Incidence of dogs possessing red blood cells with high K in Japan and East Asia

The phenotype of high K (HK) red blood cells, which is an autosomal recessive, was found in dog groups from 10 of 13 breeds or populations in Japan. The incidence of HK was 26 to 38% in the San'in-Shiba, Shinshu-Shiba and Akita breeds, and the gene frequencies of HK ranged from 0.513 to 0.612. The highest incidence (42%) was found in the Jindo breed from Korea, and the gene frequency was 0.652. Two other groups from Korea also possessed this HK variation. However, although HK cells were not found in dogs from Taiwan, Indonesia, Mongolia and Sakhalin, Russia, the HK phenotype is clearly distributed now throughout Japan and Korea.

The effect of MK-801 on extracellular neuroactive amino acids in hippocampus after closed head injury followed by hypoxia in rats

Increased neuronal vulnerability to ischemia or hypoxia has been demonstrated following traumatic brain injury but not explained. Animal data suggest that neuronal damage after traumatic brain injury is caused mainly by massive glutamate release that activates N-methyl-D-aspartate (NMDA) receptors. Using rat models with controlled closed head injury (CHI) followed by hypoxia, we investigated extracellular concentrations of neuroactive amino acids in the hippocampus by in vivo microdialysis. CHI alone produced an immediate increase of glutamate and taurine; hypoxia alone did not alter amino acid concentrations. CHI followed by hypoxia produced a biphasic increase in extracellular glutamate and taurine, with an immediate peak after CHI and a prolonged plateau after hypoxia. Though changes in gamma-aminobutylic acid (GABA) concentration is also prolonged by combined traumatic and hypoxic insults, it showed less alteration than glutamate. Pre-treatment with dizocilpine maleate (MK-801), a non-competitive NMDA antagonist, did not affect the immediate peak of glutamate after CHI but significantly diminished the prolonged plateau after hypoxia. These findings suggest that traumatic brain injury may increase hypoxic release of glutamate, contributing to increased vulnerability to hypoxia. Our data suggest that MK-801 may be beneficial in preventing secondary neuronal damages by hypoxia.

BDNF prevents NO mediated glutamate cytotoxicity in cultured cortical neurons

The effects of brain-derived neurotrophic factor (BDNF) on glutamate-induced cytotoxicity were examined using primary cultures of rat cortical neurons. BDNF induced TrkB tyrosine phosphorylation in rat cultured cortical neurons. The cell viability was significantly reduced when cultures were briefly exposed to glutamate and incubated with normal medium for 24 h. Glutamate cytotoxicity was prevented by MK-801, which is a non-competitive blocker of N-methyl-D-aspartate and N(omega)-nitro-L-arginine, which is a blocker of nitric oxide synthetase. Delayed neurotoxicity was also induced by ionomycin, a calcium ionophore, and nitric oxide (NO) donors such as S-nitrosocysteine (SNOC) and 3-morpholinosydnonimine (SIN-1). Incubating cultures with BDNF for 10 min to 24 h protected cortical neurons against glutamate neurotoxicity. The protective effects of BDNF against glutamate cytotoxicity were dependent on both its concentrations and incubation time. BDNF also prevented the ionomycin-, SNOC-, and SIN-1 induced cytotoxicity. These results indicate that BDNF protects cultured cortical neurons from NMDA receptor-mediated glutamate neurotoxicity by reducing cytotoxic action of NO.

[Susceptibilities of bacteria isolated from patients with respiratory infectious diseases to antibiotics (1995)]

