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Biomedical subjects

B G Johansson

Publications and source records attributed to B G Johansson.

At least 19 recordsLinked to original sources
PubMed2001

Release rates for pine sawfly pheromones from two types of dispensers and phenology of Neodiprion sertifer.

Comparisons of release rates, duration in the field, and catch efficiency of polyethylene and cotton roll dispensers for the sex pheromones of sawflies (Hymenoptera: Diprionidae) were conducted. The release rates of the Neodiprion sertifer (Geoffr.) and Diprion pini (L.) sex pheromones, the acetates of pentadecanol and (2S,3S,7S)-3,7-dimethyl (2S,3R,7R)-3,7-dimethyl-2-tridecanol from polyethylene dispensers were measured at different temperatures in the laboratory. The release rates for the substances depended on both the temperature and initial load in the vials. The catch from cotton rolls baited with 100 micrograms of the acetate or propionate of 3,7-dimethyl-2-pentadecanol was compared to the catch from regularly renewed cotton rolls baited with 10 micrograms of the same acetate. The catch was higher for the 100-microgram cotton rolls for, at most, 45 days, and there was no significant differences in catch between the acetate and the propionate. The catch in traps baited with polyethylene or cotton roll dispensers loaded with the acetate of 3,7-dimethyl-2-pentadecanol was compared and showed that cotton roll traps mirrored the decreasing release of the substance rather than the actual flight activity. The length of the flight period of N. sertifer in Sweden, the Czech Republic, Italy, and Greece did not exceed 100 days in any of the countries. By adjusting the initial pheromone load of the polyethylene vials to the expected temperatures, it should be possible to get a constant and sufficiently high release rate during the entire flight period.

Animals↗
PubMed1992

An object oriented approach to interpret medical knowledge based on the Arden syntax.

A method is presented where medical knowledge modules, written in the Arden Syntax, are used in a decision-support system (DSS). Knowledge modules are, after syntax-checking, translated into the object oriented programming language C++, compiled and linked to the DSS. The object oriented approach together with developed tools, such as knowledge editor and translator, makes it possible to implement the Arden Syntax and to get an efficient, easy-maintained DSS. Work on a prototype shows that this approach has several advantages when building a DSS where medical knowledge is represented in the Arden Syntax.

Artificial Intelligence↗
PubMed1986

Estrogen induction of liver proteins and high-density lipoprotein cholesterol: comparison between estradiol valerate and ethinyl estradiol.

The effects of ethinyl estradiol and estradiol valerate were compared in 135 postmenopausal women during estrogen replacement therapy. Subfractions of high-density lipoprotein (HDL) cholesterol and its apolipoproteins and the serum levels of 2 estrogen-sensitive liver proteins were followed during 3 cycles of unopposed treatment with either ethinyl estradiol 10 or 30 micrograms or estradiol valerate 2 mg daily. Estrogen therapy induced significant and dose-dependent changes in all serum factors except HDL3 cholesterol. The effects of 10 micrograms of ethinyl estradiol upon the lipoproteins were 1.5-2.5 times greater than those of 2 mg of estradiol valerate. Sex-hormone-binding globulin and the pregnancy zone protein were the most sensitive markers for the estrogenic effect and these 2 liver-derived plasma proteins were also much more sensitive to ethinyl estradiol than to estradiol valerate. Although satisfactory therapeutic effects were achieved with both estrogens, the marked influence of ethinyl estradiol on liver protein synthesis should make estradiol valerate the first choice in clinical replacement therapy.

Adult↗
PubMed1985

Subfractions of high-density lipoprotein cholesterol during estrogen replacement therapy: a comparison between progestogens and natural progesterone.

Subfractions of high-density lipoprotein cholesterol and its apolipoproteins were followed up in 58 postmenopausal women during three cycles of unopposed estrogen replacement therapy with 2 mg of estradiol valerate daily. During the last 10 days of the following three cycles the women received sequential addition of either 250 micrograms of levonorgestrel, 10 mg of medroxyprogesterone acetate, or 200 mg of natural micronized progesterone. Both progestogens significantly decreased total high-density lipoprotein cholesterol as well as subfraction 2 of high-density lipoprotein. Data suggest that doses and relative biologic activity of 19-norsteroids and 17-hydroxyprogesterone derivatives are more important for their metabolic effects than are qualitative differences. Natural progesterone had no apparent influence on high-density lipoprotein cholesterol or its subfractions and may develop into an attractive alternative to synthetic progestogens.

