ANGPTL2-mediated epigenetic repression of MHC-I in tumor cells accelerates tumor immune evasion

Loss or downregulation of major histocompatibility complex class I (MHC-I) contributes to tumor immune evasion. We previously demonstrated that angiopoietin-like protein 2 (ANGPTL2) promotes tumor progression using a Xp11.2 translocation renal cell carcinoma (tRCC) mouse model. However, molecular mechanisms underlying ANGPTL2 tumor-promoting activity in the tRCC model remained unclear. Here, we report that ANGPTL2 deficiency in renal tubular epithelial cells slows tumor progression in the tRCC mouse model and promotes activated CD8+ T-cell infiltration of kidney tissues. We also found that Angptl2-deficient tumor cells show enhanced interferon γ-induced expression of MHC-I and increased susceptibility to CD8+ T-cell-mediated anti-tumor immune responses. Moreover, we provide evidence that the ANGPTL2-α5β1 integrin pathway accelerates polycomb repressive complex 2-mediated repression of MHC-I expression in tumor cells. These findings suggest that ANGPTL2 signaling in tumor cells contributes to tumor immune evasion and that suppressing that signaling in tumor cells could serve as a potential strategy to facilitate tumor elimination by T-cell-mediated anti-tumor immunity.

Mortality and complications 1 year after treatment of hydrocephalus with endoscopic third ventriculostomy and ventriculoperitoneal shunt in children at Queen Elizabeth Central Hospital, Malawi

BACKGROUND

Over the past two decades, the management of hydrocephalus has witnessed the addition of endoscopic third ventriculostomy with or without choroid plexus cauterization (ETV ± CPC) to the traditional methods including ventriculoperitoneal shunt insertion (VPSI). We conducted this study to assess mortality and complications with surgical implications associated with the two procedures in children with hydrocephalus.

METHODS

We reviewed our operating theater registry to identify children below 17 years old who underwent hydrocephalus surgery for the first time in 2016. The patients were followed for up to 1 year from the date of the initial operation. Their vital status was confirmed by follow-up visits by a community nurse. Descriptive analyses were used to describe the characteristics of the patients and evaluate the study outcomes (i.e., mortality and complications).

RESULTS

One hundred fifty-three patients were eligible for the study; 56% were males and 73.2% had primary ETV ± CPC. Complete 1-year follow-up data was available for 79 patients, and 73.4% of these had ETV ± CPC. One-year success (event-free) rates for ETV and VPSI were similar at 67.4% and 66.7%, respectively. ETVs in infants under 6 months performed poorly; failing in half the infants, who were subsequently converted to VPS. Shunt sepsis was very high, 21.4% (95% CI 10.3-36.8). The majority of surgical complications (81.8%) occurred within 3 months of surgery.

CONCLUSION

ETV ± CPC and VPSI carry a similar frequency of mortality and complications in our setting, and therefore, both should be considered as a treatment option for patients with hydrocephalus. As VP shunt is still used for managing most of the patients, there is still a need to prioritize measures to reduce shunt infections.

A case of cardiac impalement injury with severe shock treated surgically after diagnosis using computed tomography and managed via extracorporeal membrane oxygenation in the hybrid emergency room

The Hybrid Emergency Room System (HERS) allows clinicians to perform life-saving procedures without having to transfer patients. Several studies have reported the effectiveness of the HERS in the treatment of blunt trauma patients. However, the use of a hybrid emergency room (ER) for the treatment of penetrating cardiac injuries, including impalement injuries, has not been reported. We present the case of a patient with cardiac impalement injury that was diagnosed via computed tomography (CT) and was managed via extracorporeal membrane oxygenation (ECMO) in the hybrid ER and via surgery in the operating room. A 55-year-old man was transferred to our hybrid ER due to a penetrating wood injury through the right thoracic region. The patient had unstable vital signs. A CT scan revealed a pericardial effusion, right lung contusion, and bilateral pneumothoraxes. There were no signs of hemothorax or aortic injury. Veno-arterial-ECMO was performed in preparation for surgery. The patient was then transferred to the operating room. Pericardiotomy and cardiac repair were performed, and the ECMO was discontinued postoperatively. The patient was discharged on postoperative day 10 without complications. The hybrid ER allows rapid CT examination without relocation. Thus, it facilitates the formation of a timely and effective treatment plan. This report documents the successful management of a cardiac impalement injury in the HERS.

Comparison of the stability of Mucor-derived flavin adenine dinucleotide-dependent glucose dehydrogenase and glucose oxidase

Long-term stability at near-body temperature is important for continuous glucose monitoring (CGM) sensors. However, the stability of enzymes used in CGM sensors has often been evaluated by measuring their melting temperature (T_m) values and by short heat treatment but not at around 37 °C. Glucose oxidase (GOD) is used in current CGM sensors. In this study, we evaluated the stability of modified Mucor-derived flavin adenine dinucleotide-dependent glucose dehydrogenase (designated Mr144-297) with improved thermal stability at medium to high temperatures and compared it with that of GOD. The T_m value of Mr144-297 was 61.6 ± 0.3 °C and was similar to that of GOD (61.4 ± 1.2 °C). However, Mr144-297 was clearly more stable than GOD at 40 °C and 55 °C. At 37 °C, the stability of a carbon electrode with immobilized Mr144-297 was higher than that of an electrode with GOD. Our data indicate that Mr144-297 is a more suitable enzyme for CGM sensors than is GOD.

Dual functions of angiopoietin-like protein 2 signaling in tumor progression and anti-tumor immunity

Angiopoietin-like protein 2 (ANGPTL2) is a secreted glycoprotein homologous to angiopoietins. Previous studies suggest that tumor cell-derived ANGPTL2 has tumor-promoting function. Here, we conducted mechanistic analysis comparing ANGPTL2 function in cancer progression in a murine syngeneic model of melanoma and a mouse model of translocation renal cell carcinoma (tRCC). ANGPTL2 deficiency in tumor cells slowed tRCC progression, supporting a tumor-promoting role. However, systemic ablation of ANGPTL2 accelerated tRCC progression, supporting a tumor-suppressing role. The syngeneic model also demonstrated a tumor-suppressing role of ANGPTL2 in host tumor microenvironmental cells. Furthermore, the syngeneic model showed that PDGFRα⁺ fibroblasts in the tumor microenvironment express abundant ANGPTL2 and contribute to tumor suppression. Moreover, host ANGPTL2 facilitates CD8⁺ T-cell cross-priming and enhances anti-tumor immune responses. Importantly, ANGPTL2 activates dendritic cells through PIR-B-NOTCH signaling and enhances tumor vaccine efficacy. Our study provides strong evidence that ANGPTL2 can function in either tumor promotion or suppression, depending on what cell type it is expressed in.

