Polymeric ovotransferrin and its ability to bind and deliver iron to chick-embryo red blood cells.

Polymeric forms of hen ovotransferrin have been obtained by storage at 4 degrees C for 5 years or at 57 degrees C for 14 days and fractionated as dimers and tetramers by gel filtration on Sephadex. The ability of tyrosine to undergo nitration was reduced in the tetrameric protein, so that one could hypothesize that dityrosine formation is somewhat responsible of such polymerization process. Experimental data on the biological functionality showed that: i) dimeric ovotransferrin was able neither to bind nor to deliver iron; ii) tetrameric ovotransferrin was able to bind but not to deliver iron.

Platelet catecholamines in cluster headache.

Platelet tyrosine and catecholamine (CA) content was measured in cluster headache sufferers during the different phases of the illness. Compared with controls, cluster headache sufferers had lower platelet levels of norepinephrine (NE) and epinephrine (E) in all phases of the syndrome. Tyrosine levels were increased significantly during the cluster headache attack.

NMR spectroscopic and magnetoencephalographic studies in migraine with aura: support for the spreading depression hypothesis.

The authors propose that patients who suffer from migraine with aura have a susceptibility to spontaneous neuronal discharges and subsequent spreading depression. This is based upon a state of central neuronal excitability involving the excitatory neurotransmitter glutamate, in combination with supersensitivity of the N-méthyl-D-aspartate (NMDA) receptor. This hypersusceptibility is supported by increased turnover of high-energy phosphates, low intracellular Mg2+ and large amplitude depolarizing waves on magnetoencephalography (MEG).

Structural analysis of seminal and serum human transferrin by second derivative spectrometry and fluorescence measurements.

Denaturation of human seminal transferrin (HSmT) compared with human serum transferrin (HSrT) was followed to check structural differences between these two proteins. Second derivative UV spectroscopy indicated that treatment with 6 M guanidine hydrochloride (Gnd.HCl) induced greater structural changes in HSrT than in HSmT and, in particular; (i) the exposure value of tyrosinyl residues was almost 2.

Platelet glycine, glutamate and aspartate in primary headache.

Platelet levels of glutamic and aspartic acid and glycine were measured in patients with migraine with aura, migraine without aura, tension headache and cluster headache. High levels of these amino acids were found in patients with migraine with aura compared to normal subjects and other headache groups. During headache, glutamate levels further increased in migraine with aura patients.

Some molecular properties of human seminal transferrin (HSmT) in comparison with human serum transferrin (HSrT).

In this paper we report some structural features of human seminal transferrin (HSmT) in comparison with the homologous protein purified from human serum (HSrT). In particular, the sequence of the first 13 N-terminal amino acids of HSmT shows 12/13 of identity with the first 13 N-terminal amino acids of HSrT, the ninth residue of the former protein being not definitely determined. Moreover, HSrT and HSmT analysed under the same conditions, by means of reversed phase HPLC, thiol groups determination and second derivative spectroscopy, show a different content of amino acids.

Event-related slow potentials and associated catecholamine function in migraine.

Plasma norepinephrine and dopamine and event-related slow potentials were measured at menses and ovulation in migraine with and without aura relative to normal subjects. The results indicated that at menses, but not ovulation, plasma dopamine was increased and norepinephrine was decreased relative to normal. This catecholamine imbalance was greater in migraine without aura than in migraine with aura.

The concept of migraine as a state of central neuronal hyperexcitability.

This article explores the hypothesis that migraine with aura is associated with a state of central neuronal hyperexcitability. The authors propose that this central neuronal hyperexcitability involves overactivity of the excitatory amino acids, glutamate, and possibly aspartate. Stimuli that activate the migraine attack evoke neuronal depolarization, slow depolarization shifts, and spreading suppression of spontaneous neuronal activity possible by glutamate and K+ dependent mechanisms.

Binding and iron delivering of monoferric ovotransferrins to chick-embryo red blood cells (CERBC).

1. Both monoferric forms of OTf, each of about 80 kDa, bound to CERBC enough tightly, but at a lesser extent with respect to Fe2OTf with a Bmax in the order: 59Fe2OTf greater than OTf59FeC much greater than 59FeNOTf. 2.

Electrophoretic detection of ascorbate oxidase activity by photoreduction of nitroblue tetrazolium.

A method for the detection of ascorbate oxidase in electrophoretic gels is described. This method relies on the ability of the enzyme to prevent the photoreduction of nitroblue tetrazolium (NBT). The method is based on that described by C.

Ovarian steroid levels in migraine with and without aura.

Radioimmunoassays were used to measure interictal levels of ovarian steroids (oestradiol, total oestrogens and progesterone) in migraine patients at the onset of menses and coincident with the luteinizing hormone surge preceding ovulation. Results of these verified biochemically-contrasting points of the ovarian cycle were used to compare 13 migraine patients without aura and 6 migraine patients with aura with 17 non-migraine women. No group differences were found for physiological basal levels of ovarian steroids measured at menses.

Serotonergic hypofunction in migraine: a synthesis of evidence based on platelet dense body dysfunction.

