Biomedical subjects

K Petersson

Publications and source records attributed to K Petersson.

At least 19 recordsLinked to original sources

PubMed2006

Formation of a hard tissue barrier after pulp cappings in humans. A systematic review.

AIM: To evaluate the evidence on the formation of a hard tissue barrier after pulp capping in humans. METHODOLOGY: A PubMed and CENTRAL literature search with specific indexing terms and a hand search were made. The authors assessed the level of evidence of each publication as high, moderate or low. Based on this, the evidence grade of the conclusions was rated as strong, moderately strong, limited or insufficient. RESULTS: The initial search process resulted in a total of 171 publications. After reading the abstracts and hand searching the reference lists of the retrieved publications, 107 studies were retrieved in full-text and interpreted. After the interpretation, 21 studies remained and were included in the systematic review and given a level of evidence. No study had a high level of evidence, one study had moderate and 20 studies had a low level of evidence. There was heterogeneity between the studies; therefore, no meta-analysis was performed. The majority of studies on pulp capping using calcium hydroxide based materials reported formation of hard tissue bridging, studies on other pulp capping materials such as bonding agents presented inferior results. The evidence grade was insufficient. CONCLUSIONS: Insufficient evidence grade does not necessarily imply that there is no effect of a pulp capping procedure or that it should not be used. Rather, the insufficient evidence underpins the need for high-quality studies.

Calcium Hydroxide↗

PubMed2006

The oral ecosystem: implications for education.

We propose a model that is applicable to oral health education. The model describes the oral cavity in a complexity-based ecological context. This concept includes the premise that factors from different organisational levels (biological, individual, community, society) interact in a complex way with the potential to 'stress' the ecosystem and thereby provoke changes. This mode of action complies with the understanding of the oral cavity as a complex adaptive system. An ecological model is actively used in the undergraduate problem-based curriculum at the Faculty of Odontology, Malmö University, Sweden and has recently been applied as a conceptual basis for the new dental curriculum being established at the University of Tromsø in Northern Norway. The purpose is to encourage and promote an ecological, health-oriented view and to stimulate reflections on premises for oral health and diseases in an integrated context.

Curriculum↗

PubMed2005

Dental pulp capping: effect of Emdogain Gel on experimentally exposed human pulps.

AIM: To investigate the effect of Emdogain Gel (Biora AB, Malmo, Sweden), consisting of a enamel matrix derivative (EMD) in a propylene glycol alginate (PGA) vehicle, on experimentally exposed human pulps and to register postoperative symptoms. METHODOLOGY: Nine pairs of contralateral premolars scheduled for extraction on orthodontic indications were included. Following a superficial pulp amputation performed with a small (016) diamond bur, either EMDgel or a mix of calcium hydroxide and sterile saline was placed at random in contact with the pulp wound. The subjects made records of symptoms and were also interviewed about pain/discomfort by a blinded examiner. After 12 weeks the teeth were extracted, prepared and subjected to light microscopic examination in which the inflammation and newly formed hard tissue in the pulp were analysed. Immunohistochemistry was performed using affinity-purified rabbit anti-EMD polyclonal antibodies. RESULTS: Postoperative symptoms were less frequent in the EMDgel-treated than in the calcium hydroxide-treated teeth, especially during the first six weeks. In the EMDgel-treated teeth, new tissue partly filled the space initially occupied by the gel and hard tissue was formed alongside the exposed dentine surfaces and in patches in the adjacent pulp tissue. EMD was detected in the areas where new hard tissue had been formed. The wound area of the EMDgel-treated teeth exhibited inflammation in the majority of the teeth whereas less inflammation was seen in the calcium hydroxide-treated teeth where the hard tissue was formed as a bridge. CONCLUSIONS: In the EMDgel-treated teeth, postoperative symptoms were less frequent and the amount and pattern of hard tissue formation were markedly different than in the teeth treated with calcium hydroxide. However, the operative procedure and the formulation with EMD in a PGA vehicle do not seem to be effective for the formation of a hard tissue barrier.

Adolescent↗

PubMed2004

Interplay between superantigens and immunoreceptors.