The bacteria isolated from the patients with lower respiratory tract infections were collected by institutions located throughout Japan, since 1981. Ikemoto et al. have been investigating susceptibilities of these isolates to various antibacterial agents and antibiotics, and characteristics of the patients and isolates from them each year. Results obtained from these investigations are discussed. In 23 institutions around the entire Japan, 567 strains of presumably etiological bacteria were isolated mainly from the sputa of 459 patients with lower respiratory tract infections during the period from October 1995 to September 1996. MICs of various antibacterial agents and antibiotics were determined against 74 strains of Staphylococcus aureus, 82 strains of Streptococcus pneumoniae, 104 strains of Haemophilus influenzae, 85 strains of Pseudomonas aeruginosa (non-mucoid strains), 18 strains of Pseudomonas aeruginosa (mucoid strains), 52 strains of Moraxella subgenus Branhamella catarrhalis, 25 strains of Klebsiella pneumoniae etc., and the drug susceptibilities of these strains were assessed except for those strains that died during transportation. 1) S. aureus. S. aureus strains for which MICs of oxacillin (MPIPC) were higher than 4 micrograms/ml (methicillin-resistant S. aureus) accounted for 52.7%. Arbekacin (ABK) showed the most highest activity against S. aureus with MIC80 of 0.5 micrograms/ml. Vancomycin (VCM) showed the next highest activity with MIC80 of 1 microgram/ml. These drugs showed the high activities against MRSA with MIC80S of 1 microgram/ml. 2) S. pneumoniae. Most of drugs tested showed potent activities against S. pneumoniae. Imipenem (IPM) and panipenem (PAPM), carbapenems, showed the most potent activity with MIC80S of 0.063 microgram/ml. Cefotaxime (CTX), cefmenoxime (CMX) and cefpirome (CPR) of cephems showed the next most potent activities with MIC80S of 0.25 microgram/ml. Erythromycin (EM) and clindamycin (CLDM) showed low activities with MIC80S 128 micrograms/ml or high. Among these strains, however, 48.8% and 65.9% of respective strains were quite toward sensitive these agents with MICs of 0.063 microgram/ml. 3) H. influenzae. The activities of all drugs were potent against H. influenzae test with all MICs at 4 micrograms/ml or below. Cefotiam (CTM), CMX, cefditoren (CDTR) and ofloxacin (OFLX) showed the most potent activity with MIC90S to 0.063 microgram/ml. 4) P. aeruginosa. (mucoid strains) IPM and tobramycin (TOB) showed the most potent activity against P. aeruginosa (mucoid strains) with MIC80S of 1 microgram/ml. Ceftazidime (CAZ), cefsulodin (CFS) and carumonam (CRMN) showed next potent activity, with MIC80S of 2 micrograms/ml. The MIC80S of the other drugs ranged from 4 micrograms/ml to 32 micrograms/ml. 5) P. aeruginosa (non-mucoid strains). TOB and ciprofloxacin (CPFX) showed the most potent activities against P. aeruginosa (non-mucoid strains) with MIC80S of 1 microgram/ml. The MIC80 of ampicillin (ABPC) was 128 micrograms/ml in 1994, it was 16 micrograms/ml in 1995. 6) K. pneumoniae. All drugs except ABPC were active against K. pneumoniae. CPR and CRMN showed the most potent activities against K. pneumoniae with MIC80S of 0.063 microgram/ml. The MIC80S of the other drugs ranged from 0.125 microgram/ml to 2 micrograms/ml. 7) M. (B.) catarrhalis. Against M. (B.) catarrhalis, all the drugs showed good activities with MIC80S at 4 micrograms/ml or below. And MICs of all strains were 8 micrograms/ml or below. IPM, OFLX and minocycline (MINO) showed the most potent activity with MIC80S of 0.063 microgram/ml. Also, we investigated year to year changes in the characteristics of patients, their respiratory infectious diseases, and the etiology. Patients' backgrounds were examine for 567 isolates from 459 cases. The examination of age distribution found that the proportion of patients with ages over 60 years was 66.3% of all the patients showing a slight increase over that in 1994. Proportion of differe

Sequence analysis, tissue expression and chromosomal localization of a mouse secreted superoxide dismutase gene

Using a reverse transcriptase polymerase chain reaction (RT-PCR), a complement DNA encoding secreted superoxide dismutase (s-SOD) of a mouse kidney has been isolated and the nucleotide sequence was determined. The deduced amino acid sequence of mouse s-SOD cDNA shares 79% identity with the rat seminal SOD sequence and 61% identity with the human SOD3 sequence. Northern blot analysis showed that mouse s-SOD is intensely expressed in the kidney and lung tissues and detectable in other tested tissues, including the brain. The mouse s-SOD gene was assigned to chromosome 5 using fluorescence in situ hybridization analysis and PCR analysis of mouse/hamster hybrid cells.

