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Biomedical subjects

C Nyström

Publications and source records attributed to C Nyström.

At least 37 records · Page 2Linked to original sources
PubMed1988

Relationships between EEG and biochemical parameters in major depressive disorder.

Twenty-five patients with major depressive disorder according to RDC were examined with computerized quantitative EEG before antidepressive treatment. Normal EEGs were found in 20 patients and slight abnormality in five cases. Relationships between various EEG variables and pretreatment accumulation rate of 14C-5-HT and 3H-NA in rat synaptosomes, incubated in patients' plasma, and 5-HT in whole blood were studied. Age and current treatment with benzodiazepines were taken into account. There was an inverse relationship between alpha-1 amplitude in all derivations and beta-2 amplitude in the parieto-occipital derivation on one hand and pretreatment 14C-5-HT synaptosomal accumulation rate on the other. This result indicates that low 14C-5-HT synaptosomal accumulation rate is related to increased EEG alertness. This EEG pattern is suggested to be associated with a serotonergic subgroup of depression. The relationships between the other biochemical variables and the EEG patterns did not show any consistent pattern.

Adult↗
PubMed1987

Comparison between a serotonin and a noradrenaline reuptake blocker in the treatment of depressed outpatients. A cross-over study.

Seventy-five outpatients with major depressive disorder (RDC) were randomly referred to treatment with a dominant serotonin (5-HT) reuptake blocker (zimeldine, 100 mg, b.i.d. n = 40) or a dominant noradrenaline (NA) reuptake blocker (maprotiline, 75 mg, b.i.d. n = 35). Seven patients on each drug were non-responders after up to 4 weeks of treatment and were after a washout week crossed over to the other drug for up to another 8 weeks of treatment. There was a significant and similar improvement after 4 weeks of treatment with the second drug. After up to 8 weeks of treatment all patients but one in each group were much improved with the second drug. The existence of two biochemical subgroups of depression is discussed.

Adult↗
PubMed1986

Relationships between EEG and clinical characteristics in major depressive disorder.

Twenty-five patients with major depressive disorder (MDD) according to RDC were examined with computerized EEG before antidepressive treatment was initiated. Relationships between EEG parameters and clinical characteristics were studied. Age and pharmacological treatment were taken into account. Primary MDD was associated with an increase of delta amplitude. Retarded MDD was associated with an increase of delta and theta amplitudes and EEG variability. Recurrent unipolar MDD was related to a decrease of total alpha symmetry. Thus, subdiagnoses according to RDC were validated. The anxiety subsyndrome and to some extent vital symptoms, depressed mood, and CPRS total sum, were associated with asymmetry of the EEG pattern, whereas retardation was not. The number of former depressive episodes was positively correlated to amplitude of beta activity and negatively correlated to symmetry of EEG in the delta frequency band.

Adult↗
PubMed1986

Comparison between a serotonin and a noradrenaline reuptake blocker in the treatment of depressed outpatients. Biochemical aspects.

Seventy-five outpatients with major depressive disorder (RDC) were randomly referred to treatment with a dominant 5-HT reuptake blocker (zimeldine, 100 mg b.i.d.) or a dominant NA reuptake blocker (maprotiline 75 mg b.i.d.). Pretreatment biochemical, pharmacodynamic and pharmacokinetic variables were studied and related to the treatment outcome with the two drugs. Female responders to the dominant 5-HT reuptake blocker were characterized by low pretreatment accumulation of 14C-5-HT in rat synaptosomes, when incubated in patient plasma. Among zimeldine responders there was a relationship between antidepressive effect and steady-state concentrations of zimeldine and norzimeldine. These findings support the hypothesis of a subgroup of depression characterized by serotonin disturbance.

Animals↗
PubMed1986

The use of ordered mixtures for improving the dissolution rate of low solubility compounds.

The dissolution rate of micronized griseofulvin has been investigated, both for the agglomerated raw material and the material formulated as an ordered mixture, by means of the USP XX paddle method. During the experiments, which were performed at sink condition and constant temperature, the effects of adding a surfactant and of agitation were tested. The ordered mixture with sodium chloride gave a fast dissolution rate, practically independent of the test parameters. Micronized griseofulvin alone gave dissolution profiles that were improved by adding polysorbate 80 and by increased agitation, but the dissolution rates obtained were much lower than those for the ordered mixture. It was concluded that the rate limiting step in the dissolution of griseofulvin as the raw material is the penetration of the dissolution medium into the agglomerates. With an ordered mixture, these agglomerates were deaggregated during the mixing process, producing a system in which the entire external surface area of the primary particles was exposed to the dissolution medium. This conclusion was supported by calculation of the contact surface areas taking part in the dissolution process for the systems tested. The procedure developed in this study could be applied to preformulation work where a cohesive, low solubility drug of hydrophobic nature is to be formulated.