MicroRNA-204-5p: A novel candidate urinary biomarker of Xp11.2 translocation renal cell carcinoma

Xp11.2 translocation renal cell carcinoma (Xp11 tRCC) is a rare sporadic pediatric kidney cancer caused by constitutively active TFE3 fusion proteins. Tumors in patients with Xp11 tRCC tend to recur and undergo frequent metastasis, in part due to lack of methods available to detect early‐stage disease. Here we generated transgenic (Tg) mice overexpressing the human PRCC‐TFE3 fusion gene in renal tubular epithelial cells, as an Xp11 tRCC mouse model. At 20 weeks of age, mice showed no histological abnormalities in kidney but by 40 weeks showed Xp11 tRCC development and related morphological and histological changes. MicroRNA (miR)‐204‐5p levels in urinary exosomes of 40‐week‐old Tg mice showing tRCC were significantly elevated compared with levels in control mice. MicroRNA‐204‐5p expression also significantly increased in primary renal cell carcinoma cell lines established both from Tg mouse tumors and from tumor tissue from 2 Xp11 tRCC patients. All of these lines secreted miR‐204‐5p‐containing exosomes. Notably, we also observed increased miR‐204‐5p levels in urinary exosomes in 20‐week‐old renal PRCC‐TFE3 Tg mice prior to tRCC development, and those levels were equivalent to those in 40‐week‐old Tg mice, suggesting that miR‐204‐5p increases follow expression of constitutively active TFE3 fusion proteins in renal tubular epithelial cells prior to overt tRCC development. Finally, we confirmed that miR‐204‐5p expression significantly increases in noncancerous human kidney cells after overexpression of a PRCC‐TFE3 fusion gene. These findings suggest that miR‐204‐5p in urinary exosomes could be a useful biomarker for early diagnosis of patients with Xp11 tRCC.

Metabolic control of vesicular glutamate transport and release

Fasting has been used to control epilepsy since antiquity, but the mechanism of coupling between metabolic state and excitatory neurotransmission remains unknown. Previous work has shown that the vesicular glutamate transporters (VGLUTs) required for exocytotic release of glutamate undergo an unusual form of regulation by Cl(-). Using functional reconstitution of the purified VGLUTs into proteoliposomes, we now show that Cl(-) acts as an allosteric activator, and the ketone bodies that increase with fasting inhibit glutamate release by competing with Cl(-) at the site of allosteric regulation. Consistent with these observations, acetoacetate reduced quantal size at hippocampal synapses and suppresses glutamate release and seizures evoked with 4-aminopyridine in the brain. The results indicate an unsuspected link between metabolic state and excitatory neurotransmission through anion-dependent regulation of VGLUT activity.

The pharmacokinetics and pharmacodynamics of tandospirone in rats exposed to conditioned fear stress

The 5-HT1, agonist tandospirone is generally thought to have a weak anxiolytic effect with a slow onset of action. Our recent clinical study suggested that a comparatively high dose of tandospirone has excellent anxiolytic efficacy and is without significant adverse effects. The present study was designed to clarify the relationship between the anxiolytic effect of tandospirone and its plasma and brain concentrations. The anxiolytic effect was estimated by determining the conditioned fear stress-induced freezing behavior in rats after tandospirone administration. Obvious correlations between anxiolytic effect and brain concentration of tandospirone were observed 0.5 and 4 h after tandospirone administration, while the anxiolytic effect was dependent on the plasma concentration of at 0.5 h but not 4 h after tandospirone administration. The plasma concentration was significantly correlated with the brain concentration. These findings suggest that the potency of the anxiolytic effect is dependent on both the plasma and brain concentration.

Involvement of mitogen-stimulated p70-S6 kinase in the development of sensitization to the methamphetamine-induced rewarding effect in rats

The neural plasticity associated with behavioral sensitization following repeated administration of a psychostimulant methamphetamine (METH) is thought to require synthesis of new proteins. The aim of the present study was to investigate the role of p70-S6 kinase (p70-S6K) phosphorylation, which contributes to the selective translation of a unique family of mRNA, in mediating both the METH-induced rewarding effect and its sensitization. An intra-nucleus accumbens (N.Acc.) pre-injection with 0.025 pmol/rat of a selective p70-S6K inhibitor rapamycin failed to affect the METH-induced conditioned place preference. However, this treatment clearly abolished the development of sensitization of the METH-induced conditioned place preference. Consistent with the behavioral assay, the level of the immunoreactivity of phosporylated-p70-S6K was not changed in the cytosolic fraction of the N.Acc. obtained from rats that had revealed the METH-induced rewarding effect. In contrast, the immunoreactivities in the cytosolic preparation for Western blotting and immunohistochemical density of phosphorylated-p70-S6K were significantly increased in the N.Acc. obtained from METH-sensitized rats as compared with those with chronic saline treatment. However, the immunoreactivities of phosphorylated-extracellular signal-regulated kinase and phosphorylated-ribosomal S6 protein were not significantly altered in the N.Acc. under the same condition. The present data provide evidence for the change in the translation rate, which can be regulated by S6K phosphorylation, in the N.Acc. during the development of sensitization to METH-induced rewarding effects in rats.

Implications of protein kinase C in the nucleus accumbens in the development of sensitization to methamphetamine in rats

Repeated treatment with methamphetamine leads to an enhancement in the methamphetamine-induced dopamine release and its related behaviors. This phenomenon is called sensitization or reverse tolerance. Protein kinase C (PKC) controls numerous signaling cascades by virtue of its ability to phosphorylate target proteins that include other kinases. The purpose of study was then to investigate the implication of PKC in the development of sensitization to the rewarding effect and to the extracellular dopamine release induced by methamphetamine in rats. The conditioned place preference paradigm and in vivo microdialysis assay were performed in the present study. An intra-nucleus accumbens injection of a selective PKC inhibitor chelerythrine chloride abolished the enhancement of the methamphetamine-induced place preference following repeated treatment with methamphetamine. Furthermore, intra-nucleus accumbens injection of chelerythrine chloride blocked the development of sensitization to dopamine release and to the decrease in the major dopamine metabolites, 3'4-dihydroxyphenylacetic acid and homovanillic acid, in the nucleus accumbens induced by repeated methamphetamine treatment. Under these conditions, the immunoreactivity of the cytosolic phosphorylated conventional- or classic-type PKC in the limbic forebrain region including the nucleus accumbens was slightly, but significantly increased in methamphetamine-sensitized rats. The present data provide evidence for the implication of PKC in the nucleus accumbens in the development of sensitization to the methamphetamine-induced rewarding effect, dopamine release and inhibition of dopamine metabolism/re-uptake in rats.

Localization of NBC-1 variants in human kidney and renal cell carcinoma

The Na(+)-HCO(3)(-) cotransporter (NBC-1) plays a major role in bicarbonate absorption from proximal tubules. However, which NBC-1 variant mediates proximal bicarbonate absorption has not been definitely determined. Moreover, the localization of this cotransporter in human kidney and renal cell carcinoma (RCC) tissues has not been clarified. To clarify these issues, immunohistochemical analysis was performed using the specific antibodies against kidney type (kNBC-1) and pancreatic type (pNBC-1) transporters. In Western blot analysis the expression of kNBC-1 but not of pNBC-1 was detected in both normal human kidney and RCC tissues. In immunofluorescence analysis on normal renal tissues the anti-kNBC-1 antibody strongly and exclusively labeled the basolateral membranes of proximal tubules, which was confirmed by electron microscopic observation. In RCC cells, the anti-kNBC-1 antibody labeled both plasma membranes and intracellular organelles. The labeling by anti-pNBC-1 antibody was not detected in both normal kidney and RCC tissues. These results indicate that kNBC-1 is the dominant variant that mediates bicarbonate absorption from human renal proximal tubules. They also suggest that NBC-1 may have distinct roles in cancer cells.

