Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Biogen”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 991 records · Page 55Linked to original sources
PubMed1995

Determination of human plasma biogenic amines and their metabolites using liquid chromatography with a dual-channel electrochemical detector.

BACKGROUND: Measurement of biogenic amines and their metabolites in plasma has been used for decades to explore the pathophysiology of neuropsychiatric disorders or to examine the mode of action of psychotropic medications. Many advantages of ultrafiltration and high-performance liquid chromatography (HPLC) in assaying human plasma content have been described in our previous study. METHODS: The present HPLC assay, applying a dual-channel electrochemical detector, provides an additional reliable measurement or confirmation of peaks by identifying each peak retention capacity factor and its current ratio in the dual-channel detector. Simultaneous measurements of plasma serotonin, catecholamines and their metabolites by ultrafiltration and microbore HPLC technique is applied to evaluate moclobemide and fluoxetine therapy in patients with major depression. RESULTS: This present HPLC method provides highly specific detection, free from interference by the large offscale peak of plasma ultrafiltrates. Isocratic separation of all analytes by a microbore column is achieved within 15 mins. The detection limit (signal-to-noise ratio = 3) of this method is about 0.2-0.5 pg per injection for all analytes. In addition, the required volume of plasma samples is only 100 microliters. CONCLUSIONS: This rapid, simple and sensitive method for the measurement of human plasma serotonin, catecholamines and their metabolites can be used as a clinical or biomedical research tool. Blood loss is minimal in the present assay, especially in repeated blood sampling for pharmacokinetic studies.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1995

Studies of the biogenic amine transporters. VI. Characterization of a novel cocaine binding site, identified with [125I]RTI-55, in membranes prepared from whole rat brain minus caudate.

Previous studies showed that the cocaine analog [125I]RTI-55 labels dopamine and serotonergic (5-HT) biogenic amine transporters (BATs) with high affinity. Here we characterized [125I]RTI-55 binding to membranes prepared from whole rat brain minus the caudate nuclei. Paroxetine (50 nM) was used to block [125I]RTI-55 binding to 5-HT transporter sites. Initial experiments identified drugs that displaced [125I]RTI-55 binding with moderately low slope factors. Binding surface analysis of the interaction of 3 beta-(4-chlorophenyl)tropan-2 beta-carboxylic acid phenyl ester hydrochloride (RTI-113) and 3 beta-(4-iodophenyl)tropan-2 beta-carboxylic acid phenyl ester hydrochloride (RTI-122) with [125I]RTI-55 binding sites readily resolved two binding sites for [125I]RTI-55 with Kd values of 0.44 nM and 17 nM and Bmax values of 31 and 245 fmol/mg protein. Potent 5-HT and noradrenergic uptake inhibitors had low affinity for both sites. Whereas cocaine, CFT and WIN35,065-2 were 6.0-, 25- and 14-fold selective for the first site, benztropine, PCP and the novel pyrrole, (+-)-(2RS,3aSR,8bRS)-1,2,3,3a,4,8b-hexahydro- 2-benzyl-1-methylindeno-[1,2-b]pyrrole resorcylate [(+-)-HBMP, formerly called (+-)-RTI-4793-14], were moderately selective for the second site. A single binding site with the characteristics of site 1 was resolved using COS cells transiently expressing the cloned rat dopamine transporter. Lesion studies with 6-hydroxydopamine and 5,7-dihydroxytryptamine were conducted to test the hypothesis that site 1 and site 2 are physically distinct. The data showed that these neurotoxins differentially decreased [125I]RTI-55 binding to sites 1 and 2. The differential distribution of sites 1 and 2 in rat brain provides further support for this hypothesis. Viewed collectively, these data show that [125I]RTI-55 labels a novel binding site in rat brain membranes, termed DATsite2, which is not associated with the classic dopamine, serotonin or norepinephrine transporters.

Animals↗
PubMed1976

Excretion of metabolites of biogenic amines in patients with irradiated brain tumours.

