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Biomedical subjects

L Gram

Publications and source records attributed to L Gram.

At least 73 records · Page 4Linked to original sources
PubMed1994

Fluoxetine.

Fluoxetine was developed as an antidepressant drug. It is more effective than placebo, but a dose-effect relation has not been established. Fluoxetine is almost as effective as tricyclic antidepressant drugs, but the available studies do not allow accurate comparisons. Fluoxetine may be less effective than tricyclic antidepressant drugs for the treatment of inpatients with severe melancholic depression, and it should not be the first choice of a drug for them. Fluoxetine may be most appropriate for patients with moderate depression who can be treated as outpatients. If there is little improvement after treatment for four to six weeks, an alternative treatment should be offered. Fluoxetine does not have the anticholinergic, hypotensive, and sedative effects of tricyclic antidepressant drugs and has no particular cardiovascular effects; overdoses do not cause serious toxic effects. Nausea, anorexia, insomnia, and nervousness--the most common side effects--may be controlled with a careful adjustment to the dose. Clinically important drug interactions may occur with monoamine oxidase inhibitors, tricyclic antidepressant drugs, and other drugs. The published data on the antidepressant effect of fluoxetine do not fully explain its popularity. One may speculate that fluoxetine has psychobiologic effects not strictly related to the biology of depression and that it acts primarily as a mood- or affect-modulating agent.

Depression↗
PubMed1994

Clinical experience with oxcarbazepine.

Controlled studies of oxcarbazepine (OCBZ) and the largest of the open studies of OCBZ were reviewed. The overall results indicated that OCBZ has the same clinical effect as carbamazepine (CBZ) but causes fewer adverse effects. Studies of allergic toxicity seem to indicate that OCBZ may be tolerated in the majority of patients developing allergy towards CBZ. We concluded that OCBZ is a drug of first choice for the treatment of epilepsy.

Anticonvulsants↗
PubMed1994

Tiagabine: a novel drug with a GABAergic mechanism of action.

The various possibilities for manipulating the gamma-aminobutyric acid (GABA) system to augment GABAergic inhibition have been surveyed with reference to the relevant antiepileptic compounds that have been successfully or unsuccessfully investigated in relation to these different mechanisms of action. The first clinical studies of tiagabine (TGB), a novel GABA-uptake inhibitor are now available. These studies utilized a novel design, the enrichment (Amery) design, which is put into perspective compared to classical clinical trial designs. Possible advantages and disadvantages of TGB, as seen at this stage in development, have been identified.

Animals↗
PubMed1994

Siderophore-Mediated Iron Sequestering by Shewanella putrefaciens.

The iron-sequestering abilities of 51 strains of Shewanella putrefaciens isolated from different sources (fish, water, and warm-blooded animals) were assessed. Thirty strains (60%) produced siderophores in heat-sterilized fish juice as determined by the chrome-azurol-S assay. All cultures were negative for the catechol-type siderophore, whereas 24 of the 30 siderophore-producing strains tested positive in the Csáky test, indicating the production of siderophores of the hydroxamate type. Siderophore-producing S. putrefaciens could to some degree cross-feed on the siderophores of other S. putrefaciens strains and on compounds produced by an Aeromonas salmonicida strain under iron-limited conditions. The siderophores of S. putrefaciens were not sufficiently strong to inhibit growth of other bacteria under iron-restricted conditions. However, siderophore-producing Pseudomonas bacteria were always inhibitory to S. putrefaciens under iron-limited conditions. Growth of siderophore-producing strains under iron-limited conditions induced the formation of one major new outer membrane protein of approximately 72 kDa. Two outer membrane proteins of approximately 53 and 23 kDa were not seen when iron was restricted.

Journal Article↗
PubMed1993

Spoilage and shelf-life of cod fillets packed in vacuum or modified atmospheres.

Microbial growth, sensory and chemical changes and composition of gas atmosphere were studied in vacuum packed (VP) and modified atmosphere packed (MAP) cod fillets stored at 0 degree C. Contrary to previous studies, coccobacilli and pleomorphic Gram-negative microorganisms (2-4 by 2-5 microns) and not Shewanella putrefaciens were found most likely to be the main spoilage organisms. These microorganisms, which may be Photobacterium phosphoreum, can explain the short shelf-life extension of VP and MAP fish products compared to meat products. It is suggested that they may inhibit the typical H2S-producing fish spoilage bacteria, S. putrefaciens, as the maximum concentration of H2S-producing bacteria found in MAP fish products is very low. Compared to VP, a shelf-life extension of 6-7 days was obtained with 48% CO2 in MAP. However, with pure CO2 the shelf life was only extended by 2-3 days. Poor texture and high drip loss indicated that the shelf life of these fillets was limited by chemical reactions and not only by microbial activity.

