurement system in adiabatic condition is proposed to investigate the thermodynamic properties in pulsed magnetic fields up to 55 T. With taking the advantage of the fast field-sweep rate in pulsed field, adiabatic measurements of MCEs were carried out at various temperatures. To obtain the prompt response of the thermometer in the pulsed field, a thin film thermometer is grown directly on the sample surfaces. The validity of the present setup was demonstrated in the wide temperature range through the measurements on Gd at about room temperature and on Gd3Ga5O12 at low temperatures. The both results show reasonable agreement with the data reported earlier. By comparing the MCE data with the specific heat data, we could estimate the entropy as functions of magnetic field and temperature. The results demonstrate the possibility that our approach can trace the change in transition temperature caused by the external field.

Angiotensin receptor type 1 antagonists protect against neuronal injury induced by oxygen-glucose depletion

BACKGROUND AND PURPOSE

Several clinical trials and in vivo animal experiments have suggested that blockade of angiotensin receptor type 1 (AT(1)) improves ischaemic outcomes. However, the mechanism(s) underlying these effects has not been elucidated. Here, we have investigated the protective effects of pretreatment with AT(1) receptor antagonists, losartan or telmisartan, against ischaemic insult to neurons in vitro.

EXPERIMENTAL APPROACH

Primary rat neuron-astrocyte co-cultures and astrocyte-defined medium (ADM)-cultured pure astrocyte cultures were prepared. Ischaemic injury was modelled by oxygen-glucose depletion (OGD) and lactate dehydrogenase release after OGD was measured with or without AT(1) receptor antagonists or agonists (L162313), AT(2) receptor antagonist (PD123319) or agonist (CGP-42112A) pretreatment, for 48 h. Activity of glutamate transporter 1 (GLT-1) was evaluated by [(3)H]-glutamate uptake assays, after AT(1) receptor agonists or antagonists. Immunoblot and real-time PCR were used for analysis of protein and mRNA levels of GLT-1.

KEY RESULTS

AT(1) receptor agonists augmented OGD-induced cellular damage, which was attenuated by AT(1) receptor antagonists. AT(1) receptor antagonists also suppressed OGD-induced extracellular glutamate release, reactive oxygen species production and nitric oxide generation. GLT-1 expression and glutamate uptake activity were significantly enhanced by AT(1) receptor antagonists and impaired by AT(1) receptor agonists. AT(1) receptor stimulation suppressed both ADM-induced GLT-1 protein expression and mRNA levels. AT(1)b receptor knock-down with siRNA enhanced GLT-1 expression. In postnatal (P1-P21) rat brains, protein levels of GLT-1 and AT(1) receptors were inversely correlated.

CONCLUSIONS AND IMPLICATIONS

Suppression of AT(1) receptor stimulation induced GLT-1 up-regulation, which ameliorated effects of ischaemic injury.

Neuroprotection by donepezil against glutamate excitotoxicity involves stimulation of alpha7 nicotinic receptors and internalization of NMDA receptors

BACKGROUND AND PURPOSE

Glutamate excitotoxicity may be involved in ischaemic injury to the CNS and some neurodegenerative diseases, such as Alzheimer's disease. Donepezil, an acetylcholinesterase (AChE) inhibitor, exerts neuroprotective effects. Here we demonstrated a novel mechanism underlying the neuroprotection induced by donepezil.

EXPERIMENTAL APPROACH

Cell damage in primary rat neuron cultures was quantified by lactate dehydrogenase release. Morphological changes associated with neuroprotective effects of nicotine and AChE inhibitors were assessed by immunostaining. Cell surface levels of the glutamate receptor sub-units, NR1 and NR2A, were analyzed using biotinylation. Immunoblot was used to measure protein levels of cleaved caspase-3, total NR1, total NR2A and phosphorylated NR1. Immunoprecipitation was used to measure association of NR1 with the post-synaptic protein, PSD-95. Intracellular Ca(2+) concentrations were measured with fura 2-acetoxymethylester. Caspase 3-like activity was measured using enzyme substrate, 7-amino-4-methylcoumarin (AMC)-DEVD.

KEY RESULTS

Levels of NR1, a core subunit of the NMDA receptor, on the cell surface were significantly reduced by donepezil. In addition, glutamate-mediated Ca(2+) entry was significantly attenuated by donepezil. Methyllycaconitine, an inhibitor of alpha7 nicotinic acetylcholine receptors (nAChR), inhibited the donepezil-induced attenuation of glutamate-mediated Ca(2+) entry. LY294002, a phosphatidyl inositol 3-kinase (PI3K) inhibitor, had no effect on attenuation of glutamate-mediated Ca(2+) entry induced by donepezil.

CONCLUSIONS AND IMPLICATIONS

Decreased glutamate toxicity through down-regulation of NMDA receptors, following stimulation of alpha7 nAChRs, could be another mechanism underlying neuroprotection by donepezil, in addition to up-regulating the PI3K-Akt cascade or defensive system.

Protective effect of H2O2 against subsequent H2O2-induced cytotoxicity involves activation of the PI3K-Akt signaling pathway

Preconditioning of sublethal ischemia implies a cytoprotective mechanism against subsequent ischemia—induced cell death; however, the precise mechanism by which preconditioning protects against ischemic injury is not known. In the present study, we clarified whether pretreatment with a sublethal concentration of H2O2 could counter subsequent H2O2-induced cytotoxicity and also investigated the mechanisms of the cytoprotective effect of a sublethal concentration of H2O2. Using the MTT reduction assay and Calcein-AM staining assay, we showed that pretreatment with H2O2 (10 μM, 24 hr) of COS7 cells partially protected cells against subsequent H2O2 (6 mM, 1 hr) - induced cytotoxicity. The phosphorylation of Akt/PKB, a downstream target of phosphatydylinositol-3 kinase (PI3K), at Ser473 was augmented by H2O2 (10 μM) administration. This augmentation peaked at 10 minutes after H2O2 (10 μM) treatment and fell to the basal level at 24 hr. A blocker of PI3K, LY294002, significantly attenuated H2O2 (10 μM, 24 hr) - induced cytoprotection. In addition, pretreatment with LY294002 reduced H2O2 (10 μM, 10 min)-induced phosphorylation of Akt at Ser473. These findings suggest that a sublethal concentration of H2O2 exerts a cytoprotective effect against subsequent H2O2-induced cell death and that this cytoprotective effect of H2O2 is mediated by activation of the PI3K-Akt signaling pathway.