Aged↗
PubMed1984

Effects of an antiestrogen on subfractions of HDL cholesterol during estrogen replacement therapy.

The antiestrogenic effects of tamoxifen and estriol were compared in 39 postmenopausal women during estrogen replacement therapy. Subfractions of HDL cholesterol and its apolipoproteins and the serum levels of two estrogen sensitive liver proteins were followed during three cycles of unopposed estrogen therapy with 10 micrograms ethinyl estradiol daily. During the last 10 days of the following three cycles the women received sequential addition of either 10 mg tamoxifen twice daily or 2 mg estriol twice daily. Tamoxifen clearly reduced the estrogen-induced increase of apolipoprotein AI, HDL2 cholesterol and total HDL cholesterol. In comparison the pregnancy zone protein and sex hormone-binding globulin were more sensitive to the estrogenic as well as to the antiestrogenic effect than the lipoproteins. Tamoxifen also counteracted the therapeutic effect on climacteric symptoms and it seems unlikely that this compound may be clinically useful as an alternative to progestogens during estrogen replacement therapy. The sequential addition of estriol had no apparent effects as compared to unopposed estrogen treatment.

Adult↗
PubMed1979

CVP-remission-maintenance in stage I or II non-Hodgkin's lymphomas: preliminary results of a randomized study.

The effect of adjuvant combination chemotherapy when given to non-laparotomized patients in remission after radiotherapy in stage I or II non-Hodgkin's lymphoma was studied in a prospective randomized multicenter study. Locally extended field radiotherapy was given to a target absorbed dose of 40 Gy in 20 fractions. Fifty-five patients who were in complete remission 6 weeks after conclusion of radiotherapy were randomized to either no further therapy or to 9 cycles of CVP (cyclophosphamide + vincristine + prednisolone). The relapse-free survival at 30 months was 41% for patients without and 86% for patients with adjuvant chemotherapy (p = 0.02). The survival was the same for both treatment arms, being 90% at 30 months. Fifteen patients have relapsed, 14 of them with extensions and 1 with a recurrence within the radiation target volume. Analysis of subgroups showed that adjuvant chemotherapy in the present series significantly prolonged the relapse-free survival in diffuse histiocytic lymphoma.

Adolescent↗
PubMed1979

Carcinoembryonic antigen in urine in patients with urothelial carcinoma. An expression for the extent of inflammatory reaction of the urinary tract.

The concentration of carcinoembryonic antigen (CEA) in urine and serum was determined repeatedly during one year in 213 patients followed because of previously treated urothelial carcinoma of the bladder. The findings were correlated to grade and stage of previously treated tumour, given therapy, recurrence and the cytological evaluation of a midstream urine specimen. During the period of follow up 43 recurrences were clinically observed. With the exception for the content of inflammatory cells no correlation was found between the CEA levels in urine or blood and the parameters studied. Thus CEA in urine and/or serum cannot substitute for cystourethroscopy, urography and exfoliative cytology in the follow-up of patients previously treated for urothelial carcinoma.

Adult↗
PubMed1978

Plasma lipoprotein separations by zonal ultracentrifugation.

Procedures for the separation of plasma lipoprotein classes and subclasses by zonal ultracentrifugation are described. The main density classes, very low density lipoproteins (VLDL), low density lipoproteins (LDL) and high density lipoproteins (HDL), in plasma can be separated in a single run for 20 hours. For the isolation of VLDL-LDL a centrifugation time of only 90 minutes is needed. Separations can be performed on plasma volumes varying from 10 to 400 ml in the Ti-14 rotor used; VLDL can in this way be isolated from 400 ml plasma in 30 minutes. The advantages and disadvantages of zonal ultracentrifugation in comparison with the commonly employed differential ultracentrifugation for separation of lipoproteins are discussed.

Centrifugation, Zonal↗
PubMed1978

Changes in plasma high density lipoproteins in chronic male alcoholics during and after abuse.

