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Biomedical subjects

U Persson

Publications and source records attributed to U Persson.

At least 91 records · Page 5Linked to original sources
PubMed1987

Comparison of the biological effects of humic materials under acidified conditions.

The acute and chronic effects of three types of humic material were studied using Daphnia magna at pH 5, 6, and 7. At neutral pH humic material had no biological effect. At pH 6 and 5 maximum survival and population growth rate occurred at intermediate levels of humus material (10 mg C/L, 300 mg Pt/L). Lowest survival and population growth rate occurred at pH 5 in either the absence of humus material or at concentrations exceeding 10 mg C/L (300 mg Pt/L). A second order polynomial was used to fit the dose response curve at pH 5 for both Aldrich humic acid and a natural bog water. Aldrich had greater biological activity. It is suggested that the biological behavior of aquatic humus conforms to second order rate phenomena controlled by high levels of free metals ions at low humus concentrations and direct toxic action of the dissolved organics at low pH due to increased lipophilicity.

Daphnia↗
PubMed1987

T lymphocyte subpopulations in bone-marrow-transplanted patients in relation to graft-versus-host disease and cytomegalovirus-induced infection.

T cell subpopulations were studied in peripheral blood from 62 bone marrow recipients using monoclonal antibodies and flow cytometry. Patients with acute graft-versus-host disease (GVHD), patients with chronic GVHD, and patients with cytomegalovirus (CMV) infection had decreased OKT4/8 ratios. The data suggest that in GVHD this was due to reduced absolute numbers of OKT4-positive cells. CMV-infected patients had significantly increased numbers of OKT8-positive cells. Monitoring of T cell subpopulations was not informative for diagnosis or prognosis of acute GVHD in the single patient. CMV infection should be suspected at a sudden increase in the number of OKT8-positive cells.

Blood Preservation↗
PubMed1987

Hyaluronate in bronchoalveolar lavage fluid in sarcoidosis and its relationship to alveolar cell populations.

Hyaluronate is a potential marker of activated pulmonary fibroblasts and appears in increased amounts in bronchoalveolar lavage fluid from patients with sarcoidosis. This study was performed to investigate a possible link between the local immune response and pulmonary fibroblast proliferation. The median hyaluronate concentration in the lavage fluid from 23 sarcoid patients was 12.0 (interquartile range 7.5-28.5) micrograms/l. The hyaluronate concentration was positively correlated to the concentration and proportion of lymphocytes (p less than 0.001 and p less than 0.01, respectively) as well as to the concentrations of T lymphocyte subsets (OKT4+ p less than 0.01, OKT8+ p less than 0.05). No correlation was found between the hyaluronate concentration and the OKT4+/OKT8+ ratio. Furthermore, a significant correlation was observed in the lavage fluid between hyaluronate and angiotensin-converting enzyme, a marker of monocyte/macrophage activity (p less than 0.01). Thus, the intensity of the sarcoid alveolitis was associated with biochemical signs of pulmonary fibroblast proliferation/activation in sarcoidosis.

Adult↗
PubMed1986

Alveolar lymphocytes from patients with sarcoidosis respond poorly to activation by mitogenic lectins.

Attempts have been made to activate alveolar cells obtained by bronchoalveolar lavage from 17 patients with sarcoidosis in different stages with the lectins concanavalin A and leukoagglutinin. The cells obtained from 2 of the patients responded well by proliferation whereas the cells from the other 15 patients responded poorly. Coculture experiments indicate that the low proliferative response was not due to inhibitory effects exerted by alveolar lymphocytes or macrophages, but rather to a lack of responding T cells. The results are discussed in relation to other studies showing increased immune reactivity in alveolar lymphocytes from patients with sarcoidosis.

Adult↗
PubMed1986

Sarcoidosis in an apparently healthy volunteer.

As previously reported in this journal, alveolitis may occur in asymptomatic individuals exposed to antigens known as causative agents in hypersensitivity pneumonitis. We found an alveolitis, probably of sarcoid origin, in an apparently healthy volunteer.

Adult↗
PubMed1985

Protein C in bovine plasma after warfarin treatment. Purification, partial characterization, and beta-hydroxyaspartic acid content.

Protein C was purified from the plasma of a cow treated with the vitamin K antagonist warfarin. The purified protein appeared not to bind Ca2+ ions in contrast to protein C from an untreated animal. The gamma-carboxyglutamic acid content of the abnormal protein C was reduced to approximately 10% of normal, whereas the beta-hydroxyaspartic acid content was only slightly decreased, suggesting that vitamin K is not involved in the postribosomal hydroxylation of the aspartic acid residue in position 71 of the light chain of protein C. The abnormal and normal proteins were activated at the same rates by thrombin, but normal protein C was more rapidly activated by the thrombin-thrombomodulin complex. Compared to normal protein C, the abnormal one had virtually no anticoagulant activity.