Activation of dopamine D4 receptors is protective against hypoxia/reoxygenation-induced cell death in HT22 cells

Several reports have shown that some dopamine receptor ligands modulate the ischemia-reperfusion injury in animal models; however, its underling mechanisms are still unclear. In this study, we sought to establish an in vitro experimental model of hypoxia/reoxygenation (H/R) using HT22 cells that originated from mouse hippocampal neurons and to examine protective the effect of dopamine-receptor ligands against H/R-induced cell injury. The treatment with hypoxia for 18 h followed by reoxygenation for 6 h induced the elevation of intracellular reactive oxygen species (ROS) and reduction of mitochondrial membrane potential; however, lactate dehydrogenase (LDH) release was not changed at this time point. LDH release was increased after reoxygenation for 18 h and longer, and this increase in LDH release was suppressed by dopamine receptor agonists such as apomorphine and apocodeine. The suppressive effects of these agonists were reversibly inhibited by L750667, a D(4)-receptor antagonist but not by D(2)- or D(3)-receptor antagonists. In addition, PD168077, a selective dopamine D(4)-receptor agonist, also protected against H/R-induced cell death. These results suggest that H/R causes oxidative stress-induced cell death and that the activation of dopamine D(4) receptors protects against H/R-induced cell death in HT22 cells.

Practice patterns of Japanese physicians in urologic surveillance and management of spinal cord injury patients

STUDY DESIGN

Analysis of answers to a new questionnaire.

OBJECTIVE

To examine current practice patterns of physicians in the urological surveillance and management of spinal cord injury (SCI) patients in Japan.

SETTING

Nationwide questionnaire survey to physicians in Japan.

METHODS

A Japanese version of the 14-item questionnaire survey carried out in US was mailed to 770 members of the Japanese Neurogenic Bladder Society (JNBS).

RESULTS

We received answers to our questionnaire from 333 (43.2%) members of JNBS. The responders were all urologists. For surveillance of the upper urinary tract (UUT), 239 (71.8%) respondents preferred abdominal ultrasound. Cystometry was performed routinely by 174 (52.3%) respondents for the evaluation of vesicourethral function. Cystoscopy was carried out in cases of hematuria (88.0%) and bladder stone (55.3%). Surveillance of the urinary tract was performed every year in 154 (46.2%). For detection of bladder cancer, which 119 (37.9%) respondents have experienced, 94.9% physicians perform cystoscopy, 76.3% urinary cytology, and 60.4% ultrasound. For initial treatment of detrusor-sphincter dyssynergia (DSD), 225 (69.2%) respondents chose alpha-blocker, and 94 (28.9%) chose clean intermittent catheterization (CIC) with/without anticholinergic agent(s). For initial treatment of overactive bladder, 245 (74.7%) chose anticholinergic agent(s) only and 63 (19.2%) chose anticholinergic agent(s) with CIC. For initial treatment of areflexic bladder, 233 (73.7%) chose CIC and 63 (19.9%) chose Credé maneuver or tapping.

CONCLUSIONS

This survey shows that there are some differences in urological surveillance and management of SCI patients between Japan and the US. Reasons for the discrepancy should be examined.

In-situ visualization and quantification of mineralization of cultured osteogenetic cells

An osteoblastic cell line (HOS cells) produces a prominent osteoid matrix with mineralization. Fibroblasts, on the other hand, do not exhibit this mineralization. To evaluate the degree of mineralization, we added calcein to the culture medium and then observed the culture wells by using an image analyzer. The calcein uptake into the cell/matrix layer was detected in the HOS cells but not in the fibroblasts. The calcein uptake was also quantified in situ by using an image analyzer, which revealed high levels in the HOS cells, which correlated well with the calcium content of the mineralized matrix. Rat marrow cells were also cultured in media containing calcein, fetal bovine serum, beta-glycerophosphate, L-ascorbic acid 2-phosphate, and with or without dexamethasone. With the dexamethasone, the cells exhibited osteogenic differentiation that resulted in mineralized matrix formation after about 10 days. The matrix formation coincided with the appearance of calcein uptake into the cell/matrix layer, with the amount of calcein uptake increasing with time. By contrast, the culture without the dexamethasone did not exhibit matrix formation and the calcein uptake was negligible. In the case of both HOS cell and rat marrow cell cultures in vitro, calcein did not affect expressions of their alkaline phosphatase activity or osteocalcin production. Furthermore, histologic observation revealed that rat marrow cells subcultured with calcein could show osteogenic ability after in vivo implantation. These results suggest that the current method of detecting calcein uptake in a culture allows the monitoring of the osteogenic capacity of cultured cells, as well as the measurement of the amount of mineralization produced by the osteogenic cells. Given that osteogenic cultured cells/mineralized matrices are used in bone reconstruction surgery, the in situ monitoring method is invaluable in that it allows us to evaluate the osteogenic capacity of in vitro constructs.

Extraction of total RNA from leaves of Eucalyptus and other woody and herbaceous plants using sodium isoascorbate

Rapid extraction of total RNA from Eucalyptus leaves is difficult due to the high content of polyphenolics and polysaccharides. A rapid and simple method was developed by using an extraction buffer containing sodium isoascorbate at a concentration of 500 mM. This method consisted of one or two chloroform extractions, one acid guanidium-phenol-chloroform extraction, and isopropanol precipitation alone. The yields of the RNA fractions were 246-1750 micrograms/g fresh weight when leaves of Eucalyptus, five other woody plants, and four herbaceous plants were used as samples. The contamination of the RNA fractions by proteins and polysaccharides was very limited as judged spectrophotometrically. When the RNA fractions were subjected to agarose gel electrophoresis, intact rRNA bands were detected. The RNA fractions could be used for RT-PCR. These results indicate that our new method achieves a simple and rapid preparation of high-quality RNA from leaves of Eucalyptus and other plant species.

