Circulating Insulin-Like Growth Factor I Regulates Its Receptor in the Brain of Male Mice.

The role of IGF-1 and its receptor (IGF-1R) in brain pathology is still unclear. Thus, either reduction of IGF-IR or treatment with IGF-1, two apparently opposite actions, has proven beneficial in brain diseases such as Alzheimer's dementia. A possible explanation of this discrepancy is that IGF-1 down-regulates brain IGF-1R levels, as previously seen in a mouse Alzheimer's dementia model. We now explored whether under normal conditions IGF-1 modulates its receptor. We first observed that in vitro, IGF-1 reduced IGF-1R mRNA levels in all types of brain cells including neurons, astrocytes, microglia, endothelial cells, and oligodendrocytes. IGF-1 also inhibited its own expression in neurons and brain endothelium. Next, we analyzed the in vivo actions of IGF-1. Because serum IGF-1 can enter the brain, we injected mice with IGF-1 ip. As soon as 1 hour after the injection, decreased hippocampal IGF-1 levels were observed, followed by increased IGF-1 and IGF-1R mRNAs 6 hours later. Because environmental enrichment (EE) stimulates the entrance of serum IGF-1 into the brain, we analyzed whether a physiological entrance of IGF-1 also produced changes in brain IGF-1R. Stimulation of IGF-1R by EE triggered a gradual decrease in hippocampal IGF-1 levels. After 6 hours of EE exposure, IGF-1 levels reached a significant decrease in parallel with increased IGF-1R expression. After longer times, IGF-1R mRNA levels returned to baseline. Thus, under nonpathological conditions, IGF-1 regulates brain IGF-1R. Because baseline IGF-1R levels are rapidly restored, a tight control of brain IGF-1R expression seems to operate under physiological conditions.

Changes in hydration of the stratum corneum are the most suitable indicator to evaluate the irritation of surfactants on the skin.

BACKGROUND/PURPOSE: Irritancy levels of surfactants on human skin have not been clarified completely. The relationships between skin damage and changes of skin properties caused by various surfactants were investigated using non-invasive measurements. METHODS: Aqueous solutions of seven kinds of anionic, non-ionic, and amphoteric surfactants were exposed to the inside of forearm skin of 20 human subjects in two separate studies using the cup method. Hydration of the stratum corneum (SC), transepidermal water loss (TEWL), pH, skin surface roughness, and contents of the SC were measured before and after one exposure and after five and nine consecutive exposures to various surfactants. The discontinuation ratio of subjects for testing in each surfactant was determined by skin irritation symptoms and was defined as the degree of skin damage. RESULTS: Significant changes were observed only in hydration, TEWL, and natural moisturizing factors (NMF) content in the SC following surfactant exposure. A significant correlation was observed between the discontinuation ratio of each surfactant and the changes of hydration, TEWL, and NMF. Especially, the change of SC hydration showed an excellent correlation with the discontinuation ratio both for single (r = 0.942, P < 0.001) and for chronic exposures (r = 0.934, P < 0.001). CONCLUSION: Our results indicate that the change of hydration of the SC is equivalent to the skin damage caused by surfactants, and therefore is the most suitable indicator to evaluate the irritation of surfactants on the skin.

Exercise and cerebrovascular plasticity.

Aging impairs cerebrovascular plasticity and subsequently leads cerebral hypoperfusion, which synergistically accelerates aging-associated cognitive dysfunction and neurodegenerative diseases associated with impaired neuronal plasticity. On the other hand, over two decades of researches have successfully demonstrated that exercise, or higher level of physical activity, is a powerful and nonpharmacological approach to improve brain function. Most of the studies have focused on the neuronal aspects and found that exercise triggers improvements in neuronal plasticity, such as neurogenesis; however, exercise can improve cerebrovascular plasticity as well. In this chapter, to understand these beneficial effects of exercise on the cerebral vasculature, we first discuss the issue of changes in cerebral blood flow and its regulation during acute bouts of exercise. Then, how regular exercise improves cerebrovascular plasticity will be discussed. In addition, to shed light on the importance of understanding interactions between the neuron and cerebral vasculature, we describe neuronal activity-driven uptake of circulating IGF-I into the brain.

