Biomedical subjects

D Ericson

Publications and source records attributed to D Ericson.

At least 19 recordsLinked to original sources

PubMed2005

Low salivary IgA activity to cell-surface antigens of mutans streptococci related to HLA-DRB1*04.

BACKGROUND/AIMS: Mutans streptococci are found in almost all individuals, though there are large differences in colonization levels between individuals. These differences are not readily explained, though several factors are believed to influence the colonization. One factor is the immune response to mutans streptococci, mainly provided by salivary immunoglobulin A (IgA). In a previous study, differences in salivary IgA reactions to oral streptococci were observed between human leukocyte antigen (HLA)-DR4-positive and DR4-negative individuals. A lower salivary IgA activity to Streptococcus mutans in particular was most pronounced for two DR4 subgroups, DRB1*0401 and *0404. The main purpose of this study was to further investigate, in a larger study group, the salivary IgA activity to antigens of three oral streptococci in relation to different HLA-DRB1*04 alleles. METHODS: Stimulated saliva was collected from 58 HLA-DRB1*04-positive individuals. Whole cell antigen extracts from S. mutans, Streptococcus sobrinus and Streptococcus parasanguis and the streptococcal antigen (SA) I/II were separated in SDS-PAGE, transblotted and detected with diluted saliva (Western blot), and analyzed in a computer program. All distinct immunoblot bands over 100 kDa were recorded and compared in relation to DRB1*04. RESULTS: The immunoblots revealed lower salivary IgA reactions to S. mutans, S. sobrinus and SA I/II, but not to S. parasanguis, for the DRB1*0401- and *0404-positive individuals compared to other DRB1*04 types. For the *0401 subgroup there was a significant association with a lower IgA response to S. mutans. CONCLUSION: The results confirm earlier observations and may also support previous demonstrated association between colonization by mutans streptococci and the serologically defined HLA-DR4.

Adult↗

PubMed2004

Salivary IgA reactions to cell-surface antigens of oral streptococci.

BACKGROUND: In the immunoblot technique, using whole bacteria cell extracts as antigens, both intra- and extracellular antigens are detected, which gives a large number of immunoglobulin A (IgA) reactions (immunoblot bands) when incubated with saliva. It is important to distinguish which immunoblot bands represent bacterial cell-surface antigens, since these antigens could be involved in adhesion mechanisms and be available for blocking in vivo. METHODS: Bacterial extracts of Streptococcus mutans, Streptococcus sobrinus, Streptococcus parasanguis and the streptococcal antigen I/II were separated using SDS-PAGE. The antigens were detected with saliva in Western blot. Untreated saliva and saliva in which cell-surface reactive IgA had been absorbed with whole bacteria cells were analyzed. RESULTS: Approximately half the number of the bands were absent for saliva absorbed with homologous cells, compared to untreated saliva. The absorption pattern was almost identical for S. mutans and S. sobrinus but not for S. parasanguis. Salivary IgA reactive against streptococcal antigen I/II was absorbed by S. mutans cells, to a lesser extent by S. sobrinus cells, and not at all by S. parasanguis cells. CONCLUSION: It is likely that the bands that were absent after absorption represented cell-surface antigens. For S. mutans and S. sobrinus, these bands were probably the streptococcal antigen I/II.

Absorption↗

PubMed2004

Oral pilocarpine for treatment of opioid-induced oral dryness in healthy adults.

Pilocarpine induces a profuse flow of saliva when administered orally, but effects on drug-induced oral dryness have not been examined. The aim of this trial was to investigate if pilocarpine increases production of saliva in individuals suffering from dry mouth due to treatment with opioids. Sixty-five individuals were enrolled in a randomized, double-blind, placebo-controlled trial. The subjects received tramadol (50 mg t.d.s.) to induce oral dryness, and were thereafter assigned to one of three groups. Secretion rate of saliva was measured before and after tramadol, and after the oral administration of pilocarpine (5 mg), placebo, or no treatment. Baseline characteristics did not differ among the groups (mean +/- SEM: 0.37 +/- 0.06 mL/min), and tramadol lowered the secretion at the same level in all groups (0.15 +/- 0.02 mL/min). Pilocarpine increased the flow above that observed with placebo (0.66 +/- 0.19 vs. 0.15 +/- 0.02 mL/min). Thus, pilocarpine re-establishes the flow of saliva in the state of tramadol-induced oral dryness.