Relationship between methamphetamine-induced dopamine release, hyperthermia, self-injurious behaviour and long term dopamine depletion in BALB/c and C57BL/6 mice

Differential sensitivity to neurotoxic effects of methamphetamine on striatal dopaminergic neurones between C57BL/6 and BALB/c mice has been established. In the present studies, the interaction of methamphetamine-induced dopamine release, self-injurious behaviour, the neural immune response, and the long-term (3 day) dopamine depletion were examined in these strains after administration of 8 mg/kg methamphetamine. BALB/c mice showed increased hyperthermia compared to the C57BL/6 strain, as well as induction of interleukin-1beta. Additionally, homovanillic acid (HVA) levels, as well as HVA/DA turnover ratios were elevated in the striatum and frontal cortex of BALB/c mice, both compared to untreated mice and to the C57BL/6 strain after a single injection of methamphetamine. Pretreatment with acetaminophen eliminated the methamphetamine-induced hyperthermia in BALB/c mice and reduced body temperature in C57BL/6 mice. However, acetaminophen pretreatment did not affect any parameters of dopaminergic toxicity in the striatum or frontal cortex of the BALB/c strain following repeated methamphetamine injections. Furthermore, acetaminophen pretreatment did not alter the incidence of self-injurious behaviour in BALB/c mice. Therefore, hyperthermia and methamphetamine-induced toxicity appear to be independent phenomena while self-injurious behaviour may provide a better predictor of toxicity, which, in turn, may be related to dopamine release.

Biphasic regulation of renal proximal bicarbonate absorption by luminal AT(1A) receptor

Angiotensin II (AngII) regulates renal proximal transport in a biphasic way. It has been recently shown that the basolateral type 1A receptor (AT(1A)) mediates the biphasic regulation of Na(+)-HCO(3)(-) cotransporter (NBC) by AngII. However, the receptor subtype(s) responsible for the luminal AngII actions remained to be established. To clarify this issue, the luminal AngII effects in isolated proximal tubules from wild-type (WT) and AT(1A)-deficient mice (AT(1A) KO) were compared. In WT, the rate of bicarbonate absorption (JHCO(3)(-)), analyzed with a stop-flow microspectrofluorometric method, was stimulated by 10(-10) mol/L luminal AngII but was inhibited by 10(-6) mol/L luminal AngII. Both stimulatory and inhibitory effects of AngII were completely blocked by valsartan (AT(1) antagonist) but unaffected by PD 123,319 (AT(2) antagonist). In AT(1A) KO, in contrast, luminal AngII (10(-10) - 10(-6) mol/L) did not change JHCO(3)(-). In WT, 10(-6) mol/L luminal AngII increased cell Ca(2+) concentrations ([Ca(2+)](i)), which was again blocked by valsartan but not by PD 123,319. However, luminal AngII did not increase [Ca(2+)](i) in AT(1A) KO. On the other hand, the addition of arachidonic acid similarly inhibited JHCO(3)(-) in WT and AT(1A) KO. Furthermore, the acute activation of protein kinase C by phorbol 12-myristate 13-acetate similarly stimulated JHCO(3)(-) in WT and AT1A KO, indicating that the inhibitory and stimulatory pathways necessary for the AngII actions were preserved in AT(1A) KO. These results indicate that the luminal AT(1A) mediates the biphasic regulation of bicarbonate absorption by luminal AngII, while no evidence was obtained for a role of AT(2).

Localization of Na+-HCO-3 cotransporter (NBC-1) variants in rat and human pancreas

Mutations in Na(+)-HCO(3)(-) cotransporter (NBC-1) cause proximal renal tubular acidosis (pRTA) associated with ocular abnormalities. One pRTA patient had increased serum amylase, suggesting possible evidence of pancreatitis. To further delineate a link between NBC-1 inactivation and pancreatic dysfunction, immunohistochemical analysis was performed on rat and human pancreas using antibodies against kidney-type (kNBC-1) and pancreatic-type (pNBC-1) transporters. In rat pancreas, the anti-pNBC-1 antibody labeled acinar cells and both apical and basolateral membranes of medium and large duct cells. In human pancreas, on the other hand, the anti-pNBC-1 antibody did not label acinar cells, although it did label the basolateral membranes of the entire duct system. The labeling by anti-kNBC-1 antibody was detected in only a limited number of rat pancreatic duct cells. To examine the effects of pRTA-related mutations, R342S and R554H, on pNBC-1 function, we performed functional analysis and found that both mutants had reduced transport activities compared with the wild-type pNBC-1. These results indicate that pNBC-1 is the predominant variant that mediates basolateral HCO(3)(-) uptake into duct cells in both rat and human pancreas. The loss of pNBC-1 function is predicted to have significant impact on overall ductal HCO(3)(-) secretion, which could potentially lead to pancreatic dysfunction.

Biphasic regulation of Na+-HCO3- cotransporter by angiotensin II type 1A receptor

Although angiotensin (Ang) II is known to regulate renal proximal transport in a biphasic way, the receptor subtype(s) mediating these Ang II effects remained to be established. To clarify this issue, we compared the effects of Ang II in wild-type mice (WT) and Ang II type 1A receptor-deficient mice (AT(1A) KO). The Na+-HCO3- cotransporter (NBC) activity, analyzed in isolated nonperfused tubules with a fluorescent probe, was stimulated by 10(-10) mol/L Ang II but was inhibited by 10(-6) mol/L Ang II in WT. Although valsartan (AT1 antagonist) blocked both stimulation and inhibition by Ang II, PD 123,319 (AT2 antagonist) did not modify these effects of Ang II. In AT1A KO, in contrast, this biphasic regulation was lost, and only stimulation of NBC activity by 10(-6) mol/L Ang II was observed. This stimulation was blocked by valsartan but not by PD 123,319. More than 10(-8) mol/L Ang II induced a transient increase in cell Ca2+ concentrations in WT, which was again blocked by valsartan but not by PD 123,319. However, up to 10(-5) mol/L Ang II did not increase cell Ca2+ concentrations in AT1A KO. Finally, the addition of arachidonic acid inhibited the NBC activity similarly in WT and AT(1A) KO, suggesting that the inhibitory pathway involving P-450 metabolites is preserved in AT(1A) KO. These results indicate that AT(1A) mediates the biphasic regulation of NBC. Although low-level expression of AT(1B) could be responsible for the stimulation by 10(-6) mol/L Ang II in AT1A KO, no evidence was obtained for AT2 involvement.

Transcription analysis of rpoH in Pseudomonas putida

We previously determined the complete DNA sequence of the rpoH gene encoding the heat-shock sigma factor (sigmaH) of Pseudomonas putida. In the present study, the transcriptional start sites of rpoH were determined to be 41 nucleotides (T1), 153 nucleotides (T2) and 157 nucleotides (T3) upstream from the translational start codon (AUG) of rpoH by rapid amplification of cDNA 5'-ends. Based on the locations of T2 and T3, a sigma70-type promoter (P2) was determined to be located in the open reading frame region of upstream ftsX in addition to the sigmaE-type promoter (P1; DNA Res. 6 (1999) 241). In the in vitro transcription assay with reconstituted RNA polymerases (Esigma70, EsigmaE, EsigmaH and EsigmaS) of Pseudomonas aeruginosa, EsigmaE transcribed rpoH from T1 and Esigma(70) transcribed it from T2 and T3. In both cases, the level of transcription was higher at 42 degrees C than at 30 degrees C. No transcript was detected when EsigmaH or EsigmaS was used. These results indicate that EsigmaE and Esigma70 recognize P1 promoter and P2 promoter, respectively, and also prove that the synthesis of rpoH mRNA is inducible upon heat shock.

