Biomedical subjects

A Gustafsson

Publications and source records attributed to A Gustafsson.

At least 55 records · Page 3Linked to original sources

PubMed1999

Molecular mechanisms underlying interferon-alpha-induced G0/G1 arrest: CKI-mediated regulation of G1 Cdk-complexes and activation of pocket proteins.

One prominent effect of IFNs is their cell growth-inhibitory activity. The mechanism behind this inhibition of proliferation is still not fully understood. In this study, the effect of IFN-alpha treatment on cell cycle progression has been analysed in three lymphoid cell lines, Daudi, U-266 and H9. Examination of the growth-arrested cell populations shows that Daudi cells accumulate in a G0-like state, whereas U-266 cells arrest later in G1. H9 cells are completely resistant to IFN-alpha's cell growth-inhibitory effects. The G0/G1-phase arrest is preceded by a rapid induction of the cyclin-dependent kinase inhibitors (CKIs), p21 and p15. In parallel, the activities of the G1 Cdks are significantly reduced. In addition to p21/p15 induction, IFN-alpha regulates the expression of another CKI, p27, presumably by a post-transcriptional mechanism. In the G1 Cdk-complexes, there is first an increased binding of p21 and p15 to their respective kinases. At longer exposure times, when Cdk-bound p15 and p21 decline, p27 starts to accumulate. Furthermore, we found that IFN-alpha not only suppresses the phosphorylation of pRb, but also alters the phosphorylation and expression of the other pocket proteins p130 and p107. These data suggest that induction of p21/p15 is involved in the primary IFN-alpha response inhibiting G1 Cdk activity, whereas increased p27 expression is part of a second set of events which keep these Cdks in their inactive form. Moreover, elevated levels of p27 correlated with a dissociation of cyclin E/Cdk2-p130 or p107 complexes to yield cyclin E/Cdk2-p27 complexes. In resistant H9 cells, which possess a homozygous deletion of the p15/p16 genes and lack p21 protein expression, IFN-alpha causes no detectable changes in p27 expression and, furthermore, no effects are observed on either pocket proteins in this cell line. Taken together, these data suggest that the early decline in G1 Cdk activity, subsequent changes in phosphorylation of pocket proteins, and G1/G0 arrest following IFN-alpha treatment, is not primarily due to loss of the G1 kinase components, but result from the inhibitory action of CKIs on these complexes.

Burkitt Lymphoma↗

PubMed1999

Tobacco smoking and gingival neutrophil activity in young adults.

The influence of smoking on the activity of the gingival neutrophils in young periodontally healthy adults was studied. The neutrophil activity was measured in terms of the gingival crevicular fluid (GCF) levels of elastase, lactoferrin (LF), alpha-1-antitrypsin (alpha-1-AT), alpha-2-macroglobulin (alpha-2 MG) and protein. 30 healthy dental students with no clinical signs of periodontitis, 15 smokers (8 women and 7 men) aged 20-32 years and 15 non-smokers (7 women and 8 men) aged 22-31 years, volunteered to take part in the investigation. The gingival inflammation was registered at 6 sites and the GCF volume was collected from the same sites. The GCF volume was measured with a Periotron 6000. The elastase activity was measured with a chromogenic low molecular substrate and the LF alpha-1-AT, alpha-2-MG levels were determined with ELISA. The protein concentration was measured by the Bradford method. The results showed a statistically significantly lower GCF volume among smokers as compared to non-smokers. No significant difference was found in the elastase activity/microl of the GCF supernatant between smokers and non-smokers but there was a large inter-individual variation. Nor did the concentrations of LF, alpha-1-AT, alpha-2-MG and protein per microl GCF differ significantly between the 2 groups. The results suggest that the influence of smoking on the examined factors associated with neutrophil activity is limited under healthy or slightly inflamed gingival conditions giving only small amounts of GCF.

Adult↗

PubMed1999

Increased release of elastase from in vitro activated peripheral neutrophils in patients with adult periodontitis.

