Search PubMed⌕ Search

Biomedical subjects

B Gustafsson

Publications and source records attributed to B Gustafsson.

At least 127 records · Page 7Linked to original sources
PubMed1990

Decreased nerve conduction velocity in optic nerve following early post-natal low-dose lead exposure.

A study was made on nerve conduction velocity of the optic nerve in rats subjected to lead exposure during the first 2 weeks of post-natal life. The rats were given intraperitoneal injections with a calculated daily exposure of 7.6 micrograms (low-dose) or 15.8 micrograms (high-dose) lead g-1 body weight. Growth retardation at 30 days was seen only with the higher dose. Littermates of low-dose exposed rat were injected with vehicle only and served as controls. Lead concentrations in blood and brain were measured in rats of 20 days of age in order to ascertain that exposure was adequate in the present litters. Nerve conduction velocity of the optic nerve was examined in 14 rats of 30 days of age taken from 10 different litters. The optic nerve(s) was prepared in anaesthetized rats and placed in a flow-through incubation chamber. One stimulating and two recording tungsten electrodes were used. In all rats, three positive-negative waves, regarded as representing three functional groups of optic nerve axons, could be recorded. The last one often had a long duration and a small amplitude without distinct peaks and hence was omitted from further analysis. The mean conduction velocities for the two faster axonal groups were 16.8 and 5.4 m s-1 in control rats, 10.3 and 5.8 m s-1 in low-dose rats and 9.4 and 5.2 m s-1 in high-dose rats. The difference in conduction velocity for the fastest axons was significant for controls versus low-dose and high-dose but not for low-dose versus high-dose.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Subepithelial hydrostatic pressure may regulate plasma exudation across the mucosa.

This study demonstrated in guinea pig tracheal tubes in vitro that small increases in serosal hydrostatic pressure caused significant mucosal crossing of serosal macromolecules. Reversibility and repeatability of this passage agree with inflammatory stimulus-induced appearance of exuded plasma in airway lumen in vivo. Bradykinin, histamine, and terbutaline, which induce and inhibit, respectively, plasma exudation in vivo, were without effect on the present in vitro permeability. Carbachol, similar to histamine, contracted the trachea, and did not increase, but rather decreased the pressure-induced luminal entry of serosal macromolecules. It is proposed that a plasma-exudation-induced hydrostatic pressure load transiently separates epithelial cells, providing a direction-selective and non-injurious intercellular pathway for passage of bulk plasma exudate into the airway lumen. This mechanism would allow potent plasma protein systems to operate on mucosal surfaces at sites of insults without compromising the mucosa as a barrier to luminal solutes.

Animals↗
PubMed1989

Effects of chronic and acute ethanol treatment during prenatal and early postnatal ages on testosterone levels and sexual behaviors in rats.

This study was prompted by previous findings that prenatal ethanol exposure may interfere with the differentiation of the sexual behavior in rats. Ethanol (6 g/kg) administered daily from day 15 postconception, resulted in elevated testosterone (T) levels on Day 18 in male and female fetuses. No alterations of sexual behavior in the ethanol-treated male offspring were seen under these conditions. However, in ethanol-treated female offspring the onset of regular estrous cycling was significantly delayed. Acute treatment with doses of ethanol, 2, 4 or 6 g/kg, was ineffective in influencing plasma T levels of the fetuses. Acute treatment with 3 g/kg ethanol did not prevent the rise of T levels normally occurring immediately after birth. In adulthood, but not at prepubertal age (Day 30), treatment of male rats with 2 g/kg ethanol caused a depression of plasma T levels. Possible mechanisms affected by ethanol exposure and influencing on the fetal development were discussed.

Age Factors↗
PubMed1989

Unsaturated lipids and intestinal bacteria as sources of endogenous production of ethene and ethylene oxide.

Studies of adducts to hemoglobin (Hb) have revealed levels of hydroxyethylations of i.a. N-terminus (valines) in knowingly unexposed animals and persons (non-smokers). This paper describes some exploratory experiments with mice, carried out with the aim of tracing the origin of these background levels. It is shown that the hydroxyethylvaline content in Hb is higher in animals fed unsaturated lipids and lower in bacterium-free as compared to control animals. Lipid peroxidation and metabolism of intestinal bacteria, giving rise to ethene, precursor of ethylene oxide, are thus indicated to be sources of observed background hydroxyethylations.