Administration, Oral↗

PubMed2003

Platelet storage solution improves the in vitro function of preserved platelet concentrate.

BACKGROUND AND OBJECTIVES: Stored platelets develop biochemical lesions, manifest as depressed haemostatic function, clot retraction and wound healing. ViaCyte trade mark, a proprietary experimental preservative solution (comprising D-ribose, D-glucose, Hanks solution, Hepes solution, bovine serum albumin, tic anticoagulant peptide and sterile water), was tested in comparison with the presently accepted storage solution, citrate-dextrose-phosphate-plasma (CDP-P), to evaluate its ability to preserve platelet function during storage. MATERIALS AND METHODS: Platelets stored in ViaCyte and platelets suspended in CDP-P were transferred to polypropylene tubes with PL732 covers and analysed for adenine nucleotide levels (ATP molecules), in vitro agonist-mediated P-selectin expression and aggregation. RESULTS: After 5 days of storage at room temperature, 12.2% of platelets stored in ViaCyte exhibited P-selectin expression at rest, and 64.2% exhibited P-selectin expression upon activation with thrombin challenge, an increase of 52%. Platelets stored in CDP-P exhibited 44.4% P-selectin expression at rest, suggesting significant activation during storage, and thrombin stimulation resulted in P-selectin expression of 47.9%, an increase of only 2.5% (P< or =0.002, untreated vs. treated). ViaCyte also maintained ATP levels throughout the storage period, while these levels became depressed in platelets stored in CDP-P (P< or =0.02, untreated vs. treated). Storing platelets in the experimental preservative solution maintained their ability to aggregate, while control platelets lost their ability to aggregate in response to agonist. CONCLUSIONS: ViaCyte appears to protect platelets during storage, reflected by a low level of induced lesions. Platelets stored in ViaCyte maintain energy levels at their resting state, which preserves their ability to aggregate and secrete granule contents, and ensures the availability of additional platelets for activation upon in vitro challenge.

Adenosine Triphosphate↗

PubMed2001

HLA-DR4 and salivary immunoglobulin A reactions to oral streptococci.

The aim of this study was to describe and compare salivary immunoglobulin A (IgA) antibody reactions to extracts of strains of three oral streptococci in human leukocyte antigen (HLA)-DR4-positive and -DR4-negative subjects. Whole paraffin-stimulated saliva samples were collected from 27 apparently healthy subjects. Previous HLA typing showed that 20 subjects were DR4 positive and 7 were DR4 negative. HLA-DRB1*04 subtyping was performed among the DR4-positive subjects. Whole-cell antigen extracts from Streptococcus mutans (KPSK 2), Streptococcus sobrinus (OMZ 65) and Streptococcus parasanguis (Nt 62) were separated in SDS-PAGE. The antigens were immunoblotted with diluted saliva (Western blot), scanned and analyzed in a computer system. All immunoblot bands were recorded in DR4-positive and DR4-negative saliva pools, and bands with an optical density >or=0.1 were selected for analysis in individual salivas. The DR4-negative subjects in general had more immunoblot bands and more distinct bands than did the DR4-positive subjects. A higher concentration of total IgA in saliva was correlated with more bands, especially to antigens separated from S. mutans. When the number of bands was calculated per IgA unit, significant differences were observed between DR4-positive and DR4-negative salivas. This was particularly seen for S. mutans and S. parasanguis. As the number of bands was analyzed in relation to DR4 subgroups, DRB1*04, there was a lower salivary IgA activity to S. mutans in the DRB1*0401 and *0404. The variable level of correlation previously demonstrated for S. mutans colonisation and serologically defined DR4 positive subjects might be explained by the heterogeneity in this group, and the relation should be sought on a subgroup level.