Bilobalide, a constituent of Ginkgo biloba L., potentiates drug-metabolizing enzyme activities in mice: possible mechanism for anticonvulsant activity against 4-O-methylpyridoxine-induced convulsions

Anticonvulsant effects of bilobalide, one of the constituents of Ginkgo biloba L., on the convulsions induced by 4-O-methylpyridoxine (MPN) were investigated in mice. Bilobalide reduced the duration and incidence of MPN-induced convulsions depending on its dose and the period of treatment. In addition, the anticonvulsant effect was manifested more than 24 hours after treatment and the effect lasted for 7 days after its withdrawal. In mice treated with bilobalide (30 mg/kg, p.o., once a day for 4 days), hepatic 7-methoxycoumarin O-demethylase activity was potentiated, and the disappearance of MPN in blood after MPN injection was faster than in controls. From these results, it is assumed that the anticonvulsant effect of bilobalide against convulsions induced by MPN partly involves modulation of hepatic drug-metabolizing enzyme activity, which leads to accelerated elimination of MPN.

Protective effect of acetaminophen against acute gastric mucosal lesions induced by ischemia-reperfusion in the rat

We examined the effect of acetaminophen, an analgesic and antipyretic drug, on acute gastric mucosal injury induced by ischemia-reperfusion in rats. Ischemia-reperfusion was induced by clamping the celiac artery for 30 min with a small clip. Sixty minutes after reperfusion, the total area of erosions was measured. Acetaminophen (300 and 500 mg/kg) administered intraperitoneally 90 min before the ischemia significantly reduced the total area of erosions. The drug also inhibited the increase in lipid peroxide levels induced by ischemia-reperfusion in the gastric tissue and the increase in lipid peroxidation caused by the hydroxyl radical, OH., in vitro. Gastric prostaglandin E2 (PGE2) contents tended to increase after ischemia-reperfusion in both control and acetaminophen-treated groups. A significant difference in gastric PGE2 contents between control and acetaminophen-treated groups was not observed. The results indicate that acetaminophen may protect the gastric mucosa against ischemia-reperfusion injury, probably by blocking hydroxyl-radical-induced membrane damage.

Characterization of the gene for delta1-pyrroline-5-carboxylate synthetase and correlation between the expression of the gene and salt tolerance in Oryza sativa L

A cDNA for delta1-pyrroline-5-carboxylate (P5C) synthetase (cOsP5CS), an enzyme involved in the biosynthesis of proline, was isolated and characterized from a cDNA library prepared from 14-day-old seedlings of Oryza sativa cv. Akibare. The deduced amino acid sequence of the P5CS protein (OsP5CS) from O. sativa exhibited 74.2% and 75.5% homology to that of the P5CS from Arabidopsis thaliana and Vigna aconitifolia, respectively. Northern blot analysis revealed that the gene for P5CS (OsP5CS) was induced by high salt, dehydration, treatment of ABA and cold treatment, while it was not induced by heat treatment. Simultaneously, accumulation of proline was observed as a result of high salt treatment in O. sativa. Moreover, the levels of expression of OsP5CS mRNA and content of proline under salt stress condition were compared between a salt-tolerant cultivar, Dee-gee-woo-gen (DGWG) and a salt-sensitive breeding line, IR28. It was observed that the expression of the P5CS gene and the accumulation of proline in DGWG steadily increased, whereas those in IR28 increased slightly.

Dominant negative mutant of ionotropic glutamate receptor subunit GluR3: implications for the role of a cysteine residue for its channel activity and pharmacological properties

