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Biomedical subjects

L Andersson

Publications and source records attributed to L Andersson.

At least 361 records · Page 20Linked to original sources
PubMed1986

Selective adsorption of phosphoproteins on gel-immobilized ferric chelate.

Ferric ions are very strongly adsorbed to iminodiacetic acid substituted agarose. This firmly immobilized complex acts as a selective immobilized metal affinity adsorbent for phosphoproteins. Chromatography based on this principle is illustrated by the adsorption-desorption behavior of egg yolk phosvitin before and after dephosphorylation as well as by the change in the chromatographic pattern before and after enzymic phosphorylation of selected histones. The strength of binding is dependent on the phosphate content. The difference in binding before and after phosphorylation of a single amino acid residue is demonstrated. Affinity elution can be accomplished by inclusion in the buffer of phosphoserine or a displacing metal ion such as Mg2+.

Amino Acids↗
PubMed1986

Phenotypes of placental-type alkaline phosphatase in seminoma sera as defined by monoclonal antibodies.

PLAP-like enzymes could be detected in serum of patients with primary testicular tumors, in particular seminomas. The use of a panel of monoclonal antibodies (MAbs) permitted typing into 6 different testicular serum phenotypes, of which one appeared similar to a placental type (II) and 2 have not been previously described. Most tumor sera belonged to type I, as described for seminoma tissues. With a more advanced tumor the mean serum PLAP-like levels increased. After operation, after radiotherapy or with no evidence of disease lower or non-detectable enzyme levels were found. In typing the tissue PLAP-like antigen in serum of the same patient or sera from recurrences of a seminoma in the same patient, the same phenotypes of PLAP-like antigen were usually but not always found. None of the 6 phenotypes appeared to confer a poorer prognosis. We conclude that the expression of PLAP-like antigen is eutopic and is enhanced by testicular malignancy, especially in seminoma cells.

Adult↗
PubMed1986

Improved preparation of the integral membrane proteins of human red cells, with special reference to the glucose transporter.

Human red cell membranes were isolated and partially stripped of peripheral proteins by gel filtration of hemolysates on a Sepharose CL-4B column at pH 8 connected in tandem to a Sepharose CL-6B column at pH 10.5. The eluted material was washed by centrifugations, once at pH 10.5 and twice at pH 12. In this way, water-soluble proteins and peripheral membrane proteins were thoroughly removed, and 0.2 g of integral membrane proteins could be prepared within 10 h from 0.2 litre of red cells. The exposure to high pH did not lower the D-glucose transport activity, and electrophoretically pure glucose transport protein could be isolated from this preparation. Gel filtration in sodium dodecyl sulfate separated the integral membrane components into four fractions, one of them containing 4.5-material; gel electrophoresis showed about 14 zones and two-dimensional electrophoresis resolved up to 100 mostly minor components, among which the glucose transporter focused around pH 7. However, purified glucose transporter focused around pH 8. Glucose and nucleoside transport proteins were co-purified in active form on DEAE-cellulose and a fraction isolated by adsorption to Mono Q was used for immunization of mice and production of monoclonal antibodies. One hybridoma produced antibodies that reacted with material in the 4.5-region, possibly the glucose transport protein, and not with band 3-material. Upon two-dimensional electrophoresis of integral membrane components that had been solubilized with octyl glucoside the immunoreactive and the silver-stained 4.5-material focused in a broad range from pH 6 to pH 9. A possible explanation for this heterogeneity might be interaction between the glucose and nucleoside transport proteins and negatively charged lipids.

Centrifugation↗
PubMed1986

Isolation of phosphoproteins by immobilized metal (Fe3+) affinity chromatography.

Phosphoproteins and phosphoamino acids bind to ferric ions immobilized on iminodiacetate-agarose gel and can be eluted by increasing pH or by introducing phosphate ions to the eluant. Some other metals were found to resemble iron with regard to the interaction with protein-bound phosphate and phosphoamino acids. These observations were utilized to develop purification procedures for phosphoproteins. Hen egg albumin (ovalbumin) was fractionated into three components of varying phosphate contents. Porcine pepsin was purified in a similar manner.