Superantigens (SAGs) cause a massive T-cell proliferation by simultaneously binding to major histocompatibility complex (MHC) class II on antigen-presenting cells and T-cell receptors (TCRs) on T cells. These T-cell mitogens can cause disease in host, such as food poisoning or toxic shock. The best characterized groups of SAGs are the bacterial SAGs secreted by Staphylococcus aureus and Streptococcus pyogenes. Despite a common overall three-dimensional fold of these SAGs, they have been shown to bind to MHC class II in different ways. Recently, it has also been shown that SAGs have individual preferences in their binding to the TCRs. They can interact with various regions of the variable beta-chain of TCRs and at least one SAG seems to bind to the alpha-chain of TCRs. In this review, different subclasses of SAGs are classified based upon their binding mode to MHC class II, and models of trimolecular complexes of MHC-SAG-TCR molecules are described in order to reveal and understand the complexity of SAG-mediated T-cell activation.

Amino Acid Sequence↗

PubMed2002

A pTalpha-negative subpopulation of CD25+ TN thymocytes revealed by a transgenic marker.

We have recently generated 5'lambda5-huTAC mice, which express the human CD25 (huTAC) gene under the control of the 5'-flanking region of the mouse lambda5-gene. The huTAC-transgene was expressed in pre-B cells but neither in mature B cells nor in T cells of these mice. In this report we demonstrate that the transgene is also transiently expressed by adult CD25+ CD3-CD4-CD8- (triple negative, TN) thymocytes and in fetal thymocytes. The huTAC+, in contrast to the huTAC- subpopulation of the CD44+CD25+ TN cells, was unexpectedly found not to express the pTalpha-gene. Still the huTAC+CD44+CD25+ TN cells reconstituted the development of both alphabeta and gammadelta lineage cells equally efficiently as the pTalpha-expressing huTAC- fraction, demonstrating that this pTalpha-negative subpopulation contained precursors for both T-cell lineages. Single cell reverse transcription-polymerase chain reaction (RT-PCR) experiments demonstrated that also in normal mice only a fraction of CD44+CD25+ and CD44-CD25+ TN cells expressed this gene. Taken together, these data indicate that huTAC transgene expression revealed a truly pTalpha-negative fraction of the CD44+CD25+ TN cells. The observation that not all precursors in the CD25+ TN population express the pTalpha-gene has important implications for the understanding of early T-cell development and T-cell lineage commitment.

Animals↗

PubMed2001

Crystal structure of a superantigen bound to MHC class II displays zinc and peptide dependence.

The three-dimensional structure of a bacterial superantigen, Staphylococcus aureus enterotoxin H (SEH), bound to human major histocompatibility complex (MHC) class II (HLA-DR1) has been determined by X-ray crystallography to 2.6 A resolution (1HXY). The superantigen binds on top of HLA-DR1 in a completely different way from earlier co-crystallized superantigens from S.aureus. SEH interacts with high affinity through a zinc ion with the beta1 chain of HLA-DR1 and also with the peptide presented by HLA-DR1. The structure suggests that all superantigens interacting with MHC class II in a zinc-dependent manner present the superantigen in a common way. This suggests a new model for ternary complex formation with the T-cell receptor (TCR), in which a contact between the TCR and the MHC class II is unlikely.

Amino Acid Sequence↗

PubMed2001

[Residential care after the geriatric care reform. District nurses experience extensive responsibility and limited rights].

We studied the care of patients in homes for the elderly and in special homes for the demented in the city of Malmö. Nine district nurses were interviewed using a tape recorder, and the content of the interviews was analyzed. Many patients needed extensive care, and resources were insufficient regarding both number of staff and their competence. The management of nursing in the various districts of the city was not well-defined. More consulting time was requested on the part of both district nurses and general practitioners in homes for the elderly and homes for the demented.

Aged↗

PubMed2001

Early TCR alpha beta expression promotes maturation of T cells expressing Fc epsilon RI gamma containing TCR/CD3 complexes.