Animals↗
PubMed1993

Valproate and palmitate binding to serum albumin in valproate-treated patients. Relation to obesity.

Binding of valproate and palmitate to serum albumin was studied in 29 valproate-treated epileptic patients. The results were compared with similar observations in a reference group of 43 non valproate-treated individuals. The binding affinity for palmitate was decreased (P < 0.0001) resulting in increased availability of long-chain fatty acids (P = 0.008) due to competitive valproate binding in the valproate-treated patients. The findings support a hypothesis on the pathogenesis of obesity as a complication of valproate treatment of epilepsy.

Adult↗
PubMed1993

Determination of GABA and vigabatrin in human plasma by a rapid and simple HPLC method: correlation between clinical response to vigabatrin and increase in plasma GABA.

The novel antiepileptic drug vigabatrin (Sabril) acts by inhibiting degradation of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA), increasing the GABA concentrations in the brain. Because the GABA degrading enzyme GABA aminotransferase (GABA-T) is also present in peripheral tissues, including blood platelets, measurement of plasma GABA levels might be a useful indication of the pharmacological response to vigabatrin during therapeutic monitoring. However, because of the very low concentrations of GABA in plasma, the few methods available for plasma GABA analysis are time-consuming, difficult to perform and/or not selective enough because of potential interference with other plasma constituents. In the present study, a rapid, selective and sensitive amino acid analysis HPLC method has been developed for plasma GABA determination with fluorescence detection, using o-phthaldialdehyde as a precolumn derivatizing agent. By employing a 3 microns particle size reversed-phase column and a multi-step gradient system of two solvents, the very low endogenous concentration of GABA in human plasma could be reproducibly quantitated without interference of other endogenous compounds. Incubation of human plasma samples with GABA degrading enzyme(s) resulted in an almost total loss of the GABA peak, thus demonstrating the specificity of the method for GABA analysis. In addition to GABA and other endogenous amino acids, the HPLC method could be used to quantitate plasma levels of vigabatrin. Thus, this improved HPLC amino acid assay might be used to examine whether concomitant monitoring of plasma GABA and vigabatrin is useful for clinical purposes. This was examined in 20 epileptic patients undergoing chronic treatment with vigabatrin. The average plasma GABA level of these 20 patients did not differ significantly from non-epileptic controls. However, when epileptic patients were subdivided according to their clinical response to vigabatrin, vigabatrin responders had significantly higher GABA levels than nonresponders or controls. In contrast to the difference in plasma GABA, vigabatrin responders and nonresponders did not differ in dose or plasma level of vigabatrin. These data may indicate that determination of plasma GABA is a valuable non-invasive method for therapeutic monitoring in patients on medication with vigabatrin.

Adult↗
PubMed1993

Production and specificity of poly- and monoclonal antibodies raised against Shewanella putrefaciens.

Polyclonal antibodies were raised in rabbits and mice against Shewanella putrefaciens. Murine monoclonal antibodies were produced against the type strain (ATCC 8071) as well as wild type strains isolated from fish products. The specificities of four polyclonal and 12 monoclonal antibodies were tested by dot-blotting, an indirect and a competitive ELISA against 16 Gram-negative strains; including six strains of S. putrefaciens and one strain of Pseudomonas rubescens (NC 10695). All polyclonal antibodies reacted strongly with S. putrefaciens and with Ps. rubescens and cross-reacted with the nine other bacteria (Pseudomonas spp., Aeromonas spp. and Vibrio anguillarum). The monoclonal antibodies could be divided into three groups with different patterns of specificity. The largest group (8 monoclonal antibodies) reacted strongly with S. putrefaciens and with Ps. rubescens and showed only weak reactions with the other strains. The results confirm that Ps. rubescens should be classified as S. putrefaciens.

Animals↗
PubMed1993

Innovative designs of controlled clinical trials in epilepsy.