Localization of bradykinin B(2) receptor in the follicles of porcine ovary and increased expression of matrix metalloproteinase-3 and -20 in cultured granulosa cells by bradykinin treatment

We have recently shown that not only bradykinin, but also all components for the production of bradykinin, can be detected within the follicle of porcine ovaries. To elucidate the relevance of the intrafollicular bradykinin-producing system to its physiological role, we investigated the distribution of bradykinin receptor (B(2)R) mRNA and the protein in porcine ovaries. A cDNA encoding porcine B(2)R was first cloned from a porcine uterus cDNA library. The receptor mRNA was scarcely detected in the ovary by Northern blot analysis. Polymerase chain reaction analysis with total RNAs isolated from the ovary and from granulosa cells of small and large follicles demonstrated the ovarian expression of B(2)R mRNA. The B(2)R protein was detected by Western blot analysis in extracts of isolated granulosa cells. In situ hybridization of B(2)R mRNA and immunohistochemical analysis of the protein revealed that the receptor is expressed in the theca and granulosa cells of all growing follicles. The effect of bradykinin on the expression of some matrix metalloproteinase (MMP) genes was examined using isolated granulosa cells. Bradykinin treatment induced MMP-3 and MMP-20 gene expression to an extreme degree. The expression of MT1-MMP was also affected by bradykinin treatment. These results suggest that MMPs play a role in follicle rupture during ovulation. The present study provides new information regarding the mechanisms of bradykinin-induced ovulation in porcine ovaries.

[A case of bilateral synchronous renal cell carcinoma treated with left partial nephrectomy and laparoscopic right nephrectomy]

We describe a case of bilateral synchronous renal cell carcinoma. A 70-year-old female was admitted to our department because of further examination for bilateral renal masses. Computed tomographic scanning and ultrasound examinations revealed bilateral solid enhanced renal masses, and bilateral renal cell carcinomas were suspected. First, partial left nephrectomy was performed. On the 21th day after the first operation, we confirmed the recovery of the left kidney, and performed right nephrectomy laparoscopically. The histopathological diagnosis revealed bilateral renal cell carcinomas. The patient is alive with no metastatic lesions and no recurrence at 16 months after the operations.

Repeated thermal therapy improves impaired vascular endothelial function in patients with coronary risk factors

OBJECTIVES

We sought to determine whether sauna therapy, a thermal vasodilation therapy, improves endothelial function in patients with coronary risk factors such as hypercholesterolemia, hypertension, diabetes mellitus and smoking.

BACKGROUND

Exposure to heat is widely used as a traditional therapy in many different cultures. We have recently found that repeated sauna therapy improves endothelial and cardiac function in patients with chronic heart failure.

METHODS

Twenty-five men with at least one coronary risk factor (risk group: 38 +/- 7 years) and 10 healthy men without coronary risk factors (control group: 35 +/- 8 years) were enrolled. Patients in the risk group were treated with a 60 degrees C far infrared-ray dry sauna bath for 15 min and then kept in a bed covered with blankets for 30 min once a day for two weeks. To assess endothelial function, brachial artery diameter was measured at rest, during reactive hyperemia (flow-mediated endothelium-dependent dilation [%FMD]), again at rest and after sublingual nitroglycerin administration (endothelium-independent vasodilation [%NTG]) using high-resolution ultrasound.

RESULTS

The %FMD was significantly impaired in the risk group compared with the control group (4.0 +/- 1.7% vs. 8.2 +/- 2.7%, p < 0.0001), while %NTG was similar (18.7 +/- 4.2% vs. 20.4 +/- 5.1%). Two weeks of sauna therapy significantly improved %FMD in the risk group (4.0 +/- 1.7% to 5.8 +/- 1.3%, p < 0.001). In contrast, %NTG did not change after two weeks of sauna therapy (18.7 +/- 4.2% to 18.1 +/- 4.1%).

CONCLUSIONS

Repeated sauna treatment improves impaired vascular endothelial function in the setting of coronary risk factors, suggesting a therapeutic role for sauna treatment in patients with risk factors for atherosclerosis.

Apolipoprotein J/clusterin is induced in vascular smooth muscle cells after vascular injury

BACKGROUND

Understanding the precise molecular mechanisms underlying the phenomenon of restenosis after PTCA may help us to develop a new strategy for the treatment of restenosis after PTCA. The purpose of this study was to identify the genes involved in vascular restenosis.

METHODS AND RESULTS

Applying a differential hybridization method to a model of the balloon-injured rabbit aorta, we identified 6 cDNA clones that were upregulated after injury. Northern blot showed that 5 genes, but not apolipoprotein J (apoJ)/clusterin, were constitutively expressed in noninjured aorta and upregulated after balloon injury. ApoJ mRNA was not detectable in noninjured aorta (control), began to be expressed at 6 hours after injury, showed a peak level at 24 hours (a 48-fold increase), gradually declined, and returned to the control level at 24 weeks. Western blot and immunohistochemistry demonstrated no expression of apoJ protein in noninjured aorta, an expression of apoJ at 2 days after balloon injury, and a peak level (a 55-fold increase) at 2 to 8 weeks. The expression of apoJ protein continued until 24 weeks after injury. In situ hybridization revealed that apoJ mRNA was expressed in smooth muscle cells (SMCs) of media at 2 days after injury and in SMCs of media and neointima at 2 weeks. To analyze the function of apoJ, stably transfected rabbit SMCs were created. The expression of apoJ stimulated proliferation and migration of SMCs.

CONCLUSIONS

ApoJ is dramatically induced in media and neointima after vascular injury, suggesting that apoJ contributes to restenosis after angioplasty.