Long-term mild exercise training enhances hippocampus-dependent memory in rats.

Although exercise training improves hippocampus-related cognition, the optimum exercise intensity is still disputed. Based on the lactate threshold (LT, approximately 20 m/min on treadmill) of rats, we have shown that 2 weeks of training with stress-free mild exercise (ME, LT), comprising exercise stress, promotes adult hippocampal neurogenesis (Okamoto et al., PNAS, 2012), a potential substrate for memory improvement. These results led us to postulate that long-term ME, but not IE, training leads to improved hippocampal function as assessed with a Morris water maze (MWM) task. To test this hypothesis, we investigated the changes in physiological stress levels and MWM task performance in rats assigned to 6 weeks of sedentary control (CONT), ME-training or IE-training conditions. Results showed that, compared to the other conditions, only IE causes general adaptive syndrome (GAS), including adrenal hypertrophy, thymic atrophy and hypercorticosteronemia. In the MWM, ME led to enhanced memory, but not learning, compared with CONT, while IE produced no change in either capacity, probably due to GAS. These findings support the hypothesis that 6 weeks of continuous ME training leads to enhanced hippocampus-related memory, which may have implications for both healthy adults and subjects with low physical capacity.

Noradrenergic modulation of vicarious trial-and-error behavior during a spatial decision-making task in rats.

Deliberation between possible options before making a decision is crucial to responding with an optimal choice. However, the neural mechanisms regulating this deliberative decision-making process are still unclear. Recent studies have proposed that the locus coeruleus-noradrenaline (LC-NA) system plays a role in attention, behavioral flexibility, and exploration, which contribute to the search for an optimal choice under uncertain situations. In the present study, we examined whether the LC-NA system relates to the deliberative process in a T-maze spatial decision-making task in rats. To quantify deliberation in rats, we recorded vicarious trial-and-error behavior (VTE), which is considered to reflect a deliberative process exploring optimal choices. In experiment 1, we manipulated the difficulty of choice by varying the amount of reward pellets between the two maze arms (0 vs. 4, 1 vs. 3, 2 vs. 2). A difficulty-dependent increase in VTE was accompanied by a reduction of choice bias toward the high reward arm and an increase in time required to select one of the two arms in the more difficult manipulation. In addition, the increase of c-Fos-positive NA neurons in the LC depended on the task difficulty and the amount of c-Fos expression in LC-NA neurons positively correlated with the occurrence of VTE. In experiment 2, we inhibited LC-NA activity by injection of clonidine, an agonist of the alpha2 autoreceptor, during a decision-making task (1 vs. 3). The clonidine injection suppressed occurrence of VTE in the early phase of the task and subsequently impaired a valuable choice later in the task. These results suggest that the LC-NA system regulates the deliberative process during decision-making.

Relationship between clinical factors and severity of esophageal candidiasis according to Kodsi's classification.

