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Biomedical subjects

P Lindberg

Publications and source records attributed to P Lindberg.

At least 55 records · Page 3Linked to original sources
PubMed1988

N,N-Dialkylated monophenolic trans-2-phenylcyclopropylamines: novel central 5-hydroxytryptamine receptor agonists.

N,N-Dialkylated monophenolic derivatives of trans-2-phenylcyclopropylamine were synthesized and tested for central 5-hydroxytryptamine (5-HT) and dopamine (DA) receptor stimulating activity by use of a biochemical test method in rats. A hydroxy substituent in the 2- or 3-position of the phenyl ring was required for 5-HT-receptor stimulation. N,N-Diethyl or N,N-di-n-propyl substitution gave the most potent 5-HT-receptor agonists. The 4-hydroxy and 3,4-dihydroxy derivatives of trans-2-phenyl-N,N-di-n-propylcyclopropylamine were inactive at central DA and 5-HT receptors. In contrast, the corresponding 3-hydroxy derivative 18 and some of its derivatives weakly affected both DA and NE synthesis. Two of the most potent 5-HT-receptor agonists, trans-2-(2-hydroxyphenyl)-N,N-di-n-propylcyclopropylamine (8) and the 3-hydroxy isomer 18 were resolved into the enantiomers. The 1R,2S enantiomers of 8 and 18 displayed 5-HT activity, while the 1S,2R enantiomers were inactive. Compound (1R,2S)-18, but not (1R,2S)-8, weakly affected rat brain DA and NE synthesis.

Alkylation↗
PubMed1988

Behavioural therapy in the clinical management of tinnitus.

Behavioural therapy was given to reduce discomfort and annoyance associated with severe tinnitus in 75 consecutive patients. Treatment was conducted within the routine clinical management. It included information and discussion about tinnitus, behavioural analysis and relaxation training combined with various cognitive strategies. The method of treatment was thus a form of coping technique. Self-recordings showed significant reductions of 'discomfort from tinnitus' as well as significant elevations in 'general mood' over a 3-month follow-up period. Interview findings indicated strong overall positive effects of treatment, as well as other positive side-effects on complaints such as tension headaches, dizziness, muscle tension and sleep disturbances. Implications for the clinical management of tinnitus sufferers are discussed.

Adult↗
PubMed1987

Carbamate ester derivatives as potential prodrugs of the presynaptic dopamine autoreceptor agonist (-)-3-(3-hydroxyphenyl)-N-propylpiperidine.

Twenty derivatives bearing substituents on the phenolic function of (-)-3-(3-hydroxyphenyl)-N-propylpiperidine [(-)-3-PPP] were synthesized and tested as prodrugs. The carbamate ester derivatives were found to be the most suitable prodrugs, and especially the 4-isopropylphenylcarbamate 20 was capable of escaping the first-pass metabolism and still generating high plasma levels of the parent compound. Four hours after an oral dose of 100 mumol/kg to rats, a plasma level of 2400 nmol/L of (-)-3-PPP was detected by an HPLC method. This was 90 times the level reached after 4 h (27 nmol/L) when (-)-3-PPP itself was given orally at the same dose.

Animals↗
PubMed1987

Long-term effects of psychological treatment of tinnitus.

Twenty patients with severe tinnitus who had undergone behavioural treatment, including applied relaxation and perceptual restructuring, were re-assessed 9 months after completion of treatment. Among the self-recorded variables, tinnitus loudness, discomfort from tinnitus, depression, and irritation, discomfort from tinnitus was the only variable which was still significantly reduced. As part of the 9-month follow-up assessment, the patients' recall of the loudness and discomfort from their tinnitus was studied. Correlations between original recordings and recall data were low.

Behavior Therapy↗
PubMed1987

Hearing aids and tinnitus--an experimental group study.

From a waiting list consisting of hearing-impaired patients waiting for hearing aids to be fitted, 39 subjects who at interview also stated that they had tinnitus took part in an experimental group study with the aim of investigating the effect of a hearing aid on tinnitus. No subject had any previous experience of hearing aids. The subjects were randomly allocated to a treatment and a waiting list control group. After an initial interview, the routine programme for the fitting of hearing aids started in the treatment group, while the waiting list control group had to wait for 6 weeks before starting the same hearing aid rehabilitation programme. The hearing aids were fitted exclusively for hearing purposes. As expected, the hearing aids improved the hearing capacity, but they did not reduce tinnitus as recorded on a visual analogue scale. According to information obtained at the final interview, there were significant differences in tinnitus between subjects who used their aid for more than 2 hours daily and those who used it for less than 2 hours. However, the results of scaling (pre- and post-fitting) did not support this finding. The discrepancy between the scaling and interview data is probably due to demand characteristics.