Increased constriction of the ductus arteriosus with combined administration of indomethacin and L-NAME in fetal rats

We studied age-related changes and the caliber of the ductus arteriosus (DA) after two-pathway inhibition of prostaglandin E(2) and nitric oxide (NO) by the combined administration of indomethacin, a cyclooxygenase inhibitor, and N(G)-nitro-L-arginine methyl ester (L-NAME), an NO synthase inhibitor, in fetal rats. Pregnant rats from day 18 to 21 of gestation were used. They were administered indomethacin orally (3 mg/kg) 3 h before cesarean section, and then L-NAME (50 mg/kg) was injected intraperitoneally 3 h before the rats were killed. Using rapid-freezing and shaving methods, the caliber of the DA in fetal rats was measured. Compared with the indomethacin alone group, indomethacin plus L-NAME further constricted the DA after indomethacin and L-NAME were simultaneously administered 3 h before the rats were sacrificed. The extent of the final DA constriction was almost equal to the addition of each effect of indomethacin and L-NAME. We concluded that the magnitude of DA constriction following indomethacin plus L-NAME was due to the additive effects of these agents, suggesting a possible method to treat patent DA in premature infants.

Nongenomic antiapoptotic signal transduction by estrogen in cultured cortical neurons

Estrogen replacement therapy in menopausal women has been suggested to be beneficial in preventing the progression of cognitive impairment in Alzheimer disease. We demonstrated previously that the phosphatidylinositol 3-kinase (PI3-K)/Akt signal transduction pathway plays a pivotal role on the neuroprotection provided by 17beta-estradiol against acute glutamate toxicity. In the present study, we investigated the mechanism of neuroprotection against apoptosis because acute glutamate toxicity predominantly induced necrosis. 17beta-estradiol provided neuroprotection against apoptosis induced by staurosporine. This neuroprotection was inhibited by pretreatment with a PI3-K inhibitor, LY294002. An estrogen receptor specific antagonist, ICI182780, also suppressed the neuroprotection provided by 17beta-estradiol. Western blotting analysis demonstrated that treatment with 17beta-estradiol induced the phosphorylation of Akt within 5 min, which was suppressed by pretreatment with LY294002 and ICI182780. Furthermore, 17beta-estradiol induced phosphorylation of the cAMP response element binding protein (CREB) at Ser(133) within 15 min and then upregulated Bcl-2 in a PI3-K/Akt-dependent manner. Because CREB is known to be a transcription factor for Bcl-2, these results suggest that 17beta-estradiol exerts its antiapoptotic effects by CREB phosphorylation and Bcl-2 upregulation via nongenomic activation of the PI3-K/Akt pathway in cultured cortical neurons.

Effects of Prenatal Rubratoxin-B Exposure on Behaviors of Mouse Offspring

The effects of prenatal rubratoxin-B (RB) exposure on 8 behavioral parameters in JCL:ICR mice were assessed. Pregnant mice were injected intraperitoneally with 0.1 or 0.2 mg/kg/day of RB dissolved in propylene glycol water solution on days 7-9 (Group A) or 10-12 (Group B) of gestation. Controls received the vehicle similarly on days 7-12 of gestation. Before weaning, the offspring of both sexes were examined to test their the surface righting reflex (5 days of age), cliff avoidance response (6 days), negative geotaxis response (7 days), and swimming development (8, 10, and 12 days). After weaning, male animals were examined using the rotarod test (6 weeks of age), the open-field test (7 weeks), the shuttle-box-avoidance-learning test (9 weeks), and the water E-maze test (10 weeks). The preweanling offspring in the 0.2 mg/kg-B group showed significantly lower success rates and longer response times than controls in the cliff-avoidance response. In swimming development, the offspring in the 0.2 mg/kg B group had significantly lower scores than controls for swimming angle at 10 and 12 days of age. The avoidance learning of the mice in all RB-exposed A and B groups was significantly poorer than that of controls. These results indicate that prenatal exposure to RB produced a delay of early response development and impaired learning ability in the offspring of mice exposed to RB during middle pregnancy.

alpha 7 nicotinic receptor transduces signals to phosphatidylinositol 3-kinase to block A beta-amyloid-induced neurotoxicity

Multiple lines of evidence, from molecular and cellular to epidemiological, have implicated nicotinic transmission in the pathogenesis of Alzheimer's disease (AD). Here we show the signal transduction mechanism involved in nicotinic receptor-mediated protection against beta-amyloid-enhanced glutamate neurotoxicity. Nicotine-induced protection was suppressed by an alpha7 nicotinic receptor antagonist (alpha-bungarotoxin), a phosphatidylinositol 3-kinase (PI3K) inhibitor (LY294002 and wortmannin), and a Src inhibitor (PP2). Levels of phosphorylated Akt, an effector of PI3K, and Bcl-2 were increased by nicotine. The alpha7 nicotinic receptor was physically associated with the PI3K p85 subunit and Fyn. These findings indicate that the alpha7 nicotinic receptor transduces signals to PI3K in a cascade, which ultimately contributes to a neuroprotective effect. This might form the basis of a new treatment for AD.

Nine cases of granular cell tumors in B6C3F1 mice

The histological characteristics of 9 cases of granular cell tumors (GCTs) observed in B6C3F1 mice were examined to determine their cellular origin. Seven of the 9 cases were found in the uterus and other 2 cases were in the subcutaneous tissue. Tumor cells had abundant granules in the cytoplasm which were stained with PAS and were resistant to diastase treatment. Ultrastructurally, the granules were identified as lysosomes. The cell surface had cytoplasmic processus showing interdigitation with adjacent cells. A character feature of the tumor cells was the presence of a desmosome-like structure on their cell surface but no basal lamina was demonstrated. Although GCTs have been considered to be derived from Schwann cells on the basis of their ultrastructural features and S-100 protein-immunopositive findings, the absence of basal lamina in the present cases may raise a controversy as to their origin.