The metabolities of biogenic amines were determined in the 24-hour urine samples of patients submitted to surgical removal of a malignant brain tumour and subsequently to telecobalt therapy of the corresponding head region. A significant increase in the excretion of 5-hydroxyindoleacetic acid (5-HIAA), vanillinmandelic acid (VMA) as well as of free 3-methoxy-4-hydroxy-phenylglycol (MHPG) during the period of irradiation was found. This increase is presumably the result of radiation induced release of their parent amines from the brain; in the case of VMA the secondary response of the peripheral sympathetic system might occur.

Adenoma↗
PubMed1994

[Effect of clozapine on biogenic amines within the scope of drug treatment of schizophrenic psychoses in adolescence].

Longitudinal assessments (every six weeks for one year) were made of plasma norepinephrine, dopamine, epinephrine and 3-methoxy-4-hydroxyphenylglycol (MHPG) in 40 adolescents with schizophrenia, 20 on clozapine therapy and 20 on conventional medication. In addition to the plasma catecholamine determinations, serum levels of 5-HT were determined as a measure of serotoninergic status. All analyses were performed by HPLC-ECD (high-performance liquid chromatography with electrochemical detection). Clinical ratings of symptomatology were obtained with the Brief Psychiatric Rating Scale (BPRS) and the Andreasen scales for negative and positive symptoms (SANS and SAPS). Compared with the typical neuroleptic medication, clozapine administration was accompanied by a significant increase in plasma norepinephrine and MPHG and serum serotonin levels. The fluctuations in the biogenic amines were closely associated with the observed symptomatology. Plasma MHPG was linked to depressive symptoms (BPRS), and negative symptoms (SANS) were related to changes in the serum serotonin levels. The pathophysiological implications and clinical consequences of these findings are discussed.

Adolescent↗
PubMed1993

[Enterosorption as a method for correction of biogenic amine levels in experimental bronchospasm].

The mechanism of enterosorption positive influence on the course of bronchospastic condition was studied on the model of allergic bronchospasm. The using of the sorbent (polyphepan) during the period of sensitization of rats prevented the beginning of bronchospasm or reduced its extent. The results of investigation proved that a decrease the of biogenic amines concentration in biological liquids and tissues depending on their transport and sorption in intestine is one of the main mechanisms of enterosorption.

Animals↗
PubMedDate not supplied

Structures of biogenic origin from Early Precambrian rocks of Euro-Asia.

Spheroidal microfossils mainly 20 to 100 mug in diameter and exhibiting granular surface textures have been recovered from Early Precambrian rocks by applying a new method of water separation in combination with thin chemical preparation. In contrast to the Acritarcha, these microfossils are characterized by a relatively low specific weight (close to one) and considerable fragility due to impregnation by mineral matter. They occur in Archean sediments of Hindustan, in rocks of the Baltic and Aldan Shields with ages of 3.0 to 3.5 billion (10-9) years, and in Proterozoic deposits in many regions of Euro-Asia. They commonly occur in great number in Precambrian sediments of West Africa, Australia and North America. These forms are here regarded as Menneria Lopuchin and are considered to be blue-green algae. Menneria resembles alga-like forms reported by Engel, Nagy and their co-workers from the Onverwacht Series and microfossils reported by Schopf and Barghoorn from the Fig Tree Series, both of the Swaziland System of southern Africa. In addition to spheroidal microfossils, ribbon-like and filiform microstructures are here reported from Archean deposits. The biogenic structures here described from the Early Precambrian of Euro-Asia are considered to have been photosynthetic and planktonic. Their progressive evolution, intensive production of organic matter, and biogeochemical role in concentration of rare elements is discussed.

Asia↗
PubMed1975

[The evidence of biogenic amines with Reinecke-salt as a new principle of evidence of substances in the ultrahistochemistry (author's transl)].