Severe Candida esophagitis (CE) may lead to development of strictures, hemorrhage, esophagotracheal fistula, and a consequent decrease in quality of life. Although the severity of CE has been classified based on macroscopic findings on endoscopy, the clinical significance remains unknown. The aim of the study was to elucidate the predictive clinical factors for endoscopic severity of CE. Patients who underwent upper endoscopy and answered questionnaires were prospectively enrolled. Smoking, alcohol, human immunodeficiency virus (HIV) infection, diabetes mellitus, chronic renal failure, liver cirrhosis, systemic steroids use, proton pump inhibitor use, H2 blocker use, and gastrointestinal (GI) symptoms were assessed on the same day of endoscopy. GI symptoms including epigastric pain, heartburn, reflux, hunger cramps, nausea, dysphagia, and odynophagia were assessed on a 7-point Likert scale. Endoscopic severity was classified as mild (Kodsi's grade I/II) or severe (grade III/IV). Of 1855 patients, 71 (3.8%) were diagnosed with CE (mild, n = 48; severe, n = 23). In the CE patients, 50.0% (24/48) in the mild group and 23.1% (6/23) in the severe group did not have any GI symptoms. In HIV-infected patients (n = 17), a significant correlation was found between endoscopic severity and declining CD4 cell count (Spearman's rho = -0.90; P < 0.01). Multivariate analysis revealed that GI symptoms (odds ratio [OR], 3.32) and HIV infection (OR, 3.81) were independently associated with severe CE. Patients in the severe group experienced more epigastric pain (P = 0.02), reflux symptoms (P = 0.04), dysphagia (P = 0.05), and odynophagia (P < 0.01) than those in the mild group. Of the GI symptoms, odynophagia was independently associated with severe CE (OR 9.62, P = 0.02). In conclusion, the prevalence of CE in adults who underwent endoscopy was 3.8%. Silent CE was found in both mild and severe cases. Endoscopic severity was associated with characteristic GI symptoms and comorbidity of HIV infection. A decline in immune function correlated with CE disease progression.

Digitized detection of gamma-ray signals concentrated in narrow time windows for transient positron annihilation lifetime spectroscopy.

A pulsed slow-positron beam generated by an electron linear accelerator was directly used for positron annihilation lifetime spectroscopy without any positron storage devices. A waveform digitizer was introduced to simultaneously capture multiple gamma-ray signals originating from positron annihilation events during a single accelerator pulse. The positron pulse was chopped and bunched with the chopper signals also sent to the waveform digitizer. Time differences between the annihilation gamma-ray and chopper peaks were calculated and accumulated as lifetime spectra in a computer. The developed technique indicated that positron annihilation lifetime spectroscopy can be performed in a 20 µs time window at a pulse repetition rate synchronous with the linear accelerator. Lifetime spectra of a Kapton sheet and a thermally grown SiO2 layer on Si were successfully measured. Synchronization of positron lifetime measurements with pulsed ion irradiation was demonstrated by this technique.

Application of the PKCYP-test to predict the amount of in vivo CYP2C11 using tolbutamide as a probe.

Previous reports have shown that the determination of drug metabolism capacity can be made by the pharmacokinetic estimation of the quantity of cytochrome P450 (CYP) in vivo (PKCYP-test), in which an apparent liver-to-blood free concentration gradient in vivo (qg) is introduced, which is useful for evaluating fluctuations of CYPIA2 in rats. The aim of the present study was to examine the application of the PKCYP-test to evaluate the quantity of in vivo CYP2C11 by using tolbutamide as a probe, to confirm its validity using a physiologically-based pharmacokinetic rat model. Rats treated with carbon tetrachloride (CCl4-treated rats) were used as a model for low levels of CYP2C11 in the liver. In CCl4-treated rats, the total body clearance (CLtot) of tolbutamide and the amount of CYP2C11 fell to about a quarter and a third of that in control rats, respectively. The time-course of tolbutamide concentrations in serum in control rats could be simulated by a physiologically-based pharmacokinetic model. In CCl4-treated rats, take into consideration the qg value of control rats, the level of CYP2C11 was accurately predicted by the PKCYP-test, and the time-course of tolbutamide concentrations in serum could be predicted by the same physiologically-based pharmacokinetic model. In conclusion, we have shown that the PKCYP-test can be used to predict levels of CYP2C11. It was also demonstrated that the qg and amount of CYP are useful parameters in the PKCYP-test by constructing a physiologically-based pharmacokinetic model which was applied to the PKCYP-test.

AS-924, a novel, orally active, bifunctional prodrug of ceftizoxime: physicochemical properties, oral absorption in animals, and antibacterial activity.

