Determination of histamine in microdialysis samples from rat brain by microbore column liquid chromatography following intramolecular excimer-forming derivatization with pyrene-labeling reagent.

This paper describes a sensitive and selective liquid chromatographic method with fluorescence detection for determination of histamine in brain microdialysis samples from awake rats. Samples containing histamine (10 microl) were derivatized with 20 microl of the reagent consisting of 3 mM 4-(1-pyrene)butyric acid N-hydroxysuccinimide ester (PSE), 3 mM potassium carbonate and acetonitrile (1:1:18, v/v), thereafter 20 microl volume was injected onto the microbore column packed with C18 silica gel. The histamine derivative contained two pyrene moieties, which generated intramolecular excimer fluorescence (450-540 nm) and allowed clear discrimination from the monomer fluorescence (360-420 nm) emitted by PSE itself.

Galanin attenuates basal and antidepressant drug-induced increase of extracellular serotonin and noradrenaline levels in the rat hippocampus.

Galanin is co-localized with classical neurotransmitters, such as acetylcholine, serotonin (5-HT) and noradrenaline (NA) in neurons or in brain regions implicated in cognitive and affective behaviour. In the present study, the effects of galanin on extracellular 5-HT and NA levels in the rat hippocampus were measured by in vivo microdialysis under basal conditions and following systemic administration of antidepressant drugs. Galanin (1.

Activation of 5-HT(1A) autoreceptors enhances the inhibitory effect of galanin on hippocampal 5-HT release in vivo.

The microdialysis technique was used to examine interactions between 5-HT(1A) and galanin receptors in the dorsal raphe nucleus (DRN), by measuring the extracellular levels of 5-HT in the ventral hippocampus of awake rats. The rats were pretreated with the 5-HT(1A) receptor agonist (R,S)-8-OH-DPAT (0.3 mg/kg, s.

Simultaneous determination of norepinephrine, serotonin, and 5-hydroxyindole-3-acetic acid in microdialysis samples from rat brain by microbore column liquid chromatography with fluorescence detection following derivatization with benzylamine.

A microbore column liquid chromatographic method for the simultaneous determination of norepinephrine (NE), serotonin (5-HT), and 5-hydroxyindole-3-acetic acid (5HIAA) in microdialysis samples from rat brain is described. The method is based on precolumn derivatization of NE, 5HT, and 5HIAA with benzylamine in the presence of potassium hexacyanoferrate(III) resulting in the corresponding highly fluorescent and stable benzoxazole derivatives. A 15-microl sample was mixed with 15 microl derivatization reagent solution containing 0.

Galanin is a potent in vivo modulator of mesencephalic serotonergic neurotransmission.

Neurochemical, molecular, immunohistochemical and behavioral methods were used to examine the in vivo effects of the neuropeptide galanin on central 5-HT neurotransmission and on 5-HT(1A) receptor-mediated responses. Intraventricularly infused galanin caused a long-lasting and dose-dependent reduction of basal extracellular 5-HT levels in the ventral hippocampus of awake rats as measured by microdialysis. Infusion of galanin into the dorsal raphe nucleus (DRN), but not intra-hippocampally, reduced 5-HT release.

Involvement of 5-hydroxytryptamine neuronal system in Delta(9)-tetrahydrocannabinol-induced impairment of spatial memory.

The present study investigated the involvement of the serotonin (5-hydroxytryptamine, 5-HT) neuronal system in the Delta(9)-tetrahydrocannabinol-induced impairment of spatial memory in the eight-arm radial maze in rats. Delta(9)-Tetrahydrocannabinol (6 mg/kg, i.p.

Increased serotonin release in mice frontal cortex and hippocampus induced by acute physiological stressors.

The effects of acute physiological stressors (5 s tail pinch, handling and forced swimming at +25 and +5 degrees C for 3 min each) on serotonin (5-HT) release in the mouse brain were investigated using in vivo microdialysis. The extracellular 5-HT levels were determined by a newly developed highly-sensitive and selective high-performance liquid chromatography method based on derivatization with benzylamine and fluorescence detection. The basal levels of 5-HT in 3 min microdialysates from the ventral hippocampus and frontal cortex were 0.

Determination of serotonin in microdialysis samples from rat brain by microbore column liquid chromatography with post-column derivatization and fluorescence detection.