Uncontrolled noncomparative clinical observations of investigational antiepileptic drugs (AEDs) often lead to overoptimistic efficacy results and are therefore of very limited value for clinical AED development. The classic add-on trial with placebo as control treatment, in contrast, has provided unequivocal evidence of the efficacy of classic and new AEDs and has also identified less useful AEDs. Drug interactions, carryover effects, difficulty in analyzing individual drug action, and the recognition that monotherapy is by far the more common way of prescribing AEDs have led to the development of classic active control monotherapy trials. A major problem of these trials is a no-difference outcome, which allows no useful interpretation. Recently, two alternative monotherapy designs have been developed to avoid the deadlock of a no-difference outcome. In these designs the active control drug is administered in an attenuated form (low dosage or low concentration) or a placebo control is used when standard treatment is discontinued during presurgical evaluation. Both designs have produced unequivocal evidence of the efficacy of the investigational AED during monotherapy. Ethical concerns are minimized by the introduction of preset escape criteria for patient protection. These designs are valuable new supplements for the clinical development of investigational AEDs for monotherapy in epilepsy. In our opinion, alternative monotherapy designs should be preceded by more than one pivotal add-on, placebo-controlled trial.

Anticonvulsants↗
PubMed1993

Therapeutic experiences with 947 epileptic out-patients in oxcarbazepine treatment.

Efficacy and tolerability of the new antiepileptic drug oxcarbazepine, was evaluated in a retrospective multicentre study. The records of all 947 epilepsy patients treated with oxcarbazepine in the eight participating centres from 1981 through 1990 were examined. The median daily dose of oxcarbazepine was 30 mg/kg in children, 18 mg/kg in adults, and 15 mg/kg in elderly patients, given b.i.d. or t.i.d. The mean plasma levels of the main active metabolite of oxcarbazepine was 88, 79, and 68 mumol/l in children, adults, and elderly, respectively. In patients shifted to oxcarbazepine treatment, seizure frequency was unchanged in 51-66%, 32-48% had a decrease, and 1-10% an increase in seizure frequency, considering the individual seizure types separately. Adverse events were reported in one third of patients, most frequently affecting the CNS (dizziness: 6%; sedation: 6%; fatigue: 6%). Rash was reported in 6% of patients, half of these patients had previously had an allergic reaction to carbamazepine. Hyponatremia was found in about a quarter of the patients from whom data were available. No congenital malformations were seen in nine live-born, first trimester oxcarbazepine-exposed children.

Adolescent↗
PubMed1993

Inhibitory effect against pathogenic and spoilage bacteria of Pseudomonas strains isolated from spoiled and fresh fish.

The antibacterial effects of 209 Pseudomonas strains isolated from spoiled iced fish and newly caught fish were assessed by screening target organisms in agar diffusion assays. One-third (67 strains) inhibited the growth of one or several of six target organisms (Escherichia coli, Shewanella putrefaciens, Aeromonas sobria, Pseudomonas fluorescens, Listeria monocytogenes, and Staphylococcus aureus), of which S. aureus and A. sobria were the most sensitive. The inhibitory action was most pronounced among the strains producing siderophores, and the presence of iron eliminated the antibacterial effect of two-thirds of the inhibitory strains. Siderophore-mediated competition for iron may explain the inhibitory activity of these strains. All but nine of the inhibiting strains were found to inhibit the growth of 38 psychrotrophic S. putrefaciens strains isolated from spoiling fish and fish products. Siderophore-containing Pseudomonas culture supernatants inhibited growth of S. putrefaciens, as did the addition of iron chelators (ethylenediamine dihydroxyphenylacetic acid [EDDHA]). In particular, Pseudomonas strains isolated from newly caught and spoiled Nile perch (Lates niloticus) inhibited S. putrefaciens. This suggests that microbial interaction (e.g., competition or antagonism) may influence the selection of a microflora for some chilled food products.

Animals↗
PubMed1992

Metabolic changes during treatment with valproate in humans: implication for untoward weight gain.

