Effects of the histamine H3 receptor ligands thioperamide and (R)-alpha-methylhistamine on histidine decarboxylase activity of mouse brain.

The effects of the histamine H3 receptor ligands thioperamide and (R)-alpha-methylhistamine on the histidine decarboxylase (HDC) activity and histamine content of mouse brain were examined. Thioperamide, a histamine H3 antagonist, significantly increased the HDC activity in the brain of ddY, W/Wv and ICR mice 2-6 hr after its intraperitoneal (i.p.

Age-dependent decrease in histamine H1 receptor in human brains revealed by PET.

Age-related changes in histamine H1 receptors were studied using [11C]pyrilamine or [11C]doxepin by positron emission tomography (PET). The frontal, parietal and temporal cortices showed age-related decreases in binding of approximately 13% per decade. In contrast, the thalamus showed no apparent decrease in binding during normal ageing because of its higher nonspecific binding.

Histamine H1 receptors in human brain visualized in vivo by [11C]doxepin and positron emission tomography.

Histamine H1 receptors in the living human brain were visualized by positron emission tomography (PET) using [N-11C-methyl]-(E)-doxepin ([11C]doxepin). The regional distribution of the carbon-11-labeled compound in the brain corresponded well with that of the histamine H1 receptors measured in vitro using [3H]pyrilamine. The radioactivity in the brain was significantly reduced by intravenous pretreatment with d-chlorpheniramine (5 mg), a histamine H1 antagonist.

Effects of (S)-alpha -fluoromethylhistidine and metoprine on locomotor activity and brain histamine content in mice.

We examined the effects of (S)-alpha -fluoromethylhistidine (FMH), an inhibitor of histidine decarboxylase, and metoprine, an inhibitor of histamine N-methyltransferase, on the locomotor activity and the brain histamine content of ICR mice. The brain histamine content was decreased by FMH (12.5 or 50 mg/kg, i.

Imaging of neurotransmitter receptors in the living human brain by positron emission tomography (PET).

More than 30 receptors or subtypes will be investigated in various neurological and psychiatric disorders using PET in the near future. However, the data obtained by PET should be carefully evaluated, because the PET method is based on the ligand-receptor binding in vivo. Extensive studies on animals and autopsied human brain samples are important to assess the significance of the findings revealed by PET technique to substantiate its validity.

[Reevaluation of the unilateral pulmonary artery occlusion test--hemodynamics after lobectomy and pneumonectomy for lung cancer].

After lobectomy, it is recognized that functional as well as absolute reduction occurs in residual lobes of the operated side. So whether lobectomy is indicated or not is determined by the same criteria as those for pneumonectomy, namely, by the unilateral pulmonary artery occlusion (UPAO) test. However, is it really appropriate to use the same criteria for both lobectomy and pneumonectomy? To answer to this question, in patients with lung cancer we compared the hemodynamics after lobectomy (13 cases) and pneumonectomy (14 cases) with that at the UPAO test.

Imaging histamine H1 receptors in the living human brain with carbon-11-pyrilamine.

The brain distribution and kinetics of the H1 receptor antagonist, carbon-11-pyrilamine (11C-pyrilamine) were examined in vivo in two baboons and one human by positron emission tomography. After i.v.

Labeling of histamine H1-receptors in vivo: a compartment model analysis and positron emission tomographic imaging.

Binding of [3H]-pyrilamine to guinea-pig brain in vivo was studied and analyzed kinetically on the basis of a four-compartment model to establish the method of analysis for the in vivo binding. The pharmacological properties of the [3H]-pyrilamine binding in vivo were similar to those of the in vitro binding to brain homogenate. The distribution of histamine H1-receptors in dog brain, which was obtained by positron emission tomography (PET) with [11C]-pyrilamine or doxepin as a tracer, was in good correlation to that obtained by the in vitro binding method.

Effects of thioperamide, a histamine H3 receptor antagonist, on locomotor activity and brain histamine content in mast cell-deficient W/Wv mice.

The purpose of this study was to examine the effects of thioperamide, a histamine H3 antagonist, on the locomotor activity and the brain histamine content in mast-cell-deficient W/Wv mice. Thioperamide (12.5 and 25 mg/kg) showed significant increase in the locomotor activity of W/Wv mice, measured by a photo-beam system, 1 hr after the intraperitoneal injection.

Visualization of histamine H1 receptors in dog brain by positron emission tomography.

Histamine H1 receptors were visualized in the living dog brain using [11C]pyrilamine or [11C]doxepin by positron emission tomography (PET). The regional distribution of these carbon-11 labeled compounds in the brain corresponded well with that of the histamine H1 receptors separately determined by in vitro binding assay. The radioactivity in the brain was reduced by treatment with triprolidine (1 mg/kg), a histamine H1 antagonist.

Cerebral circulation and oxygen metabolism associated with subclinical periventricular hyperintensity as shown by magnetic resonance imaging.

A combined magnetic resonance imaging and positron emission tomography study was performed on 21 patients with cerebrovascular risk factors but without neurological abnormalities. Our purpose was to investigate the hypothesis that periventricular hyperintensity (PVH) reflects ischemia. Periventricular hyperintensity was evaluated with a method we devised, and cerebral circulation and oxygen metabolism were evaluated with the oxygen-15 steady-state technique.

Specific binding of [3H]pyrilamine to histamine H1 receptors in guinea pig brain in vivo: determination of binding parameters by a kinetic four-compartment model.