We studied the platelet dense body as a model for serotonergic vesicular function. Headache-free migraine sufferers had increased numbers of dense bodies, decreased dense body secretion, a defective link between cytosolic ionized calcium and platelet activation, an abnormal sensitivity to activation by platelet-activating factor and decreased serotonin metabolism in the presence of an unactivated platelet. These findings are interpreted as evidence for low platelet serotonin turnover.

Kinetic features of ascorbic acid oxidase after partial deglycation.

By means of specific exoglycosidases, sugars have been removed under non-denaturing conditions from ascorbic acid oxidase (AAO), different deglycation schedules being followed. Our results indicate that deglycation clearly affects the kinetic features of AAO, leading to an increase of 'affinity' and 'catalytic ability' of the enzymic forms so generated. A better exposure of the catalytic-site residues could be supposed to occur upon treatment with exoglycosidases.

A plasmatic factor may cause platelet activation in acute ischemic stroke.

To study the pathogenesis of platelet activation in ischemic stroke, ionized calcium ([Cai2+]) was measured in aequorin-loaded gel-filtered platelets in the basal and stimulated state. Basal [Cai2+] was increased in stroke patients maximally 36-72 hours after onset. The increase in [Cai2+] after stimulation with thrombin, collagen, and platelet-activating factor were also greater in stroke patients, but the profiles of these [Cai2+] changes were parallel to control.

Platelet norepinephrine and serotonin balance in migraine.

Platelet serotonin (5 hydroxytryptamine, 5-HT) and norepinephrine (NE) were measured in common and classic migraine patients and healthy controls. Common migraine sufferers had high NE levels and a low 5-HT/NE ratio. Classic migraine patients had a high 5-HT level and a high 5-HT/NE ratio.

Platelet serotonin metabolism and ultrastructure in migraine.

Biochemical and ultrastructural techniques were used to study the nature of platelet serotonin involvement in migraine. Serotonin levels were increased to a moderate degree in classic migraine, but not in common migraine. The platelet content of 5-hydroxyindoleacetic acid was equally reduced in both classic and common migraine.

Platelet ultrastructure and secretion in acute ischemic stroke.

We used transmission electron microscopy to count the organelles (dense bodies, alpha granules, and mitochondria) contained within platelets from 11 acute ischemic stroke patients and 12 healthy controls. We randomly selected for evaluation 25 platelet profiles in ultrathin sections cut from three separate blocks. Compared with those from controls, platelets from stroke patients contained significantly fewer alpha granules (p less than 0.

Effect of synthetic carrier ampholytes on saturation of human serum transferrin.

We have investigated the effect in solution of synthetic carrier ampholytes on the saturation of human serum transferrin. By spectrophotometric titrations of human serum transferrin with various Fe3+-carrier ampholyte solutions, we demonstrated that under these conditions carrier ampholytes behave as typical chelators, their binding curves being very similar to that obtained with disodium nitrilotriacetate. On performing titration experiments at three different pH values, carrier ampholytes act like nitrilotriacetate at pH 7.

Effect of therapy on platelet activating factor-induced aggregation in acute stroke.

Platelet activating factor, a potent inducer of in vivo platelet activation and thrombosis, has been shown to be excessively active in acute ischemic stroke patients. Therefore, we studied the effect of aspirin/dipyridamole therapy in inhibiting platelet activating factor-induced platelet activation in acute ischemic stroke patients, 23 taking aspirin/dipyridamole and 21 untreated. Aspirin/dipyridamole-treated patients failed to show suppression of platelet activating factor-induced platelet aggregation even though collagen-induced activation was inhibited, suggesting that platelet activating factor acts by cyclooxygenase-independent mechanisms.

Preliminary observations on brain energy metabolism in migraine studied by in vivo phosphorus 31 NMR spectroscopy.

We measured brain energy phosphate metabolism and intracellular pH (pHi) in a cross-sectional study of migraine patients by in vivo phosphorus 31 NMR spectroscopy. During a migraine attack the ratio ATP/total phosphate signal (mole % ATP) was preserved, but there was a decrease in mole % phosphocreatine (PCr) and an increase in mole % inorganic phosphate (Pi) resulting in a decrease of the PCr/Pi ratio, an index of brain phosphorylation potential. This was found in classic but not common migraine.

Evidence for the presence of red and white cells within "platelet" aggregates formed in whole-blood.

Collagen-induced platelet aggregation and secretion (ATP-release) in whole-blood and platelet-rich plasma was compared. Although the amount of ATP released was comparable in whole-blood and platelet-rich plasma, the maximum extent of aggregation was greater when platelets were studied in their natural milieu, i.e.

Platelet catecholamines in migraine.

We measured platelet levels of norepinephrine (NE), epinephrine (E), and dopamine (DA) in migraine patients. Platelet NE was selectively increased in common migraine. This is attributed to platelet dense body hyposecretion.

Personality and memory in childhood migraine.

A series of neuropsychological tests were administered to a group of healthy children and another group suffering from common migraine. The tests demonstrated that children with common migraine do not have definitely abnormal personality traits even though inhibition of aggressivity and greater anxiety levels following certain environmental stimuli were seen. We also observed a decreased short- and long-term memory function in children with common migraine.