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E Roth

Publications and source records attributed to E Roth.

At least 19 recordsLinked to original sources
PubMed1992

Chemical modification of Torpedo acetylcholinesterase by disulfides: appearance of a "molten globule" state.

Modification of Torpedo californica acetylcholinesterase (AChE) both by bis(1-oxy-2,2,5,5-tetramethyl-3-imidazolin-4-yl)disulfide (biradical) and by 4,4'-dithiopyridine, via a thiol-disulfide exchange reaction, was monitored by EPR and optical spectroscopy, respectively. Incubation with these reagents caused complete loss of enzymic activity. Treatment with glutathione of AChE modified by either of the two disulfides led to rapid release of the bound reagent with simultaneous regeneration of the single free thiol group of the enzyme. However, no concomitant recovery of catalytic activity was observed. SDS-PAGE showed that both the modified and demodified enzymes retained their structure as a disulfide-linked dimer. Circular dichroism revealed that modification of AChE by the disulfide agents with or without demodification by glutathione led to a complete disappearance of the ellipticity in the near-UV and to a much smaller decrease in ellipticity in the far-UV. The CD spectra observed are typical of the "molten globule" state of proteins. 1-Anilino-8-naphthalenesulfonate binding measurements and an enhanced susceptibility to trypsinolysis supported the supposition that chemical modification had transformed native AChE to a "molten globule".

Acetylcholinesterase↗
PubMed1992

D-myo-inositol 1,3,4,5-tetrakisphosphate releases Ca2+ from crude microsomes and enriched vesicular plasma membranes, but not from intracellular stores of permeabilized T-lymphocytes and monocytes.

In the human T-lymphocyte cell lines Jurkat and HPB.ALL and the human monocytoid cell line U937, Ins(1,3,4,5)P4 triggers a dose-dependent release of Ca2+ from crude microsomal preparations, with a half-maximal effective concentration (EC50) of 1.2-2.3 microM. Similar results were obtained with enriched vesicular plasma membranes from U937 cells. However, in permeabilized preparations of the same cell types only Ins(1,4,5)P3 was able to release Ca2+ from intracellular stores, with EC50 values in the range 0.11-0.84 microM. In crude microsomes the effects of Ins(1,3,4,5)P4 and Ins(2,4,5)P3, a non-metabolizable InsP3 isomer, occurred independently of each other, indicating subpopulations of Ins(1,3,4,5)P4- and Ins(1,4,5)P3-sensitive vesicles. The Ins(1,3,4,5)P4 preparation used for the Ca(2+)-release experiments contains neither Ca2+ nor contaminating Ins(1,4,5)P3 and was not metabolized to Ins(1,4,5)P3 during the Ca(2+)-release experiments. We conclude that Ins(1,3,4,5)P4 independently of Ins(1,4,5)P3 induces a Ca2+ flux via a membrane compartment, most likely the plasma membrane, that is functionally destroyed during the permeabilization of the cells.

Calcium↗
PubMed1992

Complex inositol polyphosphate response induced by co-cross-linking of CD4 and Fc gamma receptors in the human monocytoid cell line U937.