We reported that a 33-amino-acid deletion (from tyrosine-715 to glycine-747) in a putative extracellular loop of GluR3 produced a mutant that exhibited dominant negative effects upon the functional expression of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors [Sekiguchi et al. (1994) J. Biol. Chem. 269, 14559-14565]. In this study, we searched for a key residue in the dominant negative effects to explore the mechanism and examined the role of the residue in the function of the AMPA receptor. We prepared 20 GluR3 mutants with amino acid substitutions within the 33-amino-acid-region, and dominant negative effects were tested electrophysiologically in Xenopus oocytes co-expressing the mutant and normal subunits. Among the mutants, only a GluR3 mutant in which an original cysteine (Cys)-722 was replaced by alanine exhibited a dominant negative effect comparable with that of the original mutant in which the entire 33-amino-acid segment is deleted. The co-expression of the Cys-722 mutant did not inhibit the translation of normal subunits in oocytes. The Cys-722 mutant formed a functional homomeric receptor with significantly higher affinity for glutamate or kainate than a homomeric GluR3 receptor. The Cys-722 mutation greatly enhanced the sensitivity of GluR3 for aniracetam, which alters kinetic properties of AMPA receptors. The kainate-induced currents in oocytes expressing the Cys-722 mutant alone showed strong inward rectification. These results suggest that the Cys-722 in GluR3 is important for dominant negative effects and plays a crucial role in the determination of pharmacological properties in AMPA receptor function.

Changes in expression and distribution of the glutamate transporter EAAT4 in developing mouse Purkinje cells

EAAT4 is a Purkinje cell (PC)-specific, postsynaptic glutamate transporter in the adult mouse brain. Here, we performed developmental analyses to reveal its temporal expression in relation to PC differentiation. Using in situ hybridization, EAAT4 mRNA was specifically detected in the PC layer of the cerebellar primordium at embryonic day 13 (E13). During late fetal and neonatal periods, the transcripts were detected only in the PC layer in the caudal cerebellum. At postnatal day 7 (P7) and, thereafter, the prominent transcripts were found on monolayered PCs in the entire cerebellum. Using immunohistochemistry, low levels of EAAT4 immunoreactivity were first observed at E18 in the perikarya of PCs in the caudal cerebellum, and this pattern of immunostaining was maintained at P1 and P7. At P14 and, thereafter, the molecular layer in the entire cerebellum became immunopositive for EAAT4, and the intense immunoreactivity was detected preferentially in PC spines synapsing with parallel fiber terminals. Therefore, the present study has clarified that the transcription of EAAT4 begins in PCs from early embryonic stages, and that the synaptic localization of EAAT4 is established during the second postnatal week. When considered in the light of the synaptogenesis of parallel fiber-PC synapses which actively occurs in the rodent cerebellum during the second and third weeks of life, synaptic localization of the glutamate transporter EAAT4 may be closely associated with the synapse formation.

Determination of the effects of caffeine and carbamazepine on striatal dopamine release by in vivo microdialysis

The effects of carbamazepine and caffeine on adenosine receptor subtypes were determined using in vivo microdialysis in an attempt to elucidate their different psychotropic mechanisms of action. Adenosine and a selective adenosine A1 receptor agonist decreased the striatal extracellular dopamine level, whereas caffeine, carbamazepine and a selective adenosine A1 receptor antagonist increased it, but neither an adenosine A2 receptor agonist nor an antagonist affected it. Under conditions of adenosine A1 receptor blockade, adenosine, carbamazepine and a selective adenosine A2 receptor agonist increased the striatal extracellular dopamine level, whereas caffeine and a selective adenosine A2 receptor antagonist decreased it. These results suggest that adenosine A1 receptor stimulation reduces the striatal extracellular dopamine level, and that adenosine A2 receptor stimulation under conditions of adenosine A1 receptor blockade increases it. Therefore, caffeine is an antagonist of both adenosine A1 and A2 receptor subtypes, and carbamazepine is an adenosine A1 receptor antagonist as well as an adenosine A2 receptor agonist. These properties support the hypothesis that the central actions of both carbamazepine and caffeine result from effects on both adenosine A1 and A2 receptors.