Reinecke-salt (ammonium tetracyanato diamine chromate) is known as amine precipitating reagens in applied chemistry. Its amine precipitates can be demonstrated in electron micrographes. The amine reineckates are unable to diffuse and difficult to dissolve. Depending from that they are localized in the cells. From our findings received in the boundary layer between adrenal cortex and adrenal medulla, we conclude that there are no non-specific precipitations with other cell components caused by Reinecke-salt. It could be determined that the catecholamines are accumulated in the cells of the adrenal medulla in granular shape in a typical manner. In the adrenal medulla cells of Acomys cahirinus first investigated by us we found amine containing vesicles with a diameter of 200 to 250 nm. In the neighbouring cells of the adrenal cortex no precipitates were visable. In the adrenal cortex we noticed the mitochondria from the tubulus typ specific for this region. The assumption that Reinecke-salt is a specific amine precipitating substance able of forming localized amin precipitates was confirmed by these investigations. So the Reineck-salt precipitation of biogenic amines is a new method beside the known ones for the ultrahistochemical amine demonstration. In our method the precipitation of amines by Reinecke-salt is the first step followed later by the tissue fixation with glutaraldehyde.

Adrenal Cortex↗
PubMed1979

Biogenic amines derived from tryptophan in systemic and cutaneous scleroderma.

Blood levels of serotonin (5-HT) and urinary excretion of 5-hydroxyindole-acetic acid (5-HIAA), tryptamine (T), and indole-acetic acid (IAA) were determined in 39 cases of systemic scleroderma and in 7 cases of very severe cutaneous scleroderma. The T/IAA ratio was normal and serotonin elevated in mild and rather severe acrosclerosis alike, i.e. in systemic scleroderma with pronounced vascular involvement. The T/IAA ratio was increased and serotonin normal in severe acroscleroderma, representing an intermediate form or transition to diffuse scleroderma, in severe diffuse scleroderma, and in severe cutaneous scleroderma. The T/IAA ratio and serotonin level were both elevated in a few cases of systemic scleroderma and in severe generalized morphea with concomitant vascular changes. The findings suggest impaired monoamine oxidase (MAO) activity in scleroderma with consequent accumulation in the organism of biogenic amines derived from tryptophan. An increased T/IAA ratio seems to be of prognostic significance in scleroderma, suggesting an adverse course of the disease.

Colorimetry↗
PubMed1995

Biogenic amorphous silica.

Biogenic amorphous silica (BAS) is a natural constituent of living matter (eg, unicellular organisms and crop plants). Diatoms, whose siliceous remains are the geologic precursors to diatomaceous earth, actively process soluble silica into BAS. In some plants, a portion of the BAS exists externally as pointed or irregularly shaped fibers. Although silica-related adverse health effects are usually attributed to crystalline forms, such effects could occur as a result of exposure to BAS at high temperatures (above 800 degrees C), where crystalline silica, a known human toxicant is formed. BAS fibers from food crops can be ingested and lead to adverse health effects due to irritative processes. Airborne BAS fibers from rice can be inhaled during burning or incineration. Fibrous or nonfibrous BAS can adsorb toxic organic compounds and facilitate their entry into the lung. Recommendations for research are suggested to address the issue of potential health effects due to exposure to BAS.

Agriculture↗
PubMed1996

[Optimal isotope composition of biogenic chemical elements on board of manned spacecrafts].

Isotope composition of biogenic chemical elements (BCE) is discussed. A hypothesis is offered that biochemical and biomedical processes must be influenced as by the isotope composition of hydrogen and oxygen, so by the composition of stable isotopes of all the BCE constituting plants, animals, and humans. Biochemical, toxicological and other biomedical analyses should be performed to determine the best BCE isotope composition. These must be followed by development of methods, technologies, and life support systems to form and maintain the best isotope composition inside spacecraft habitable modules.

Humans↗
PubMed1996

[The clinical assessment of the efficacy of using a biogenic composite material in dental implantology].

A new biogenic composite material based on hydroxyapatite and collagen with silamine was effectively used in dental implantology. Use of this material was conductive to a better course of the implant integration in the adjacent tissue structures and prevented the development of resorptive and atrophic changes in the alveolar process. Use of composite material in patients with relative indications for implantation precluded the development of complications in the early postoperative period and in remote periods of the follow-up.

Adult↗
PubMed1997

[Biogenic decomposition of bone collagens].