The cell-surface Ag CD4, which is characteristic for Th lymphocytes, can also be found with a lower density on monocytes/macrophages. Co-cross-linking of CD4 and Fc gamma R by an anti-CD4 mAb (MAX.16H5) and by excess of goat anti-mouse Ig induced a biphasic increase of the free cytosolic Ca(2+)-concentration ([Ca2+]i) in the human monocytoid cell line U937 as measured by FURA-2 fluorescence. A rapid rise from 100 to 150 nM [Ca2+]i to 750 to 900 nM within 1 min was followed by a decline to about 200 to 300 nM within the next 2 to 3 min. This kinetic is characteristic also for blood monocytes and differs significantly from CD4-mediated Ca(2+)-mobilization in T lymphocytes. The rise in [Ca2+]i in U937 cells was not observed when F(ab)2 fragments of MAX.16H5 and F(ab)2 fragments of the cross-linker were used indicating the involvement of Fc gamma R. Time course analysis using HPLC and a recently developed post-column dye system for mass analysis revealed a complex inositol polyphosphate response with rapid increases not only in inositol 1,4,5-trisphosphate and inositol 1,3,4,5-tetrakisphosphate, but also in D/L-inositol 1,4,5,6-tetrakisphosphate, inositol 1,3,4,5,6-pentakisphosphate, and inositol hexakisphosphate after co-cross-linking of CD4 and Fc gamma R. In conclusion, co-cross-linking of CD4 and Fc gamma R, which may occur in vivo during HIV infection or treatment with therapeutic anti-CD4 antibodies, appears to be a strong activation mechanism for the inositol polyphosphate/Ca2+ signal transduction pathway in U937 cells.

Antigens, Differentiation↗
PubMed1992

Nutritional behaviour and quality of life during oncological polychemotherapy: results of a prospective study on the efficacy of oral nutrition therapy in patients with acute leukaemia.

A total of 29 patients with acute leukaemia were prospectively randomized before starting cytostatic treatment to be nourished either with intensified oral nutrition (intervention group) or ad libitum nutritional intake during the whole tumour therapy (median 22 weeks). All received menus of free choice (daily offer of 1.0-2.0 g protein, 30-50 kcal kg-1 body weight (BW)). Beyond this, intervention patients received nutrition education, daily visits by the dietician and record of food intake, as well as a weekly assessment of subjective well-being (linear analogue self assessment 'LASA'). From the LASA items, the factors: 'malaise', 'psychological distress', 'therapy side-effects' were extracted by principal component analysis, and correlated to nutrient intake and nutritional status. At the end of antineoplastic induction therapy, after continuous hospitalization of 10 weeks (median), 31.3% of the controls had regained their initial nutritional status, and 68.8% of the intervention group. Mean daily energy intake was 23.2 kcal kg-1 BW during weeks with weight loss (constant weight: 30.9, weight gain: 39.3 kcal kg-1 BW). Nutritional behaviour correlated with subjective well-being, low intake with complaints of tumour treatment side effects and weight loss with malaise.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

Requirement of active human immunodeficiency virus type 1 integrase enzyme for productive infection of human T-lymphoid cells.

The human immunodeficiency virus type 1 (HIV-1) integrase enzyme exhibits significant amino acid sequence conservation with integrase proteins of other retroviruses. We introduced specific amino acid substitutions at a number of the conserved residue positions of recombinant HIV-1 integrase. Some of these substitutions resulted in proteins which were not able to be purified in the same manner as the wild-type enzyme, and these were not studied further. The remaining mutant enzymes were assessed for their abilities to perform functions characteristic of the integrase protein. These included specific removal of the terminal dinucleotides from oligonucleotide substrates representative of the viral U5-long terminal repeat, nonspecific cleavage of oligonucleotide substrates, and mediation of the strand transfer (integration) reaction. Substitution at position 43, within the protein's zinc finger motif region, resulted in an enzyme with reduced specificity for cleavage of the terminal dinucleotide. In addition, a double substitution of aspartic acid and glutamine for valine and glutamic acid, respectively, at positions 151 and 152 within the D,D(35)E motif region rendered the integrase protein inactive for all of its functions. The introduction of this double substitution into an infectious HIV-1 provirus yielded a mutant virus that was incapable of productively infecting human T-lymphoid cells in culture.

Amino Acid Sequence↗
PubMed1992

Glycylglutamine: metabolism and effects on organ balances of amino acids in postabsorptive and starved subjects.