The main object of this study was to determine if there was a difference between patients with adult periodontitis and healthy controls in the release of elastase. We also wanted to test the release of alpha-1-antitrypsin and lactoferrin from in vitro-activated peripheral neutrophils. A leukocyte-rich preparation from venous blood was made by lysing the red blood cells. The leukocytes were stimulated for 1 h at 37 degrees C with opsonized Staphylococcus aureus and the released elastase was measured with a chromogenic substrate. The release of elastase after stimulation with bacteria was significantly higher in patients than in controls. The amounts of elastase from unstimulated cells, i.e., both released extracellularly and extracted from the pellet, were similar in the 2 groups. However, after stimulation, the amount of elastase in the patient group, but not in the control group, was significantly increased. Similar releases of alpha-1-antitrypsin (AIAT) and lactoferrin were found in both groups of subjects. In conclusion, this study shows that peripheral neutrophils from patients with adult periodontitis release more active elastase after in vitro activation compared to healthy controls. The release of A1AT and lactoferrin showed no differences, indicating that the increased elastase activity was not due to a impaired inhibition by A1AT and that the differences in degranulation were limited to the primary granula.

Adult↗

PubMed1999

Repeated administration of trimethoprim/sulfadiazine in the horse--pharmacokinetics, plasma protein binding and influence on the intestinal microflora.

Six healthy adult horses were given repeated administrations of trimethoprim/ sulfadiazine (TMP/SDZ) intravenously (i.v.) (2.5 mg/kg TMP and 12.5 mg/kg SDZ) and orally (p.o.) as a paste (5 mg/kg TMP and 25 mg/kg SDZ). Both formulations were given twice daily for 5 days, with a 3-week interval between i.v. and oral administration. The influence of the drug combination on the intestinal microflora was examined and the plasma concentrations, pharmacokinetic parameters and plasma protein binding were determined. There were no major changes in the bacterial intestinal flora and no clinical evidence of gastrointestinal disturbances following the i.v. and oral TMP/SDZ administration. An initial reduction in the number of coliform bacteria during the treatment was notable, though with no evident difference between i.v. and oral treatment. The minimum concentration during a dose interval at steady state (Cminss), the elimination half-life (t1/2beta) and the mean residence time (MRT) were significantly greater after oral administration compared to i.v. for both TMP and SDZ. The plasma protein binding was measured to be 20% for SDZ and 35% for TMP. Oral administration of TMP/SDZ in a dose of 30 mg/kg given twice daily in the form of paste appeared as a satisfactory method for obtaining plasma levels above MIC (minimum inhibitory concentration in vitro) values during the interdosing interval.

Administration, Oral↗

PubMed1999

The effect of faecal enema on five microflora-associated characteristics in patients with antibiotic-associated diarrhoea.

BACKGROUND: Patients with antibiotic-associated diarrhoea (AAD) show significant disturbances in short-chain fatty acid pattern. In the present study five more microflora-associated characteristics (MACs) were investigated before and after administration of an enema containing faecal microflora from a healthy person on a Western diet. METHODS: The functions of the microflora were determined with gas chromatography, electrophoresis, and spectrophotometry. RESULTS: The conversion of cholesterol to coprostanol and the concentration of urobilinogen and trypsin were significantly reduced in comparison with healthy persons. The pattern of mucin was altered, but beta-aspartylglycine remained the same as in healthy persons. Enema treatment influenced these functions to different extents. CONCLUSION: Most MACs were significantly disturbed in patients with AAD. Administration of a human faecal enema modified these changes and relieved diarrhoea, usually within 4 days.

Adult↗

PubMed1999

Periodontitis increases chemiluminescence of the peripheral neutrophils independently of priming by the preparation method.

OBJECTIVE: The aim was to investigate whether increased Fcgamma-receptor (FcgammaR)-induced chemiluminescence (CL) from peripheral neutrophils in periodontitis could be due to increased sensitivity to non-specific priming by the cell preparation. DESIGN: Two methods of preparation were used: (1) cells purified by density centrifugation and lysis of erythrocytes; and (2) cells in a leukocyte suspension obtained by lysis of erythrocytes alone. METHODS: Neutrophils from 17 subjects with periodontitis and pair-matched healthy controls were studied by CL and flow cytometry (CD16, CD15 and CD11b). RESULTS: Higher CL was found in the purified neutrophils, indicating higher non-specific priming by the Percoll density centrifugation. Priming with TNFalpha and lipopolysaccharide abolished this difference. The net effect of specific priming was significantly lower in the purified neutrophils, indicating a depletion of the priming sensitivity by the density centrifugation. Both preparations reduced CD15 in relation to whole blood, while there was no difference between the two methods in any of the membrane markers. Thus, in both preparations, lysis alone changed the membranes to the same extent. Both methods gave nearly the same relative CL increase in the periodontitis patients as in the controls. CONCLUSION: There was no difference between the neutrophils from patients and controls in sensitivity to non-specific priming by the preparation method. The higher FcgammaR-induced CL in patients with periodontitis is not related to such a non-specific priming by density centrifugation.