Griseofulvin↗
PubMed1986

Coulter Counter measurements of solubility and dissolution rate of sparingly soluble compounds using micellar solutions.

A Coulter Counter, Model TAII, was used to determine both solubility and surface specific dissolution rate of two sparingly soluble materials suspended in micellar solutions. The equilibrium solubility increased linearly with surfactant concentration, thereby making it possible by extrapolation to characterize materials with an aqueous solubility down to 1 ppm or less. At high concentrations (greater than 0.1% w/v) the effect of surfactant concentration on the surface specific dissolution rate was less than that predicted from the increased bulk solubility.

Felodipine↗
PubMed1985

Double-blind comparison between a serotonin and a noradrenaline reuptake blocker in the treatment of depressed outpatients. Clinical aspects.

Seventy-five outpatients with major depressive disorder (RDC) were randomly referred to treatment with a dominant serotonin (5-HT) uptake inhibiting drug (zimeldine, 100 mg b.i.d.) or a dominant noradrenaline (NA) uptake inhibiting drug, (maprotiline, 75 mg b.i.d.). The total antidepressive effect was similar in the two groups for up to 4 weeks of treatment. Both drugs gave an effect on the depressive syndrome as a whole, with no preference for mood, anxiety, retardation or vital symptoms. Good response to the NA drug correlated to few prior episodes and few years since first episode, whereas the 5-HT drug had its best effect when there were several previous episodes.

Adult↗
PubMed1985

Dissolution rate measurements of sparingly soluble compounds with the Coulter Counter model TAII.

A Coulter Counter, Model TAII was used to determine both solubility and dissolution rate from suspensions of griseofulvin and hydrocortisone acetate, where the initial particle size and shape had been characterized. The method assesses the weights and surface areas of particles remaining undissolved as a function of time. A comparison with a conventional method, assessing dissolved quantities of materials, showed that solubility data of the same order of magnitude can be obtained. The TAII data fitted a previously established equation that linearly relates log solubility and log of the intrinsic dissolution rate and indicated that the dissolution process was not diffusion controlled. The TAII method described is a rapid and convenient means of estimating the solubility and dissolution rate where no adequate technique for analysing the dissolved fraction exists.

Chromatography, High Pressure Liquid↗
PubMed1983

The safety of zimeldine in long-term use in depressive illness.

The aim of this study was to evaluate the safety of zimeldine, a 5-HT reuptake inhibitor, in the long-term treatment of depressive disorders. The study was an open label, multicentre investigation involving 147 patients who were suffering from depressive illness and who needed long-term anti-depressant treatment. Sixty-five patients completed the intended treatment period of 1 year, 75 terminated prematurely, and 7 are still in the programme. The reasons for termination were mainly ineffectiveness of the drug and adverse reactions. During the long-term treatment the most common emergent symptoms were, in order of decreasing frequency, dizziness, dry mouth, sleep disorders, sweating, tremor, nausea and headache. The side-effects were, however, mild and they generally decreased during the treatment period. No new adverse symptoms were reported. In the long-term treatment group, body weight showed a slight mean decrease. Clinical chemistry and cardiovascular investigations were judged to show no changes of clinical importance. It is concluded that zimeldine was shown to be a safe drug in this 1-year treatment programme of depression.

Adolescent↗
PubMed1981

Zimelidine vs maprotiline in depressed outpatients. A preliminary report.

Outpatients with endogenous depression diagnosed according to the research diagnostic criteria of Feighner et al. were randomly referred to treatment with zimelidine (100 mg b.i.d., group Z) or maprotiline (75 mg b.i.d., group M). Patients who did not respond to treatment by days 28 were crossed over to the other drug. This preliminary report comprises results up to day 28 and includes antidepressive effect as rated by CPRS and globally, side effects, clinical chemistry and ECG. Ratings were double-blind at days 0, 7, 14 and 28, and a washout period of 4--7 days preceeded the trial. Group Z includes 27 and group M 28 patients with equal distribution of sex, age, duration of present episode, initial severity, etiology and previous course. There were 11 dropouts in group M and 5 in group Z due to side effects or treatment failure. On the other hand, 8 patients in group Z had to cross over to the other drug versus 2 in group M. According to the total CPRS score and the global score the antidepressive effect was somewhat better in group Z at 2 weeks but similar at 1 and 4 weeks. Group Z is less sedative but still seems to have a better anti-anxiety effect. Side effects were on a low level. There was a greater number of patients in group Z who complained of nausea, vomiting, loose stools, sleep disorder and sweating, and in group M dry mouth, drowsiness, dizziness and accomodation difficulties. Chemical analyses and ECG showed slight and inconsistent changes.

Adult↗