The present study was designed to investigate the metabolism of glycylglutamine and its effects on organ balances of amino acids during intravenous infusion of this dipeptide (100 mumol.h-1.kg-1) in postabsorptive and briefly starved (84-86 h) human subjects. Arterial concentrations of glycylglutamine were not significantly different in postabsorptive (265 +/- 18 microM) and starved (241 +/- 13 microM) subjects. Among the organs examined, kidney predominated in clearance of glycylglutamine from plasma. Moreover, renal clearance of glycylglutamine was reduced by starvation (87 +/- 7 vs. 52 +/- 5 mumol/min, P less than 0.01), whereas neither splanchnic nor muscle clearance was significantly affected. Infusion of glycylglutamine raised plasma concentrations of glycine and glutamine by increasing renal release of these amino acids. In postabsorptive subjects the infusion significantly increased splanchnic balances of glycine and glutamine with little or no effect on the muscle balances; the opposite was found in starved subjects. As far as other amino acids are concerned, the infusion decreased the muscle release of alanine and increased renal release of serine. We conclude that the amino acid residues of glycylglutamine are largely metabolized by the splanchnic organs in postabsorptive subjects and by peripheral organs in starved subjects. The latter results in selective inhibition of muscle release of amino acids.

Adult↗
PubMed1992

Prescription medication misuse among persons with spinal cord injuries.

Use of prescription medication, alcohol, and illicit substances, and problems resulting from their use as well as depression and disability acceptance, were reported by 96 persons with long-term spinal cord injuries (SCI). Forty-three percent of the sample used prescription medications with misuse potential, and of these persons, 24% reported misusing one or more medications. Persons who used prescription medications were less accepting of their disability and were more depressed than persons who were not using prescription medications. Additionally, persons reporting problems resulting from prescription medication use were more depressed, and persons reporting problems resulting from nonprescription substance use were less accepting of their disability than were persons not reporting these problems. These results suggest that use of prescription and nonprescription substances by persons with SCI is associated with negative psychological outcomes.

Adaptation, Psychological↗
PubMed1991

Reduced neutrophil superoxide generation and plasma lipoperoxide levels in pigs fed with cod liver oil.

Circulating neutrophils, isolated from pigs fed for 8 weeks with a diet supplemented with CLO, had an accentuated n-3 fatty acid incorporation into the plasma membrane, as evidenced by an approximately four-fold greater n-3/n-6 ratio as compared with the control diet group. Moreover, the neutrophils of the CLO fed pigs produced less superoxide when stimulated with PMA or f-MLP, as well as showing a more prolonged latency period before O2(-)-generation. In the plasma of pigs fed with CLO there were higher levels of thiobarbituric reactive material and lipofuscin, while the content of GSSG was similar in both dietary groups. The results of this study indicate that dietary supplementation with CLO reduces the activation of circulating neutrophils and favours the presence in the plasma of lipoperoxides.

Animals↗
PubMed1991

Effect of alpha-ketoglutarate infusions on organ balances of glutamine and glutamate in anaesthetized dogs in the catabolic state.

1. The salt complex of L-(+)-ornithine and alpha-ketoglutarate (2-oxoglutarate) has recently been proposed for the treatment of patients in the catabolic state. As yet, it is unclear which of the two substrates (ornithine or alpha-ketoglutarate) is responsible for the anticatabolic effect. We infused alpha-ketoglutarate into anaesthetized post-operative dogs in order to investigate whether infusion of alpha-ketoglutarate affects the flux of glutamine and glutamate between skeletal muscle and the splanchnic bed. We used three infusion rates: 3, 10 and 20 mumol min-1 kg-1. A steady state of alpha-ketoglutarate concentration in arterial whole-blood was attained only when the infusion rate was 3 mumol min-1 kg-1. 2. Arterial whole-blood concentrations of alpha-ketoglutarate were 8.8 +/- 1.2 mumol/l in the basal period and rose to 208 +/- 41, 344 +/- 61 and 1418 +/- 315 mumol/l after 60 min infusions of alpha-ketoglutarate at 3, 10 and 20 mumol min-1 kg-1, respectively. 3. alpha-Ketoglutarate uptake was measured in skeletal muscle, liver, gut and kidneys in the basal period and during the infusion of alpha-ketoglutarate. The net uptake of infused alpha-ketoglutarate was highest in the skeletal muscle, followed by kidneys, liver and gut. 4. The alpha-ketoglutarate load increased the muscular tissue content of alpha-ketoglutarate from 49.5 +/- 5 to 142 +/- 15 nmol/g of dry substance (P less than 0.001), but did not alter the muscular glutamate or glutamine contents.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Utilization of tyrosine dipeptides and acetyltyrosine in normal and uremic humans.