Antibodies, Bacterial↗

PubMed2000

The comparison of the efficacy and safety of intravenous versus subcutaneous immunoglobulin replacement therapy.

To compare the efficacy of immunoglobulin replacement therapy given intravenously versus subcutaneously to prevent infections in patients with primary antibody deficiency syndromes, an international, multicenter, open label, crossover study was designed. Forty patients were randomized to receive either subcutaneous or intravenous immunoglobulin replacement therapy for 1 year. In the second year, patients were switched to the alternative treatment, enabling patients to act as their own controls. Equivalent doses were given by both routes. Ethical approval was obtained from the review boards of the hospitals in which the patients were seen and written consent obtained from each patient. Patients with a primary antibody deficiency syndrome, either common variable immunodeficiency or IgG subclass deficiency or specific antibody deficiency, who required immunoglobulin replacement therapy were included in the study. Patients were excluded if they had significant thrombocytopenia (defined as platelets less than 50 x 10(9)/liter), had high levels of anti-IgA antibodies (defined as greater than 1:8192), or had severe adverse reactions to a blood product within the last 2 years. The primary end point was the number of infections and their severity (moderate and major) during the two treatment periods. Secondary end points were adverse reactions, length of infections, days lost from school or work due to infections, and acceptability of treatment regimens to the patients. Based on the assumption that it was difficult to prove equivalence of therapies statistically in crossover studies, an arbitrary number of 40 patients was selected on the basis that this might be achievable in 2 years. There are no significant differences in efficacy or adverse reaction rates between immunoglobulin replacement therapy given subcutaneously or intravenously.

Adolescent↗

PubMed1999

Transient reduction of mutans streptococci on tooth surfaces using a chlorhexidine-containing glass ionomer cement varnish.

Chlorhexidine (CHX) has been incorporated in polymer-based varnishes to reduce mutans streptococci (ms) by the sustained release of CHX. Such varnishes often adhere well to teeth initially but are easily peeled off. To be effective, repeated application is necessary. Glass ionomer (GI) cements interacts with tooth minerals to form a stronger bond, and the inherent brittleness of the cement makes it difficult to remove in large fragments. The fluoride content may also reduce demineralisation. The aim of this study was to observe whether ms could be reduced interproximally and in saliva by a single application of a GI cement containing 3.3% CHX gluconate (CHX-GI). After professional tooth cleaning and a mouth rinse for 2 min with 0.2% CHX, the teeth of six subjects were coated with CHX-GI cement. An additional six subjects were treated with a GI cement that did not contain CHX, and seven subjects received professional tooth cleaning only. Ms samples were taken interproximally with the tooth pick method before and after treatment. Interproximal levels were classified according to the number of colony-forming units (c.f.u.) found: 0, 1-20, 21-100, and > 100. Saliva ms were sampled with the Strip Mutans method. After four weeks, the interproximal levels of ms had decreased only in the CHX-GI group (p < 0.05). In this group 9 of 14 highly colonised sites (> 100 c.f.u.) remained reduced throughout this period. In the GI and the untreated group a slight increase of ms interproximally was seen after one week. The interproximal ms scores in all groups approached baseline levels after 8 weeks. There were no significant differences in saliva ms levels between the groups during the test period. GI cement may be a possible vehicle for CHX in reducing ms interproximally.

Administration, Topical↗

PubMed1998

Fissure penetration and antibacterial effect in vitro of a glass ionomer cement containing chlorhexidine gluconate.