In a previous study we presented data indicating that the expanded population of CD4(-)CD8(-) (DN) alphabeta T cells in TCRalpha-chain-transgenic mice was partially if not entirely derived from gammadelta T cell lineage cells. The development of both gammadelta T cells and DN alphabeta T cells is poorly understood; therefore, we thought it would be important to identify the immediate precursors of the transgene-induced DN alphabeta T cells. We have in this report studied the early T cell development in these mice and we show that the transgenic TCRalpha-chain is expressed by precursor thymocytes already at the CD3(-)CD4(-)CD8(-) (triple negative, TN) CD44(+)CD25(-) stage of development. Both by using purified precursor populations in reconstitution experiments and by analyzing fetal thymocyte development, we demonstrated that early TN precursors expressing endogenous TCRbeta-chains matured into DN alphabeta T cells at several stages of development. The genes encoding the gamma-chain of the high affinity receptor for IgE (FcepsilonRIgamma) and the CD3zeta protein were found to be reciprocally expressed in TN thymocytes such that during development the FcepsilonRIgamma expression decreased whereas CD3zeta expression increased. Furthermore, in a fraction of the transgene-induced DN alphabeta T cells the FcepsilonRIgamma protein colocalized with the TCR/CD3 complex. These data suggest that similarly to gammadelta T cells and NKT cells, precursors expressing the TCR early in the common alphabetagammadelta developmental pathway may use the FcepsilonRIgamma protein as a signaling component of the TCR/CD3 complex.

Animals↗

PubMed2001

Frequency of human parvovirus B19 infection in intrauterine fetal death.

BACKGROUND: Parvovirus B19 is known to cause fetal death in the second trimester, mainly in combination with hydrops fetalis. However, the frequency of parvovirus-B19-associated non-hydropic fetal loss in the late second and third trimester has not been thoroughly investigated. We aimed to investigate the frequency of parvovirus B19 infection in unselected cases of intrauterine fetal death and to assess the sensitivity of different diagnostic procedures. METHODS: Of 14147 deliveries in three hospitals in the major Stockholm area of Sweden, all cases of intrauterine fetal death (>22 gestational weeks) that occurred between January, 1998, and May, 1999 (n=47), referred cases of miscarriage (<22 gestational weeks, n=37), and induced abortions (n=29), were included in the study. Placental and fetal tissues were examined by means of parvovirus-B19-specific PCR, histopathology, and immunohistochemistry. Placental tissues from 53 normal pregnancies at term were also examined. FINDINGS: Significantly more cases of intrauterine fetal death were positive for parvovirus B19 DNA (seven [15%]) than were normal pregnancies at term (zero, p=0.049). Furthermore, parvovirus B19 DNA was found in two (5%) of the miscarriages but not in any of the cases of induced abortion. Only three of nine DNA-positive cases had parvovirus-B19-associated inclusions and stained positive for viral proteins. All but one of the DNA-positive cases of intrauterine fetal death were non-hydropic. INTERPRETATION: The presence of parvovirus B19 DNA in cases of late second-trimester and third-trimester fetal death is common, and most are non-hydropic. The sensitivity of conventional diagnostic procedures for intrauterine fetal death could be greatly improved by addition of parvovirus B19 PCR.

Adult↗

PubMed2001

Low incidence of toxoplasma infection during pregnancy and in newborns in Sweden.

To estimate the burden of disease due to congenital toxoplasmosis in Sweden the incidence of primary infections during pregnancy and birth prevalence of congenital toxoplasmosis in 40,978 children born in two regions in Sweden was determined. Women possibly infected during pregnancy were identified based on: 1, detection of specific IgG based on neonatal screening of the phenylketonuria (PKU) card blood spot followed by retrospective testing of stored prenatal samples to detect women who acquired infection during pregnancy and follow up of their children to 12 months: 2, detection of specific IgM on the PKU blood spot. The birth prevalence of congenital toxoplasmosis was 0.73/10,000 (95 % CI 0.15-2.14) (3/40,978). The incidence of primary infection during pregnancy was 5.1/10,000 (95% CI 2.6-8.9) susceptible pregnant women. The seroprevalence in the southern part was 25.7% and in the Stockholm area 14.0%. The incidence of infection during pregnancy was low, as the birth prevalence of congenital toxoplasmosis. Neonatal screening warrants consideration in view of the low cost and feasibility.