The impact of renal failure on the elimination and hydrolysis of three sources of tyrosine for parenteral nutrition, the dipeptides alanyltyrosine (Ala-Tyr), glycyltyrosine (Gly-Tyr), and N-acetyltyrosine (NAc-Tyr) was investigated in eight patients on regular hemodialysis therapy (HD) and seven healthy controls (CON). In CON, whole body clearance (Ctot) of Ala-Tyr (3,169 +/- 198 ml/min) was higher than Gly-Tyr (1,781 +/- 184, P less than 0.001), and both exceeded NAc-Tyr (284 +/- 24, P less than 0.001). In HD, Ctot of Ala-Tyr was not different from CON, but Ctot of Gly-Tyr (858 +/- 73, P less than 0.001) and NAc-Tyr (129 +/- 30, P less than 0.02) was decreased. The rise in plasma levels of constituent amino acids was higher in Ala-Tyr vs. Gly-Tyr (P less than 0.01). In HD, the pattern was similar, although the increase in Tyr was less than in CON. Plasma Tyr did not increase with NAc-Tyr in either group. Urinary loss of peptides was neglible, but 60% of NAc-Tyr infused was excreted by CON. The half-life of peptides incubated in CON and HD plasma was unchanged for Ala-Tyr (12.3 +/- 0.9 vs. 14.6 +/- 1.9 min) and prolonged for Gly-Tyr in HD (101.7 +/- 4.9 vs. 131.3 +/- 12, P less than 0.05). Thus renal failure does not impair Ala-Tyr disposal and delays Gly-Tyr utilization. These differential effects on peptide assimilation underscore the importance of peptide structure on metabolism. Both peptides, but not NAc-Tyr, may serve as a nutritional substrate in renal failure patients.

Adult↗
PubMed1990

Increased serotoninergic and noradrenergic activity in hepatic encephalopathy in rats with thioacetamide-induced acute liver failure.

Functional changes of various neurotransmitter systems have been implicated in the pathogenesis of hepatic encephalopathy. In this study the role of brain monoaminergic neurotransmitter systems in hepatic encephalopathy was investigated in rats with thioacetamide-induced acute liver failure. Concentrations of serotonin, dopamine, noradrenaline and of their metabolites 5-hydroxyindoleacetic acid, dihydroxyphenylalanine (following inhibition of dihydroxyphenylalanine-decarboxylase), dihydroxyphenylacetic acid, homovanillic acid and 3-methoxy-4-hydroxyphenyl-glycol, were measured in the cerebral cortex, striatum and hippocampus by high performance liquid chromatography with electrochemical detection. In hepatic encephalopathy concentrations of 5-hydroxyindoleacetic acid were increased in all three brain areas (196%, 204% and 264% of saline-treated controls, p less than 0.01), and concentrations of serotonin were increased in the frontal cortex (121%, p less than 0.01). In the frontal cortex and hippocampus of encephalopathic rats dopamine levels were increased (157% and 289%, p less than 0.05), and levels of noradrenaline (53% and 46%, p less than 0.05) were decreased associated with increased 3-methoxy-4-hydroxyphenylglycol levels (173% and 206%, p less than 0.05). The extent of these changes correlated with the stage of hepatic encephalopathy. In hepatic encephalopathy dihydroxyphenylalanine accumulation was increased in the hippocampus and unchanged in the cerebral cortex. Dopamine, noradrenaline, dihydroxyphenylacetic acid and homovanillic acid concentrations were unchanged in the striatum. The results of this study indicate that hepatic encephalopathy in thioacetamide-induced acute liver failure in rats is associated with neurochemical changes, suggesting an increased activity of the noradrenergic and serotoninergic neurotransmitter systems.

