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Biomedical subjects

M Larsson

Publications and source records attributed to M Larsson.

At least 199 records · Page 11Linked to original sources
PubMed1983

A high-performance liquid chromatographic method for the assay of perphenazine and its dealkylated metabolite in serum after therapeutic doses.

A new high-performance liquid chromatographic method for the assay of perphenazine and its dealkylated metabolite is presented. The procedure is based on the use of thiethylperazine maleate as internal standard. Concentrations of perphenazine and its dealkylated metabolite could be analysed simultaneously in serum from patients being treated with the drug. The intraassay variability was 6.5% and 8.5% and the interassay variability 8.9% and 11.1% for drug and metabolite, respectively.

Chromatography, Gas↗
PubMed1983

Effects of isotonic fluid load on plasma water and extracellular fluid volumes in the rat.

An isotonic fluid load was given to rats by infusing 12 ml saline i.v. in 60 min. The plasma water and extracellular fluid volumes of the whole animal and selected tissues were subsequently studied with 125I human serum albumin and 51Cr EDTA. The fluid infused was equivalent to 130% of the plasma water volume. The total extracellular fluid volume increased by 17%, while the total plasma water measured with RIHSA remained unchanged. The regional extracellular fluid volumes increased in the lung (14%), the gastric fundus (15%), large intestine (21%) and skin (28%). The results illustrate the selective distribution of an isotonic fluid overload, those tissues being effected having high compliances.

Animals↗
PubMed1983

The A-rod--a new possibility for cervical dilation and/or induction of uterine contractions for abortion or delivery by combined pharmacological and mechanical action.

A hydrogel compound (Sauflex, Special Polymers Ltd., London) which has the capacity to swell by absorbing surrounding fluid, was found to be capable of absorbing prostaglandins (PGE1, PGF2 alpha) in alcohol or saline during this process. After evaporation of the hydratized hydrogelic compound which restored its initial proportions and stiffness, rehydratization of the hydrogelic compound caused it to release the respective prostaglandin to the surrounding medium or tissues. The endocervical canal of first-trimester abortions was dilated by plain mechanical action of a rod-shaped hydrogel body (A-rod) inserted in the cervical canal. By loading the A-rod with PGF2 alpha (2-110 mg) the cervical canal was additionally widened and abortive contractions were elicited in the uterus. Further implications of the medical use of the A-rod are discussed.

Abortion, Induced↗
PubMed1982

Regulation by amino acids of photorespiratory ammonia and glycolate release from ankistrodesmus in the presence of methionine sulfoximine.

Methionine sulfoximine induced release of ammonia from illuminated cells of Ankistrodesmus braunii (Naegeli) Brunnth, in normal air, but less in air enriched to 3% CO(2). In normal air, methionine sulfoximine also induced glycolate release. Addition of either glutamate, glycine, or serine suppressed glycolate release, whereas glutamate and glycine at the same time stimulated ammonia release. The results indicate that inhibition of glutamine synthetase and thereby inhibition of photorespiratory nitrogen cycling restricts the sink capacity for glycolate in the photorespiratory carbon cycle. An external supply of glutamate, glycine, or serine seems to stimulate glyoxylate transamination and thus partly restores the sink capacity. Calculations of total glycolate formation rates in air from glycolate and ammonia release rates in the presence of methionine sulfoximine and glutamate revealed values of approximately 20 micromoles glycolate per milligram chlorophyll per hour on the average. Similar calculations led to an estimated rate of photorespiratory ammonia release in air, in the absence of methionine sulfoximine, of about 10 micromoles per milligram chlorophyll per hour on the average, a value comparable to the primary nitrogen assimilation rate of 8 micromoles per milligram chlorophyll per hour.

Journal Article↗
PubMed1981

On the distribution and elimination of haloperidol in cholecystectomized patients.

A single oral dose of haloperidol was given to 19 patients prior to cholecystectomy. The concentration of haloperidol was assessed in serum, urine, fatty tissue, liver tissue, choledochal bile and bile bladder contents. The biological half-life of the drug in the serum was 25.1 +/- 12.9 hours, which is comparable to that in healthy volunteers. Only minute amounts of the drug were excreted with the urine. The drug concentration was only slightly elevated in choledochal bile but in the bile bladder contents it was about 11 times higher than that in the serum. The low concentration of haloperidol in the bile indicated that there was no substantial enterohepatic recirculation of the drug in this patient material. The concentration of haloperidol in fatty tissue was about 20 times, and in liver tissue 900 times higher than that in the serum. The corresponding figures for intramuscular administration of haloperidol were 10 and 325, respectively. A possible relationship between the side-effects and the route of administration is discussed.

Adipose Tissue↗
PubMed1981

Posthemorrhagic changes in plasma water and extracellular fluid volumes in the rat.