Algorithms↗

PubMed2001

Nurses' first encounters with parents of new-born children--public health nurses' views of a good meeting.

The nurse's view of the first meeting with parents of new-born children ma have consequences for the quality of future contact. A good start will lay a soli foundation for a lasting relationship, and have an affect on the nurse's work to support parents and children and to promote health. We do not know wha nurses mean by a 'good meeting'. The aim of this study was to discover how nurses view the first meeting as a general preventive measure aimed at all parents and their new-born children. Four focus groups interviews were held with nurses from different primary health care areas in the county of Skåne, southernmost Sweden. Analysis of the content in the transcribed interview texts disclosed eight subcategories: good contact/reciprocal relationship; willingness to listen; guest/ equal roles; time/peace and quiet; the family in its environment; socio-cultural aspects; confirmation/support; and individual advice. Three categories were established: creating trust; creating a supportive climate; and creating a picture of the family's life situation. The home visit was seen as an important way to establish trust and obtain a picture of the family's life situation, which was in turn essential for creating a supportive climate.

Adult↗

PubMed2001

Blood pressure measurement--an observational study of 21 public health nurses.

The purpose of this study was to observe how public health nurses perform blood pressure measurement. Structured observations were made of 21 randomly selected public health nurses while they performed three blood pressure measurements. The public health nurses used an overall correct method for blood pressure measurement. Five nurses out of 21 used the Tri-cuff but the soft cuff was most frequently used. When choosing the breadth of the cuff, 10 nurses decided by eye and not by the marks on the cuff. To ensure a completely correct method additional information is needed by nurses.

Blood Pressure Determination↗

PubMed2001

Counseling Hypertensive patients: an observational study of 21 public health nurses.

This study observed the public health nurse's and the patient's activity level during blood pressure measurement and the kind of nonpharmacological treatment that was given. Using the Nurse Practitioner Rating Form, three structured observations were made of 21 public health nurses at their offices at health care centers. The nurses were randomly selected from 22 health care centers in Southern Sweden. The public health nurses used nonpharmacological treatment at 18 out of 63 visits, mainly diet and physical activity. The nonpharmacological conversation had a psychosocial aspect at 15 observations. During the visits, most of the facts and advice concerned somatic aspects of health promotion. Almost all patients were asked about their medication. At more than half of the observations, the nurses and the patients met at the same medium or high communication level. The nurses need training and information about nonpharmacological treatment to practice health promotion in hypertension care.

Antihypertensive Agents↗

PubMed2001

Long-lasting orofacial pain--a study of 109 consecutive patients referred to a pain group.

The aim was to register and evaluate the orofacial pain condition, with special focus on the equalities/inequalities between the sexes, in consecutive patients referred to the pain group at the Centre for Oral Health Sciences in Malmö, Sweden. The 109 patients, 85 (78%) women and 24 (22%) men, were referred to the pain group during the years 1988 to 1993 and were clinically examined using a standardised procedure. Pain duration of one year or more was experienced by 83% of the patients. The pain onset was related to dental care or toothache by 56% of the patients. Temporomandibular disorders were the most common diagnoses (52%) and were more common among women than among men (p < 0.05). Multiple pain locations were frequently reported, range 1-47 locations, and the women had significantly (p < 0.05) more pain locations than the men. Equalities between the sexes were more frequent than inequalities among patients referred for long-lasting orofacial pain. It can be discussed whether the sex difference in the prevalence of pain of musculoskeletal origin emerges from biological differences or can be explained by different psychosocial circumstances.

Adult↗

PubMed2000

The crystal structure of staphylococcal enterotoxin H: implications for binding properties to MHC class II and TcR molecules.