Animals↗
PubMed1989

Rapid detection of Bordetella pertussis by a monoclonal antibody-based colony blot assay.

Monoclonal antibodies to Bordetella pertussis filamentous hemagglutinin (FHA) and lipopolysaccharide (LPS) were used in a colony blot enzyme-linked immunosorbent assay designed for rapid detection of B. pertussis. Bacterial colonies from Bordet-Gengou agar plates were blotted onto nitrocellulose filter disks, lysed by immersion in chloroform, and reacted with monoclonal antibodies. Following reaction with peroxidase-conjugated rabbit anti-mouse immunoglobulin antisera and 4-chloro-1-naphthol, blue dots representing single colonies appeared on the filters. Blotting of single B. pertussis colonies could be performed after incubation for 40 h, i.e., before the colonies were visible by eye on the agar surface. Ten of ten B. pertussis strains showed positive blotting reactions with antibodies specific for B. pertussis FHA and LPS. Fourteen of fourteen B. parapertussis strains reacted with two of the FHA-specific antibodies but not with two of the LPS-specific antibodies. Strains of B. bronchiseptica showed a variable reaction pattern. No cross-reactions were observed with strains of Streptococcus mitis, S. pyogenes, S. pneumoniae, Staphylococcus aureus, Branhamella catarrhalis, or Klebsiella pneumoniae. This assay may be useful for identification of B. pertussis and B. parapertussis in suspected cases of whooping cough.

Antibodies, Bacterial↗
PubMed1989

Effect of three weeks' treatment with budesonide on in vitro contractile and relaxant airway effects in the rat.

An investigation was carried out to determine whether the sensitivity of rat tracheal smooth muscle to contractile and relaxant drugs was affected by three weeks' treatment with subcutaneous budesonide before death. Budesonide treatment was associated with a lower thymus weight and a smaller gain in body weight than in control animals. There was, however, no difference in the carbachol concentration-response curves or maximum responses to carbachol of tracheal smooth muscle from control and budesonide treated rats. Isometric and isotonic recordings agreed in these respects. Glucocorticoid treatment did not increase the sensitivity of tracheal smooth muscle to the relaxant drugs terbutaline and enprofylline; if anything there was a tendency for terbutaline and enprofylline to be less potent after budesonide treatment. The data suggest that in vivo effects of glucocorticoids on airway responsiveness to bronchodilating and bronchoconstricting drugs are unlikely to be due to a direct effect on bronchial smooth muscle.

Animals↗
PubMed1989

Budesonide reduces sensitivity to antigen but does not alter baseline tone or responsiveness to carbachol, terbutaline, and enprofylline in IgE-sensitized guinea-pig tracheae.

In vitro incubation of IgE-sensitized guinea-pig tracheal rings with 10(-7) M budesonide for 24 h significantly shifted the concentration-response curve to antigen by 5-fold to the right. Smooth muscle characteristics such as baseline tone, muscarinic contraction or relaxation to beta 2-receptor agonists and xanthines were not or only marginally affected by this exposure of airway tissue to a glucocorticoid drug. It is concluded that budesonide reduced anaphylactic IgE-driven release of contractile mediators.

Airway Resistance↗
PubMed1988

Facilitation of hippocampal long-term potentiation in slices perfused with high concentrations of calcium.

The effect of increased extracellular calcium on long-term potentiation (LTP) of synaptic transmission has been examined in the CA1 region of guinea pig hippocampal slice preparation using extracellular recordings from the dendritic layer. The application of high calcium (4 mM) led to an increase in the initial slope of the field potential that reversed following return to control (2 mM calcium) solution. The magnitude of the field potential change was unaffected by prior induction of LTP, and inputs tetanized after return to control solution showed the same amount of LTP as those tetanized before the high calcium application. These results suggest that the calcium application by itself did not induce LTP. Inputs tetanized in the high calcium solution showed a greater amount of potentiation than in control solution, any given train producing about twice as much potentiation. However, using long trains (40 impulses) at high strength (2 x test strength) gave similar LTP values in the two solutions. The facilitatory effect of high calcium on LTP was completely blocked by raising extracellular magnesium from 2 to 4 mM. As in control solution. LTP evoked in the high calcium solution was blocked by 2-amino-5-phosphono-valerate. The results support the view that calcium influx through postsynaptic N-methyl-D-aspartate receptor channels is directly involved in the induction of LTP.