Adult↗

PubMed1999

Effect of periodontitis and smoking on blood leukocytes and acute-phase proteins.

BACKGROUND: We have previously found hyperreactive neutrophils, intrinsic or induced, in periodontitis patients by in vitro quantitation of free oxygen radicals. The effects of periodontitis and cigarette smoking on blood parameters have generally been described separately. Our aim was to compare these systemic effects of periodontitis and cigarette smoking, separately and in combination, in order to study the hyperreactivity in peripheral neutrophils. METHODS: Blood cells and acute-phase proteins were studied in 40 periodontitis patients and 43 healthy controls. The generation of free oxygen radicals from neutrophils was measured as luminol-enhanced chemiluminescence (CL) after activation of their Fcgamma receptors with opsonized Staphylococcus aureus. RESULTS: An increase in CL in peripheral neutrophils from periodontitis patients was confirmed. Smoking had no significant effect on CL. The periodontitis patients had higher concentrations of C-reactive protein (CRP) than the controls. ANOVA analysis showed that the increase in neutrophil count, haptoglobin, and alpha-1 antitrypsin levels was significantly influenced by cigarette smoking. IgG2 was lower in patients than in controls (P <0.017, ANOVA), and there was an interaction between periodontitis and smoking (P<0.047, ANOVA). The lower concentration of IgG2 in patients who smoke may impair neutrophil function and be a mechanism by which smoking aggravates periodontitis. CONCLUSIONS: In general, the combination of periodontitis and cigarette smoking alters the parameters studied. The effects of periodontitis on CRP and IgG2 means that periodontal lesions may also leak agents, priming the peripheral neutrophils to increased CL.

Adult↗

PubMed1999

Increased interleukin-1beta concentration in gingival crevicular fluid as a characteristic of periodontitis.

BACKGROUND: The levels of interleukin-1beta (IL-1beta) have been reported to be higher in sites with periodontitis than in healthy controls. This may be the result of a more severe inflammation and/or constitutional differences in IL-1beta production. Our aim was to test the hypothesis that the level of IL-1beta in gingival crevicular fluid (GCF) is a characteristic trait of periodontitis, regardless of the degree of tissue destruction. As a secondary aim, we investigated the correlation between IL-1beta and neutrophil elastase. An untreated population was used. METHODS: GCF samples from inflamed sites in 13 patients with gingivitis (GG), and from inflamed sites with shallow (GP) and deep (PP) pockets in 18 patients with periodontitis were collected. Interleukin-1beta, elastase-alpha-1-antitrypsin complex (E-A1AT), alpha-1-antitrypsin (A1AT), and alpha-2-macroglobulin (A2MG) were measured with ELISA. Elastase activity was measured with a specific substrate. RESULTS: The concentration of IL-1beta was significantly higher in PP than in GG, but no significant differences were detected between PP and GP. A weak positive correlation between the elastase activity and IL-1beta was also observed. The elastase activity had a tendency to be higher in PP, although no significant difference was found among the 3 groups. The concentrations of E-A1AT, A1AT, and A2MG were similar in the 3 types of sites. CONCLUSIONS: The levels of IL-1beta in GCF were increased in samples from periodontitis patients, regardless of the severity of disease at the sampled site, suggesting that the levels of IL-1beta are typical of a given patient.

Adult↗

PubMed1999

Breast cancer risk after radiotherapy in infancy: a pooled analysis of two Swedish cohorts of 17,202 infants.