AS-924 is an oral prodrug of the antibiotic ceftizoxime (CTIZ), a parenteral use cephalosporin. This novel prodrug, produced by esterifying CTIZ with a lipophilic pivaloyloxymethyl (POM) group and introducing a water soluble L-alanyl group, is expected to increase the bioavailability and thereby, augment the antibacterial activity of CTIZ in vivo compared with existing prodrugs. To study the effect of the L-alanyl group in AS-924 on its bioavailability, the plasma concentration profiles of CTIZ in dogs were examined following the dosing of AS-924 and CTIZ-POM, in powder form, after pretreatment with the antacid ranitidine, and following the dosing of AS-924 after pretreatment with a gastrointestinal motility stimulant metoclopramide or suppressant scopolamine butylbromide. The absorption rate of AS-924 was constant under these different conditions due to its unique balance of lipophilicity and water solubility. CTIZ is as antibacterially active as pre-existing oral cephalosporins against Gram-positive clinical isolates, while being more active against all Gram-negative isolates-particularly Enterobacteriaceae and Haemophilus influenzae. A simulation model for the eradication profile of bacteria in computer programmed pharmacokinetic (PK) system was carried out to study the antibacterial action of CTIZ in human. CTIZ was proven to eradicate Streptococcus pneumoniae and H. influenzae effectively, while cefpodoxime (CPOD), the active moiety of CPOD proxetil, eradicated S. pneumoniae, but not H. influenzae. These results confirm that, AS-924 is a potent oral antibiotic and would be expected to be clinically effective and efficient.

Functional fitness may be related to life satisfaction in older Japanese adults.

The relationship between functional fitness status and life satisfaction was assessed in older Japanese people from the perspective of quality of life (QOL). A total of 123 older men and women (M = 74.3 years, SD = 5.4) participated in the study. The questionnaire contained 21 questions covering eight structural factors pertaining to the feelings of life satisfaction in older people. The functional fitness test consisted of nine items representing the following five areas of fitness: muscular strength, agility, coordination, balance, and flexibility. The analysis revealed no overall correlation between the total fitness and the total life satisfaction scores, but some of the life satisfaction factors were significantly related to some functional fitness items (P < .01). The results suggest it is important for older people to maintain their functional fitness in order to manage a high quality of life.

Pulsatility of brachial artery pressure is associated with an increased risk of coronary artery disease in men.

OBJECTIVES: The purpose of this study was to evaluate whether the pulsatility of brachial artery pressure is related to an increased risk of coronary artery disease (CAD). On the basis of vascular mechanics, we recently reported that relative pulse pressure can predict the occurrence of restenosis after percutaneous transluminal coronary angioplasty. We also hypothesized that relative pulse pressure of the brachial arterial pressure waveform is associated with an increased risk of CAD. DESIGN: A cross-sectional study. PATIENTS: We enrolled 172 men who had the same cardiac performances. MAIN OUTCOME MEASURES: We measured their brachial artery pressures with a sphygmomanometer. To quantify the relative magnitude of the pulsatility to diastolic pressure, we made use of the ratio of pulse pressure to diastolic pressure (PP/DP). We investigated the effects of the PP/DP in relation to the risk of CAD. RESULTS: PP/DP was associated with an increased risk of CAD. The prevalence rates of significant stenosis were 28.1% for the lowest, 43.1% for the middle and 49.1% for the highest tertile of PP/DP levels. The age-adjusted odds ratio of CAD was 2.23 (95% confidence interval 0.98-5.04) for the middle tertile of the PP/DP level and 2.55 (1.10-5.93) for the highest tertile compared with the lowest tertile. CONCLUSIONS: The pulsatility of the brachial artery pressure was associated with an increased risk of CAD.

Production of dwarf lettuce by overexpressing a pumpkin gibberellin 20-oxidase gene.

