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Biomedical subjects

I Larsson

Publications and source records attributed to I Larsson.

At least 55 records · Page 3Linked to original sources
PubMed1984

Interference of endogenous lactoperoxidase antibodies in a solid-phase immunosorbent radioassay for antibodies to protein hormones.

Interference of endogenous antibodies to lactoperoxidase (EC 1.11.1.7) has been demonstrated in a solid-phase immunosorbent radioassay for the detection of antibodies to protein hormones. On enzymic iodination with lactoperoxidase, a little of the 125I is incorporated in the enzyme itself by self-iodination. Because the 125I-labeled lactoperoxidase was not removed from the tracer by chromatography on Sephadex G-50, G-100, and G-200 columns, endogenous antibodies to the enzyme, which were present in 25 of 28 sera from apparently healthy individuals, were detected in conjunction with the measurement of antibodies to growth hormone (somatotropin), prolactin, and thyroglobulin, thus causing false-positive results. Contaminating radioactive lactoperoxidase can be removed by adsorption chromatography on cellulose or by liquid chromatography, and can be avoided by performing the iodination with immobilized lactoperoxidase or with Chloramine-T.

Animals↗
PubMed1983

Diagnosis of deep venous thrombosis by 99mTc-human serum albumin microcolloid.

99mTc-human serum albumin microcolloid (HSAC) was evaluated for diagnosis of deep venous thrombosis (DVT) in the legs of 38 consecutive patients. Five and thirty minutes after IV injection, the 99mTc-HSAC activity in both legs was measured by external counting using a collimated NaI (T1)-detector. The relative predominance of 99mTc-HSAC activity in the diseased leg was calculated. Phlebography was performed as a control after the 99mTc-HSAC test. In our hands the non-invasive 99mTc-HSAC test appeared to be rapid, easy to perform and convenient to the patient. The test showed a high sensitivity (11/13) and a low specificity (10/20) compared with phlebography. No adverse reactions were found. The results seem promising and further studies are in progress to establish the value of the 99mTc-HSAC test in screening for DVT.

Adult↗
PubMed1983

Radioimmunoassay of delta sleep-inducing peptide using an iodinated p-hydroxyphenylpropionic acid derivative as tracer.

A highly sensitive radioimmunoassay for delta sleep-inducing peptide (DSIP) has been developed. A p-hydroxyphenylpropionic acid conjugate of DSIP was used for radioiodination. Using reversed-phase high performance liquid chromatography the labelled DSIP derivative was isolated in a high yield and with a high specific activity. The assay allows measurement of DSIP-like material in body fluids with a minimum detectable concentration of 0.1 ng/ml standard DSIP (10 pg/tube).

Delta Sleep-Inducing Peptide↗
PubMed1983

Tri-iodothyronine and thyroxine in human milk.

The concentration of tri-iodothyronine (T3) and thyroxine (T4) in human milk was determined by radioimmunoassay (RIA). The analysis of T3 was performed on unextracted milk and on ethanol extracts of defatted milk. Analysis of unextracted milk was complicated by artifacts. Reliable and reproducible results were achieved only with the milk extracts. In 10 colostral milk samples the mean T3 levels +/- SD were 0.80 +/- 0.52 nmol/l before feeding (early milk) and 0.93 +/- 0.62 after feeding (hind milk). The T3 concentration in colostrum did not change significantly during the feeding to the infant. In 12 mature milk samples collected between infant feedings, the mean T3 +/- SD was 1.19 +/- 0.42 nmol/l. T4 was not detected in any of the samples analysed (detection limit 3 nmol/l).

Colostrum↗
PubMed1983

Methods of reducing the effect of spontaneous dissociation of antigen-antibody interactions in radioimmunoassays with special reference to internal sample attenuator counting (ISAC).

A time dependent decrease of sample counts was observed in an adsorption radioimmunoassay with internal sample attenuator counting. The drift caused a bias in the estimate of the amount of antigen in the samples. The size of this deviation was dependent upon the length of time after the calibration curve was made that the samples were measured. This was essentially due to dissociation of the antigen-antibody complexes as the adsorber can act as a second receptor to the antigen. Addition of slowly sedimenting starch microspheres or starch particles inhibited the drift by forming a diffusion barrier on the attenuating pellet.

Adsorption↗
PubMed1982

Radioimmunoassay of pro-gamma-melanotropin, the amino-terminal fragment of proopiolipomelanocortin.