Chlorhexidine has been incorporated in different varnishes to provide a slow release system on the tooth surface in order to reduce mutans streptococci. To provide an alternative vehicle for chlorhexidine with better adhesion properties compared to resin-based varnishes, glass ionomer cement (GI) has been suggested. However, one disadvantage for glass ionomers is a longer setting time compared to the resin-based varnishes. The aim with this study was to compare the fissure penetration and antibacterial characteristics of a glass-ionomer cement (GI) with a GI containing chlorhexidine gluconate (GI-CHX), and GI-CHX with added tataric acid (GI-CHX-TA) to reduce its setting time. Antibacterial properties against mutans streptococci were assessed by agar diffusion. GI, GI-CHX and GI-CHX-TA were applied with a microbrush on the occlusal surfaces of 4, 4 and 6 extracted molars respectively. After setting of cements, sections were ground with 1 mm intervals and photographed. The fissure penetration and adaptation of the cements were scored excellent, acceptable or unacceptable under blind conditions according to a standard. Seventy percent scored excellent with GI-CHX-TA (n = 54) compared with 40% with GI-CHX (n = 48) and 38% with GI (n = 40), (p < 0.05). GI-CHX and GI-CHX-TA had significant better antibacterial properties compared to GI or GI with added tataric acid only.

Analysis of Variance↗

PubMed1997

Clinical guidelines and self-assessment in dental education.

This paper describes an educational programme where clinical guidelines are used in dental education and assesses the value of these guidelines as perceived by undergraduate students. It presents a comparison of students' own assessments of their performance with those of their instructors, according to such guidelines. The educational programme at the Faculty of Odontology, Lund University, is described through 3 main principles: problem-based learning, adoption of a holistic attitude to patient care and the promotion of oral health. The dental curriculum occupies 5 years comprising 10 semesters. 41, 5th semester students (16 male and 25 female) participated in the study. Students were introduced to guidelines in group discussions at the beginning of the semester. At the completion of a patient's planned course of treatment, the outcome was formally assessed both by students and clinical instructors. Performance was scored in various categories as "excellent", "acceptable" or "unacceptable" according to the standards defined. A total of 1373 scores were made by both students and instructors. 88% cent of students used the guidelines often or almost always and found them useful. Overall, no students received an "unacceptable" score and 40% of students achieved a score of "excellent". Female students tended towards a higher score, but this was not significant. Instructors' and students' scores agreed in almost 90% of instances. Students under-scored their performance more frequently than they over-scored it. It appears that the use of clinical guidelines may encourage an increased awareness of the decision-making processes involved in clinical practice, but it must be acknowledged that these guidelines are complex both in derivation and application.

Curriculum↗

PubMed1997

HLA-DR4 and number of mutans streptococci in saliva among dental students and staff.

Our aim was to corroborate previous findings that HLA-DR4 carriers are characterized by higher levels of mutans streptococci in saliva than are individuals expressing other HLA-DR types. Of 68 subjects (dental students, staff, and faculty) who were sampled for salivary counts of mutants streptococci, 13 subjects with the lowest counts of mutans streptococci and 15 subjects with the highest counts were selected for HLA-typing. Of the 13 who expressed HLA-DR4, 8 were heavily colonized by mutants streptococci. Although a trend towards a relationship was found between HLA-DR4 carriage and high levels of mutans streptococci, it was not statistically significant. In this selected population, knowledge of how to minimize the risk of caries and mutans streptococci level may have influenced the results.

Adult↗

PubMed1995

Gating of thrombin in platelet aggregates by pO2-linked lowering of extracellular Ca2+ concentration.

Platelet accretion at sites of vascular injury yields a neo-tissue comprising packed platelets and having an interstitial space not supplied with blood. Within growing thrombi platelet masses become anoxic and depolarize to yield interstitial cation concentrations characteristic of the more voluminous platelet cytosol, with extracellular [Ca2+] falling below that adequate to support the plasma clotting system. The platelet-associated clotting system reactivates during disaggregation of the thrombi in vitro, which proceeds with high yield of apparently basal, functional platelets when specific anticoagulants are included in the disaggregating media. The capacity of regulatory demand to lower extracellular [Ca2+] in the microenvironment of platelet aggregates provides a physiological basis for evolution of the highly cooperative calcium interactions of the hemostasis system.

Adenosine Triphosphate↗

PubMed1995

Subcutaneous immunoglobulin replacement in patients with primary antibody deficiencies: safety and costs.