The present paper describes a new method for on-line determination of 5-HT in brain microdialysates from awake rats by microbore column liquid chromatography with post-column derivatization and fluorescence detection. The derivatization reagent contained 1 mM benzylamine and 0.5 mM potassium hexacyanoferrate (III), both dissolved in a mixture of acetonitrile and 25 mM borate buffer (pH 11.

Microdialysis in freely moving mice: determination of acetylcholine, serotonin and noradrenaline release in galanin transgenic mice.

In the present study, we describe micro-surgical methods for simultaneous implantation of a microdialysis probe and an intraventricular injection cannula via their respective guide cannulas into the mouse brain. Basal and stimulated release of acetylcholine (ACh), serotonin (5-HT) and noradrenaline (NA) was determined in the ventral hippocampus of freely moving mice. NA and 5-HT were determined in one run by a newly developed HPLC method based on precolumn derivatization with benzylamine and fluorescence detection.

Determination of norepinephrine in microdialysis samples by microbore column liquid chromatography with fluorescence detection following derivatization with benzylamine.

A microbore column liquid chromatographic method is described for the determination of norepinephrine (NE) in microdialysis samples from rat brain. The method is based on precolumn derivatization of NE with benzylamine in the presence of potassium hexacyanoferrate(III) resulting in a highly fluorescent and stable benzoxazole derivative. Typically, a 10-microl sample was mixed with 10 microl derivatization reagent containing 0.

Modulation of acetylcholine and serotonin transmission by galanin. Relationship to spatial and aversive learning.

This paper presents evidence that galanin is a potent in vivo modulator of basal acetylcholine release in the rat brain with qualitatively and quantitatively differential effects in the dorsal and ventral hippocampus. Galanin perfused through the microdialysis probe decreased basal acetylcholine release in the ventral hippocampus, while it enhanced acetylcholine release in the dorsal hippocampus. Galanin (3 nmol/rat) infused into the ventral hippocampus impaired spatial learning acquisition, while it tended to facilitate acquisition when injected into the dorsal hippocampus.

Cytokeratin expression in normal human thymus at different ages.

Subsets of thymic epithelial cells were examined immunohistochemically to determine whether or not their phenotypes change during thymic growth and at early involution in terms of cytokeratin (CK) expression. Five monoclonal antibodies specific for CK4, CK8, CK13, CK18 and CK19 were used and applied to 16 neonatal, three infantile and one adult thymus specimen, which had been obtained at autopsy, that were normal macroscopically and microscopically. CK4, CK8, CK13, CK18 and CK19 were expressed simultaneously in the cortex, medulla and subcapsular area with the exception of CK4, which showed expression on the adult thymus.

Diabetes and cardiovascular disease in a prospective population survey in Japan: The Hisayama Study.

To elucidate the effect of glucose intolerance on cardiovascular disease in the current Japanese population, we performed a 75-g oral glucose tolerance test in 2,427 Hisayama residents aged 40-79 years in 1988, who were free from a previous history of stroke or myocardial infarction, and followed them prospectively for 5 years. The prevalence of diabetes (NIDDM) among men was 13% and that of impaired glucose tolerance (IGT) was 20%; the corresponding values for women were 9 and 19%, respectively. The age- and sex-adjusted incidence of cerebral infarction (6.

Assay for tryptophan hydroxylase activity in rat brain by high-performance liquid chromatography with fluorescence detection.

A highly sensitive and selective liquid chromatographic (HPLC) method with post-column fluorescence detection has been developed for the determination of tryptophan 5-monooxygenase activity in rat brain tissue homogenate. 5-Hydroxytryptophan, formed enzymatically from tryptophan (incubation time, 20 min), is extracted with perchloric acid and determined by HPLC. Detection is performed fluorometrically after post-column derivatization by a reaction with benzylamine in the presence of potassium hexacyanoferrate (III).

Malignant neoplasms in the Japanese community of Hisayama: mortality and changing pattern during a 30-year observation period based on a consecutive autopsy series.

To obtain a relatively true mortality from malignant neoplasms, we studied the frequency of cancers in the different sites and the changing patterns of the frequency and sites over time among residents of the community of Hisayama, where an autopsy-based population survey (autopsy rate, 80%) has been conducted since 191. During the 30-year period from 1962 to 1991, we found 438 malignant neoplasms in 407 cases among 1,250 consecutive autopsies. Stomach cancer was not frequent in type of cancer, with 123 cases (9.

Danger of urokinase as an anticoagulant with left ventricular assist devices.