Involvement of corticotropin-releasing factor receptor subtype 1 in morphine withdrawal regulation of the brain noradrenergic system

Effects of pretreatment with the selective corticotropin-releasing factor (CRF) subtype 1 (CRF(1)) receptor antagonist, 2-(N-(2-methylthio-4-isopropylphenyl)-N-ethyl-amino-4-(4-(3-fluorophenyl)-1,2,3,6-tetrahydropyridin-1-yl)-6-methylpyrimidine (CRA1000) on the behavioral and biochemical changes after naloxone-precipitated morphine withdrawal were examined in ICR mice. Mice were chronically treated with morphine (8-45 mg/kg) for 5 days. Naloxone (3 mg/kg, s.c.) precipitated jumping, diarrhea, and body weight loss in morphine-dependent mice. In addition, 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) and noradrenaline turnover (MHPG/noradrenaline) levels in the cerebral cortex were increased following naloxone challenge in morphine-dependent mice. However, 5-hydroxytriptamine turnover did not alter the increase following naloxone challenge in morphine-dependent mice. Pretreatment with CRA1000 (20 mg/kg, i.p.) attenuated the incidence of withdrawal signs and naloxone-precipitated increases in noradrenaline turnover. These results suggest that the activation of CRF(1) receptor may play an important role in the elevation of noradrenaline transmission, but not in 5-hydroxytriptamine transmission, in the cerebral cortex, which projects from the locus coeruleus during morphine withdrawal.

Differential effects of psychological stress on activation of the 5-hydroxytryptamine- and dopamine-containing neurons in the brain of freely moving rats

We investigated the effects of psychological stress, lacking direct physical stimulus, on the release of 5-hydroxytryptamine (5-HT) and dopamine (DA) in the basolateral nucleus of the amygdala (BLA) and the dorsal raphe nuclei (DRN) in the rat using the in vivo microdialysis technique with dual probes, one in each region of the same animals. Psychological stress was employed using the communication box paradigm. Psychological stress for 1 h significantly increased dialysate 5-HT levels in the DRN and the BLA. Psychological stress-induced 5-HT release in the BLA was significantly greater than those in the DRN, indicating that modifications of the serotonergic neurons in the BLA are more sensitive to psychological stress than are those of the DRN. Psychological stress also increased DA release in the BLA, while the dialysate DA levels in the DRN were unchanged. These results suggest that psychological stress preferentially activates ascending serotonergic neurons from the DRN to the BLA but not those of dopaminergic neurons. Furthermore, our findings indicate that both the serotonergic neurons and the dopaminergic neurons in the BLA may have a distinct role to play in the neuronal responses to psychological stress.

Molecular basis of ocular abnormalities associated with proximal renal tubular acidosis

Proximal renal tubular acidosis associated with ocular abnormalities such as band keratopathy, glaucoma, and cataracts is caused by mutations in the Na(+)-HCO(3)(-) cotransporter (NBC-1). However, the mechanism by which NBC-1 inactivation leads to such ocular abnormalities remains to be elucidated. By immunological analysis of human and rat eyes, we demonstrate that both kidney type (kNBC-1) and pancreatic type (pNBC-1) transporters are present in the corneal endothelium, trabecular meshwork, ciliary epithelium, and lens epithelium. In the human lens epithelial (HLE) cells, RT-PCR detected mRNAs of both kNBC-1 and pNBC-1. Although a Na(+)-HCO(3)-cotransport activity has not been detected in mammalian lens epithelia, cell pH (pH(i)) measurements revealed the presence of Cl(-)-independent, electrogenic Na(+)-HCO(3)-cotransport activity in HLE cells. In addition, up to 80% of amiloride-insensitive pH(i) recovery from acid load in the presence of HCO(3)(-)/CO(2) was inhibited by adenovirus-mediated transfer of a specific hammerhead ribozyme against NBC-1, consistent with a major role of NBC-1 in overall HCO(3)-transport by the lens epithelium. These results indicate that the normal transport activity of NBC-1 is indispensable not only for the maintenance of corneal and lenticular transparency but also for the regulation of aqueous humor outflow.

Incubation in tissue culture media allows isolated rabbit proximal tubules to regain in-vivo-like transport function: response of HCO3-absorption to norepinephrine

Using a new stop-flow perfusion technique with microspectrofluorometric determination of luminal fluid pH, we have studied which substrates or incubation conditions allow isolated rabbit proximal tubules to attain in-vivo-like rates of HCO3- absorption (J(HCO3)) and maximal responses of J(HCO3) to norepinephrine (NE). Essentially three incubation media were tested: plasma-like HCO(3-)-Ringer solution containing 5 mmol/l D-glucose (G-Ringer sol.), the same solution also containing 10 mmol/l lactate and 5 mmol/l L-alanine, (LAG-Ringer sol.), and two tissue culture media (DMEM and RPMI 1640). Compared to G-Ringer sol., application of LAG-Ringer sol. in the bath and/or lumen, or application of DMEM or RPMI 1640 in the bath either slightly increased or decreased J(HCO3) with borderline significance. However, RPMI 1640 plus 1 mmol/l pyruvate stimulated J(HCO3) by 55%. While NE (10(-5) mol/l), if applied in G-Ringer sol., had no effect, in the presence of LAG-Ringer sol. it increased J(HCO3) by approximately =40%, and in the presence of DMEM or RPMI 1640 it increased J(HCO3) by approximately =100%. This stimulation by NE followed Michaelis-Menten kinetics with an EC50 value of 0.25 micromol/l and was probably mediated by alpha1-adrenergic receptors. Additional cell pH measurements suggest that NE stimulates the basolateral Na+-HCO3- cotransporter which then becomes susceptible to inhibition by cAMP. We conclude that incubation in tissue culture media allows isolated proximal tubules to maintain a better functional state than the commonly used solutions with unphysiologically high substrate concentrations.

Intracellular pH regulatory mechanism in a human renal proximal cell line (HKC-8): evidence for Na+/H+ exchanger, CI-/HCO3- exchanger and Na+-HCO3- cotransporter

In the present study we investigated whether an immortalized human renal proximal cell line, HKC-8, expresses a recently cloned Na+-HCO3- cotransporter (NBC-1) and, if so, which isoform (kNBC-1 from kidney or pNBC-1 from pancreas) is expressed in this cell line. Cell pH (pHi) measurements using a pH-sensitive fluorescence probe in the absence of HCO3-/CO2 revealed the presence of a Na+/H+ exchanger that required high concentrations of amiloride for full inhibition. In the presence of HCO3-/CO2 another pHi recovery process, dependent on Na+ but independent of Cl-, was identified. This process was electrogenic and was inhibited by 4,4'-diisothiocyanatodihydrostilbene-2,2'-disulphonic acid (DIDS), being consistent with the Na+-HCO3- cotransporter. In addition, the pHi responses to Cl- removal were compatible with the presence of a Na+-independent Cl-/HCO3- exchanger that was also inhibited by DIDS. Reverse transcriptase polymerase chain reaction (RT-PCR) using primers designed for specific and common regions detected mRNAs of both kNBC-1 and pNBC-1 and Western blot analysis confirmed the expression of NBC-1 protein. These results indicate that HKC-8 has transport activities similar to intact proximal tubules and also suggest that both kNBC-1 and pNBC-1 may contribute to the Na+-HCO3- cotransport activity in this cell line.