Animals↗
PubMed1984

The appearance of cytotoxic lymphocytes in unstimulated and concanavalin A-activated human peripheral mononuclear cells.

The presence of a mitogenic lectin during the cytotoxicity assay enables the detection of non-specific cytotoxicity (lectin-dependent cell-mediated cytotoxicity (LDCC]. Human mononuclear cells cultured at 37 degrees C in vitro became cytotoxic after 1 day, as detected by the LDCC. In some individuals, the presence of adherent cells during culture inhibited the development of cytotoxicity. Activation by concanavalin A (Con A) resulted in enhanced cytotoxicity after a few days in culture. There was no clear relationship between the lectin doses required for optimal induction of cytotoxicity and [3H]thymidine uptake. High Con A concentrations that induced a proliferative response often inhibited cytotoxicity in mononuclear cells depleted of adherent cells.

Cell Adhesion↗
PubMed1984

Concanavalin A-induced activation of human T cell subpopulations.

The proliferative response to concanavalin A (Con A) in human peripheral lymphocytes is dependent on the presence of adherent cells. OKT 8-positive cells respond less well to Con A than OKT 4-positive cells, especially to high concentrations of the activator. The response in both subpopulations of cells is dependent on the number of adherent cells added, the dose of the mitogen used, the day of testing as well as the presence of lymphocyte-produced factors. The data presented in the paper clearly show the importance of caution in evaluation of results obtained by in vitro-induced mitogen activation due to the number of known and unknown variables that affect the magnitude of the response.

Antibodies, Monoclonal↗
PubMed1984

Recording of bone marrow activity in liver-spleen (RES) scintigraphy.

The bone marrow activity in the liver-spleen (RES) scintigraphy has been difficult to estimate correctly. If the activity of the bone marrow is to be decided as counts/time unit it is of importance that structures with a high activity as the liver and spleen are excluded from the registration. A dorsal registration of the pelvis during 180 s will give a rather correct information of bone marrow activity and besides an image of the pelvic bone marrow is obtained. Using 270 to 280 MBq 99Tcm-Albures all 45 normal cases had values below 150 KCNT (1 KCNT = 1 000 counts). All cases with cirrhosis (n = 15) or metastases in the liver (n = 14) had values over 150 KCNT. Values over 150 KCNT were also found in 29 of 34 patients with an increase in ASAT and ALAT (GOT, GPT) as the only pathologic finding and in 12 of 21 patients with a carcinoma but without metastases in the liver.

Aged↗
PubMed1983

The use of thiol-disulphide exchange chromatography for the automated isolation of alpha 1-antitrypsin and other plasma proteins with reactive thiol groups.

A method has been developed for the rapid isolation of alpha 1-antitrypsin and other thiol proteins from plasma by an automated chromatography system. The thiol-proteins are initially bound to matrix-linked activated thiol-compounds by an SH-SS interchange reaction. The mixed disulphides are then reduced in two steps and subfractionated by passage through Blue-Sepharose and AH-Sepharose columns. The rate of the interchange reactions varies with the microenvironment of the reacting thiols. alpha 1-Antitrypsin is recovered with 95% purity in 60% yield within two days from 1 l of plasma.

Blood Proteins↗
PubMed1983

Are increased IgE-levels a signal of an acute graft-versus-host reaction?

IgE-levels are markedly elevated following bone-marrow transplantation in patients with and without GVHD. In patients with GVHD, there is a significant correlation between the timing of the IgE-increase and the appearance of clinical GVHD (p less than 0.01). The highest IgE-level (8000 kU/l) was noted in a recipient of a syngeneic graft. During the IgE-peak, the serum from this patient contained low concentrations of IgE reacting with several tested allergens as well as for the hapten TNP, which indicated polyclonal activation. In a patient with a known allergy to animal danders, RAST tests were positive against dog and cat both before and six weeks after total body irradiation and transplantation with marrow from a non-allergic donor. A slight increase in the amount of allergen-specific, IgE-antibodies was seen during the increase in total IgE. A non-allergic patient was transplanted with marrow from a donor allergic to timothy. Timothy-specific, IgE-antibodies were detected immediately after transplantation but they disappeared within a few days and could not be detected during the period of increase in total IgE. We believe that the IgE-elevation seen after conditioning with cytotoxic drugs and total body irradiation in BMT-patients is a polyclonal response in host B-cells induced during an acute, GVHR and influenced by disturbed regulatory T-cells. Lymphocytes from patients with acute GVHD had unusually large numbers of IgG/PFC in vitro after stimulation with staph. aureus Cowan 1 (p less than 0.001), which may reflect a clonal expansion of responsive B-cells.