The sole administration of urokinase causes no initial prolongation of activated partial thromboplastin time (A-PTT), but thereafter produces serious progressive prolongation of A-PTT; it also causes a progressive, severe decrease in fibrinogen levels and alpha 2-plasmin inhibitor activity by depletion. The antithrombogenicity of urokinase is not caused by prevention of blood coagulation system activation by antithrombin effect, but by secondary fibrinolysis by plasmin. Consequently, the administration of urokinase as a sole anticoagulant results in activation of coagulation and fibrinolysis, and, as a result, induces disseminated intravascular coagulation.

Ideal anticoagulation for use with a left ventricular assist device.

To establish ideal anticoagulation therapy for use with a left ventricular assist device, a study was done administering various anticoagulants: heparin, argatroban, a prostacyclin analogue combined with a protease inhibitor, or a protease inhibitor alone. Cardiac asisting by LVAD without any anticoagulants results in marked activation of blood coagulation or fibrinolysis. Administration of argatroban, as well as heparin, produces a bleeding tendency.

Incidence and risk factors of vascular dementia and Alzheimer's disease in a defined elderly Japanese population: the Hisayama Study.

We followed 828 nondemented residents of Hisayama Town, Kyushu, Japan, aged 65 years or older (88.3% of the elderly population) for 7 years starting in 1985 in order to determine the type-specific incidence of dementia and its risk factors in the general Japanese population. Only two subjects were lost to the follow-up, during which period 103 subjects developed dementia.

[Thymic lymphoid hyperplasia of myasthenia gravis patients: correlation with clinical features and efficacy of thymectomy].

Thirty nine thymus tissues from myasthenia gravis patients without thymoma who underwent extended thymectomy were evaluated on thymic lymphoid hyperplasia with special emphasis on clinical features and the efficacy of thymectomy. Of 39 patients, 31 were women, but 3 of 7 patients without thymic lymphoid hyperplasia were men. The hyperplastic index of the thymus correlated largely with serum anti-Ach-R antibody titers before surgery.

A case of encapsulated noninvasive thymoma (stage I) with myasthenia gravis showing metastasis after a 2-year dormancy.

We herein describe a case of thymoma in which metastasis to the left lower visceral and parietal pleura was noticed after a 2-year dormancy. A closer examination revealed no evidence that the metastatic tumors were of lymph node origin. The initial thymoma was well encapsulated, and thus it was thought that the development of metastasis might have reflected a sudden rapid growth of the thymoma cells after a 2-year period of inactivity.

Simultaneous high-performance liquid chromatographic determination of 6 beta-hydroxycortisol and cortisol in urine with fluorescence detection and its application for estimating hepatic drug-metabolizing enzyme induction.

A simple and sensitive high-performance liquid chromatographic method is described for the simultaneous determination of 6 beta-hydroxycortisol (6 beta-OHF) and cortisol (F) in urine. Urine (1 ml) containing fludrocortisone as the internal standard is extracted with ethyl acetate. The extract is washed successively with sodium hydroxide solution and water, and subsequently dried under a stream of nitrogen.

Hyperinsulinaemia and blood pressure in a general Japanese population: the Hisayama Study.

Objectives: To study the relationship between serum insulin and blood pressure, as well as the prevalence of hypertension according to the insulin level in a general Japanese population.

Design: In 1988 a cross-sectional community survey was conducted among Hisayama residents aged 40-79 years.

Methods: A total of 1073 males and 1407 females (72.

[Mortality from major causes of death and its risk factors in the elderly--26-year follow-up study in Hisayama].

The authors studied mortality from major causes of death and risk factors in the elderly in a long-term prospective survey conducted in a Japanese suburban community, Hisayama. In the baseline survey in 1961, we scrutinized 1658 residents of the town aged 40 years or older accounting for 92% of the total population in this age range. Of those, 591 residents (245 men and 346 women) aged 60 years or older, who were free from major cardiovascular disease, were selected for the present study.

The association of the insulin resistance syndrome with impaired glucose tolerance and NIDDM in the Japanese general population: the Hisayama study.

To elucidate the risk factors for initiating glucose intolerance, the relevant factors were explored in a cross-sectional survey conducted in a sample population aged 40-79 years old selected from a Japanese community, Hisayama, Japan in 1988. A 75-g oral glucose tolerance test was used to classify 1,073 men (72.5% of the entire population in the same age range) and 1,407 women (80.