Involvement of caspase 3-like protease in methylmercury-induced apoptosis of primary cultured rat cerebral microglia

Methylmercury (MeHg) has been implicated to induce massive neurodegeneration by disruption of neuron-glia interactions besides a direct potent neurotoxicity. In the present study, we examined potential cytotoxic effects of MeHg on primary cultured rat microglia. Following treatment with a relatively low concentration (0.5 microM) of MeHg, microglia had induced cell death accompanied by DNA fragmentation and an activation of caspase-3-like protease. MeHg-induced microglial death was significantly suppressed by the caspase-3-like protease inhibitor benzyloxycarbonyl-Try-Val-Ala-Asp-fluoromethyl-ketone indicating the occurrence of caspase-3-like protease-executed apoptosis. The aspartic protease inhibitor pepstatin A had a partial but significant inhibitory effect on MeHg-induced microglial apoptosis. These results indicate that a relatively low concentration of MeHg predominantly induces caspase-3-like protease-executed apoptosis of microglia, while the endosomal/lysosomal system is also partially involved in the cell death pathway.

Dopamine inhibits renal Na+:HCO3- cotransporter in rabbits and normotensive rats but not in spontaneously hypertensive rats

BACKGROUND

Dopamine (DA) is thought to regulate renal proximal transport through the inhibition of the Na+,K+-ATPase and/or Na+/H+ exchanger. Defects in this dopaminergic system are proposed to be a pathogenic factor of genetic hypertension. However, microperfusion studies have not consistently confirmed direct tubular effects of DA.

METHODS

Isolated proximal straight tubules were perfused peritubularly with Dulbecco's modified Eagle's tissue culture medium (DMEM) containing norepinephrine (NE) to improve incubation conditions. Intracellular Na+ concentrations ([Na+]i) and cell pH (pHi) were measured with fluorescence probes.

RESULTS

When incubated in DMEM plus NE, DA increased [Na+]i in rabbit tubules. Inhibition of Na+,K+-ATPase could not explain this response, as it was not suppressed by ouabain. An analysis of pHi responses to bath HCO3- reduction revealed that DA, SKF 38393 (a DA1 agonist), and adenosine 3',5'-cyclic monophosphate (cAMP) inhibited the basolateral Na+:HCO3- cotransporter in rabbit and Wistar-Kyoto rat (WKY), if its transport stoichiometry was converted to 3 HCO3-:1 Na+ by DMEM plus NE incubation. The inhibitory effect of DA was abolished by SCH 23390, a DA1 antagonist, but not by (-)-sulpiride, a DA2 antagonist. In spontaneously hypertensive rats (SHRs), however, DA and SKF 38393 failed to inhibit the cotransporter, although the inhibitory effects of cAMP and parathyroid hormone were comparable to those in WKY.

CONCLUSION

These results indicate that DA inhibits the Na+:HCO3- cotransporter in renal proximal tubules and also suggest that dysregulation of the cotransporter, possibly through the defect in DA1 receptor signaling, could play an important role in development of hypertension in SHRs.

Odor distinctiveness between enantiomers of linalool: difference in perception and responses elicited by sensory test and forehead surface potential wave measurement

The effects on humans of inhalation of optically active linalools were examined in terms of sensory tests and portable forehead surface electroencephalographic (IBVA-EEG) measurements in order to assess their odor distinctiveness by chiral isomers. (R)-(-)-Linalools with specific rotation of [alpha](D) = -15.1 degrees were isolated by repeated flash column chromatography from lavender oil, while (S)-(+)-linalools with [alpha](D) = +17.4 degrees and (RS)-(+/-)-linalools with [alpha](D) = 0 degrees and content of (R)-form 50.9% and (S)-form 49.1% were obtained from coriander oil and commercial linalool, respectively, by using the same method. With the use of an inhalator, each was administered to subjects both before and after 10 min of work. It was found that administration after work evoked different subjective impressions when compared with that before work depending on the configuration of the isomers and the type of work employed. For instance, inhalation of (R)-(-)-linalool after hearing environmental sounds not only produced a much more favorable impression in the sensory test but was also accompanied by a greater decrease in beta waves after work in comparison with that before work. This is in contrast to the case of mental work, which resulted in a tendency for agitation accompanied by an increase in beta waves. These findings led us to conclude that enantiomeric stereospecificity of linalool evoked different odor perception and responses not only with chiral dependence but also with task dependence. In addition, in comparing these sensory profiling features and IBVA-EEG tendencies between hearing environmental sound and mental work, a tendency was observed for (R)-(-)-linalool to coincide with (RS)-(+/-)-linalool but not with (S)-(+)-linalool.

Alteration of perceived fragrance of essential oils in relation to type of work: a simple screening test for efficacy of aroma

The perceptional change of fragrance of essential oils is described in relation to type of work, i.e. mental work, physical work and hearing environmental (natural) sounds. The essential oils examined in this study were ylang ylang, orange, geranium, cypress, bergamot, spearmint and juniper. In evaluating change in perception of a given aroma, a sensory test was employed in which the perception of fragrance was assessed by 13 contrasting pairs of adjectives. Scores were recorded after inhaling a fragrance before and after each type of work, and the statistical significance of the change of score for 13 impression descriptors was examined by Student's t-test for each type of work. It was confirmed that inhalation of essential oil caused a different subjective perception of fragrance depending on the type of work. For example, inhalation of cypress after physical work produced a much more favorable impression than before work, in contrast to orange, which produced an unfavorable impression after physical work when compared with that before work. For mental work, inhalation of juniper seemed to create a favorable impression after work, whereas geranium and orange both produced an unfavorable impression then. From these studies, together with those conducted previously with lavender, rosemary, linalool, peppermint, marjoram, cardamom, sandalwood, basil and lime, we thus concluded that the sensory test described here might serve not only as a screening test for efficacy of aroma but also as a categorized table for aroma samples which can act as a reference to each other.

Interleukin-9 receptor alpha chain mRNA formation in CD8+ T cells producing anti-human immunodeficiency virus type 1 substance(s)

A search for gene(s) associated with anti-human immunodeficiency virus type 1 (HIV-1) activity of CD8+ T cells was attempted using molecular cloning and the relation between the anti-HIV activity of CD8+ T cells and the interleukin-9 receptor alpha chain (IL-9R-alpha) mRNA expression from the cDNA clones obtained was examined. The anti-HIV-1 activity of CD8+ T cell culture supernatants was assessed by measuring the level of HIV-1 replication of a CD4+ T cell line transfected with an infectious HIV-1 DNA clone. IL-9R-alpha mRNA was assayed by reverse transcriptase-polymerase chain reaction (RT-PCR). Of 5 cases showing high level of anti-HIV-1 activity (more than 80% suppression of HIV-1 replication), the mRNA was detected in 4 cases. Of 10 cases showing low level of anti-HIV-1 activity (less than 80% suppression of HIV-1 replication), the mRNA was detected in one case. Soluble recombinant human IL-9 receptor (rhIL-9sR) did not suppress HIV-1 replication at a concentration of 1 microgram/ml. These data suggest that the IL-9R-alpha mRNA formation in CD8+ T cells may correlate with and play some role in the anti-HIV-1 activity of CD8+ T cells from HIV-1-infected individuals.