2-Amino-5-phosphonovalerate↗
PubMed1988

Phorbol ester-induced synaptic potentiation differs from long-term potentiation in the guinea pig hippocampus in vitro.

The relationship between the synaptic potentiations evoked by the protein kinase C activator phorbol-12,13-diacetate and by afferent tetanization has been examined in the CA1 region of the hippocampal slice preparation using extracellular recording. It has been found that the potentiation of the field excitatory postsynaptic potential produced by 1 microM phorbol ester does not affect the amount of long-term potentiation (LTP) that can be evoked by afferent tetanization, and vice versa. A dissociation between phorbol ester-induced and tetanus-induced potentiation is also indicated by the fact that only the former was associated with changes in paired-pulse facilitation. On the other hand, as previously described, higher concentrations (10 microM) of phorbol ester blocked the tetanus-induced potentiation. Since the total potentiation given by 10 microM phorbol ester and tetanization depended on the order of presentation of the potentiation-inducing stimuli, it appears that the blockade of LTP is, at least partly, independent of the phorbol ester-induced potentiation.

Action Potentials↗
PubMed1988

Xanthines--symptomatic or prophylactic in asthma?

Perhaps xanthines should not be classified as bronchodilators because their clinical efficacy may reflect their antiinflammatory properties more than smooth muscle relaxation. Xanthines inhibit late phase airway reactions induced by allergen or chemical sensitizers. But, they offer little protection against methacholine-, histamine, or allergen-induced immediate bronchoconstriction and any protection seen is unrelated to the extent of the initial bronchodilatation. The antiinflammatory effects of xanthines include stabilization of a variety of inflammatory cells that are present in asthmatic airways. Another potentially important effect is the increase in number, and activity, of "suppressor" T-lymphocytes. Xanthines may also stabilize the barrier functions of both the airway epithelium and the airway microvessel (venular) wall. As a result less cellular and plasma-derived mediators are released, less plasma is exuded into the airway wall and less plasma enters the airway lumen. Penetration of inhaled macromolecules across the epithelium and into the airway wall may also be reduced. Future prospects for xanthines are interesting. A novel xanthine which lacks adenosine antagonist activity, enprofylline, has been shown to exert potent antiasthma actions without producing several of the excitatory, extrapulmonary, theophylline-like effects. We are only now starting to learn how xanthines actually work in the inflamed asthmatic and bronchitic airway. Nevertheless, the currently available data show that xanthines are likely to be more prophylactic than symptomatic in the treatment of asthma and chronic obstructive airway disease.

Adenosine↗
PubMed1988

Suppression of leukotriene synthesis in human leukocytes by a urea extract of Bordetella pertussis: evidence for mediation by adenylate cyclase toxin.

Incubation of human leukocytes with a urea extract of Bordetella pertussis led to inhibition of zymosan-induced leukotriene generation. The proteins in this extract are known to include an adenylate cyclase which suppresses certain defense mechanisms of leukocytes against bacterial invasion. The formation of leukotriene B4 and leukotriene C4, induced by serum-coated zymosan, was almost completely inhibited in the presence of 75 micrograms of urea-extracted proteins/ml cell suspension. This suppression by the bacterial urea extract was rapid, with the maximum effect occurring in the first min of incubation. The reduction in leukotriene generation was accompanied by a dramatic increase in intracellular cyclic AMP levels. Since leukotrienes are potent pro-inflammatory compounds, the present study indicates that Bordetella pertussis-induced suppression of leukotriene formation might be an important factor in the increased susceptibility to secondary bacterial infection, which occurs as a result of this disease.

Adenylate Cyclase Toxin↗
PubMed1988

Monoclonal antibody-based sandwich enzyme-linked immunosorbent assay for detection of Bordetella pertussis filamentous hemagglutinin.