Pharmacological profile of YM087, a novel nonpeptide dual vasopressin V1A and V2 receptor antagonist, in dogs

The pharmacological profile of YM087 (4'-[(2-methyl-1,4,5,6-tetrahydroimidazo[4,5-d][1]benzazepin -6-yl) carbonyl]-2-phenylbenzanilide monohydrochloride) was investigated in dogs. YM087 showed high affinity for vasopressin V1A and V2 receptors in radioligand receptor binding studies with dog platelets (V1A) and kidney (V2). Intravenously injected YM087 (3-100 micrograms/kg) dose dependently inhibited the pressor response to exogenous vasopressin in anesthetized dogs. Intravenous (10-100 micrograms/kg) and oral (30-300 micrograms/kg) administration of YM087 dose dependently increased urine flow with little effect on urinary sodium and potassium excretion in normally hydrated conscious dogs. Concomitantly, the urine osmolality dropped below the plasma osmolality (300 mOsm/kg H2O). In contrast, intravenously injected furosemide (300 micrograms/kg) increased urine flow with marked increases in urinary sodium and potassium excretion. These results indicate that YM087 is the first orally effective dual vasopressin V1A and V2 receptor antagonist and that it will be a new tool in the investigation of the physiological and pathophysiological role of vasopressin in the cardiovascular system and kidney. YM087 may be useful for the treatment of patients with congestive heart failure, renal diseases and water-retaining diseases.

Induction of cyclooxygenase 2 in gastric mucosal lesions and its inhibition by the specific antagonist delays healing in mice

BACKGROUND & AIMS

The role of two forms of cyclooxygenase (COX-1 and COX-2) in gastric mucosal lesions is not well understood. The regulation of both forms of COX and the effect of COX-2 on the repair process of gastric mucosal lesions in mice were investigated.

METHODS

Gastric mucosal erosions and ulcers were induced experimentally in mice. The level of COX messenger RNA (mRNA) was determined by reverse-transcription polymerase chain reaction. COX proteins were detected by Western blot analysis, and COX activity was determined in the presence or absence of NS-398, a specific COX-2 antagonist. The effects of long-term administration of NS-398 on gastric ulcers were examined.

RESULTS

COX-2 mRNA levels were not detected in control conditions but were high during the acute stages of gastric erosions and ulcers. COX-2 protein was detected 5 days after ulcer induction but not in control mice. Gastric ulceration was not associated with a change in COX-1 mRNA and protein levels. Administration of NS-398 to mice with ulcers at acute stages impaired the healing of ulcers.

CONCLUSIONS

High levels of COX-2 mRNA and protein during the acute stages of gastric mucosal lesions may be involved in the repair process of these lesions in mice.

Effects of sucralfate on acute gastric mucosal injury and gastric ulcer induced by ischemia-reperfusion in rats

We have revealed that acute gastric mucosal injury induced by a single ischemia-reperfusion (I-R) treatment develops into an ulcerative lesion within a few days. In the present studies, we examined the effects of oral administration of sucralfate on gastric damage induced by I-R. Sucralfate (1-100 mg/kg, 15 min before I-R) significantly reduced the total erosion area observed immediately after I-R. A high dose of sucralfate (30-100 mg/kg) inhibited the increase in the thiobarbituric acid-reactive substances, an index of lipid peroxidation, induced by I-R, although a low dose of it failed. When sucralfate (30 mg/kg, once a day) was orally administered after I-R, it prevented mucosal damage from developing into gastric ulcers: the total area of the ulcers was significantly reduced compared to that without sucralfate administration 72 h after I-R. High concentrations of sucralfate (3-10 mg/ml) reduced the superoxide radicals generated by leukocytes or xanthine-xanthine oxidase, and protected erythrocyte membrane ghosts against lipid peroxidation induced by hydrogen peroxide and Fe2+ in vitro. These results indicate that sucralfate may prohibit both the generation of acute gastric mucosal injury and its progression to ulcer induced by I-R, probably due to a cytoprotective action on the mucosal surface. However, the protective mechanism may involve an inhibitory action on superoxide and hydroxyl radicals at high doses.

Intraischemic hypothermia during pretreatment with sublethal ischemia reduces the induction of ischemic tolerance in the gerbil hippocampus

We examined whether mild brain hypothermia during pretreatment with sublethal 2-min ischemia affected the tolerance to subsequent lethal 5-min ischemia. The neuronal densities in the hippocampal CA1 sector of gerbils preconditioned at mild brain hypothermia (32% of normal) were significantly lower than those in gerbils preconditioned at brain normothermia (70% of normal). 72-kDa heat-shock protein immunoreactivity in the CA1 sector preconditioned at mild hypothermia was reduced. These results suggests that mild brain hypothermia during pretreatment with sublethal ischemia reduces the tolerance to subsequent lethal ischemia.