The binding of [3H]pyrilamine, a selective ligand of histamine H1 receptors, to guinea pig brain in vivo was compared with its binding to a brain homogenate. The pharmacological properties (regional distribution, saturability, and stereoselectivity) of the [3H]pyrilamine binding in vivo were similar to those of the in vitro binding to brain homogenate. A dynamic four-compartment model was proposed for the analysis of the kinetics of [3H]pyrilamine binding in vivo.

Reduced regional cerebral metabolic rate for glucose at the terminal stage in a case of late infantile neuronal ceroid lipofuscinosis.

Regional cerebral metabolic rate for glucose was determined for six different areas of the gray matter in an 8-year-old girl with late infantile neuronal ceroid lipofuscinosis. In all regions, the rates were almost half of the control values. The regional cerebral metabolic rate for glucose was relatively preserved in the striatal region and severely reduced in the frontal cortex.

Stability of cerebral blood flow and oxygen metabolism during normal aging.

Cerebral blood flow and oxygen metabolism in aged normal subjects were measured with positron emission tomography and their relationship with brain atrophy was evaluated. Brain atrophy progressed in a linear fashion during aging while cerebral blood flow and oxygen metabolism were well preserved. The finding suggests that brain atrophy is an aging process less dependent on cerebral blood flow and metabolism over the course of normal aging.

Biodistribution and radiation absorbed dose of (N-methyl[11C])pyrilamine: a histamine H-1 receptor radiotracer.

The in vivo biodistribution for (N-methyl[11C])pyrilamine in mice is reported for various times after i.v. bolus injection, together with estimates of the radiation absorbed dose for the same radiotracer in man.

Adrenergic projection from the caudal part of the nucleus of the tractus solitarius to the parabrachial nucleus in the rat: immunocytochemical study combined with a retrograde tracing method.

The presence of an adrenergic projection from the nucleus of the tractus solitarius (NTS) to the parabrachial nucleus (PB) was demonstrated by the immunocytochemistry combined with a retrograde tracing method. Numerous neurons containing both phenylethanolamine N-methyltransferase, a marker for adrenaline, and wheat germ agglutinin-conjugated horseradish peroxidase, a retrograde tracer, were detected in the dorsolateral part of the NTS at the level of the area postrema after injection of the tracer into the dorsal PB.

Primary structure of a base non-specific ribonuclease from Rhizopus niveus.

The primary structure of a base non-specific ribonuclease from Rhizopus niveus (RNase Rh) was determined by nucleotide sequence analysis of the DNA fragment encoding RNase Rh gene including signal peptide sequence, and amino acid sequence analysis of the peptide obtained from RNase Rh and RNase Rh' (a protease-modified RNase Rh created during the course of purification). The sequence determined was: MKAVLALATLIGSTLASSCSSTA LSCSNSANSDTCCSPEYGLVVLNMQWAPGYGPANAFTLHGLWPDKCSGAYAPSGGCDSN RASSSIASVIKSKDSSLYNSMLTYWPSNQGNNNVFWSHEWSKHGTCVSTYDPDCYDNYE EGEDIVDYFQKAMDLRSQYNVYKAFSSNGITPGGTYTATEMQSAIESYFGAKAKIDCSSG TLSDVALYFYVRGRDTYVITDALSTGSCSGDVEYPTK (the sequence of signal peptide is underlined). The sequence indicates that the homology with the sequence of RNase T2 from A.

Isolation and identification of beta-nitrostyrene from smoked chicken.

Extraction and identification of beta-nitrostyrene from smoked chicken is described. Commercially obtained smoked chicken was homogenised and extracted with chloroform-methanol (2:1). The extracts were fractioned by silicic acid column chromatography.

Isolation and sequencing of a genomic clone encoding aspartic proteinase of Rhizopus niveus.

A gene encoding Rhizopus niveus aspartic proteinase was isolated from an R. niveus genomic library by using oligonucleotides probes corresponding to its partial amino acid sequence, and its nucleotide sequence was determined. By comparing its deduced amino acid sequence with the amino acid sequence of rhizopuspepsin (5, 26), we concluded that the R.

(N-methyl-[11C])pyrilamine, a radiotracer for histamine H-1 receptors: radiochemical synthesis and biodistribution study in mice.

The histamine H-1 receptor antagonist, pyrilamine (N-((4-methoxyphenyl)methyl)-N',N'-dimethyl-N-2-pyridinyl-1,2-ethaned i ami ne) was labeled with carbon-11 by N-alkylation of desmethylpyrilamine with [11C]iodomethane, and purified by preparative high performance liquid chromatography. The chemically and radiochemically pure labeled pyrilamine was obtained with specific activity of approximately 2500 mCi/mumol (EOS). In vivo distribution studies in mice suggest that the distribution of this compound parallels the known histamine H-1 receptor density in the brain.

Synthesis and biodistribution of [11C]fludiazepam for imaging benzodiazepine receptors.

As a tracer for in vivo studies on benzodiazepine receptors, 7-chloro-1,3-dihydro-5-(2-fluorophenyl)-1-[11C]methyl-2H-1,4- benzodiazepin-2-one, [11C]fludiazepam, was synthesized by the methylation of nor-derivative with [11C]CH3I, and purified by high-performance liquid chromatography. Within 60 min [11C]fludiazepam was obtained for injection in high radiochemical yields and in high radiochemical purity with a specific activity of up to 230 mCi/mumol. After i.

Regional cerebral metabolic rate for glucose and cerebrospinal fluid monoamine metabolites in subacute sclerosing panencephalitis.

Regional cerebral metabolic rate for glucose (rCMRglu) and cerebrospinal fluid monoamine metabolites were measured in two cases of subacute sclerosing panencephalitis (SSPE) with different clinical courses. A marked decrease in rCMRglu was found in the cortical gray matter of a patient with rapidly developing SSPE (3.6-4.