PubMed Health⌕ Search

Biomedical subjects

K M Marnela

Publications and source records attributed to K M Marnela.

36 records · Page 2Linked to original sources
PubMed1984

Free amino acids and the uptake and binding of taurine in the central nervous system of rats treated with guanidinoethanesulphonate.

The content of free amino acids in the central nervous system, the uptake of taurine by slices and synaptosomes and taurine binding to synaptic membranes have been studied on adult male Wistar rats after a prolonged administration of 2-guanidinoethanesulphonate with or without a taurine-free diet. The 2-guanidinoethanesulphonate administration both alone and together with a taurine-free diet considerably reduced taurine levels in all regions studied, viz. cerebrum, cerebellum, brain stem and spinal cord, but the contents of methionine and gamma-aminobutyric acid were increased. On the normal diet the maximal taurine loss occurred after a 3-week 2-guanidinoethanesulphonate administration, when also the 2-guanidinoethanesulphonate accumulation in the cerebrum was largest. On the taurine-free diet the taurine levels were still low after the 4-week 2-guanidinoethanesulphonate administration when the taurine content in cerebral synaptosomes was also reduced to almost one half. 2-Guanidinoethanesulphonate treatment modified the uptake and binding processes of taurine in the synaptosomal preparations. The maximal high-affinity taurine uptake was reduced, whereas the affinity of the specific sodium-independent binding sites for taurine increased. The results suggest that the neuromodulator properties of taurine could be affected by the reduced taurine levels and/or by the accumulated 2-guanidinoethanesulphonate.

Amino Acids↗
PubMed1984

Mass spectrometric analyses of brain synaptic peptides containing taurine.

The structure of a number of low-molecular-weight acidic peptides containing taurine prepared from calf brain synaptosomes and their subcellular vesicles was studied using electron impact mass spectrometry. At least seven sequences could be identified: N-acetylaspartyl-glutamyl-taurine, N-acetylaspartyl-taurine, N-acetylglutamyl-taurine, glutamyl-taurine, aspartyl-taurine, seryl-glutamyl-seryl-taurine, and seryl-taurine.

Animals↗
PubMed1984

Mass spectrometric studies of some synaptosomal and synthetic peptides.

Mass spectra were recorded using direct inlet and electron impact ionization from two synthetic peptides, N-acetyl-aspartyl-4-aminobutyric acid and gamma-glutamyl-taurine and a natural peptide, N-acetyl-aspartyl-glycyl-alanyl-aspartyl-serine, isolated from calf brain synaptosomes. The peptides were studied either underivatized or first acetylated with acetic acid anhydride and then permethylated with methyl iodide. The synthetic peptides were used to check the completeness of the derivatization reactions.

Animals↗
PubMed1984

Effect of L-tryptophan supplementation on ischemic pain.

The synthesis of neurotransmitter amines in mammalian brain is known to respond to changes in precursor availability. After dietary manipulation including L-tryptophan supplementation 3 subjects out of 11 showed a significant reduction of experimentally induced ischemic pain. It is suggested that dietary manipulation aimed at an increase in central nervous system serotonin can alter pain perception in some individuals.

Adult↗
PubMed1984

GABA, taurine and hypotaurine in developing mouse brain.

The cerebral concentrations and synaptosomal uptake of taurine and hypotaurine, two putative neuromodulators, were compared with those of GABA, an established neurotransmitter, in developing mice starting from the birth until 3 months of age. The taurine and hypotaurine contents of blood serum and the sodium-independent binding of GABA and taurine to synaptic membranes were also monitored. In the brain the maximum concentration level was reached for taurine at one week, for hypotaurine at 3 weeks, and for GABA at 4 weeks of age. In the serum the hypotaurine content was maximal in the youngest mice (1-week-old) and the taurine concentration during the three first weeks of life. The uptakes of GABA, taurine and hypotaurine were also high during the first three weeks of age, subsequently declining to a constant level. GABA binding to brain membranes was highest at 2 weeks of age. Taurine binding was also higher in the immature than in the adult brain. These developmental alterations suggest that GABA, taurine and hypotaurine are already functionally active in the brain in early postnatal life.