N-methyl-D-aspartate receptor-mediated mitochondrial Ca(2+) overload in acute excitotoxic motor neuron death: a mechanism distinct from chronic neurotoxicity after Ca(2+) influx

Mitochondrial uptake of Ca(2+) has recently been found to play an important role in glutamate-induced neurotoxicity (GNT) as well as in the activation of Ca(2+)-dependent molecules, such as calmodulin and neuronal nitric oxide synthase (nNOS), in the cytoplasm. Prolonged exposure to glutamate injures motor neurons predominantly through the activation of Ca(2+)/calmodulin-nNOS, as previously reported, and is, in part, associated with the pathogenesis of amyotrophic lateral sclerosis (ALS). In the present study, we investigated how mitochondrial uptake of Ca(2+) is involved in GNT in spinal motor neurons. Acute excitotoxicity induced by exposure to 0.5 mM glutamate for 5 min was found in both motor and nonmotor neurons in cultured spinal cords from rat embryos and was dependent on extracellular Ca(2+) and on N-methyl-D-aspartate (NMDA) receptor activation. Mitochondrial uncouplers markedly blocked acute excitotoxicity, and membrane-permeable superoxide dismutase mimics attenuated acute excitotoxicity induced by glutamate and NMDA but not by alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) or kainate. Fluorimetric analysis showed that mitochondrial Ca(2+) was elevated promptly with subsequent accumulation of reactive oxygen species (ROS) in the mitochondria. An NMDA receptor antagonist and a mitochondrial uncoupler eliminated the increase in fluorescence of mitochondrial Ca(2+) and ROS indicators. These data indicate that acute excitotoxicity in spinal neurons is mediated by mitochondrial Ca(2+) overload and ROS generation through the activation of NMDA receptors. This mechanism is different from that of chronic GNT.

Nicotinic receptor-mediated protection against beta-amyloid neurotoxicity

Multiple lines of evidence, from molecular and cellular to epidemiologic, have implicated nicotinic transmission in the pathology of Alzheimer's disease. In this review we present evidence for nicotinic receptor-mediated protection against beta-amyloid and glutamate neurotoxicity, and the signal transduction involved in this mechanism. The data are based mainly on our studies using rat-cultured primary neurons. Nicotine-induced protection was blocked by an alpha7 nicotinic receptor antagonist, a phosphatidylinositol 3-kinase inhibitor, and an Src inhibitor. Levels of phosphorylated Akt, an effector of phosphatidylinositol 3-kinase; Bcl-2; and Bcl-x were increased by nicotine administration. From these experimental data, our hypothesis for the mechanism of nicotinic receptor-mediated survival signal transduction is that the alpha7 nicotinic receptor stimulates the Src family, which activates phosphatidylinositol 3-kinase to phosphorylate Akt, which subsequently transmits the signal to upregulate Bcl-2 and Bcl-x. Upregulation of Bcl-2 and Bcl-x could prevent cells from neuronal death induced by beta-amyloid and glutamate. These findings suggest that an early diagnosis of Alzheimer's disease and protective therapy with nicotinic receptor stimulation could delay the progress of Alzheimer's disease.

[Two cases of B cell lymphoma associated with hemophagocytic syndrome]

B cell lymphoma-associated hemophagocytic syndrome (B-LAHS) is clinically characterized by hepatosplenomegaly and bone marrow invasion without lymphadenopathy and skin lesions. Several cases of B-LAHS have been reported to demonstrate histopathologic findings of intravascular lymphomatosis (IVL), which in Western countries is characterized by a high rate of skin involvement and, rarely, bone marrow involvement and hemophagocytosis. Here we describe two interesting cases of B-LAHS. One patient was a 52-year-old woman whose bone marrow showed proliferation of large CD20-positive cells and hemophagocytosis at presentation. Combination chemotherapy was not effective, and the patient died of progressive disease. At autopsy, the lymphoma cells showed extravascular proliferation in many organs such as the bone marrow and liver, whereas in the adrenal glands, the lymphoma cells showed intravascular proliferation. The other patient was a 50-year-old man who had swellings of the bilateral kidneys and adrenal glands at presentation. Skin involvement by large lymphoma cells, a rare complication of B-LAHS, was observed. At autopsy, there was no evidence of IVL. Both of these patients showed high fever and cytopenia, and the disease took an aggressive clinical course, as in other reported cases of B-LAHS.

Repeated Thermal Therapy Upregulates Arterial Endothelial Nitric Oxide Synthase Expression in Syrian Golden Hamsters

It has been previously reported that sauna therapy, a thermal therapy, improves the hemodynamics and clinical symptoms in patients with chronic heart failure and also improves endothelial function, which is impaired in such patients. The present study investigated whether the improvements observed with sauna therapy are through modulation of arterial endothelial nitric oxide synthase (eNOS) expression. Eight male Syrian golden hamsters underwent sauna therapy, using an experimental far infrared-ray dry sauna system, at 39 degrees C for 15 min followed by 30 degrees C for 20 min daily for 4 weeks. Control group hamsters were placed in the sauna system switched off at room temperature of 24 degrees C for 35 min. Immunohistochemistry found greater amounts of the immunoreactive products of eNOS in the endothelial cells of the aorta and carotid, femoral and coronary arteries in the sauna group than in the control group. Western blot analysis also revealed that 4-week sauna therapy significantly increased eNOS expression in aortas by 50% in 4 series of independent experiments with an identical protocol (p<0.01). In reverse transcription polymerase chain reaction assay, the eNOS mRNA in aortas was greater in the sauna group than in controls, with a peak at 1-week of sauna therapy (approximately 40-fold increase). In conclusion, repeated thermal therapy upregulates eNOS expression in arterial endothelium.

Release of plasminogen activator inhibitor-1 from human astrocytes is regulated by intracellular ceramide

The present study underscores a regulatory role of intracellular ceramide in astrocytes for the release of an extracellular serine protease, tissue-type plasminogen activator (t-PA), and its inhibitor, plasminogen activator inhibitor-1 (PAI-1). Treatment of cultured human astrocytes with N-acetylsphingosine, a cell-permeable short-chain ceramide analogue or daunorubicin that could increase intracellular ceramide via activation of ceramide synthase or sphingomyelin hydrolysis increased the release of t-PA and conversely decreased the PAI-1 release. Interestingly, treatment of the astrocytes with tumor necrosis factor (TNF)-alpha also increased the intracellular ceramide levels but caused the elevation of PAI-1 release without altering the t-PA release. These data suggest that the generation of ceramide in astrocytes is linked at least with the regulation of PAI-1 release. We also demonstrate that the suppression of PAI-1 release with daunorubicin accelerates the cell death of neuronally differentiated PC12 cells and suggest an antiapoptotic role of PAI-1 in the nervous system.