Alterations in plasma high density lipoproteins (HDL) were studied in thirty-eight male chronic alcoholics. Twenty-four (63%) of the patients had increased HDL protein (measured immunochemically) and twenty-five (66%) had increased HDL cholesterol (determined after polyanion precipitation of very low density lipoproteins (VLDL) and low density lipoproteins (LDL)). A statistically significant correlation was found between HDL protein and HDL cholesterol (r = 0.39). gamma-Glutamyltransferase (GT) was elevated in eighteen (47%) of the alcoholics. No significant correlations were found between GT and HDL protein or HDL cholesterol. The increase in HDL, as studied by rate zonal ultracentrifugation, was heterogeneous with changes in the HDL2 as well as HDL3 subfractions. It is suggested that determination of HDL total cholesterol, in combination with GT, may represent a valuable and sensitive test for detection of alcoholism.

Adult↗
PubMed1978

Lipoproteins in plasma from patients with low LCAT activity due to biliary obstruction.

A high density lipoprotein (HDL) fraction, designated cholestatic HDL1, has been isolated by zonal ultracentrifugation from patients with long-standing biliary obstruction. This lipoprotein fraction consists exclusively of disc-shaped particles rich in phospholipid and unesterified cholesterol. The fatty acid composition of the minor cholesteryl ester fraction was characterized by a low content of linoleic acid. Apoprotein E was the dominating protein' component, while only small amounts of apolipoprotein A-I were found. Immunochemical studies of cholestatic HDL1 indicate that a considerable proportion of the particles contained apo E as its only protein constituent. All patients had a markedly reduced endogenous cholesterol-esterifying ability. The finding of apparently primary LpE particles in biliary obstruction may be related to this secondary LCAT deficiency.

Apoproteins↗
PubMed1977

Plasma lipoprotein changes in experimental cholestasis in the dog.

Plasma lipoproteins were compared before and after surgical induction of extrahepatic biliary obstruction in dogs by immunochemical techniques, zonal ultracentrifugation and gel filtration. A considerable increase in LDL was found one week after operation, with a zonal ultracentrifugal pattern which was more complex than that found before operation. The lipid composition was characterized by an increase of phospholipids and a decrease of triglycerides in cholestatic LDL fractions. None of the fractions displayed the inverse cholesterol-cholesterol ester ratio, characteristic for human LP-X. The apoprotein composition of cholestatic LDL was also markedly changed. Apoprotein A I, already present in the normal LDL2 subclass, increased and two apoproteins with apparent molecular weight of 35000-40000 appeared in considerable amounts. The amount of HDL was decreased during cholestasis without any appreciable changes in composition.

Animals↗
PubMed1977

Mitogenic properties of Fab and F(ab')2 fragments of rabbit anti-human beta2-microglobulin for human lymphocytes.

Bivalent F(ab')2 fragments and monovalent Fab fragments of rabbit anti-human beta2-microglobulin (anti-beta2m) stimulated DNA synthesis in human lymphocytes. Mitogenicity of anti-beta2m antibodies can therefore be ascribed to the antigen-binding site and not to the Fc portion of the molecule. The mitogenic response to F(ab')2, and sometimes Fab, fragments of anti-beta2m IgG was comparable to that obtained with original IgG antibodies when tested at the same protein concentration. Since Fab monomers of anti-beta2m can cause lymphocyte activation, 'cross-linking' of hypothetical beta2-microblobulin-containing lymphocyte receptors does not seem necessary for activation. F(ab')2, as well as Fab, fragments of anti-beta2m blocked the cytotoxic effect of anti-beta2m IgG, showing that the fragments did indeed react with beta2-microblobulin on the cell surface. F(ab')2 dimers, but not Fab monomers, of anti-beta2m were capable of inhibiting the cytotoxic effect of an anti-HLA-A2 antiserum. The mitogenic activity of both anti-beta2m IgG and Fab monomers of such antibodies disappeared after absorption with highly purified beta2-microblobulin. The mitogenic effect of anti-beta2m IgG was inhibited to a minor extent by exposure of cells to high concentrations of pooled multispecific anti-HLA antibodies. This effect was probably nonspecific.

Antibodies↗