We investigated the effect of overexpressing a pumpkin gibberellin (GA) 20-oxidase gene encoding an enzyme that forms predominantly biologically inactive products on GA biosynthesis and plant morphology in transgenic lettuce (Lactuca sativa cv Vanguard) plants. Lettuce was transformed with the pumpkin GA 20-oxidase gene downstream of a strong constitutive promoter cassette (El2-35S-Omega). The transgenic plants in which the pumpkin gene was detected by polymerase chain reaction were dwarfed in the T(2) generation, whereas transformants with a normal growth phenotype did not contain the transgene. The result of Southern-blot analysis showed that the transgene was integrated as a single copy; the plants segregated three dwarfs to one normal in the T(2) generation, indicating that the transgene was stable and dominant. The endogenous levels of GA(1) and GA(4) were reduced in the dwarfs, whereas large amounts of GA(17) and GA(25), which are inactive products of the pumpkin GA 20-oxidase, accumulated in these lines. These results indicate that a functional pumpkin GA 20-oxidase is expressed in the transgenic lettuce, resulting in a diversion of the normal pathway of GA biosynthesis to inactive products. Furthermore, this technique may be useful for controlling plant stature in other agricultural and horticultural species.

Diurnal variations of post-exercise parasympathetic nervous reactivation in different chronotypes.

The purpose of this study was to investigate the diurnal variation and chronotype differences, i.e., in morning-types and evening-types, in post-exercise vagal reactivation. Twelve healthy male college students who were classified as morning-type (6) and evening-type (6), based on responses to a questionnaire, participated in this study. Postexercise vagal reactivation was assessed as the time constant of the beat-by-beat heart rate decrease for the first 30 sec after exercise (T30) at an intensity lower than the ventilatory threshold. The subjects performed 3-min cycle ergometer exercise at an intensity corresponding to 80% of the ventilatory threshold after a 1 min warm-up exercise in the morning (7:00 - 8:00) and evening (17:00 - 18:00) to obtain the T30. A significant interaction (chronotype-by-time) effect was found for T30. The morning value of the T30 in evening-type subjects was significantly larger than their evening value and the morning value in morning-type subjects. There was no significant interaction effect for heart rate and oxygen uptake during exercise. These results suggest that diurnal variation in post-exercise vagal reactivation is different between morning-type and evening-type, and post-exercise vagal reactivation in evening-type individuals is sluggish in the morning.

Pulsatility of ascending aortic blood pressure waveform is associated with an increased risk of coronary heart disease.

BACKGROUND: Although it was reported that pulse pressure of the peripheral artery could differentiate patients with coronary heart disease (CHD) from those without CHD, it is not known whether pulsatility of the ascending aortic pressure waveform differentiates patients with CHD from those without CHD. The purpose of this study was to evaluate whether the pulsatility of ascending aortic pressure is associated with an increased risk of CHD. METHODS: For this study, we enrolled 293 subjects who had chest pain, normal contractions, no local asynergy, and no history of myocardial infarction. We measured the ascending aortic pressure using a fluid-filled system. To quantify the relative magnitude of the pulsatile to mean artery pressure, we normalized the pulse pressure to the mean pressure and referred to this value as the fractional pulse pressure (PPf). We investigated the association between the PPf and the risk of CHD. RESULTS: The PPf of the ascending aorta was associated with an increased risk of CHD. The multiple-adjusted odds ratio of CHD was 2.93 (95% CI, 1.44 to 5.94) for the middle tertile of the PPf level and was 3.93 (95% CI, 1.74 to 8.85) for the highest tertile compared with the lowest tertile. CONCLUSION: Ascending aortic pulsatility is related to an increased risk of CHD.

Assessment of smoking related risks for respiratory symptoms among elderly people.