Amino Acids↗
PubMed1984

Effects of prolonged guanidinoethanesulphonate administration on taurine and other amino acids in rat tissues.

In order to deplete tissue taurine, 2-guanidinoethanesulphonate, a structural analogue of taurine was administered in drinking water with taurine-free diet to adult rats for four weeks. As a consequence the taurine concentrations in the blood serum, liver, kidney, spleen, intestine, lung, heart, muscle and cerebellum fell by nearly one half. Threonine, serine, glycine, alanine, methionine, tyrosine, lysine and histidine concentrations increased in blood plasma. Similar changes were also discernible in the heart and muscle. In the kidney and the lung the concentrations of several other amino acids fell as well, though increments occurred in the threonine content in the kidney and in threonine, serine and methionine contents in the lung. Taurine was practically the only amino acid the level of which fell in the liver, spleen, intestine and cerebellum. These findings indicate that 2-guanidinoethanesulphonate combined with taurine-free diet effectively lowers tissue taurine levels, but its action is not specific to taurine. It may be used as a tool to elucidate the physiological functions of taurine in the body.

Amino Acids↗
PubMed1983

Mass spectral and hydrolytic determination of amino acid sequences in synaptosomal peptides from calf brain.

Calf brain synaptosomes contained acidic peptides, which could be separated into two spots with two-dimensional thin-layer chromatography. These two spots contained several peptides or their partial degradation products. Mass spectrometry and various hydrolytic procedures were used in order to determine their amino acid sequences. The following original structures could be identified: N-acetyl-aspartyl-glutamyl-taurine, N-acetylaspartyl-taurine, N-acetylglutamyl-taurine, aspartyl-taurine, glutamyl-taurine and seryl-taurine in one spot, and N-acetylaspartyl-glycyl-alanyl-aspartyl-serine or -phosphoserine, alanyl-glycyl-glutamyl-serine or -phosphoserine, glutamyl-alanyl-glycyl-glutamyl-serine, glutamyl-aspartyl-phosphoserine and glutamyl-seryl-seryl-alanyl-aspartic acid in the second spot.

Amino Acid Sequence↗
PubMed1982

Augmentation of delayed-type hypersensitivity in antigen-primed guinea pigs by human dialyzable leukocyte extract. Chromatographic and enzymatic characterization of the active principle.

Column chromatographic purification and sensitivity towards enzymatic treatments of dialyzable transfer factor (TFd), the immunologically specific component of dialyzable leukocyte extract (DLE), have previously been used in its biochemical characterisation. In the present work we studied the effect of enzymes and the Sephadex G-10 chromatographic separation of the components of DLE augmenting delayed-type hypersensitivity. Skin reactivities to streptokinase-streptodornase (SK-SD) and tuberculin PPD were significantly augmented by injecting DLE into antigen-primed guinea pigs. The augmentation caused by DLE treatment correlated to the pre-existing level of immunity in the recipients. Most of the augmentory activity resided in 2 adjacent fractions, eluting early from a Sephadex G-10 column. This augmentation was destroyed by alkaline hydrolysis, by treatment with pronase, proteinase K, ribonuclease, and nuclease P1, but not by alkaline phosphatase or phosphodiesterase II. The observed sensitivities towards these enzymes, except that for ribonuclease, were closely similar to those described for the specific TFd component of DLE. These results are compatible with the idea that either the nonspecific augmenting and the specific TFd molecules are principally similar, or that the TFd molecules, in addition to their capacity to transfer specific immunity, also have an augmenting effect, which needs in its manifestation a sub-threshold dose of immunogen.

Adjuvants, Immunologic↗
PubMed1980

Free amino acids in the synaptosome and synaptic vesicle fractions of different bovine brain areas.