Animals↗
PubMed1986

The "forced-attention paradigm" in dichotic listening to CV-syllables: a comparison between adults and children.

The present study was concerned with the effects of directional attention on the right-ear-advantage (REA) in dichotic listening. It was suggested that if selective attention contributes to the REA during a non-forced, free recall condition, then comparing the unattended left and right ear scores when attention is forced to the right and the left ear, respectively, would yield an "attention-free" estimate of the REA. Each subject participated in a non-forced, free recall, condition; in a forced-right condition; and in a forced-left condition. During the two forced conditions, subjects were instructed to only attend to and report the right and left ear inputs, respectively. The stimuli were the six stop-consonants paired with the vowel a. Four right-handed groups participated (N = 18): Adult males, adult females, boys (8-9 years), girls (8-9 years). The results showed a significant REA in all groups during the non-forced condition. During the forced-right condition, significantly more correct recalls were obtained from the right compared to the left ear in all groups. During the forced-left condition, significantly more correct recalls from the left compared to the right ear was obtained only in the two adult groups, but not in the children groups. Finally, comparing correct recalls from the unattended right ear (during the forced-left condition) with the unattended left ear (during the forced-right condition) revealed a significant REA in all groups except for the adult females.

Adolescent↗
PubMed1986

Diagnosis and treatment of the unicystic ameloblastoma.

Two cases of unicystic ameloblastoma are presented. The lesions were pain-free and expanded the mandible. They were removed by curettage. Recurrent lesions had similar clinical appearances and histological pictures compared to the original lesions. The unicystic ameloblastoma manifested itself as a cystic cavity without solid neoplastic features, which differs from the solid ameloblastoma with regard to the age of the patients and the rate of recurrence. The behavior of the unicystic ameloblastoma was similar to that of the primordial cyst. Despite the obvious risk of recurrence, conservative treatment with enucleation and curettage seemed to be justified in preference to mutilating radical surgery.

Adolescent↗
PubMed1986

Genomic hybridization of bovine class II major histocompatibility genes: 2. Polymorphism of DR genes and linkage disequilibrium in the DQ-DR region.

Class II genes of the bovine major histocompatibility complex have been investigated by Southern blot analysis using human cDNA probes for DQ alpha, DQ beta, DR alpha and DR beta. In this report restriction fragment length polymorphisms of DR alpha and DR beta are described. The polymorphisms were interpreted genetically by analysing five paternal half-sib families of the Swedish Red and White Breed, comprising altogether 28 offspring. Using the restriction enzymes BamHI, EcoRI and PvuII, three DR alpha and three DR beta allelic fragment patterns were resolved. The DR alpha and DR beta genes thus appear to be much less polymorphic than the previously described DQ alpha and DQ beta genes. Also, the observed linkage disequilibrium between DR genes was less pronounced than that between DQ genes, whereas the association between DR and DQ haplotypes was very strong. The family data available indicated strongly that the DQ alpha, DQ beta, DR alpha and DR beta genes are all closely linked.

Animals↗
PubMed1986

Genomic hybridization of bovine class II major histocompatibility genes: 1. Extensive polymorphism of DQ alpha and DQ beta genes.

Class II genes of the bovine major histocompatibility complex (MHC) were investigated by Southern blot analysis using human cDNA probes for DQ alpha, DQ beta, DR alpha and DR beta. The presence of a DQ-like and a DR-like subregion in cattle was clearly indicated. Highly polymorphic restriction fragment patterns were obtained when genomic DNA, digested with any one of the BamHI, EcoRI or PvuII restriction enzymes, was hybridized with the DQ alpha and the DQ beta probe. The polymorphisms were interpreted genetically by analysing five paternal half-sib families of the Swedish Red and White breed. The material comprised, besides the bulls, 28 offspring and their dams. The analysis resolved 9 and 12 allelic variants of DQ alpha and DQ beta respectively. Thus, this investigation establishes a method for routine typing of MHC class II gene polymorphism in cattle. The results were entirely consistent with close linkage of DQ alpha and DQ beta since no recombinant was found and since alleles at these loci occurred in complete linkage disequilibrium in the material investigated. Close linkage between DQ and the blood group locus M, which has previously been found to be closely linked to the serologically defined BoLA-A locus, was also indicated. In this study DNA was isolated from frozen semen samples of dead bulls, which shows that this type of analysis will be useful in genetic investigations in cattle breeds, where artificial insemination is practised.