Soil bacteria, which are an always present component of all burial conditions, substantially contribute to the decomposition of bone collagen, i.e. even modifications of preserved bone collagen. Archaeometric data, which were derived from collagen remnants, therefore may always contain diagenetic components which disturb the biological signals and must subsequently be eliminated. To adequately assess probable diagenetic influences one should refer to our model of the biogenic steps of decomposition. The taphonomic experiments and their verifications of archaeological human bones, which were gathered from different origins and of different historical times, were done with histological, biochemical and biophysical methods. Experimentally, as well as through archaeological bone analysis, we were able to identify a "high" molecular product of decomposition, which contains (1) changes in the amino acid composition caused by specific soil conditions and (2) significant deviations of stable nitrogen and carbon isotopes. Due to decomposition procedures, isotope analysis of isolated amino acids indicate rearrangements of collagen fragments.

Amino Acids↗
PubMedDate not supplied

[Secondary biogenic radiation of gamma-irradiated human blood].

The samples of blood freshly taken from healthy men were gamma-irradiated with a dose of 10 Gy. It was shown that after the treatment the blood gained the capacity to emit secondary biogenic radiation. Emission lasted for some hours, passed through quartz-glass cuvette and was revealed by stimulating influence on biological detector (sprouting seeds).

Background Radiation↗
PubMed1998

Competition involving biogenic NO.

This review considers competitive reactions of NO biosynthesis and its interaction with its targets including enzyme competition for arginine, competition between the substrates in the NO-synthase active sites, competitive sources of arginine, multiple states of NO-synthases resulting from competition of reducible cofactors (FAD, FMN, BH4, heme), competition between aqueous and lipophilic phases for NO resulting in efficient micellar catalysis, and other aspects of competition involving biogenic NO.

Animals↗
PubMed1989

Effects of biogenic amines and adrenergic drugs on oviposition in the cattle tick Boophilus: evidence for octopaminergic innervation of the oviduct.

Oviposition in the cattle tick Boophilus microplus was arrested by octopamine and the alpha-adrenergic agonists clonidine, tolazoline, and naphazoline, at doses of 25 micrograms per tick. The same effect was obtained with a sublethal dose of Amitraz of 10 micrograms per tick. In contrast, the alpha-adrenergic agonists apomorphine, synephrine, phentolamine, metaclopromide and chlorpromazine were ineffective. No mortality was observed at any of the doses tested. Reserpine, which depletes endogenous adrenergic terminals, mimicked the effects of octopamine in blocking oviposition. Acetylcholine agonists also blocked oviposition but dopaminergic agonists did not. Evidence is presented suggesting that control of the oviduct is mediated by octopaminergic receptors.

Adrenergic Agonists↗
PubMed1975

Biogenic amines and depression. Biochemical and pharmacological separation of two types of depression.

Recent research findings indicate that depressive disorders may be divided into two groups, A and B, using specific biochemical and pharmacological criteria. It is suggested that in the A group there is a disorder of norepinephrine systems are not altered. Further, there is the possibility that B types patients have disorder of serotonin, but not norepinephrine or dopamine systems. This biochemical heterogeneity of human depression has implications for both investigators and clinicians, and may account for disparate findings in biological studies of patients with affective disorders.

Amitriptyline↗
PubMed1983

CSF and urinary biogenic amines and metabolites in depression and mania. A controlled, univariate analysis.

Levels of 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenylglycol (MHPG) in the CSF, and norepinephrine (NE), epinephrine (E), vanillylmandelic acid, normetanephrine, metanephrine, and MHPG in the urine, were measured in 151 hospitalized patients with affective disorders and in 80 healthy controls following a two-week drug-free period. Unipolar and bipolar depressed subjects differed only in NE and E levels. Compared with controls, depressed subjects had higher CSF MHPG levels, women had higher 5-HIAA levels, and men had lower HVA levels. All urinary metabolites were elevated in depression and mania, with the exception of MHPG. The patterns of NE-E differences discriminated among the forms of affective disorders. These data suggest an imbalance of monoamine transmission in depression, characterized by the hyperactive sympathetic nervous system and adrenal medulla. However, MHPG may not be the measure of choice to reflect this imbalance, necessitating measurement of total body monoamine output.

Adult↗