Hybrid cell lines producing monoclonal antibodies against Bordetella pertussis filamentous hemagglutinin (FHA) were established. The specificity of the antibodies was ascertained by enzyme-linked immunosorbent assay (ELISA), sandwich ELISA, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by electroblotting. The monoclonal antibody-based sandwich ELISA was developed for detection of B. pertussis FHA. The assay had a detection limit of B. pertussis FHA in concentrations ranging from 7 to 15 ng/ml. The assay was also able to detect whole B. pertussis, Bordetella parapertussis, and Bordetella bronchiseptica bacteria. No cross-reactions were observed with strains of Branhamella catarrhalis, Neisseria meningitidis, Haemophilus influenzae, Klebsiella pneumoniae, Legionella pneumophila, Streptococcus miteor, or Streptococcus pneumoniae. The monoclonal antibodies might be useful for the detection of soluble antigens and whole bacteria in clinical samples and for studies of the immunochemical structure of B. pertussis FHA.

Animals↗
PubMed1988

Production and characterization of monoclonal antibodies directed against Bordetella pertussis lipopolysaccharide.

Hybrid cell lines producing monoclonal antibodies against Bordetella pertussis lipopolysaccharide (LPS) were established. The specificity of the antibodies was ascertained by enzyme-linked immunosorbent assay (ELISA) and ELISA-inhibition experiments with LPS and delipidated polysaccharide fragments (PS-1 and PS-2) prepared from B. pertussis LPS. Monoclonal antibody 9-1-H5 reacted with B. pertussis LPS only, whereas monoclonal antibodies 6-4-H6 and 9-2-A8 reacted with PS-1 and PS-2 as well as B. pertussis LPS. The antibodies did not react with LPS prepared from B. parapertussis and B. bronchiseptica in an LPS-specific ELISA. A monoclonal antibody-based sandwich ELISA was developed for detection of B. pertussis LPS. This assay had a detection limit of B. pertussis LPS in concentrations ranging from 0.16 to 0.32 microgram/ml. The assay was also shown to be specific for the detection of whole B. pertussis bacteria. No cross-reactions were observed with strains of Branhamella catarrhalis, Neisseria meningitidis, Streptococcus miteor, Haemophilus influenzae, or Legionella pneumophila. The monoclonal antibodies might be useful for the detection of soluble antigens and whole bacteria in clinical samples and for studies of the immunochemical structure of B. pertussis LPS.

Animals↗
PubMed1987

Methodological aspects and application of the immunoperoxidase staining technique in diagnostic fine-needle aspiration cytology.

The immunoperoxidase method was modified and adapted for use on cells obtained by fine-needle aspiration biopsy for routine diagnostic cytology. Combinations of different modes of fixation and graded trypsinization were tested. Best results were obtained with fixation in formol-acetone followed by enzyme digestion for 3-6 min; exact times were adjusted for the individual antigen. With optimal conditions as to fixation and proteolytic digestion, the method was found to be sensitive and reproducible and without artifactual background staining. Various intracytoplasmic antigens of diagnostic importance such as immunoglobulins, prostate-specific antigen, keratin, thyroglobulin, S-100, alpha-1-antitrypsin, and lysozyme in lymphoid cells, bone marrow cells, and tumor cells of epithelial and mesenchymal origin were detected. Staining of newly prepared or up to 2-yr-old specimens gave equally good results. Both cellular morphology and the results of immunoperoxidase staining can be studied simultaneously. The method is considered valuable for increasing accuracy of diagnostic cytology.

Antigens, Neoplasm↗
PubMed1987

Facilitated induction of hippocampal long-term potentiation in slices perfused with low concentrations of magnesium.

The generation of long-term potentiation of synaptic transmission in area CA1 of hippocampal slices of the guinea-pig has been examined in solutions containing low concentrations of magnesium ions. It was found that the induction of long-term potentiation is greatly facilitated in slices perfused with 0.1 mM magnesium but much less so with 0.5 mM magnesium solution. The long-term potentiation evoked by brief tetanization in 0.1 mM magnesium was prevented following application of the N-methyl-D-aspartate receptor antagonist 2-amino-5-phosphonovalerate. Moreover, the response to tetanization, recorded in the dendritic layer, contained a much greater than normal component blocked by 2-amino-5-phosphonovalerate. The latter represents current through postsynaptic N-methyl-D-aspartate receptor channels, suggesting that the facilitation of long-term potentiation is related to a facilitated opening of these channels. The results support the notion that the generation of long-term potentiation is related to current through N-methyl-D-aspartate receptor channels which is under the control of extracellular magnesium ions.

2-Amino-5-phosphonovalerate↗