Amino Acids↗
PubMed1990

Splanchnic, renal, and muscle clearance of alanylglutamine in man and organ fluxes of alanine and glutamine when infused in free and peptide forms.

The present study was designed to investigate organ metabolism of intravenously (IV) infused (100 mumol.h-1.kg-1) alanylglutamine and its amino acid constituents in a group of healthy subjects. The dipeptide clearance (mumol/min) by kidney (51 +/- 3) was significantly (P less than .01) greater than the clearance by either splanchnic organs (19 +/- 6) or skeletal muscle (21 +/- 8). Infusion of alanylglutamine significantly (P less than .01) increased arterial plasma concentrations of free alanine (260 +/- 31 v 330 +/- 38 mumol/L) and free glutamine (620 +/- 66 v 764 +/- 65 mumol/L) when compared with the baseline period. Concurrently, splanchnic uptake of alanine and glutamine increased and muscle release of alanine ceased. However, muscle release of glutamine remained unaffected. Renal balances of alanine and glutamine changed from neutral to negative (net release) and from positive (net uptake) to neutral, respectively. Infusion of a corresponding mixture of alanine and glutamine had similar effects on arterial plasma concentrations and splanchnic and muscle balances of alanine and glutamine, but had no effect on renal balances of these amino acids. From these studies in man, we conclude that kidney predominates over other organs in clearance of alanylglutamine from plasma and that this may account for the different effect of infusion of alanine and glutamine in free and peptide forms on renal fluxes of these amino acids.

Adult↗
PubMed1990

Coronary reperfusion studies with pro-urokinase in acute myocardial infarction: evidence for synergism of low dose urokinase.

Pro-urokinase is a single chain precursor of two chain urokinase, which has been shown to induce fibrin-selective plasminogen activation. In the present study, thrombolytic efficacy of 9 million U of glycosylated pro-urokinase administered intravenously was compared with that of a combined regimen utilizing 4.5 million U of pro-urokinase and 0.2 million U of urokinase. Seventy-five patients with a first myocardial infarction were randomized to receive high dose pro-urokinase (n = 40, group A) or the combination therapy (n = 35, group B). Reperfusion of the infarct-related artery was assessed by repeat coronary angiography. Thrombolysis in Myocardial Infarction trial (TIMI) grade II or III reperfusion was achieved in 73% of group A patients compared with 66% of group B patients (p = NS). A trend toward faster reopening of the infarct-related artery was observed in patients in group B. Coronary artery reocclusion occurred in 5 (10%) of 49 patients in whom angiography was repeated within 36 h after the start of therapy. Clot-selective thrombolysis was indicated by a minimal fibrinogen decline (15% and 13%, respectively, in groups A and B). Alpha 2-antiplasmin levels, however, decreased more rapidly in patients in group B (p less than 0.05). This finding and the equivalent reperfusion rate in the combined treatment group strongly suggest synergistic interaction between these two thrombolytic agents. In summary, the high incidence of reperfusion, the low rate of early reocclusion and the paucity of side effects, particularly with regard to bleeding complications, indicate that pro-urokinase possesses the characteristics of an ideal thrombolytic agent.

Drug Synergism↗
PubMed1990

Lesions of nonvisual inputs affect plasticity, norepinephrine content, and acetylcholine content of visual cortex.