A RIA has been developed for natural porcine pro-gamma MSH, the 103-amino acid peptide that represents the amino-terminal part of proopiolipomelanocortin. Rabbits were immunized with the purified peptide polymerized with glutaraldehyde. The antiserum is directed against the amino-terminal end of the antigen and does not cross-react with corticotropin, beta-lipotropin, beta-endorphin, gamma 3MSH, or gamma 2MSH. The minimum detectable concentration is 0.15 ng/ml standard pro-gamma MSH (15 pg/tube). Pro-gamma MSH-like immunoreactivity was detected in plasma and extracts of the hypothalamus and pituitary of pigs. Gel chromatography of these extracts revealed at least three immunoreactive peaks in the anterior and neurointermediate lobes of the pituitary, whereas two immunoreactive peaks were found in extracts of the hypothalamus.

Amino Acid Sequence↗
PubMed1981

Scintigraphic evaluation and dynamic studies with thallium-201 in thyroid lesions with suspected cancer.

Scintigraphic studies of the thyroid with thallium-201 chloride were performed in 46 patients in whom the final diagnosis was established by histology. In dynamic studies of 36 patients, sequential imaging was performed the first 40 min after injection. A single exponential, Cexp(-lambda t), was fitted to each of the curves generated from apparently pathological and from normal regions in each patient, as determined by earlier conventional scintigrams. To minimize the effects of normal individual variations, the relation between pathological (p) and normal (n) regions in the same patient was emphasized and quantified by two parameters, namely the extrapolated zero-time intercept (Cp/Cn) and the time development (lambda p-lambda n) of the ratio of counting rates/unit area in the two regions. The turnover appears to be somewhat slower for pathological tissue than for normal tissue. Although this difference was significant on the 5% level for both cancer and adenoma as a group, only the relative disappearance rate (lambda p-lambda n) resolved cancer frm adenoma and from goiter on the same level. All but one of the differentiated cancers had an increased uptake.

Adenocarcinoma↗
PubMed1981

On the presence of serotonin in the gut lumen and possible release mechanisms.

The possible presence of a luminal release of serotonin (5-HT) from gut enterochromaffin cells (EC) of the rat, was studied after the injection of the tritiated 5-HT precursor 5-hydroxytryptophan (3H]-5-HTP by electron microscopic autoradiography. The uptake of 5-HTP into gut epithelial cells was also studied by fluorescence histochemistry according to the Hillarp-Falck technique at the same post-injection interval as in the autoradiography experiments. 3 h after the injections of 5-HTP (100 mg/kg i.v.) the fluorescence intensity of EC was increased and numerous, probably enteroendocrine, cells had an increased yellow tryptamine induced fluorescence due to an uptake of 5-HTP and probably decarboxylation to 5-HT. However, the labelled precursor [3H]-5-HTP was taken up not only into granules of enteroendocrine cells but also incorporated into the cytoplasm and nucleus of nonendocrine cells when studied by autoradiography. After 10 min of efferent electrical stimulation of the vagal nerve much of the label was found in the gut lumen suggesting a release of the amine. The hypothesis of a luminal release of 5-HT was further corroborated in starved cats, where considerable amounts of 5-HT were detected by fluorimetric assays in the lumen of isolated jejunal loops under resting conditions. The experiments demonstrate that :(i) 5-HTP is taken up not only into typical EC but also into other enteroendocrine cells, and most probably decarboxylated to 5-HT. (ii) Also intestinocytes take up [3H]-5-HTP and incorporate the amino acid into peptides to a certain extent. (iii) Following vagal nerve stimulation labelled material, probably 5-HT, is secreted into the gut lumen. (iv) 5-HT normally occurs in the gut lumen.

5-Hydroxytryptophan↗
PubMed1981

Scintillation camera renography with 99mTc-DTPA and 131I-Hippuran.

Two different indicators for scintillation camera renography, 99mTc-DTPA and 131I-Hippuran, were compared directly in 37 patients. Quantitative data were obtained by means of a small digital computer. 99mTc-DTPA gave better kidney image quality, but also higher background than 131I-Hippuran. The two indicators gave renographic curves of slightly different shape, those after DPTA being flatter, but estimations of separate kidney function were not significantly different. Early kidney uptake of indicators was roughly proportional to glomerular filtration rate, but with a wide scatter.

Adolescent↗
PubMed1980

The effects of adrenergic antagonists on the serotonin levels of feline enterochromaffin cells after splanchnic nerve stimulation.

Cut splanchnic nerves were stimulated electrically at the preganglionic level in efferent direction in anesthetized cats with the adrenals ligated bilaterally. A significant decrease of the intracellular serotonin (5-HT) levels in populations (n = 20) of individual enterochromaffin cells (EC) in the mucosa from three different levels of the small intestine (distal duodenum, mid-jejunum and terminal ileum) was obtained. The intracellular 5-HT levels before and after stimulation were studied cytofluorimetrically in biopsies treated according to the Falck-Hillarp technique. One group of cats was pretreated with propranolol prior to stimulation. This prevented the decrease in fluorescence intensity effectively. Two other groups of cats were pretreated with phenoxybenzamine or phentolamine. These drugs also blocked the expected decrease in fluorescence intensity in 7 of 8 cats. In some biopsies there was an increased fluorescence intensity after nerve stimulation in cats given propranolol or phentolamine even though the drugs themselves had no intrinsic effects on the fluorescence intensity in control animals. It is concluded that efferent electrical stimulation of the splanchnic nerves can cause a release of 5-HT from gut EC by an adrenergic mechanism.