[Coumarin-containing chiral discriminating agents. VII. New crystalline 1H-NMR enantiomeric excess determination reagent for alcohols and amines, (R)-(-)- and (S)-(+)-O-coumarinylmandelic acids]

The Mitsunobu reaction of commercial 4-hydroxycoumarin with both (R)-(-)- and (S)-(+)-tert-butyl mandelates derived from commercial enantiopure mandelic acids furnished (S)-(+)- and (R)-(-)-tert-butyl O-coumarinylmandelates which were, then, treated with trifluoroacetic acid to give novel crystalline optically pure (S)-(+)- and (R)-(-)-O-coumarinylmandelic acids [SCMOH and RCMOH], respectively in good overall yields. Diastereotopic nonequivalence 1H-NMR examination of the resultant esters and amides without any racemization or kinetic resolution by way of a Steglich's procedure (a DCC-DMAP method) has proved each acid to be a useful, efficient and reliable chiral derivatizing agent for the enantiomeric excess determination of chiral alcohols and amines.

[The effect of coronary intervention on renal function in patients with chronic renal failure]

To investigate the effect of coronary intervention on renal function in patients with chronic renal failure (CRF) we investigated 19 patients with CRF [serum creatinine (Scr) > 1.5 mg/dl] who underwent coronary intervention for the treatment of acute myocardial infarction or unstable angina recruited from 516 consecutive patients admitted to the coronary care unit of Nara Medical University Hospital from January, 1992 to July, 1995. Serum creatinine levels were measured at 3 points: on admission, at peak level, and at discharge. Nineteen patients were divided into two groups on the basis of increases in Scr (delta Scr): a worsened group (group A) (delta Scr > or = 1mg/dl after coronary intervention; 6 patients) and an unchanged group (group B) (delta Scr < 1 mg/dl ; 13 patients). In group A, except for one patient, the renal function recovered to the level before coronary intervention after adequate hydration or hemodialysis. The volume of contrast medium in group A (420 +/- 134 ml) was significantly higher than group B (253 +/- 97 ml) (p < 0.01). There was significant positive correlation (r = 0.42, p < 0.05) between delta Scr and the volume of contrast medium. In conclusion, coronary intervention for patients with CRF can be performed safely under treatment with adequate hydration and hemodialysis, even at higher serum creatinine levels of up to 4.0 mg/ml.

Isolation and characterization of two cDNA clones for mRNAs that are abundantly expressed in immature anthers of rice (Oryza sativa L.)

The relationship between the length of anthers and the stage of development of microspores was examined in rice (Oryza sativa L. cv. Hayayuki). Anthers of < or = 2 mm and 2.1-2.2 mm in length and those ready to dehiscence were determined to be at the uninucleate, binucleate and trinucleate microspore stage, respectively. Two cDNAs (YY1 and YY2), representing genes that are specifically expressed in anthers at the uninucleate microspore stage, were isolated and characterized. YY1 cDNA encoded an open reading frame of 95 amino acids. Eight cysteine residues with the potential to form disulfide bridges were present in the amino acid sequence. There was a hydrophobic region at the N-terminus of the putative protein, suggesting that the YY1 protein might be secreted. This cysteine motif and the hydrophobic N-terminus are conserved among products of several anther-specific genes or cDNAs isolated from various plant species. These proteins are thought to form a superfamily of proteins that are confined to anthers. The YY1 transcript was localized in the tapetal cells and the peripheral cells of the vascular bundle. YY2 cDNA encoded an open reading frame of 389 amino acids and the deduced amino acid sequence exhibited substantial homology to that of chalcone synthase. Expression of YY2 mRNA was confined to the tapetal cells. The genes correspond to YY1 and YY2 cDNAs were shown to exist as single copies in the rice genome.

Analysis of randomly isolated cDNAs from developing endosperm of rice (Oryza sativa L.): evaluation of expressed sequence tags, and expression levels of mRNAs

Using a cDNA library prepared from poly(A)+ RNA from 10-day-old rice endosperm, partial nucleotide sequences of randomly isolated clones were analyzed. A total of 153 (30.6%) out of 500 cDNA clones showed high amino acid identity to previously identified genes. There was significant redundancy in cDNAs encoding prolamine and glutelin. About 21.0% of the cDNA clones were found to code for seed storage protein genes. Consequently, 37 independent genes were identified. Using cDNA clones encoding glutelin, prolamine, seed allergen, alpha-1,4-glucan branching enzyme, glycine-rich RNA binding protein, metallothionein, non-specific lipid-transfer protein and ubiquitin conjugating enzyme the accumulation of mRNA during rice seed development was compared. Genes associated with seed storage protein and starch biosynthesis were expressed according to expected developmental stages. Glycine-rich RNA binding protein genes as well as metallothionein-like protein genes were highly expressed in developing seeds, but low in leaves of whole plants.

Methylcobalamin attenuates the hypoxia/hypoglycemia- or glutamate-induced reduction in hippocampal fiber spikes in vitro

The effects of methylcobalamin, a vitamin B12 analogue, on the hypoxia/hypoglycemia- or glutamate-induced reduction in hippocampal CA1 presynaptic fiber spikes elicited by Schaffer collateral stimulation in rat brain slices were evaluated. Hippocampal slices were exposed to 15 min of hypoxia/hypoglycemia, and then these slices were returned to oxygenated and glucose-containing buffer for 3 h. Hypoxia/hypoglycemia reduced CA1 presynaptic potentials in vitro. Treatment with 10 microM methylcobalamin attenuated the impairment of CA1 presynaptic potentials induced by hypoxia/hypoglycemia or glutamate application (10 mM). Daily injection of methylcobalamin (0.5 mg/kg i.p./day) for 3 days in vivo also attenuated the hypoxia/hypoglycemia- or glutamate-induced reduction in presynaptic potentials in hippocampal slices. Pretreatment with cyanocobalamin at 10 microM failed to attenuate the impairment of CA1 presynaptic potentials. However, daily injection of cyanocobalamin (0.5 mg/kg i.p./day) for 3 days caused a protective action against the hypoxia/hypoglycemia- or glutamate-induced functional deficit. Furthermore, co-treatment of L-arginine (100 microM), a substrate for nitric oxide synthase, with methylcobalamin in vitro reversed the methylcobalamin-induced functional recovery. The present results demonstrate that methylcobalamin application in vivo or in vitro leads to functional recovery from hypoxia/hypoglycemia- or glutamate-induced impairment of CA1 presynaptic potentials. Neuroprotection was obtained by in vivo application of cyanocobalamin, but not by its in vitro application. It is reported that in vivo injected cyanocobalamin converted to methylcobalamin in the hepatic cells. Therefore, the results suggest that a transmethylation reaction in the hippocampal regions may be involved in the methylcobalamin-induced functional recovery from ischemic impairment.