1. The depletion of both norepinephrine (NE) and acetylcholine (ACh) in the visual cortex can decrease plasticity. This decrease in plasticity, although dramatic under some circumstances, fails to occur under others. 2. We depleted cortical NE and ACh in 35- to 42-day-old kittens by making a lesion of the white matter behind the cingulate gyrus. One eye was sutured on the day of the lesion. We recorded from the visual cortex 7 days or 2-3 mo later and used the influence of the deprived eye on the cortical cells as a measure of plasticity. 3. We measured NE content by high-pressure liquid chromatography (HPLC) and inferred ACh depletion from depletion of choline acetyltransferase (ChAT) activity. NE depletion averaged 60% in the successfully depleted animals. Depletion of ChAT activity was consistent with NE depletion. 4. When recording occurred 7 days after the lesion and the sutured eye was contralateral to the lesion, plasticity was decreased on the side with the lesion; 70% of the cells were driven by the deprived eye. On the control, uninjured side only 15% of the cells were driven by the deprived eye. 5. In two circumstances the lesion did not cause a decrease in plasticity. In animals with suture ipsilateral to the lesion, the cortex remained plastic. In these animals only 26% of the cells in the hemisphere with the lesion were driven by the deprived eye. The cortex also retained its plasticity if the contralateral eye remained sutured for several months after the lesion, even though there was no recovery from NE and ACh depletion. 6. We conclude that depletion of NE and ACh does decrease plasticity; that is, it protects the deprived eye from losing its ability to drive cortical cells, at least for a short period of time. Depletion protects only the normally dominant contralateral pathway; the ipsilateral visual pathway remains plastic. 7. Perhaps the importance of the side of the deprived eye can be explained by assuming that depletion of NE and ACh removes facilitatory input. This would decrease the ability of cortical cells on the side with lesion to potentiate the input from the nondeprived eye relative to the deprived eye; that is, it would decrease the molecular deprivation (MD) effect. A removal of facilitation would also increase the visual input required to drive cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Acetylcholine↗
PubMed1990

Torpedo acetylcholinesterase is inactivated by thiol reagents.

A number of sulphydryl reagents inhibit AChE of Torpedo california with pseudo-first-order kinetics, and inhibition can be retarded by quaternary ligands which bind at either the catalytic or peripheral anionic binding sites. Colorimetric determination with one of the inhibitory sulphydryl agents, 5,5'-dithiobis (2-nitrobenzoic acid), reveals the presence of a single thiol group per catalytic subunit; our data thus suggest that inhibition is achieved by reaction with the single free sulphydryl group of Cys231.

4-Chloromercuribenzenesulfonate↗
PubMed1990

Plasmodium falciparum carbohydrate metabolism: a connection between host cell and parasite.

Selected aspects of the metabolism of Plasmodium falciparum are reviewed, but conclusions based on the study of other species of plasmodia are intentionally not included since these may not be applicable. The parasites increase glucose consumption 50-100 fold as compared to uninfected red cells; most of the glucose is metabolized to lactic acid. The parasite contains a complete set of glycolytic enzymes. Some enzymes such a hexokinase, enolase and pyruvate kinase are vastly increased over corresponding levels in uninfected red cells. However, the pathway for synthesizing 2,3-diphosphoglycerate (2,3-DPG) is absent. Parasitized red cells show a decline in the concentration of 2,3-DPG which may function as an inhibitor for certain essential enzyme pathways. Pentose shunt activity is increased in absolute terms, but as a percent of total glucose consumption, there is a decrease during parasite infection of the red cell. The parasite contains a gene for G6PD and can produce a small quantity of parasite-encoded enzyme. It is not clear if the production of this enzyme can be up-regulated in G6PG deficient host red cells. The NADPH normally produced by the pentose shunt can be obtained from other parasite pathways (such as glutamate dehydrogenase). NADPH may subserve additional needs in the infected red cell such as driving diribonucleotide reductase activity--a rate limiting enzyme in DNA synthesis. The role of NADPH in protecting the parasite-red cell system against oxidative stress (via glutathione reduction) remains controversial. Parasitized red cells contain about 10 times more NAD(H) than uninfected red cells, but the NADP(H) content is unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