Disease risk among elderly smokers is considered to be doubled due to their smoking habits and age as compared with elderly non-smokers. The investigators conducted risk assessments of smoking for respiratory symptoms among elderly people.A questionnaire survey on smoking habits and respiratory symptoms was conducted among 3,000 persons of 56 years of age and over who were randomly selected from suburban residents in a prefecture in Japan in October, 1997. A total 1,954 or 65.1%, of individuals responded, consisting of 42.8% for men and 57.2% for women, with an average age of 73.6 years.In addition to descriptive analysis, multiple logistic regression analysis was conducted. The results are summarized as follows: Smokers accounted for 28.1% of men and 3.6% of women. Among all age-groups, the highest rate of smokers was observed in men of 56-69 years old (34.7%) which was lower than the national average rate for the 60-69 year-old group (56.1% of men and 14.5% of women in '97). The odds ratios and 95 percent confidence interval (95%CI) for "having phlegm every day" and "having phlegm for more than 4 days a week" among smokers were 2.06 (95%CI=1.41-3.01) and 2.77(95%CI=1.80-4.27). Significantly higher odds ratios among smokers were also observed for "wheezing" and "shortness of breath when hurrying".Odds ratios for some respiratory symptoms including "having phlegm for more than 4 days per week" among inhalers were significantly high compared with non-smokers, whereas those among non-inhalers were not significantly different from 1.0. Odds ratios for symptoms of phlegm and wheezing were significantly higher (Odds ratio≥2.0) among heavy smokers (Brinkman Index [B.1] >900) compared to non-smokers, while odds ratios of the same symptoms were not different from 1.0 among light smokers (B. I. ≤500).

Percutaneous peptide immunization via corneum barrier-disrupted murine skin for experimental tumor immunoprophylaxis.

H-2K(b)-restricted tumor epitope peptides, including tyrosinase-related protein 2 residues 181-188 (TRP-2) and connexin 37 residues 52-59 (MUT1), were applied to permeability barrier-disrupted C57BL/6 (B6) mouse skin from which the stratum corneum of the epidermis had been removed by tape-stripping. This procedure primed tumor-specific cytotoxic T lymphocytes (CTLs) in the lymph nodes and spleen, protected mice against subsequent challenge with corresponding tumor cells, and suppressed the growth of established tumors. Preventive and therapeutic effectiveness was correlated with the frequency of tumor-specific CTL precursors. MHC class II Ia(b+) cells separated from tape-stripped skin, compared with those from intact skin, exhibited a strong antigen-presenting capacity for CTL, suggesting that CTL expansion after peptide application is primarily mediated by epidermal Langerhans cells. Thus, percutaneous peptide immunization via barrier-disrupted skin provides a simple and noninvasive means of inducing potent anti-tumor immunity which may be exploited for cancer immunotherapy.

Distribution of mefE and ermB genes in macrolide-resistant strains of Streptococcus pneumoniae and their variable susceptibility to various antibiotics.

From February to October 1995, 62 erythromycin-resistant strains of Streptococcus pneumoniae isolated at Yamanashi Red Cross Hospital were tested to determine their susceptibility to various macrolides, subjected to resistance induction tests by the disc diffusion method and analysed for genes encoding resistance to macrolides (ermB and mefE). On the basis of resistance induction testing, the isolates were classified as having either inducible (59.7%) or non-inducible (40.3%) macrolide resistance. The ermB gene was always detected in resistance-inducible type isolates, either alone or in combination with mefE. The mefE gene alone was found only in non-inducible type isolates. Isolates with non-inducible resistance (those with only the mefE gene) had an intermediate level of resistance to 14-membered macrolides, and were susceptible to rokitamycin, a 16-membered macrolide. According to NCCLS guidelines, 9.6% of S. pneumoniae strains were judged to be susceptible to penicillin, 62.9% of reduced susceptibility and 27.4% penicillin resistant. No correlation was detected between the presence of particular macrolide-resistance genes (ermB, ermB + mefE, or mefE) and resistance to penicillin G.

Photohapten TCSA painting plus UVA irradiation of murine skin augments the expression of MHC class II molecules and CD86 on Langerhans cells.