Quantitative analysis of cyclooxygenase-2 gene expression on acute gastric injury induced by ischemia-reperfusion in rats

The rat model of acute gastric damage induced by ischemia-reperfusion (I-R) has been used to evaluate the protective effect of various drugs on gastric injury. However, the quantitative expression state of cyclooxygenase-2 (COX-2), a protein which induces cytoprotective prostaglandins during inflammation, is still unknown in acute gastric injury induced by I-R. Therefore, we have quantitatively investigated the level of expression of COX-2 mRNA in injured gastric tissue of this model using the reverse transcription-competitive polymerase chain reaction method. The mRNA for COX-2 was expressed at low or undetectable levels in the normal gastric tissues in control rats, which were fasted for 18 hrs without I-R. The mRNA levels of COX-2 in injured gastric tissues were higher than those of control tissues between 6 hrs and 48 hrs after I-R. The maximum expression of COX-2 mRNA was recorded at 24 hrs (approximately a 200-fold increase). The expression state of COX-2, which has been ascertained in this study, should be useful in evaluating the effect of various drugs on the expression of COX-2 in acute gastric damage.

Frozen-section-guided breast-conserving surgery: implications of diagnosis by frozen section as a guide to determining the extent of resection

This study was conducted to analyze retrospectively the results of performing sector resection on 56 breasts in 54 patients with breast cancer. The glands were resected with a 2-cm tumor-free margin on both lateral sides and the distal side, and with more than a 3-cm tumor-free margin on the nipple side. The frequency of positive resection margins for the cancer cells was 7/56 (12.5%) on the nipple side and 12/46 (26.1%) on the lateral sides, with an overall frequency of 15/56 (26.8%). There were positive resected margins for cancer cells on both the nipple and lateral sides in 4/46 patients (9%). Assuming the equivocal margins were positive for cancer cells, an accurate diagnosis by frozen section examination was made in 51 of the 56 operations (91.1%). Additional resection of the margins was performed in all 20 cases of a positive resected margin for cancer cells according to the diagnosis by frozen section. Thereafter, the resected margins became negative in 13 cases (65%), but remained positive in 7 cases (35%). These results show that performing diagnosis by frozen section of the surgical margins is an effective guide to resecting tumors adequately.

Inhibition by cigarette smoke of lipid peroxidation-induced neurotransmitter release

Effects of water-soluble substance in cigarette smoke on neurotransmitter release were investigated using nerve terminals (synaptosomes) prepared from rat cerebral cortex. 2,2'-Azobis (2-amidinopropane) dihydrochloride (ABAP), a peroxyl radical-generator, enhanced the depolarization-evoked release of glutamate and aspartate from synaptosomes with concomitant increase in thiobarbituric acid-reactive substances (TBA-RS) levels in membrane lipids of synaptosomes. The trapped smoke-substance attenuated the lipid peroxidation-enhanced release of excitatory amino acids during the depolarization with reduction in TBA-RS, although it failed to affect the basal release of neurotransmitters. These data suggest that cigarette smoke may possess antioxidant properties to reduce oxidation-induced enhancement of transmitter release from nerve terminals.

SHP-2 is involved in neurotrophin signaling

To investigate the involvement of SHP-2 in the signal transduction pathway stimulated by neurotrophins, the association of SHP-2 with components of the pathway was examined. Following NGF stimulation of PC12 cells, SHP-2 was found to be associated with the p85 subunit of PI3-kinase and the Shc proteins. In retinoic acid-differentiated SH-SY5Y cells and primary cultures of rat cortical neurons, BDNF treatment similarly caused the association of SHP-2 with p85. In addition, a tyrosine-phosphorylated protein, which is probably TrkB, was coimmunoprecipitated with SHP-2 in both cultures. These results show that SHP-2 becomes associated with signaling proteins after treatment with neurotrophins and suggest that SHP-2 plays a fundamental role in neurotrophin signaling.