Animals↗
PubMed1980

Management of massive gastroduodenal haemorrhage.

A special program for management of massive gastrointestinal bleeding was 1976 introduced in the surgical service of Sahlgren's Hospital in Göteborg. The main points in this program were: careful observation in an intensive care unit, standardized treatment, early diagnostic gastroduodenoscopy, strict indications for emergency operation and recommendation of type operation. This paper deals with 55 patients subjected to emergency operations in 1976 with the diagnosis erosive gastritis, gastric ulcer or duodenal ulcer. The results are compared to an earlier study in 1962-71 in the same hospital. It was found that the mortality was unchanged during the two periods, 25% during 1962-71 and 24% during 1976. At a first glance the new program might seem ineffective. However, the part of elderly patients was much higher during 1976 than during 1962-71. Thus, the patients during 1976 must be considered much more of a surgical challenge. As old patients often have coexisting severe diseases they are surgically most unfit. Probably a more conservative attitude is justified in this particular group of patients.

Adult↗
PubMed1979

The effects of splanchnic nerve stimulation on the plasma levels of serotonin and substance P in the portal vein of the cat.

The blood levels of serotonin (5-HT) and substance P (SP) in the portal vein were studied after splanchnic nerve stimulation in the cat. The portal levels of both substances were studied before, during and after splanchnic nerve stimulation. There was a twofold increase in 5-HT during stimulation whilst the SP concentration remained unchanged. These results suggest that the nervous control of the amine release into the portal stream and the mechanism that regulates the release of the polypeptide is not the same.

Animals↗
PubMed1979

Effects of leukocyte and fibroblast interferon on events in the fibroblast cell cycle.

Serum-depleted human foetal skin fibroblasts were stimulated by addition of 10% foetal calf serum to proliferate synchronously for at least one cell cycle. This proliferation was suppressed by leukocyte or fibroblast interferon (IF), which prolonged the G1 phase and diminished the rate of DNA synthesis during the S phase in a dose-dependent manner. When used in identical concentration, as judged in terms of units of antiviral activity, fibroblast IF had more pronounced effects on cell cycle events than leukocyte IF. Interferon exerted its effect in early G1, before the cells were irreversibly committed to DNA synthesis.

Cell Cycle↗
PubMed1979

Turnover of human lactoferrin in the rabbit.

Lactoferrin turnover was studied in the rabbit with 125I- and 131I-labelled human lactoferrin. Plasma lactoferrin activity showed a rapid decrease during the first 24 h, followed by a 'final slope' with a T1/2 of about 25 h. Turnover studies after transfer of plasma from one rabbit (A) 3 h after injection to another rabbit (B), showed a recovery of 100% compared to 30% in A rabbits but otherwise a similar disappearance curve. The rapid turnover was confirmed in whole body studies. Concomitantly with the initial dissapearance from the plasma, there was a marked accumulation of proteinbound activity only in the liver in both A and B rabbits. From these results, the rate of synthesis in normal man can be estimated at around 25 mg per d. The disappearance pattern and hepatic uptake are discussed in relation to knowledge about lactoferrin receptors in macrophages, asialo elimination, and fucose group recognition. Concerning the significance of lactoferrin turnover for iron metabolism it is concluded that the plasma turnover results are insufficient to explain the disturbance in iron kinetics seen in the anaemia of chronic disorders; however, it is likely that lactoferrin plays a role in iron metabolism within the extravascular space.

Animals↗
PubMed1979

The effect of transmural field stimulation on the serotonin content in rat duodenal enterochromaffin cells--in vitro.

The effect of transmural field stimulation (TFS)--in vitro--on the sertonin (5-HT) content in enterochromafffin cells (EC) in rat duodenum was studied with a cytofluorimetric method. TFS caused a significant 25% decrease of 5-HT in EC. The presence of tetrodotoxin or d,1-propranolol in the stimulation bath antagonized the effect of TFS. In biopsies from rats pretreated with 6-OH-dopamine TFS had no effect of the 5-HT content in EC. The results of the present study strongly suggest, that the TFS induced decrease in 5-HT content is due to a direct neural, probably beta-adrenoceptor mediated, influence on the EC.

Adrenergic Fibers↗