Adolescent↗
PubMed1983

Markedly elevated serum IgE levels following allogeneic and syngeneic bone marrow transplantation.

Serum IgE levels were studied in 25 bone marrow transplant recipients (in 12 patients twice weekly and in 13 patients, at random). A 2-748-fold increase in serum IgE was recorded in 20 of the 25 patients after transplantation, the highest IgE value observed being 8,000 kU/liter. The IgE elevation appeared concomitantly with acute graft-versus-host disease (GVHD) in 14 patients. Both events occurred on day 24 +/- 2 (mean +/- SE). When the acute GVHD was diagnosed, there was a significant increase in serum IgE as compared to the first posttransplantation value. In one patient in whom GVHD recurred, a second IgE peak was seen, and in another patient with flaring GVHD, IgE levels increased on several occasions. In 6 patients without clinical signs of GVHD, a rise in IgE occurred on day 35 +/- 12. One of these patients was grafted with marrow from her identical twin. The rise in IgE did not correlate with an elevated proportion of eosinophil granulocytes. In the majority of the patients, no correspondent increases in serum IgG, IgA, or IgM were seen during the period with increased IgE after transplantation.

Adolescent↗
PubMed1982

Concanavalin A inhibits the effector phase of specific cytotoxicity.

The effects of concanavalin A (Con A) on the effector phase of specific and nonspecific cytotoxicity were studied. The addition of the lectin to the cytotoxicity assay resulted in inhibition of specific cytotoxicity and induced the lysis of nonspecific targets only when the lectin was added after the target cells. Preincubation of the effector cells with the ligand strongly inhibited specific cytotoxicity and did not induce nonspecific cytotoxicity. However, preincubation of the target cells with Con A before addition to the assay had no effect on the specific lysis and strongly facilitated the lysis of nonspecific targets. The inhibitory effect was not due to the agglutinating property of the lectin, since another agglutinogenic and non-mitogenic lectin (Helix pomatia) did not inhibit cytotoxicity. Induction of effector-to-effector killing seemed unlikely, since the addition of Con A to 51Cr-labelled effector cells did not significantly enhance the release of isotope. The inhibitory effect could be reversed by a subsequent incubation of the Con A-treated effectors with alpha-methyl-d-mannoside. We suggest that Con A inhibits specific alloreactive cytotoxicity by blocking the antigen-binding receptors of T cells and induces nonspecific cytotoxicity by already activated cytotoxic T lymphocytes (CTLs) by binding to the major histocompatibility complex (MHC) antigens of the targets and creating structures mimicking allogenic MHC products that will be recognized by CTLs via the antigen-binding receptors.

Animals↗
PubMed1980

Influence on symptoms and transit-time of Vi-SiblinR in diverticular disease.

Nine patients complaining of constipation and with diverticuli of the colon on barium-enema were examined with regard to transit-time, bowel movements and subjective symptoms. They were treated with placebo and Vi-SiblinR, using a doubleblind cross-over technique. The transit-time remained normal during the Vi-SiblinR treatment. The feces became softer and increased in weight and the subjective symptoms were significantly reduced (p less than 0,05).

Aged↗
PubMed1978

Functional characterization of lanatoside-C-responsive cells.

Lanatoside C, a digitalis glycoside previously shown to be a polyclonal B-cell activator (PBA), was found to stimulate immature cells residing in fetal liver, bone marrow and spleen but also to activate cells from peripheral lymph nodes and peripheral blood. The proliferative response obtained in spleen cells was not affected by macrophage removal, whereas anti-Ig or anti-Ia antiserum pretreatment partially inhibited the responses. Removal of T cells by a pretreatment with anti-Thy 1.2 antiserum plus complement caused a marked increase in the proliferative response of the remaining cells, suggesting the existence of a naturally occurring suppressor T cell for glycoside-induced mitogenesis. Synergy experiments with 'classical' PBAs and lanatoside C, given simultaneously or subsequently, suggest an overlap between the lanatoside-C-responding cell population and the dextran sulphate (DxS)- and lipopolysaccharide (LPS)-sensitive cells. Since DxS-induced activation of B cells is dependent on macrophages, it is suggested that lanatoside C may be used as a functional marker for direct activation of immature B cells.

Animals↗