Changes in levels of mRNAs of transforming growth factor (TGF)-beta1, -beta2, -beta3, TGF-beta type II receptor and sulfated glycoprotein-2 during apoptosis of mouse uterine epithelium

To examine the roles played by transforming growth factors (TGF)-beta1, -beta2, -beta3, and TGF-beta type II receptors in the induction of apoptosis in the mouse uterine epithelium after estrogen deprivation, we investigated the expression of their mRNAs and the mRNA of sulfated glycoprotein-2 (SGP-2). Pellets containing 100 microg estradiol-17beta (E2) were implanted into ovariectomized mice and removed four days later. Apoptotic indices (percentage of apoptotic cells) of both luminal and glandular epithelia increased after E2 pellets were removed, but administration of progesterone (P), 5alpha-dihydrotestosterone (DHT), or continued implantation of E2 pellets suppressed this increase. Levels of mRNAs of TGF-beta1, -beta2, and -beta3, and SGP-2 did not increase after estrogen deprivation. However, estrogen deprivation caused a gradual increase in the level of TGF-beta type II receptor mRNA, and its level increased about six-fold six days later. Moreover, E2, P, and DHT markedly decreased the level of TGF-beta type II receptor mRNA. In situ hybridization demonstrated that mRNAs of TGF-beta1, -beta2, -beta3 and TGF-beta type II receptor were localized to the epithelium. Exogenous administration of TGF-beta1 into the uterine stroma induced apoptosis in the epithelium, a finding that suggests that signals produced by TGF-betas can induce apoptosis. Therefore, the present results suggest that increased sensitivity of uterine epithelial cells to TGF-betas, as demonstrated by an increase in TGF-beta type II receptor mRNA, is involved in the induction of apoptosis after estrogen deprivation, although signals produced by TGF-betas do not appear sufficient to induce apoptosis.

Repeated hyperbaric oxygen induces ischemic tolerance in gerbil hippocampus

Hyperbaric oxygen (HBO; 100% oxygen at 2 atmospheres absolute) was administered for 1 h to male Mongolian gerbils either for a single session or every other day for five sessions. Two days after HBO pretreatment, the gerbils were subjected to 5 min of forebrain ischemia by occlusion of both common carotid arteries under anesthesia. Seven days after recirculation, neuronal density per 1-mm length of the CA1 sector in the hippocampus was significantly better preserved in the five-session HBO pretreatment group (n = 10: 175.7 (47.8/mm, 54.9% of normal) than in the ischemic control group (n = 10: 26.2 (11.6/mm, 8.0% of normal) and in the single-session HBO pretreatment group (n = 7: 37.3 (21.7/mm, 11.4% of normal). Immunohistochemical staining for the 72-kDa heat-shock protein (HSP-72) in the CA1 sector performed 2 days following pretreatment revealed that the five-session HBO pretreatment increased the amount of HSP-72 present compared with that in the ischemic control group and in the single HBO pretreatment group. These results suggest that tolerance against ischemic neuronal damage was induced by repeated HBO pretreatment, which is thought to occur through the induction of HSP-72 synthesis.

Effects of cigarette smoke on nitric oxide-induced increase in cyclic GMP in nerve terminals of rat cerebral cortex

Since nitric oxide (NO) has been widely accepted as a novel neuromodulator, which activates soluble forms of guanylate cyclase to increase in guanosine 3':5'-cyclic monophosphate (cyclic GMP) levels, the effect of water-soluble substance in cigarette smoke on cyclic GMP levels were investigated using nerve terminals prepared from rat cerebral cortex. Although the smoke-substance itself failed to affect cyclic GMP levels in the synaptosomes, the smoke-substance significantly inhibited the increases in cyclic GMP levels induced by NO donors. The blocking effect of the smoke-substance was inhibited by concomitant incubation with superoxide dismutase, but not with mannitol. In addition, the effect of smoke-substance was mimicked by products of the xanthine/xanthine oxidase system, but not by nicotine. The effect of smoke-substance was preserved at least 7 days after they were stored at room temperature. Therefore, these results suggest that the smoke-substance may possess long half-lives to produce the radicals which inactivate NO, and to inhibit the increase in cyclic GMP levels in nerve terminals. The interference with NO may explain the part of mechanism in effects of cigarette smoke on neuronal functions.