Anesthetized rats were submitted to a standardized hemorrhage to 40 mm Hg by withdrawing 35 to 40% of the total blood volume. The plasma water and the extracellular fluid volumes of the whole animal and selected tissues were estimated with 125 I human serum albumin and 51Cr EDTA, respectively, after recovery periods of 10 and 90 minutes. The plasma water volume of the whole animal decreased, but approximately 50% of the shed plasma water was restored within 10 minutes after the hemorrhage. The extracellular fluid volume of the whole animal did not change significantly after hemorrhage, whereas this fluid compartment was regionally reduced in the liver, spleen, and subcutaneous fat after a 10-min recovery period but only in the liver after a 90-min recovery period.

Animals↗
PubMed1981

Effects of intestinal obstruction of plasma water and extracellular fluid volumes in the rat.

Total and regional plasma water and extracellular fluid volumes were measured in rats after obstruction of the small intestine. The rats lost 12.6 per cent of their initial weight. The volume of the sequestrated fluid in the obstructed intestine corresponded to 91 per cent of the plasma water volume. Intestinal obstruction caused a 19 per cent reduction of the total plasma water volume, while the total extracellular fluid volume was unchanged. Regional extracellular fluid volumes were diminished in the lung, liver and gastric antrum and increased in omental fat. The results indicate regional differences in fluid space responses to obstruction of the small intestine.

Animals↗
PubMed1980

Plasma water and 51Cr EDTA equilibration volumes of different tissues in the rat.

The EDTA space and the plasma water volume of the whole animal and selected tissues were investigated with constant EDTA infusions of different duration in the rat. The calculated EDTA space increased with the duration of the infusion both in the whole animal and the tissues sampled. The plasma water volume remained constant, and therefore the calculated increase of the EDTA space suggests a slow intracellular accumulation of the tracer. As intracellular accumulation of EDTA increases with experimental time, it is necessary to use as short an experimental interval as possible to reduce this error when determining extracellular fluid volumes.

Animals↗
PubMed1980

Effects of dehydration on plasma water and extracellular fluid volumes in the rat.

Dehydration was induced in rats by depositing 3 ml of hyperosmolar glucose (1670 mOsm/kg) in a closed small bowel loop. The plasma water and extracellular fluid volumes of the whole animal and selected tissues were subsequently studied with 125I human serum albumin and 51Cr EDTA. The fluid accumulation in the bowel was equivalent to 122% of the plasma water volume. The plasma water volume of the whole animal was significantly reduced by 31%, while the extracellular fluid volume reduction by 8% was not statistically significant. The regional extracellular fluid volumes decreased in the lung (9%), the liver (34%), the gastric antrum (15%) and the omental fat (24%). The results show regional differences in tissue response to dehydration.

Animals↗
PubMed1979

Determination of bromocriptine in plasma: comparison of gas chromatography, mass fragmentography and liquid chromatography.

Gas chromatographic, mass fragmentographic and liquid chromatographic techniques for the determinations of bromocriptine (2-bromo-alpha-ergocriptine; Parlodel) in human plasma are described. These methods were found to be suitable for determining concentrations of bromocriptine down to 0.5, 1.0 and 10.0 microgram/l, respectively. Accuracy, specificity and analytical capacity were satisfactory for all three methods. Gas chromatography was compared with liquid chromatography, and the two methods were demonstrated to give identical results in patients treated with bromocriptine for Parkinson's disease. Gas chromatography was also compared with mass fragmentography, and the results from these two assays were also in agreement.

Bromocriptine↗
PubMed1977

Neurometabolic and behavioural effects of haloperidol in relation to drug levels in serum and brain.

A method has been developed for the quantitative determination of haloperidol in brain and other tissues. Such determinations have been made after acute and chronic administration of haloperidol to Sprague-Dawley rats. Different regions of the brain including the striatum, the limbic forebrain and the cerebellum have been analyzed separately. The haloperidol effects on Dopa formation have been studied in the same tissue samples. The stimulation of prolactin secretion via blockade of hypothalamic dopaminergic mechanisms and behavioural effects of the drug have been evaluated in parallel experiments. The elimination of haloperidol from brain tissue is a multiphasic process. The fourth phase of elimination is the slowest with a half life of 4 days. No strict correlation was found between serum and brain concentrations of haloperidol. Both after acute and chronic administration there exists apparently a saturating dose above which the brain concentration of the drug increases very little. The dose seems to coincide with that beyond which little increase in Dopa formation is observed. A pharmacokinetic analysis suggests an element of saturable binding or transfer of haloperidol to brain tissue. This mechanism is not preferentially localized to areas of brain rich in dopaminergic synapses. A good correlation was found between the haloperidol concentration in the brain on the one hand and its effects on behaviour, on serum prolactin values and on Dopa formation on the other.

Animals↗