Aged↗
PubMed1987

Effect of Se status on some haematological parameters in neonatal piglets.

Blood samples were taken from 74 1-3 day old piglets, the offspring of sows maintained during pregnancy on a commercial ration with 0.1 ppm of added Se as sodium selenite. At the time of blood sampling, all piglets were treated subcutaneously with 200 mg Fe+3 from iron dextran. Additional blood samples were taken 14 days after the iron treatment. Piglets with 14 day whole blood Se concentrations greater than 74.0 micrograms/l (n = 43) had significantly higher mean numbers of red blood cells than those with whole blood Se less than or equal to 74.0 micrograms/l (p = 0.016). The mean increase in erythrocyte numbers during the 14 day period was significantly higher in the higher than in the lower Se group (p = 0.007) as also in the piglets with plasma GSH-Px activity greater than 799 U/l at 1-3 days of age when compared to the piglets with the GSH-Px activity less than or equal to 799 U/l (p = 0.017).

Animals↗
PubMed1986

Treatment of tinnitus by external electrical stimulation.

Transcutaneous electrical stimulation was used in 5 consecutive patients suffering from troublesome tinnitus. The study included three parts. Part one constituted an open trial using the stimulation equipment. During this part, 2 patients reported a reduced subjective tinnitus loudness. These 2 patients proceeded to part two where the effect from the stimulation equipment was compared with the effect from a placebo apparatus in an experimental double-blind trial. One of these 2 patients reported similar effects from active stimulation and placebo, while the other patient reported a constant positive effect from the active stimulation and no effect at all from placebo. The latter patient continued to part three where the effect of the equipment was studied over a 3-month period. Throughout the study, continuous self-recordings of the complaints was used. The results show that the electrical stimulation had a genuine tinnitus-reducing effect in one patient, remaining over a 3-month period, a positive placebo effect in one patient, but no effect in 3 patients. To determine the applicability of this method in the clinical population, carefully designed outcome studies, with appropriate control conditions, are required.

Adult↗
PubMed1985

Resolved monophenolic 2-aminotetralins and 1,2,3,4,4a,5,6,10b-octahydrobenzo[f]quinolines: structural and stereochemical considerations for centrally acting pre- and postsynaptic dopamine-receptor agonists.

A detailed structure-activity relationship is revealed for resolved, centrally acting dopamine (DA) agonists acting on both pre- and postsynaptic DA receptors. The compounds resolved are 5- and 7-hydroxy-2-(di-n-propylamino)tetralin and cis- and trans-7-hydroxy-4-n-propyl-1,2,3,4,4a,5,6,10b-octahydrobenzo [f]quinoline. By the superimposition of the structures of the more active enantiomers of these compounds with those of known dopaminergic agonists, apomorphine and ergolines, a new DA-receptor model is proposed as an outgrowth of current DA-receptor theories. One of the most important concepts of this receptor model is its emphasis on the possible positions taken by the N-substituents of dopaminergic compounds. One of these positions i sterically well defined while the other direction is sterically less critical. The model has been used to explain the lack of dopaminergic activity of some previously reported structures and also to predict properties of novel structures, including inherent chirality, which should be active at DA receptors. Hopefully, this heuristic DA-receptor model will lead to the discovery of more selective and potent pharmacological tools, which ultimately might lead to the development of therapeutic agents for treating diseases of dopaminergic function in the central nervous system.

Animals↗
PubMed1985

Structure activity relationships of substituted benzimidazoles.

The omeprazole molecule consists of three parts, a substituted pyridine ring, a substituted benzimidazole ring and CH2SO chain connecting the 2-positions of these ring systems. All three are essential for the antisecretory effect. In order to maintain a good effect the pyridine ring has to be substituted by alkyl or alkoxy groups, but not in the 6-position. The substituents in the benzimidazole ring are not that important, but substituents with strongly electron withdrawing groups such as NO2 or highly hydrophilic groups such as NHCOCH3 tend to give compounds with low antisecretory effects.

Animals↗
PubMed1985

Psychological treatment of tinnitus. An experimental group study.

Twenty-four patients with moderately severe (grade 2) to severe (grade 3) subjective tinnitus participated in an experimental group study. The patients were randomly assigned to a treatment group and a waiting-list control group. Treatment was given with a coping technique and comprised 10 one-hour sessions. Following a corresponding period without treatment, the control group was treated similarly. Daily self-recording of the subjective tinnitus loudness, the discomfort from the tinnitus, depression and irritation was performed before and after treatment. In addition, psychoacoustic measurement was undertaken on three occasions. The treatment group improved significantly more than the waiting-list control group. After treatment of the latter group, combined data of both groups showed statistically significant improvements in all variables. The results show that tinnitus annoyance can be treated by psychological methods.

Adult↗