Free amino acids were quantitatively estimated in intact tissues and isolated synaptosome and synaptic vesicle fractions of the bovine brain regions with the aid of a sensitive amino acid analyzer. The brain areas studied were frontal, parietal and occipital cerebral cortices, cerebellar cortex, caudate and lenticular nuclei, superior colliculi, thalamus, pons and medulla. The most abundant amino acid in tissue samples and synaptosome fractions was glutamic acid, followed by glutamine, aspartic acid, GABA and taurine. The dominatating amino acid in all isolated synaptic vesicle fractions was taurine. The concentrations of glutamic acid, glutamine, GABA and aspartic acid were generally much lower. The 5 transmitter candidates, viz. GABA, glycine, glutamic acid, as particaid and taurine, comprised about one-half of the total amino acids in all samples. Taurine was the only amino acid highly enriched in the vesicle fractions. This enrichment was discernible in all brain areas. It is suggested therefore that taurine is rather a ubiquitous associate of synaptic membrane structures than a specific inhibitory transmitter.

Amino Acids↗
PubMed1980

Taurine and other amino acids of platelets and plasma in retinitis pigmentosa.

The biochemical cause of human retinitis pigmentosa (RP) is unknown, although in kittens it is related to taurine deficiency. The concentrations of free amino acids were therefore determined in the plasma and platelets of 16 patients with RP and 27 controls. No statistically significant change was found in the plasma, but the concentration of taurine and aspartic acid of platelets calculated per number of platelets were significantly (p < 0.05) lower in RP patients than in controls. This finding correlates with the decreased uptake of taurine by platelets of RP patients and may be connected with the pathogenesis of this disease.

Adolescent↗
PubMed1979

Human transfer factor in vitro. II. Augmentation of the secretion of leucocyte migration inhibitory factor (LIF) by leucocyte dialysate and by its components L-serine and glycine.

The effect of human transfer factor (TF) or its components L-serine and/or glycine in tuberculin (PPD), or leucoagglutinin (LA) induced leucocyte migration inhibitory factor (LIF) secretion was studied. Augmentation of LIF secretion was seen with low concentration ( = 0.078 g/l) of TF when lymphocytes were cultured in minimum essential medium for suspension cultures (MEM-S), a culture medium lacking L-serine and glycine. High concentrations (0.3125-5.0 g/l dry weight) of TF were inhibitory in MEM-S. In RPMI 1640, a culture medium containing L-serine and glycine, TF was either inhibitory or had no effect. The combination of L-serine and glycine, at concentrations equivalent or lower than the optimum of TF, had an augmenting effect on LIF secretion identical to that of TF, but no inhibition at higher concentrations was seen. The results indicate that human TF contains components which have suppressive or augmenting effects on LIF secretion in vitro. The augmenting effect may be mainly due to L-serine and glycine and thus not related to TF's activity in vivo.

Cells, Cultured↗
PubMedDate not supplied

Amino acids and glucose in human cerebrospinal fluid after acute ischaemic brain damage.

In the search for potential biochemical markers of value for prognosis after acute hypoxic brain damage, amino acids and glucose were assessed in the cerebrospinal fluid (CSF) and glucose in blood. Samples were taken by lumbar puncture 4, 28, 76 and 172 h after resuscitation from 20 patients and once from 10 control patients. Eight of the resuscitated patients recovered neurologically but 12 remained comatose. The concentrations of alanine (P less than 0.001) and phenylalanine (P less than 0.035) differed most in 4-h samples between the groups. The concentration of alanine was higher in all patient groups with hypoxic brain damage as compared to the controls, the concentrations in patients dying within 76 h (disabled-s group) being higher than in the recovered patients. Phenylalanine in the disabled-s group was significantly higher than the control value. Furthermore, there were significant differences between various patient groups in the concentrations of glutamine, isoleucine, leucine, lysine, serine, tyrosine and valine. When taking into account the permeability of the BBB to these amino acids, alanine, valine and isoleucine most clearly represent brain amino acid metabolism. CSF glucose in the control group and in the recovered patients was lower than in patients dying within 76 h.

Acute Disease↗