The incidence of breast cancer was studied in a cohort of 17,202 women irradiated for skin hemangioma in infancy at the Radiumhemmet, Stockholm, or the Sahlgrenska University Hospital, Gothenburg. A major part of the cohort had been treated with radium-226 applicators, and the mean absorbed dose to the breasts was 0.29 Gy (range <0.01-35.8 Gy). Two hundred forty-five breast cancers were diagnosed in the cohort during the period 1958-1993, and the standardized incidence ratio (SIR) was 1.20 (95% CI 1.06-1.36). Different dose-response models were tested, and a linear model gave the best fit. Neither age at exposure, breast dose rate, ovarian dose nor time since exposure had any statistically significant modifying effect, and breast dose was the only determinant of risk. The excess relative risk per gray (ERR/Gy) was 0.35 (95% CI 0.18-0.59), which is lower than in most other studies.

Adolescent↗

PubMed1998

An evolutionary approach to the design of glutathione-linked enzymes.

Studies of protein structure provide information about principles of protein design that have come into play in natural evolution. This information can be exploited in the redesign of enzymes for novel functions. The glutathione-binding domain of glutathione transferases has similarities with structures in other glutathione-linked proteins, such as glutathione peroxidases and thioredoxin (glutaredoxin), suggesting divergent evolution from a common ancestral protein fold. In contrast, the binding site for glutathione in human glyoxalase I is located at the interface between the two identical subunits of the protein. Comparison with the homologous, but monomeric, yeast glyoxalase I suggests that new domains have originated through gene duplications, and that the oligomeric structure of the mammalian glyoxalase I has arisen by 'domain swapping'. Recombinant DNA techniques are being used for the redesign of glutathione-linked proteins in attempts to create binding proteins with novel functions and catalysts with tailored specificities. Enzymes with desired properties are selected from libraries of variant structures by use of phage display and functional assays.

Binding Sites↗

PubMed1998

Faecal short-chain fatty acids in patients with antibiotic-associated diarrhoea, before and after faecal enema treatment.

BACKGROUND: Antibiotic-associated diarrhoea (AAD) may range from mild disturbances to severe pseudomembranous colitis. Many antibiotics affect several intestinal microflora-associated characteristics, such as short-chain fatty acid (SCFA) pattern. In the present study we investigated SCFAs in 31 patients on admittance to the hospital for severe AAD. Nine patients were followed up more extensively after they had received an enema containing faecal microflora from a healthy person on a Western diet. METHODS: Faecal SCFAs were determined by gas chromatography. The enema was characterized before use. RESULTS: AAD patients showed significant disturbances in faecal SCFA pattern. Clinically, most enema-treated patients recovered within days and had no relapses within 18 months. CONCLUSIONS: Intestinal microflora showed great disturbances, and the amounts of SCFAs were reduced, although the diarrhoea was not related to total amount SCFAs. Administration of a faecal enema resulted in the clinical recovery of most patients with severe diarrhoea within 4 days.

Adult↗

PubMed1998

Evaluation of attenuation corrections using Monte Carlo simulated lung SPECT.

SPECT (single photon emission computed tomography) images are distorted by photon attenuation. The effect is complex in the thoracic region due to different tissue densities. This study compares the effect on the image homogeneity of two different methods of attenuation correction in lung SPECT; one pre-processing and one post-processing method. This study also investigates the impact of attenuation correction parameters such as lung contour, body contour, density of the lung tissue and effective attenuation coefficient. The Monte Carlo technique was used to simulate SPECT studies of a digital thorax phantom containing a homogeneous activity distribution in the lung. Homogeneity in reconstructed images was calculated as the coefficient of variation (CV). The isolated effect of the attenuation correction was assessed by normalizing pixel values from the attenuation corrected lung by pixel values from the lung with no attenuation effects. Results show that the CV decreased from 12.8% with no attenuation correction to 4.4% using the post-processing method and true densities in the thoracic region. The impact of variations in the definition of the body contour was found to be marginal while the corresponding effect of variations in the lung contour was substantial.

Algorithms↗

PubMed1998

Protease activity in gingival crevicular fluid: presence of free protease.