[Nonmyeloablative stem cell transplantation with low-dose total body irradiation (200 cGy) for a 55-year-old woman with acute lymphoblastic leukemia]

We describe a 55-year-old woman with acute lymphoblastic leukemia (ALL) in the first remission who underwent nonmyeloablative stem cell transplantation with conditioning consisting of low-dose total body irradiation and postgrafting cyclosporine and mycophenolate mofetil. Myelosuppression was mild, but on day 28 her bone marrow showed 8.8% lymphoblasts. We withdrew the cyclosporine, but the patient developed grade 2 acute GVHD and eosinophilia. The proportion of bone marrow lymphoblasts decreased transiently to 1.0% on day 40, but later increased again and the patient died on day 85. Application of this approach to patients with ALL needs to be examined on a large scale.

Protection of cultured spinal motor neurons by estradiol

Estrogens have been reported to exert neuroprotection in the brain, but there have been no reports of such neuroprotection in spinal motor neurons, the neurons selectively involved in amyotrophic lateral sclerosis (ALS). In this study, we demonstrated that 17beta-estradiol and its biologically inactive stereoisomer, 17alpha-estradiol, prevented glutamate- and nitric oxide (NO)-induced selective motor neuronal death observed in primary cultures of the rat spinal cord. The dose of estradiols required for motor neuron protection was greatly reduced by co-administration with glutathione. The results of this study shows that estradiol protects spinal motor neurons from excitotoxic insults in vitro, and may have application as a treatment for ALS.

Synthesis and evaluation of multisubstrate analogue inhibitors of purine nucleoside phosphorylases

1,1-Difluoro-2-(tetrahydro-3-furanyl)ethylphosphonic acids (+/-)-cis-4a and (+/-)-trans-4a possessing a (purine-9-yl)methyl functionality at the ring as well as their homologues (+/-)-cis-4b and (+/-)-trans-4b were synthesized and tested as 'multi-substrate analogue' inhibitors for purine nucleoside phosphorylases. Radical cyclization of allylic alpha,alpha-difluorophosphonates 8a,b was applied to construct the alpha,alpha-difluorophosphonate-functionalized oxacycles 9a,b. The IC50 values of the nucleotide analogues (+/-)-cis-4a and (+/-)-cis-4b were 88 and 38 nM, respectively, for human erythrocyte PNP-catalyzed phosphorylation of inosine in the presence of 100mM orthophosphate. The stereochemistry of the inhibitors was found to affect significantly the inhibitory potency. The transisomers (+/-)-trans-4a and (+/-)-trans-4b were ca. 4-fold less potent than the corresponding cis-isomers. At an intracellular concentration of orthophosphate (1 mM), (+/-)-cis-4b, the most potent compound of this series, was shown to have IC50 and Ki values of 8.7 and 3.5 nM, respectively.

Identification of porcine follipsin as plasma kallikrein, and its possible involvement in the production of bradykinin within the follicles of porcine ovaries

To determine the identity of porcine follipsin, a plasma kallikrein cDNA clone was isolated from a porcine liver cDNA library. The clone encoded a protein of 643 amino acids, exhibiting identities 79.7, 72. 9, and 74.4% homologous to human, rat, and mouse plasma prekallikrein, respectively. The amino acid sequences of four internal peptides isolated from the tryptic digest of follipsin were all found in the deduced sequence. Authentic plasma kallikrein was purified from porcine plasma and compared directly with follipsin. Actions on synthetic substrates and behaviors with proteinase inhibitors were indistinguishable between these two enzymes. The cDNA was expressed in COS-7 cells and the recombinant protein was prepared from the culture medium of these cells. No active enzyme could be obtained, but the expressed protein was reacted with anti-porcine plasma kallikrein antibody. The mRNA was detected only in the liver in northern blot analysis. RT-PCR analysis of RNAs revealed that porcine testis, in addition to the liver, expressed the corresponding mRNA. In the ovary, plasma kallikrein was detected as a main band of the active form (Mr = 85,000) and the band of the minor inactive precursor form (Mr = 80,000), respectively. In contrast, the liver extract contained only the precursor form. Incubation of high molecular weight kininogen with follicular fluid plasma kallikrein resulted in an increased production of bradykinin. Further, the fresh fluid of large-sized follicles of porcine ovaries was found to contain this peptide hormone at a detectable level. These results indicate that porcine follipsin is plasma kallikrein, and that the enzyme may be involved in the production of bradykinin within ovarian follicles.

Overexpression of mitochondrial citrate synthase in Arabidopsis thaliana improved growth on a phosphorus-limited soil

The gene for mitochondrial citrate synthase (CS) was isolated from Daucus carota (DcCS) and introduced into Arabidopsis thaliana (strain WS) using Agrobacterium tumefaciens-mediated transformation. Characteristics of citrate excretion were compared between T3 transgenic plants, which were derived from the initial transgenic plants by self-fertilization and homozygous for DcCS, and the control plants that had no DcCS. The highest CS activity 0.78 micromol protein min(-1) exhibited by the transgenic plants was about threefold greater than that found in the control plants (0.23-0.28 micromol protein min(-1)). Western analysis of the transgenic plants showed two CS signals corresponding to signals obtained from both D. carota and A. thaliana. Thus, it appears that the CS polypeptides by ectopic expression of DcCS were processed into the mature form and localized in the mitochondria of A. thaliana. The signal corresponding to the mature form of DcCS were greater in the transgenic plants having higher levels of CS activity. When the transgenic plants were grown in Al-phosphate media, a correlation between the levels of CS activity and the amounts of citrate excreted into the medium. The highest value (5.1 nmol per plant) was about 2.5-fold greater than that from control plants (1.9 nmol per plant). Both growth and P accumulation were greater in transgenic plants with high CS activity than that in control plants when they were grown on an acid soil where the availability of phosphate was low due to the formation of Al-phosphate. It appears that the overexpression of CS in A. thaliana improves the growth in phosphorous limited soil as a result of enhanced citrate excretion from the roots.