Immunoglobulins (IgG) as replacement therapy in primary antibody deficiencies can be given as intramuscular injections, or as intravenous or subcutaneous infusions. Our aims were to obtain information on the frequency of adverse systemic reactions during subcutaneous therapy, the occurrence and intensity of tissue reactions at the infusion sites, and serum IgG changes. Furthermore, we compared costs between the different replacement regimes. Our study included 165 patients (69 women, 96 men, aged 13-76 years) with primary hypogammaglobulinaemia or IgG-subclass deficiencies. Data were compiled from questionnaires filled in by the patients and from their medical records. 33,168 subcutaneous infusions (27,030 in home therapy) had been given. 106 (of which 16 were at home) adverse systemic reactions (100 mild, 6 moderate) were recorded in 28 patients (17%). No severe or anaphylactoid reactions occurred. Despite large immunoglobulin volumes given during 434 patient years (28,480 infusions), no signs have been found that indicate the transmission of hepatitis virus. Transient tissue reactions occurred at the infusion sites but were not troublesome to most patients and we found significant increases in mean serum IgG. The use of subcutaneous instead of intravenous infusions at home would reduce the yearly cost per patient for the health-care sector by US $10,100 in Sweden alone. We conclude that subcutaneous administration of IgG is a safe and convenient method of providing immunoglobulins. We were able to reach serum IgG concentrations similar to those by the intravenous therapy and we found that the method could also be used successfully in patients with previous severe or anaphylactoid reactions to intramuscular injections.

Adolescent↗

PubMed1995

Lifelong treatment with gammaglobulin for primary antibody deficiencies: the patients' experiences of subcutaneous self-infusions and home therapy.

Primary antibody deficiencies are chronic conditions and the patients usually need lifelong replacement therapy with gammaglobulin to prevent or reduce infections. It has been shown that the gammaglobulin can be given safely as subcutaneous infusions, instead of intramuscular injections or intravenous infusions. The major aim of this multi-centre study was to investigate the perceptions of the subcutaneous method among patients using it, both in hospital settings and as self-infusions at home. The study included 152 patients: 89 women, 63 men, mean age 44 years (range 18-76). Data were collected by using questionnaires. The patients were found to have a strongly positive attitude towards receiving the replacement therapy as subcutaneous infusions, perceived the method as effective in preventing infections and wished to retain the treatment. However, the younger patients found the subcutaneous infusions more uncomfortable and were less determined to continue with the therapy as compared with the older individuals. The responsibility for self-infusions at home was accepted by the patients, leading to an increased independence from the health care personnel and to a feeling of flexibility and freedom. As these patients have a chronic disease and are in need of lifelong treatment, it is important to discuss the development of structured education and training programmes in which special emphasis is placed on the support of the younger patients. It is suggested that Orem's nursing model of self-care may serve as a conceptual framework for nurses working in this specific area of nursing care.

Adolescent↗

PubMed1994

Intestinal and circulating antibody-forming cells in IgA-deficient individuals after oral cholera vaccination.

In search for a possible explanation for the different susceptibility to mucosal infections in IgA-deficient (IgAd) individuals, the frequency of total immunoglobulin-secreting cells (ISC) and vaccine-specific antibody-secreting cells (ASC) in intestinal mucosa and peripheral blood was determined by the enzyme-linked immunospot (ELISPOT) assay before and after peroral vaccination with a B subunit-whole cell cholera vaccine. Two groups of IgAd individuals, frequently infected and non-infected respectively, and normal controls were studied. Before cholera vaccination there were significantly higher frequencies of total IgM and IgG ISC in the gut, but not in the blood, in the IgAd individuals than in the controls. However, there were no significant differences between healthy and infection-prone IgAd individuals in this respect. In response to oral cholera vaccination, intestinal cholera toxin (CT)-specific IgG and IgM ASC were significantly more abundant among the IgAd individuals with a history of frequent infections than among the healthy IgAd individuals and controls. A similar difference in IgG and IgM ASC, although not significant, was also noted in blood. In IgAd individuals with frequent infections the vaccine induced variable anti-CT IgM ASC responses in the gut, ranging from no increase to a few strikingly high responses. In the controls, the CT-specific responses were dominated by IgA ASC. The data show that oral cholera vaccination evoked strong CT-specific IgG ASC responses, and in some cases also strong IgM ASC responses in the intestinal mucosa of IgAd patients with a history of frequent infections. The healthy IgAd individuals unexpectedly responded with lower numbers of CT-specific IgG ASC and did not show any increase of CT-specific IgM ASC in the intestinal mucosa. Thus, inability to mount a mucosal immune response to an oral antigen cannot in itself explain recurrent infections among many IgAd individuals.