Our aim was to study protease activity in GCF from inflamed sites with or without tissue destruction. 19 patients with both periodontitis and gingivitis sites and 12 patients having gingivitis alone participated in the study. GCF samples were collected by an intracrevicular washing method. The protease activity was measured as degradation of FITC-conjugated casein. To obtain a semiquantitative estimate of the harvested GCF volume, we measured the transferrin concentration in the wash-fluid. The protease activity was significantly higher in the deep pockets in periodontitis patients than in shallow pockets in the same patients. This difference was still higher when the ratio of protease activity to the amount of transferrin in the sample was plotted. Although protease activity was lower in samples from gingivitis patients than in the deep pockets in periodontitis patients, the difference was not significant. About 90% of the activity could be inhibited by the addition of an excess amount of alpha-1-antitrypsin (A1AT). This study shows that protease activity is higher in inflamed sites with tissue destruction than in inflamed sites without. Most of this activity could be inhibited by A1AT, which suggests that the activity is due to an imbalance between protease and antiprotease rather than to proteases insensitive to A1AT.

Adult↗

PubMed1998

Hyper-reactive peripheral neutrophils in adult periodontitis: generation of chemiluminescence and intracellular hydrogen peroxide after in vitro priming and FcgammaR-stimulation.

We have earlier reported a higher Fcgamma-receptor (FcgammaR)-mediated generation of reactive oxygen species, measured as luminol-enhanced chemiluminescence (CL) from peripheral neutrophils in adult periodontitis patients. The aims of this study were to confirm our previous results and to elucidate the mechanism of this phenomenon by measuring CL in parallel with the intracellular production of hydrogen peroxide, after stimulation with opsonized bacteria. To determine whether the higher CL was associated with altered responsiveness to priming, the cells were preincubated with tumor necrosis factor alpha (TNFalpha) and lipopolysaccharide (LPS). While CL was significantly higher in subjects with periodontitis, there was no difference in hydrogen peroxide production between the patients and the controls, indicating that the hyperreactivity is related to the generation of other oxygen species than H2O2 and/or to processes in the outer cell membrane. The responsiveness to priming with LPS on CL was slightly but not significantly higher in the periodontitis group, suggesting that priming could be of value for distinguishing subjects with periodontitis. When assaying intracellular production of H2O2, TNFalpha and LPS had both a priming and an activating effect. There were no significant differences between the two groups. In conclusion, this study shows a higher FcgammaR-mediated CL of peripheral neutrophils from adult patients with periodontitis, thus confirming our earlier results. The hyperreactivity seems to be related to the outer cell membrane or to oxygen species other than H2O2.

Adult↗

PubMed1998

Activity and inhibition of elastase in GCF.

The aim of this study was to investigate the presence of free elastase in GCF Samples were taken from inflamed sites in 12 subjects with gingivitis alone and from inflamed sites with and without tissue destruction in 19 patients having periodontitis. Elastase activity was measured with a low molecular weight substrate. To distinguish between free elastase and elastase bound to alpha-2-macroglobulin (A2MG), an excess of alpha-1-antitrypsin (A1AT) was added to the samples. The activity that could be inhibited by A1AT was considered as free elastase, and the uninhibited activity as derived from the elastase-A2MG complex. The elastase-A1AT complex was measured with an ELISA. Free elastase was found in almost all samples, but both the total amount and the proportion of free elastase were higher in samples from sites showing destruction. The elastase-A2MG complex was also increased in sites with tissue destruction, while there was no significant difference in the amount of A1AT complex between the 3 categories of sites. In conclusion, our study clearly reveals free elastase in GCF The elevated levels of free elastase in sites showing tissue destruction seem to be due to a combination of increased release of elastase and an inactivation of A1AT.

Adult↗

PubMed1998

Clostridium difficile associated with acute colitis in mares when their foals are treated with erythromycin and rifampicin for Rhodococcus equi pneumonia.