Movement-related desynchronization of the cerebral cortex studied with spatially filtered magnetoencephalography

Event-related desynchronization (ERD) within the alpha and beta bands on unilateral index finger extension and hand grasping was investigated on six normal volunteers with magnetoencephalography (MEG). A novel spatial filtering technique for imaging cortical source power, synthetic aperture magnetometry (SAM), was employed for the tomographic demonstration of ERD. SAM source image results were transformed into statistical parametric images. On the same hand grasping task, a functional MRI (fMRI) study was conducted on two subjects and compared with the ERD result. When the MEG data were analyzed with the fast Fourier transformation, power attenuation within the alpha and beta bands was evident on the contralateral sensorimotor area just prior to movement onset. The tomographic distribution of ERD was clearly obtained with SAM statistical imaging analysis. The equivalent current dipole (ECD) for the signal-averaged motor field was localized to the hemisphere contralateral to the hand movement, roughly at the center of the region displaying beta-band ERD. The signal increase on fMRI roughly colocalized with the ERD on the contralateral sensorimotor area. In conclusion, with the novel spatial filtering technique for the brain magnetic field, SAM, cortical regions contributing to ERD on finger movement were successfully demonstrated in a tomographic manner. The relative colocalization of the contralateral SAM ERD with ECD as well as the fMRI activation suggests that SAM is a practically useful technique to extract event-related signals from brain noise.

Synthesis of novel nucleotide analogues possessing a difluoromethylenephosphonato group. Evaluation of the inhibitory activity for purine nucleoside phosphorylase

Novel nucleotide analogues 1-6 were prepared as "multi-substrate" analogue inhibitors for purine nucleoside phosphorylases (PNPs). The cyclopropane and the tetrahydrofuran moieties of the alkyl spacer connecting a nucleobase and difluoromethylene phosphonic acid were found to be effective for good inhibition of PNPs.

Role of nitric oxide in regulating the ductus arteriosus caliber in fetal rats

The role of nitric oxide (NO) on the ductus arteriosus (DA) patency was examined in fetal rats at various stages of gestation. N(G)-nitro-L-arginine methyl ester (L-NAME, 50 mg/kg, i.p.), an NO synthase (NOS) inhibitor, or indomethacin (3 mg/kg, p.o.), a cyclooxygenase inhibitor, was administered at 3 hr before cesarean section to pregnant rats ranging from day 17 to day 21 of gestation. Dams were decapitated and the fetuses were obtained by cesarean section. The fetuses were rapidly frozen in an acetone-dry ice mixture. Using rapid-freezing and shaving methods, the calibers of the DA and pulmonary artery were measured. The constrictive effect of L-NAME on the fetal DA caliber was stronger than that of indomethacin in 19-day-old and immature fetuses. In near-term fetuses, the constrictive effects of L-NAME were reduced, while indomethacin caused marked DA constriction. We conclude that endogenous NO may play a major role in regulating the patency of the DA in earlier fetal stages, while dilator prostaglandins may play a greater role in regulating the ductal patency in the near-term fetus.

Mechanisms of antiapoptotic effects of estrogens in nigral dopaminergic neurons

Parkinson's disease is characterized by the mesencephalic dopaminergic neuronal loss, possibly by apoptosis, and the prevalence is higher in males than in females. The estrogen receptor (ER) subtype in the mesencephalon is exclusively ER beta, a recently cloned novel subtype. Bound with estradiol, it enhances gene transcription through the estrogen response element (ERE) or inhibits it through the activator protein-1 (AP-1) site. We demonstrated that 17beta-estradiol provided protection against nigral neuronal apoptosis caused by exposure to either bleomycin sulfate (BLM) or buthionine sulfoximine (BSO). BLM and BSO-induced nigral apoptosis was blocked by inhibitors for caspase-3 or c-Jun/AP-1. The antiapoptotic effect by estradiol was blocked by ICI 182,780, an antagonist for ER, but not by a synthesized peptide that inhibits binding of the ER to the ERE. Estradiol had no effects on caspase-3 activation and c-Jun NH(2)-terminal kinase (JNK), which were activated by BLM. It also suppressed apoptosis by serum deprivation, which was independent of caspase-3 activation. Therefore, the antiapoptotic neuroprotection by estradiol is mediated by transcription through AP-1 site downstream from JNK and caspase-3 activation. Furthermore, 17alpha-estradiol, a stereoisomer without female hormone activity, also provided an antiapoptotic effect. Therefore, the antiapoptotic effect is independent of female hormone activity.

Phosphatidylinositol 3-kinase mediates neuroprotection by estrogen in cultured cortical neurons

It has been shown that estrogen replacement in menopausal women is effective in slowing down the progression of cognitive impairment in Alzheimer's disease. Although recent studies have demonstrated the neuroprotective effects of estrogen, the precise mechanism of neuroprotection has not been elucidated. In the present study, we show that the phosphatidylinositol 3-kinase (PI3-K) cascade is involved in the neuroprotective mechanism stimulated by estrogen. Exposure to glutamate reduced the viability of rat primary cortical neurons. Pretreatment with 10 nM 17beta-estradiol significantly attenuated the glutamate-induced toxicity. This neuroprotective effect of 17beta-estradiol was blocked by co-administration with LY294002, a selective PI3-K inhibitor, but not by co-administration with PD98059, a selective mitogen activated protein kinase kinase inhibitor. Pretreatment with ICI182780, a specific estrogen receptor antagonist, also blocked the neuroprotection. Immunoblotting assay revealed that treatment with 17beta-estradiol induced the phosphorylation of Akt/PKB, an effector immediately downstream of PI3-K. These results suggest that PI3-K mediates the neuroprotective effect of 17beta-estradiol against glutamate-induced neurotoxicity.