This study was initiated to elucidate the mechanisms behind valproate-induced weight gain. Eight patients with epilepsy were studied with identical examination programs before and during the end of the first month of treatment with sodium valproate (VPA). The measurements included registration of food intake, indirect calorimetry, and determination of pancreatic and thyroid hormones, catecholamines, albumin, electrolytes, glycerol, and free fatty acids. Measurements were performed both at the basal condition and during a 3-hour oral glucose tolerance test (OGTT). After the start of VPA treatment, the mean levels during the OGTT of plasma glucose and catecholamines were significantly decreased by 7% and 25%, respectively (P less than .05). The mean ratio of insulin to glucagon decreased by 37% (P less than .01). During the glucose load, the decreases in free fatty acids were less pronounced after the start of VPA treatment, whereas the mean levels of glycerol were found to be unchanged. We detected no differences between the two periods with regard to total energy intake or macronutrient selection, energy expenditure, or thyroid hormones. As VPA is known to affect the concentration of carnitine in humans, it is hypothesized that a possible VPA-induced deficiency of the beta-oxidation of fatty acids is important for the development of obesity in epileptic patients in long-term treatment with VPA, but changes in catecholamines or other hormones might also be of importance.

Adult↗
PubMed1992

Evaluation of the bacteriological quality of seafood.

Bacteria largely determine the quality of fresh and lightly preserved fish products. This paper surveys traditional and rapid methods for estimation of bacterial levels in seafood. The use of traditional agar techniques is discussed with reference to development of substrates and procedures suited for fish and fish products. This includes estimation of the bacteria specifically involved in the spoilage process. During the last decade, several microbiological rapid methods or principles (DEFT, microcolonies, Limulus lysate, ATP, conductance, microcalorimetry, reduction of trimethylamine oxide (TMAO)) have been suggested for estimating the bacteriological quality of seafoods. A brief survey of these methods and the results obtained is given. Preliminary results on development of poly- and monoclonal antibodies against Shewanella putrefaciens are mentioned. Future research may involve the development of DNA-probes against genes coding for specific spoilage reactions.

Agar↗
PubMed1992

Phenytoin-loading: pharmacokinetic comparison between an intravenous bolus injection and a diluted standard solution.

Phenytoin (PHT) is considered a first or second choice in the treatment of status epilepticus that is refractory to benzodiazepines. The use of an intravenous bolus injection of PHT is hazardous due to the risk of cardiac conduction disturbances, dose-dependent side effects in general, as well as the possibility of severe necrotic lesions in case of extravasation. We compared the number and intensity of side effects and serum level profiles of a highly concentrated, non-dilutable bolus (46 mg/ml) of PHT [Fenytoin, DAK] with a dilutable standard solution (1.5 mg/ml) [Phenhydan] administered intravenously in 500 ml saline. Six healthy volunteers received both regiments (9.1 mg/kg). The diluted solution showed a curvilinear saturation curve with a lower concentration maximum (C-max) than the concentrated solution. Lower toxicity of the diluted solution was indicated by a clinical rating of side effects. Based on a higher incidence and degree of side effects following administration of the more concentrated formulation of PHT, compared with the more diluted preparation, we recommend the use of the less concentrated formulation.

Adult↗
PubMed1992

Pharmacology of vigabatrin.

Vigabatrin (gamma-vinyl GABA) is a relatively new antiepileptic drug. Vigabatrin increases the concentration of gamma-aminobutyric acid (GABA) in the brain by inhibiting the major GABA metabolizing enzyme, GABA transaminase. Controlled clinical trials have demonstrated an excellent antiepileptic effect of vigabatrin, especially in the treatment of partial epilepsies. Long-term evaluations have shown no signs of tolerance development. Vigabatrin decreases the plasma concentration of phenytoin during concomitant therapy, the only drug with which an interaction seems to occur. In general, vigabatrin is well tolerated. Psychotic reactions occur in 3-6% of patients. Other frequent side effects are sedation and weight increase. Chronic vigabatrin intoxication in animals caused development of intramyelinic oedema, appearing as microvacuoles in brain white matter. No microvacuolation has been observed in humans, even after long-term treatment. Vigabatrin seems a very valuable new antiepileptic drug.

4-Aminobutyrate Transaminase↗
PubMed1992

Treatment of pediatric epilepsies with gamma-vinyl GABA (vigabatrin).

Three large studies, all including more than 60 children, on the efficacy on gamma-vinyl GABA (vigabatrin, GVG) in the treatment of childhood epilepsy have been reviewed. On the basis of these and other studies, we conclude that (a) GVG is a promising drug for the treatment of childhood epilepsy, (b) GVG is effective both in partial and generalized epilepsies, (c) GVG seems to be effective in the treatment of symptomatic infantile spasms, (d) no clear dose-response relationship has been demonstrated, (e) a dose of 40-80 mg/kg/day is recommended, and (f) although tolerance is excellent, hyperactivity seems to occur more frequently in children than in adults.

Age Factors↗