Molecular states of fungal nuclease composed of heterogeneous subunits as estimated from the effects of urea and chelating agents

Fungal nuclease composed of subunits with molecular weights of 8.0 x 10(4) (80K subunit), 5.0 x 10(4) (50K subunit), and 2.5 x 10(4) (25K subunit) (K. Ito, Y. Matsuura, and N. Minamiura (1994) Arch. Biochem. Biophys. 309, 160-167) was inactivated by urea and dissociated into its subunits. The urea inactivation depended on the concentration of urea, the incubation period and the temperature. The urea-inactivated enzyme had about 25% activity restored by removal of urea, and the native form of the enzyme was also reconstituted. The urea inactivation and the dissociation of subunits were almost completely prevented by Ca2+ but not by glycerol. The enzyme was also inactivated by ethylenediaminetetraacetic acid (EDTA). From this method of inactivation, the 50K and 25K subunits were still associated, but the complex showed no nuclease activity. About 80% of the activity of the EDTA-inactivated enzyme was restored by the addition of Ca2+ or Sr2+ and 20-40% by Mn2+, Ba2+, Mg2+, or Co2+. The reactivation of the enzyme by these metal ions was accompanied by the reconstitution of the native form of the enzyme. The enzyme was inactivated by ethylene glycol bis(beta-aminoethyl ether)-N,N'-tetraacetic acid (EGTA) at much higher concentrations compared with the inactivation by EDTA. On the other hand, dissociation of the subunits by EGTA proceeded in a manner similar to that of the inactivation of the enzyme by EDTA. The 50K and 25K subunits were still associated, and the complex showed nuclease activity. These results indicated that the enzyme contains two kinds of metal ions. One metal ion, represented by Ca2+, is thought to stabilize the quanternary structure of the enzyme, especially to connect the 80K subunit and the complex of the 50K and 25K subunits. Another metal ion, represented by Mg2+, is thought to be bound to the complex of the 50K and 25K subunits and to be required for activity appearance of the complex. Along with these results, possible molecular states of the enzyme under various conditions are proposed.

Alteration in circadian rhythm of plasma corticosterone in rats following sociopsychological stress induced by communication box

The purpose of present study was to investigate the physiological characteristics of sociopsychological stress induced by the communication box method. In this method, the nonfoot shocked rats were used as the psychological stressed experimental group. The stress exposure was loaded for 1 h between 0900 and 1000, daily. The changes in circadian rhythm of plasma corticosterone were studied following the 3-day, 5-day, or 10-day stress exposure, respectively. Plasma corticosterone levels of foot shocked rats and nonfoot shocked rats following the 3-day or 5-day stress exposure were significantly higher than those of control rats. Particularly, the marked elevation of plasma corticosterone was observed at the peak time of circadian rhythm (2100) in the both stress groups. Consequently, the amplitude of 24 h rhythm increased significantly, but the acrophase was not changed. However, the changes of plasma corticosterone levels of both stress groups following the 10-day stress exposure approached those of control group. These results suggest that the repeated exposure of sociopsychological stress can influence the circadian rhythm of plasma corticosterone. The communication box method may be a valuable tool for researching the etiology of human psychiatric disorders with rhythm disturbance.

An antitumor, branched (1-->3)-beta-D-glucan from a water extract of fruiting bodies of Cryptoporus volvatus

A water-soluble, (1-->6)-branched (1-->3)-beta-D-glucan (H-3-B) was isolated from a hot-water extract of the fruiting bodies of the fungus, Cryptoporus volvatus (Basidiomycetes). Enzymatic analysis using exo-(1-->3)-beta-D-glucanase and methylation analysis indicated that this polysaccharide has a main chain composed of beta-(1-->3)-linked D-glucopyranosyl residues, and single, beta-(1-->6)-linked D-glucopyranosyl residues attached as side chains to, on average, every fourth sugar residue of the main chain. This structure was confirmed by 13C NMR spectra of the glucan in Me2SO-d6. The weight-average molecular weight (Mw) of H-3-B was determined to be 44.0 x 10(4) by gel permeation chromatography equipped with a low-angle laser-light-scattering photometer. The electron microscopic observations showed that H-3-B and its sonicated sample (S-H-3-B, Mw = 13.7 x 10(4)) can be described as linear worm-like chains. The mass per unit length for native and sonicated H-3-B was determined to be 1750 and 1780 g mol-1 nm-1, respectively, from the contour lengths obtained by electron microscopy and the molecular weights. These values are in good agreement with that expected for the triple stranded structure. A sample denatured in 0.1 M NaOH and subsequently renatured by neutralization showed a mixture of linear and cyclic structures, and larger aggregates with less well-defined morphology. The H-3-B and S-H-3-B had antitumor activity against the Sarcoma 180 tumor.

Expressed sequence tags from cultured cells of rice (Oryza sativa L.) under stressed conditions: analysis of transcripts of genes engaged in ATP-generating pathways

Large-scale sequencing of randomly selected cDNA clones was used to isolate numerous genes in rice (Oryza sativa L.). Total RNA used for cDNA synthesis was prepared from suspension-cultured cells of rice grown under stressed conditions, such as in saline or nitrogen-starvation conditions. A total of 780 cDNA clones were partially sequenced and about 15% could be identified as putative genes. In the library constructed under saline conditions, we identified several genes associated with signal transduction, such as protein kinase and small GTP-binding protein genes. Many stress-related genes were isolated from both the saline and nitrogen-starvation libraries. These results indicate that stress treatment of suspension-cultured cells makes it possible to efficiently isolate various types of plant genes. To examine the usefulness of such tagged cDNAs for the study of gene expression in a specific metabolic pathway, we analyzed mRNA levels of genes engaged in the ATP-generating pathways in cultured cells of rice under different stresses, such as 20% sucrose, salt stress, cold stress and nitrogen-starvation stress. The results suggest that the coordinated induction of several genes in key steps under stressed conditions may be essential for activation of the entire energy-producing pathway to maintain homeostasis in rice cells. Expressed sequence tags identified by random cDNA sequencing provide the opportunity to generate a transcript map of rice genes.

Evaluation of depression in rats exposed to chronic (unpredictable) electric shock

The present study was undertaken to evaluate the applicability of a proposed behavioral stress paradigm as an animal model for depression. Rats were trained to press a lever under a fixed ratio (FR) 5 schedule in a Skinner box for 10 days and were subsequently exposed to a daily regimen of 20 cycles of FR 5 and 10 cycles of variable ratio (VR) 10 for about a week. This exposure resulted in a reduction of the number of lever presses and successful escapes compared to the level achieved after training. In addition, weight gain was significantly suppressed compared with other treatments. Acute and chronic administration of psychotropic drugs (imipramine and chlordiazepoxide) showed that treatment with imipramine increased both the number of lever presses and successful escapes while chlordiazepoxide increased only the number of lever presses. The results suggest that this simplified animal model utilizing chronic unpredictable electric shock may be useful in the study of human depression.

Comparison of the anticonflict effect of buspirone and its major metabolite 1-(2-pyrimidinyl)-piperazine (1-PP) in rats

The anxiolytic effects of buspirone and its major metabolite, 1-(2-pyrimidinyl)-piperazine (1-PP) have been investigated with a conflict (shock-induced suppression of drinking) paradigm in rats. Buspirone (10 mg/kg, p.o.) showed an anticonflict activity with a bell-shaped dose-response relationship without any effect on spontaneous water consumption. Higher doses of buspirone reduced the punished response. Diazepam (20 and 40 mg/kg, p.o.) also showed an anticonflict activity in a dose-dependent manner, but animals with diazepam showed an increase in spontaneous water consumption at these doses. On the other hand, 1-PP (6.25-200 mg/kg, p.o.) showed a weak anticonflict activity with a significant effect at 25 mg/kg without any effect on spontaneous water consumption. In the 7-day treatment test, buspirone (5 and 10 mg/kg, p.o.), 1-PP (5 and 25 mg/kg, p.o.) and diazepam (10 and 40 mg/kg, p.o.) did not develop the tolerance to the anticonflict activity. Conversely, the anticonflict activity of diazepam was increased by the repeated treatment. Diazepam (10 mg/kg, p.o.) showed an anticonflict activity without any effect on spontaneous water consumption in this test. These results demonstrated that buspirone clearly exhibited an anticonflict effect similar to that of diazepam in a Vogel-type conflict test, and its real anxiolytic effect may not be always based on 1-PP, the main metabolite of buspirone.