In Sweden, mares sometimes develop acute, often fatal, colitis when their foals are treated orally with erythromycin and rifampicin for Rhodococcus (R.) equi infection. Clostridium (C.) difficile, or its cytotoxin, was demonstrated in faecal samples from 5 of 11 (45%) mares with diarrhoea. By contrast C. difficile was not found in the faecal flora of 12 healthy mares with foals treated for R. equi infection or in 56 healthy mares with healthy untreated foals. No other enteric pathogen was isolated from any diarrhoeic mare. Of 7 investigated treated foals, 4 had a high (1651.0, 1468.3, 273.0 and 88.8 microg/g) faecal concentration of erythromycin. The dams of those 4 foals developed acute colitis, whereas the dams of 3 foals with a lower (26.3, 4.6 and 3.7 microg/g) faecal erythromycin concentration remained healthy, indicating that there might have been an accidental intake of erythromycin by mares. The foals treated with antibiotics were regarded as asymptomatic carriers and potential reservoirs, as C. difficile was found in 7 of 16 foals investigated, while 56 untreated foals proved negative. The isolated C. difficile strains proved resistant to both erythromycin (MIC>256 mg/l) and rifampicin (MIC>32 mg/l), a fact that may have favoured the growth of C. difficile in the foal intestine. All mares found positive for C. difficile were, or had recently been, hospitalised together with their foals, indicating that C. difficile may be a nosocomial infection, in horses. The results emphasise that routine testing for C. difficile and its cytotoxin is recommended when acute colitis occurs in mares when their foals are treated with erythromycin and rifampicin. Preventive measures in order to avoid accidental ingestion of erythromycin by mares from the treatment of their foals are suggested.

Actinomycetales Infections↗

PubMed1998

Neutrophil response and microbiological findings around teeth and dental implants.

The aim of this study was to compare the neutrophil response, measured as both functional and antigenic elastase, around teeth and titanium implants and to relate these findings to the microbiota. The 31 patients included in the study had been treated successfully for total or partial edentulism with titanium implants. Crevicular fluid and microbiological samples were taken from 3 sites: 1) crevices around teeth and 2) implants in 16 partially edentulous patients and 3) crevices around implants in 15 edentulous patients. All sites sampled showed similar degrees of inflammation assessed by gingival index and total protein concentration. The samples were analyzed for elastase activity and immunoreactive elastase. The elastase activity was significantly higher in crevices surrounding implants in partially edentulous patients compared with implants in edentulous patients. The antigenic elastase showed no difference among the 3 sites. Gram-positive cocci were the main bacterial species in all 3 groups. Edentulous patients tended to have lower frequency of black pigmenting anaerobes. No correlation of analyzed bacteria and elastase activity was found between the 3 sites. This study indicates that, despite a similar appearance of clinical parameters and absence of significant differences in the microbiota, the inflammation around implants in partially edentulous patients induces a stronger neutrophil response than does the inflammation around implants in edentulous patients.

Adult↗

PubMed1998

Engraftment and chimerism, particularly of T- and B-cells, in children undergoing allogeneic bone marrow transplantation.

The spectrum of pediatric bone marrow transplantation has changed in recent years. Mismatched and unrelated donor transplants are common, demanding an increased vigilance to detect incipient graft failure, secondary lymphoma as well as relapse and other problems, which now are potentially treatable. To diagnose these complications it may be important to know whether blood and marrow cells are of recipient or donor origin. To evaluate the role of mixed donor-recipient chimerism in relation to clinical problems we adapted a polymerase chain-reaction technique, using fluorescent primers analyzing DNA fragment length polymorphisms, to follow prospectively 17 bone marrow grafted children. To increase the precision of chimerism analysis, immunomagnetically isolated leukocyte populations were assayed in selected cases. Five patients encountered clinical problems related to chimerism. One infant with adenosine deaminase deficiency failed to engraft stem cells, yet succumbed to graft-versus-host disease, mediated by mature donor T-cells. Three children developed significant mixed chimerism. One of these three patients died in relapse of leukemia, while the two other patients who had received T-cell depleted grafts had persistent recipient T-cells, in spite of engraftment. After 5 months, these were displaced by donor T-cells in one of the patients. In the fifth patient, also after T-cell depleted BMT, a fatal donor cell lymphoma occurred. Twelve children had stable full chimerism or in one case a low grade mixed chimerism and remain disease-free throughout follow up (median 9 months). In conclusion, the analysis of chimerism, particularly of separated leukocyte populations, offers an almost indispensable insight and a basis for therapeutic decisions in complicated situations such as grafting involving unrelated or mismatched donors, graft manipulation, adoptive immunotherapy and in immunodeficiency patients.

B-Lymphocytes↗