Animals↗
PubMed1986

Contact lens wear in dry environments.

The relation between relative humidity at the place of work and subjective discomfort as well as a number of objective parameters was studied in 34 contact lens wearers. Subjects in a low relative humidity (less than about 30%) showed significantly shorter BUT on the lens and more prominent lens deposits than subjects in a higher relative humidity (greater than 40%). A short BUT on the lens was associated with lens deposits (and vice versa) and restricted lens movements. Discomfort was particularly prominent when humidity was less than about 25%, when BUT on the lens was less than 20 sec, and when lens deposits were present. An experiment where relative humidity was manipulated between about 20 and 50% showed that subjects with a short BUT on the lens and prominent lens deposits were much more sensitive to a low relative humidity than other subjects. Enzymatic cleaners, frequent lens replacements, and loose fits were valuable to lessen discomfort.

Adult↗
PubMed1985

Combined bleomycin and radiation therapy in carcinoma of the penis.

Cancer of the penis is an uncommon disease in the western part of the world but it represents a significant portion of male cancer in other countries as in Asia, Africa, and South America, where in certain areas it accounts for 20% of the cancer occurrence in male patients. The treatment has been based mainly on surgical excision with or without regional lymphadenectomy. Chemotherapy with bleomycin has had some effectiveness in advanced disease. A mode of combination therapy with bleomycin and irradiation has been evaluated in patients with carcinoma of the penis. The results compare favorably with surgical treatment with respect to cure of the disease and patient survival, and it has the advantage of preserving sexual function in most of the cases. This combined therapy is useful even in patients with relatively extensive local tumor.

Adult↗
PubMed1985

Use of secondary isotope effects and varying pH to investigate the mode of binding of inhibitory amino aldehydes by leucine aminopeptidase.

Ki values for leucine aldehyde, a competitive inhibitor of leucine aminopeptidase, vary with pH in a manner compatible with binding of uncharged inhibitor. The pH dependence of kcat/Km suggests likewise that the substrate leucine p-nitroanilide is productively bound as the uncharged species. Comparison of pKa values of the model compounds aminoacetone and aminoacetal indicates that the equilibrium constant for hydration of amino aldehydes is reduced by a factor of about 2 when a proton is lost from the alpha-ammonium group near pH 8. Effects of deuterium substitution at C-1 on equilibrium binding of leucine aldehyde were determined with immobilized enzyme and inhibitors doubly labeled with radioisotopes. The observed isotope effect (KD/KH) is approximately unity, suggesting that leucine aldehyde combines with the enzyme as an oxygen adduct, not as the intact aldehyde.

Deuterium↗
PubMed1985

Urinary modified nucleosides as tumor markers in cancer of the urinary organs or female genital tract.

Using a sensitive and specific method involving high-performance liquid chromatography, urinary levels of four modified nucleosides--pseudouridine (psi), 1-methylinosine (m1I), 1-methyladenosine (m1A), and 1-methylguanosine (m1G)--were investigated before and after treatment in 31 patients with cancer of the urinary organs or the female genital tract. Before treatment m1I was the most frequently elevated nucleoside (77%). Pretreatment urinary levels of psi, m1I, and m1A in patients with stage 2-4 cancer of the female genital tract were significantly elevated compared to human healthy volunteers (p less than 0.005). Compared with the other nucleosides, psi appeared to correlate more closely with the clinical outcome (progression or regression) of patients with cancer of the female genital tract. In the case of patients with cancer of the urinary organs, m1I followed the clinical outcome better than the other nucleosides measured. Therefore psi and m1I seem to be useful for monitoring genito-urinary cancers.

Adenosine↗