Physicochemical properties of (1-->6)-branched (1-->3)-beta-D-glucans. 1. Physical dimensions estimated from hydrodynamic and electron microscopic data

The physical dimensions of several (1-->6) branched (1-->3)-beta-D-glucan samples obtained from different organisms and their derivatives have been studied by electron microscopy, light scattering measurements, viscometry, and gel permeation chromatography. The electron micrographs indicate that in most samples these biopolymers are adequately described as linear worm-like coils. A sample reconstituted from alkaline media appeared as a blend of the linear, circular, and aggregated polymer morphologies. The average mass per unit length, ML = Mw/Lw for the macroscopically linear samples, was estimated to be 2100 +/- 200 g mol-1 nm-1. The parameter ML was determined from the contour lengths obtained by electron microscopy and the molecular weight by light scattering measurements. The observed ML was consistent with the triple-helical structure reported from x-ray diffraction studies and observed degree of side-chain substitution. From the molecular snapshots shown in the electron micrographs, the persistence lengths of these beta-D-glucans were determined to be 140 +/- 30 nm. The experimentally determined intrinsic viscosities were consistent with these estimates of ML and persistence length. Comparison of the molecular weight distributions obtained from gel permeation chromatography and those deduced from the electron micrographs indicates that number and weight average contour lengths are more reliable than z and z + 1 averages.

Anxiolytic activity of SC-48274 compared with those of buspirone and diazepam in experimental anxiety models

The present study was performed to assess the anxiolytic activity of the novel anxiolytic SC-48274 in comparison with those of buspirone and diazepam. Drugs were administered p.o. The experimental anxiety models included gastric lesions of mice induced by socio-psychological stress in the communication box (CB) and the passive avoidance paradigm in rats. In the CB experiments, non-foot-shocked mice (responder) exposed to the emotional responses of foot-shocked mice (sender), 3 hr per day for 3 days, developed gastric lesions. Single treatments of diazepam (1, 2, 5 mg/kg) and SC-48274 (25, 50 mg/kg) prevented gastric lesion formation, but buspirone at 2.5-10 mg/kg did not. A 3-day treatment with SC-48274 at doses over 5 mg/kg prevented gastric lesions; and a 3-day treatment with buspirone at 2, 5 and 10 mg/kg prevented the lesions with a U-shaped dose-response. Diazepam also prevented gastric lesion formation at the doses of 1 and 2 mg/kg. In the passive avoidance response study, rats which had a single acquisition trial for 2 days were used. The step-down latency for rats to enter from the illuminated compartment to the dark one was recorded. Single treatments of SC-48274 (25 mg/kg), diazepam (5, 10 mg/kg) or buspirone (25 mg/kg) shortened the delayed latency. These results suggest that SC-48274 has anxiolytic activity of the same potency as buspirone and repeated-dose administration is needed to induce anxiolytic activity.

Plasma corticosterone response of rats with sociopsychological stress in the communication box

The purpose of present study was to investigate the physiological characteristics of sociopsychological stress induced by the communication box method. In this method, the nonfoot shocked rats were used as the psychologically stressed experimental group. In acute stress experiments, nonfoot shocked rats were exposed to emotional responses from foot shocked rats for 6 h in the light (0900-1500) or in the dark phase (2100-0300). In the light phase, the induced increase in plasma corticosterone levels of nonfoot shocked and foot shocked rats returned to corresponding control levels 6 h following the initiation of stress session, whereas those in the dark phase were significantly higher. Although there were some differences in corticosterone responses between both phases, the acute effect of sociopsychological stress was unclear. Chronic stress experiment with daily exposure for 1 h to sociopsychological stress caused the plasma corticosterone levels of nonfoot shocked rats to increase significantly not only in the postexposure level (just after stress exposure) but also in the preexposure level (before stress exposure) when naive rats were used daily as foot shocked animals. These results suggest that the repeated exposure of sociopsychological stress can induce physiological changes, and stressful situation can be established with only emotional responses from foot shocked rats.

Feeding conditions and estrous cycle of female rats under the activity-stress procedure from aspects of anorexia nervosa

The present study investigated the application of female rats with activity stress as an animal model for anorexia nervosa. Young female rats were singly housed in activity-wheel cages with food-restricted schedule (2, 3, or 4 h of food availability per day) for 3 weeks. Estrous cycle, body weight, food intake, and wheel revolution were recorded daily. Gastric pathology was also observed using the endoscopic technique. Rats that were subjected to either a 3- or 4-h feeding schedule exhibited the cessation of estrous cycle, loss of body weight, and suppression of food intake. These animals also showed a remarkable increase in running activity. However, they had no gastric lesions throughout the experimental period. On the contrary, the 2-h feeding schedule elicited severe gastric lesions and high mortality. The results suggest that behavioral and physiological changes of the young female rats with 3 or 4 h feeding share some symptoms of anorexia nervosa, although their anorexia is not self starvation.

Mitogenic and colony-stimulating factor-inducing activities of polysaccharide fractions from the fruit bodies of Dictyophora indusiata Fisch

Biological effects (mitogenic and colony-stimulating factor (CSF)-inducing activities) of five homogeneous polysaccharides and a conjugated polysaccharide fraction isolated from the fruit bodies of Dictyophora indusiata Fisch. were investigated. Fucomammogalactan (T-3-Ad) and conjugated polysaccharide fraction (T-2-A) exhibited significant mitogenic and CSF-inducing activities. Among two beta-(1----6)-branched (1----3)-beta-D-glucans (T-4-N and T-5-N), only T-4-N showed both mitogenic and CSF-inducing effects. Partially O-acetylated (1----3)-alpha-D-mannans (T-2-HN and T-3-M') did not show these effects.

Relationship between running activity rhythm and the development of activity-stress ulcer in rats

In the present study, the relationship between the development of activity-stress (A-S) ulcer and the behavioral and physical changes of rats with the A-S paradigm was investigated. We applied the endoscopic technique to establish the A-S ulcer as a model for studying the therapeutic or healing process of ulcers. Male and female rats were subjected to daily 1 hr feeding in the light (L)-phase (09:00-10:00) or in the dark (D)-phase (21:00-22:00). Prior to peak-revolution of running-activity, ulcer occurred earlier in the L-phase feeding group than in the D-phase feeding group. The ulcer development was accompanied with a change in the circadian rhythm of running-activity; e.g., the running-activity of the L-phase was higher than that of the D-phase. This phenomenon was more marked in the L-phase feeding group than in the D-phase feeding group. In addition, the ulcer development was closely related to body weight loss. No sex differences were found in these phenomena. The results suggest that change in the circadian rhythm of running-activity, body weight loss and high running-activity are important variables for predicting the A-S ulcer production, avoiding the need to kill the animals to determine ulcer formation.