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Biomedical subjects

I Larsson

Publications and source records attributed to I Larsson.

82 records · Page 5Linked to original sources

Determination of urinary fibrin/fibrinogen degradation products by radioimmunoassay.

Glomerular fibrin/fibrinogen related material is often found in the early stage of especially proliferative types of glomerulonephritis and during rejection of renal grafts after transplantation. The presence and concentration of urinary fibrin/fibrinogen degradation products (FDP) have been found to be correlated to the extent of glomerular fibrin deposits. Most methods for FDP determination hitherto available are not sensitive enough to detect such small amounts of the fibrin/fibrinogen related material in the urine as are found in early glomerulonephritis. A radioimmunoassay for determining urinary FDP is described, in which the high molecular weight degradation products (HMWDP) are first converted into end degradation products (D and E) by addition of plasminogen and streptokinase to the urine sample. In the test an antiserum against purified D-products is used, which avoids the influence of varying binding properties and therefore makes the method more specific.

Cross Reactions↗

A scintillation camera technique for quantitative estimation of separate kidney function and its use before nephrectomy.

A scintillation camera technique was used for measuring renal uptake of [131I]Hippuran 80-110 s after injection. Externally measured Hippuran uptake was markedly influenced by kidney depth, which was measured by lateral-view image after injection of [99mTc]iron ascorbic acid complex or [197Hg]chlormerodrine. When one kidney was nearer to the dorsal surface of the body than the other, it was necessary to correct the externally measured Hippuran uptake for kidney depth to obtain reliable information on the true partition of Hippuran between the two kidneys. In some patients the glomerular filtration rate (GFR) was measured before and after nephrectomy. Measured postoperative GFR was compared with preoperatively predicted GFR, which was calculated by multiplying the preoperative Hippuran uptake of the kidney to be left in situ, as a fraction of the preoperative Hippuran uptake of both kidneys, by the measured preoperative GFR. The measured postoperative GFR was usually moderately higher than the preoperatively predicted GFR. The difference could be explained by a postoperative compensatory increase in function of the remaining kidney. Thus, the present method offers a possibility of estimating separate kidney function without arterial or ureteric catheterization.

Adult↗

Hydra head activator-like immunoreactivity in human brain astrocytomas grade III-IV and the surrounding brain tissue.

We have developed a specific and sensitive radioimmunoassay for the hydra head activator neuropeptide (HHAP). The antibody recognizes the C-terminal portion of HHAP and shows no cross-reactivity with other neuropeptides. The assay allows measurement of HHAP-like material in tissue extracts with a minimum detectable concentration of 22 fmol/ml standard HHAP (2 fmol/tube). The concentration of immunoreactive (IR) HHAP in histopathologically characterized tissues was determined in 43 specimens from astrocytomas grade III-IV and surrounding brain tissue from 18 patients. Twenty-two control specimens of gray and white matter and five from hypothalamus were taken from 5 brains at autopsy. The concentration of IR-HHAP in the brain tumors, including the actively growing tumor front, is lower than in normal brain, and thus appears not to act as a growth factor. High performance liquid chromatography (HPLC) of extracts of hypothalamus and tumors revealed two major peaks of IR-HHAP; one eluted with the same elution volume as synthetic HHAP. HPLC of cerebral cortex extracts revealed only one major peak of IR-HHAP eluting close to the void volume, which may indicate a posttranslational processing variability of HHAP in different brain regions. By immunocytochemistry HHAP immunoreactivity was localized to the cytoplasma of neuroectodermal cells.

Amino Acid Sequence↗

Influence of approximal caries in primary molars on caries rate for the mesial surface of the first permanent molar in swedish children from 6 to 12 years of age.

The objective was to assess the influence on the caries rate for the mesial surface of the first permanent molar (6m) of the caries status of the distal surface of the second primary molar (05d) in children from 6 to 12 years of age. The study design was retrospective and included 374 children with an average of 5 sets of bite-wing radiographs. The mean age of the children was 6.7 years when the first bite-wing radiographs were taken and 11.5 years at the time of the latest radiographs included in the study. The approximal surfaces were classified according to a scoring system: 0 = no visible radiolucency, 1= radiolucency in the outer half of the enamel, 2 = radiolucency in the inner half up to the enamel-dentin border, 3 = radiolucency with a broken enamel-dentin border but with no obvious involvement of the dentin, 4 = radiolucency with obvious spread in the outer half of the dentin, and score 5 = radiolucency in the inner half of the dentin. The influence of the status of 05d on the caries rate for 6m (state > or =2) was assessed by using a model for dependence between the two neighbouring surfaces. Presence or absence of approximal caries in the distal surface of the first primary molars (04d) and/or the mesial surface of the second primary molars (05m) at the time of eruption of 6m was also related to the caries rate for 6m. The caries rate for 6m was 15 times higher if 05d had developed enamel/enamel-dentin border caries (state 2 or 3) compared to a radiographically sound 05d (state 0 or 1). No significant increase in the caries rate for 6m was found when 05d had deeper unrestored dentin caries than when 05d had superficial caries (state 2 or 3). Furthermore, for preventing caries in 6m, no benefit could be found from restoring an 05d with dentin caries with amalgam as opposed to leaving the carious lesion unrestored until exfoliation. The caries rates for 6m and 05d were 3.4 and 2.7 times higher, respectively, in the presence of dentin caries/restoration in 04d/05m compared to absence of dentin caries in these molar surfaces at the time of eruption of 6m. In conclusion, the caries rate for 6m depended on the status of 05d and increased 15 times if 05d had enamel/enamel-dentin border caries compared to a sound 05d. Deeper unrestored or restored dentin lesions in 05d did not result in a higher caries rate for 6m compared with more shallow carious lesions in 05d.

Chi-Square Distribution↗

A method for determination of blood flow with 133Xe in human nasal mucosa.

The 133Xe wash-out technique was used as a method for calculation of the blood flow in human nasal mucosa. The disappearance of 133Xe from the nasal mucosa was followed using scintillation detectors. In laryngectomies it was shown that the disappearance of 133Xe from the mucosa depended mainly on the blood flow. Leakage of 133Xe from the mucosa to the nasal air was unimportant. The disappearance rate of 133Xe was decreased by oxymetazoline and increased by histamine, mostly likely due to the effects of these vasoactive drugs on the mucosa blood flow. The 133Xe wash-out technique would seem to be a simple method to study nasal mucosal blood-flow changes in humans.

Adult↗