Identification of components of the intrafollicular bradykinin-producing system in the porcine ovary

As a step in elucidating the biological role of plasma kallikrein (PK) present in the follicular fluid of mammalian ovaries, we examined pig ovary fluid to determine its constituent activators and substrates. Using the inactive precursor form of plasma kallikrein (prePK) as a substrate, we purified an enzyme capable of activating this protein. The prePK-activating enzyme was shown to be the active enzyme blood coagulation factor XIIa. We also isolated high molecular weight kininogen (HMW-K) from the same fluid. Incubation of HMW-K with the ovarian follicular fluid PK resulted in the production of the nanopeptide bradykinin (BK). Expression of prePK, blood coagulation factor XII, and HMW-K was examined by Northern blot analysis using ovary and liver poly(A)(+) RNA. All these transcripts were found in the liver, but none were found in the ovary. In addition, it was found that BK levels in the fluid derived from the small follicles were approximately 6 times higher than those from medium and large follicles. These results demonstrate the presence of a BK-producing system in the ovarian follicles and suggest the physiological importance of this peptide hormone in the early stages of follicular development and at ovulation.

omega-agatoxin IVA-sensitive Ca(2+) channel blocker, alpha-eudesmol, protects against brain injury after focal ischemia in rats

omega-Agatoxin IVA-sensitive Ca(2+) channels have been thought to be involved in physiological excitatory amino acid glutamate release and these channels may also contribute to the development of ischemic brain injury. Recently, we demonstrated that alpha-eudesmol from Juniperus virginiana Linn. (Cupressaceae) inhibits potently the presynaptic omega-agatoxin IVA-sensitive Ca(2+) channels. In the present study, we investigated the effects of alpha-eudesmol on brain edema formation and infarct size determined after 24 h of reperfusion following 1 h of middle cerebral artery occlusion in rats. We first found that alpha-eudesmol concentration-dependently inhibited glutamate release from rat brain synaptosomes and that its inhibitory effect was Ca(2+)-dependent. In the middle cerebral artery occlusion study, intracerebroventricular (i.c.v.) treatment with alpha-eudesmol significantly attenuated the post-ischemic increase in brain water content. alpha-Eudesmol also significantly reduced the size of the infarct area determined by triphenyltetrazolium chloride staining after 24 h of reperfusion. Using a microdialysis technique, we further demonstrated that alpha-eudesmol inhibits the elevation of the extracellular concentration of glutamate during ischemia. From these results, we suggest that alpha-eudesmol displays an ability to inhibit exocytotic glutamate release and to attenuate post-ischemic brain injury.

Neuroprotective mechanism of glial cell line-derived neurotrophic factor in mesencephalic neurons

Glial cell line-derived neurotrophic factor (GDNF) provides neuroprotection, but its neuroprotective mechanism has not been resolved. We investigated the neuroprotective mechanism of GDNF using primary culture of the rat mesencephalon. Bleomycin sulfate (BLM) and L-buthionine-[S,R]-sulfoximine (BSO) caused apoptosis in both dopaminergic and nondopaminergic neurons, as revealed by the presence of chromatin condensation, and positive staining by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL). GDNF preincubation blocked the neurotoxicity and reduced the number of the TUNEL-positive cells caused by BLM and BSO exposure. In contrast, GDNF did not provide neuroprotection against glutamate toxicity, which was not accompanied by these apoptotic features. The neuroprotection was mediated by phosphatidylinositol 3-kinase, an effector downstream from c-Ret, because it was blocked by LY294002. GDNF pretreatment caused up-regulation of Bcl-2 and Bcl-x. Furthermore, GDNF suppressed oxygen radical accumulation caused by BLM. Apoptosis induced by BLM and BSO was blocked by a caspase-3 inhibitor. Caspase-3 activity was elevated by BLM and suppressed by GDNF pretreatment. These findings indicate that GDNF has no effect on necrosis but exerts protection against apoptosis by activation of phosphatidylinositol 3-kinase and the subsequent up-regulation of Bcl-2 and Bcl-x, which suppresses accumulation of oxygen radicals followed by caspase-3 activation.

Hepatic heme metabolism in rats with fever induced by interleukin 1beta

We have recently reported that the content of hepatic cytochrome P450 (CYP) apparently decreased in fever model rats, which were created by repeated injection of recombinant human interleukin-1beta (rhIL-1beta) into the cerebroventricle. To make clear the biochemical mechanism of the decreased CYP content, we examined the effect of fever on the activities of hepatic enzymes involved in the biosynthetic and degradative pathways of heme. The activities of delta-aminolevulinic acid synthase, a rate-limiting enzyme in the heme biosynthesis, and porphobilinogen synthase in the liver of rhIL-1beta-induced fevered rat were significantly lower than those in the control, whereas the activity of heme oxygenase, a key enzyme in the heme-degradative pathway, markedly increased in the fevered rat. Moreover, the heme saturation of tryptophan 2,3-dioxygenase in the fevered rat liver was decreased to 43% of the control. These results indicate that fever diminishes the hepatic heme content by decreasing the heme biosynthesis and by accelerating the heme degradation. The deficiency of hepatic heme pool may be one of the main mechanisms that cause the impairment of CYP synthesis.

Effects of prenatal aflatoxin B1 exposure on behaviors of rat offspring

The effects of prenatal aflatoxin B1 (AFB) exposure on eight behavioral parameters in Jcl:Wistar rat offspring were assessed. Pregnant rats were injected subcutaneously with 0.3 mg/kg/day of AFB dissolved in dimethylsulfoxide on days 11-14 (Group A) or 15-18 (Group B) of gestation. Controls received the vehicle similarly on days 11-18 of gestation. Before weaning, the offspring were examined using the cliff avoidance response (5 days of age), the negative geotaxis reflex (7 days), and swimming development (6, 8, and 10 days). After weaning, animals were examined using the rotarod test (5 weeks of age), the open field test (6 weeks), a conditioned avoidance learning test (14 weeks), an underwater T-maze test (15 weeks), and a reproduction test (16 weeks). The preweaning offspring in the AFB-A group showed significantly lower success rates than controls in cliff avoidance responses. In swimming development, the offspring in the AFB-A group had significantly lower scores than controls for swimming direction. In the rotarod test, the AFB-A group remained on the rod for a significantly shorter time than the controls at 15 rpm on both the first and second trial days. The avoidance performance of the rats in AFB-A and AFB -B groups was significantly poorer than that of controls. These results indicate that prenatal exposure to AFB produced a delay of early response development, impaired locomotor coordination, and impaired learning ability in the offspring of rats exposed to AFB during middle pregnancy, and the early gestational exposure appears to produce more effects than latter exposure.