Administration, Oral↗

PubMed1994

Reduction of cusp deflection resulting from composite polymerization shrinkage, using a light-transmitting cone.

For investigation of whether the use of a transparent plastic cone (Light-tip) influenced cusp deflection, as compared with a conventional method (control), the following experiments were performed. Mesiodistocclusal (MOD) cavities were prepared in 10 extracted premolars, and stainless steel pins were placed on the cusps. The cavities were bonded with Scotchbond Multipurpose, and the distance between the pins was measured. Control restorations using P-50 were placed in three increments, each increment having been polymerized for 40 s. For placing the test restorations, the Light-tip was fitted to the end of the curing wand and pressed into the resin in the proximal box, and the curing light was turned on. The next increment filled the recess created after the removal of the cone in the resin, and curing was performed with the plastic cone in the occlusal box. The third increment was cured without the cone. Each tooth was used for four restorations. In 16 of 20 cases, a significantly decreased cuspal flexure was found when the cone was used. The flexure decreased 24%, as compared with control.

Bicuspid↗

PubMed1993

Increase of in vitro curing depth of class II composite resin restorations.

Simulated class II cavity preparations were made in black Plexiglas acrylic, and various posterior composite resins were placed in the preparations and cured with and without a transparent cone-shaped "Light-tip" device. The transparent Light-tip device improved the curing depth approximately 2.2 mm, and this ability to illuminate the deeper portions of the restoration increases the potential to improve the curing of composite resin.

Acrylic Resins↗

PubMed1992

Influence of transient salivary flora on assessment of mutans streptococci level by the "Strip mutans" method.

The Dentocult SM ("Strip mutans") method occasionally shows decoloration of broth and of colonies of mutans streptococci on the plastic strip, thereby making interpretation difficult. In an attempt to explain the phenomenon and to investigate the influence of the salivary flora on the "Strip mutans" method, a total of 46 subjects were sampled. Saliva was analyzed using the "Strip mutans" method and conventional plating techniques to identify mutans streptococci, enterococci, staphylococci, enteric bacteria, and yeasts. Approximately 85% of the "Strip mutans" scores coincided with the conventional MSB-plating method. Two samples showed decolored mutans streptococci colonies on the "Strip mutans" strip. Enterococcus spp. were present in the saliva of these test subjects and could grow in the "Strip mutans" broth. Enterococcus faecalis was able to induce the same type of decoloration under experimental pure culture conditions. Three "Strip mutans" samples showed small colonies of mutans streptococci, visible only under magnification (x 10-20). Staphylococcus epidermidis was present in these saliva samples and showed heavy growth in the broth. Under experimental pure culture conditions S. epidermidis also inhibited the growth of mutans streptococci to some extent.

Adult↗

PubMed1991

Reduction of cervical gaps in class II composite resin restorations.

Class II cavities prepared in brass models and in extracted teeth were restored with three light-cured composite resins. A transparent cone-shaped device (Light-tip) at the end of the light source was pressed into the filling material in the proximal box for curing the resin. A second layer was filled in the recess left by the cone and cured without the cone. Controls consisted of fillings cured in two layers. In the brass cavities the contraction gap was 10 microns (+/- 10.6) with use of the cone compared with 109.5 microns (+/- 46.5) in control fillings (p less than 0.001). Extracted teeth were restored without etching of the enamel. Cervical contraction gaps in control restorations were reduced by more than half with the use of the transparent cone technique.

Acrylic Resins↗