Hapten painting of skin is known to augment the expression of major histocompatibility complex (MHC) class II, CD54, and CD86 on Langerhans cells. We investigated whether painting with 3,3',4',5-tetrachlorosalicylanilide (TCSA), the representative photohapten, and subsequent irradiation with ultraviolet A (UVA) alter the expression of these surface molecules on epidermal Langerhans cells (LC). BALB/c mice were painted with 5 microl of 0.1% TCSA on the earlobes and irradiated with 16 J/cm2 (at 365 nm) of UVA. Epidermal cells were prepared from these earlobes 24 h later, and the levels of MHC class II, CD54, CD80, and CD86 on these cells were analyzed by flow cytometry. As compared with untreated earlobes, the levels of MHC class II and CD86 on LC were markedly augmented and those of CD54 and CD80 were slightly elevated in earlobes treated with TCSA/UVA. Since neither TCSA painting nor UVA exposure alone enhanced the expression, both treatments were essential for enhancement. A dot plot analysis showed the presence of subpopulations of LC expressing MHC class II and CD86 at high levels. The percentage of these highly expressing LC was increased with increasing concentrations of TCSA and doses of UVA up to 1% and 24 J/cm2, respectively. In addition, keratinocyte expression of CD54 was also augmented by TCSA plus UVA. These results suggest that photohaptens, with following UVA exposure, augment the expression of immunologically functional molecules on LC as do ordinary haptens, leading to effective sensitization and elicitation of contact photoallergy.

Immunofluorescent detection of ice-ice disease-promoting bacterial strain Vibrio sp. P11 of the farmed macroalga, Kappaphycus alvarezii (Gigartinales, Rhodophyta).

A specific immunofluorescent probe consisting of polyclonal antibodies was developed to detect a marine bacterium, Vibrio sp. strain P11, which was found in a previous study to promote the ice-ice disease in the cultivated red macroalga, Kappaphycus alvarezii. The method involves a combined application of the fluorescent stains, 4',6-diamidino-2-phenylindole (DAPI) and the P11 PAbs, into a homogenized seaweed sample (<1 g wet wt), which is prediluted to make bacteria countable under an epifluorescence microscope without serious interference from autofluorescing algal debris. The algal tissue homogenate is then filtered through a 0.2-µm-pore size Nuclepore membrane filter, serving as a mounting pad, and viewed using alternating ultraviolet and IB excitation filters to detect total and specific bacteria, respectively, on the same microscopic field, at the same time. The immunofluorescent probe could be used as a valuable tool in studying the infection mechanism of the bacterium in the macroalga in vitro.

Increases in levels of brain-derived neurotrophic factor mRNA and its promoters after transient forebrain ischemia in the rat brain.

Expression of brain-derived neurotrophic factor (BDNF) may play a role in the mechanism of neuronal cell death after cerebral ischemia. We investigated the changes in levels of mRNAs encoding BDNF and its promoters in the rat brain after transient forebrain ischemia. Transient forebrain ischemia was induced by occlusion of bilateral common carotid arteries and systemic hypotension for 8 min. The alterations in BDNF gene expression in the hippocampus and in the cerebral cortex were examined by in situ hybridization using a mouse BDNF cDNA probe and cDNA probes including exon-specific promoters. BDNF transcripts were rapidly enhanced after the ischemic insult, both in the hippocampus and the cerebral cortex. NBQX suppressed the enhanced gene expression of BDNF markedly in the dentate gyrus (DG). In contrast, MK-801 had little effect on BDNF expression. In the piriform cortex, MK-801 or NBQX reduced the expression only moderately. After the ischemic insult, promoter specific BDNF 5'-exon I and exon III were increased remarkably in the DG. The increase in exon I in DG was suppressed partially by MK-801 and NBQX, while the increase in exon III in CA3 was suppressed by MK-801 but that in DG was not suppressed by either antagonist. In the piriform cortex, exon III was increased remarkably and this increase was not influenced by either agonist. These results suggest that the gene expression of BDNF was enhanced by transient ischemia both in the hippocampus and the cerebral cortex and that the cerebral ischemia stimulated at least two different promoter- and neuron type-specific pathways regulating expression of the BDNF gene mediated by glutamate receptors of non-NMDA type and NMDA type.