The X-ray structure of the superantigen staphylococcal enterotoxin H (SEH) has been determined at 1.69 A resolution. In this paper we present two structures of zinc-free SEH (apoSEH) and one zinc-loaded form of SEH (ZnSEH). SEH exhibits the conventional superantigen (SAg) fold with two characteristic domains. In ZnSEH one zinc ion per SEH molecule is bound to the C-terminal beta-sheet in the region implicated for major histocompatibility complex class II (MHC class II) binding in SEA, SED and SEE. Surprisingly, the zinc ion has only two ligating amino acid residues His206 and Asp208. The other ligands to the zinc ion are two water molecules. An extensive packing interaction between two symmetry-related molecules in the crystal, 834 A(2)/molecule, forms a cavity that buries the zinc ions of the molecules. This dimer-like interaction is found in two crystal forms. Nevertheless, zinc-dependent dimerisation is not observed in solution, as seen in the case of SED. A unique feature of SEH as compared to other staphylococcal enterotoxins is a large negatively charged surface close to the Zn(2+) site. The interaction of SEH with MHC class II is the strongest known among the staphylococcal enterotoxins. However, SEH seems to lack a SEB-like MHC class II binding site, since the side-chain properties of structurally equivalent amino acid residues in SEH and those in SEB-binding MHC class II differ dramatically. There is also a structural flexibility between the domains of SEH. The domains of two apoSEH structures are related by a 5 degrees rotation leading to at most 3 A difference in C(alpha) positions. Since the T-cell receptor probably interacts with both domains, SEH by this rotation may modulate its binding to different TcR Vbeta-chains.

Amino Acid Sequence↗

PubMed2000

Seroprevalence of Toxoplasma gondii among pregnant women in Sweden.

BACKGROUND: Primary infection with Toxoplasma gondii during pregnancy can cause fetal infection with a risk of complications for the fetus. The proportion of women at risk of acquiring the infection during pregnancy in Sweden is not known. METHODS: The seroprevalence of Toxoplasma gondii among pregnant women in Sweden was calculated when 40,978 blood samples collected on filter paper eluates from newborns were tested for Toxoplasma specific immunoglobulin G. The newborns in two geographically different areas (Stockholm County and Skåne County) were investigated during a 16-month period between April 1997 and July 1998. The anti-toxoplasma IgG antibodies detected in the eluates were considered to be of maternal origin and to reflect the immune status of the mother. RESULTS: The seroprevalence was 14.0% in Stockholm County and 25.7% in Skåne County. The seroprevalence among women born in the Nordic countries was 11.1% in Stockholm and 24.9% in Skåne. The corresponding figures for women born outside the Nordic countries were 24.3% and 29.4%. On comparing the seroprevalence found in this study with older data, the overall seroprevalence in pregnant women born in the Nordic countries and living in Stockholm was found to have decreased between 1969 and 1998. The seroprevalence in different birth cohorts, longitudinally followed in the previous and the present studies, remained at the same level over 20 years despite the increasing age of the women. CONCLUSION: These results suggest that the majority of seropositive pregnant women in Sweden today have seroconverted before entering the childbearing period and that the percentage of women in Sweden acquiring toxoplasmosis during the childbearing period is low.

Adolescent↗

PubMed1999

Three children with congenital toxoplasmosis: early report from a Swedish prospective screening study.

The aim of this prospective study was to define the incidence of congenital toxoplasmosis in Sweden. Blood eluates collected on filter papers, Guthrie cards, from 40978 newborn babies were analysed for specific immunoglobulin M (IgM) and IgG antitoxoplasma antibodies. This is a preliminary report of three children with congenital toxoplasmosis, defined by the occurrence of antitoxoplasma-specific IgM antibodies. Two children were asymptomatic at birth. They were both normally developed at the age of 12 and 15 months, respectively. The third child had unidentified but uncomplicated symptoms of infection in the neonatal period. As a result of the screening congenital toxoplasmosis was confirmed and treatment instituted. Microphthalmus and peripheral chorioretinitis were detected in one eye. In spite of the chemotherapeutic treatment he developed hydrocephalus needing neurosurgical intervention at the age of 3 months. His development at 14 months was normal. The incidence in Sweden of congenital toxoplasmosis detected by specific IgM antitoxoplasma antibodies in blood from filter papers is less than 1:10000.

Anti-Bacterial Agents↗

PubMed1999

Evaluation of the ability of thermal and electrical tests to register pulp vitality.

The aim of the present study was to evaluate the ability of thermal and electrical tests to register pulp vitality. Sensitivity, specificity, negative predictive value and positive predictive value were calculated by comparing the test results with a "gold standard". The thermal tests studied were a cold test (ethyl chloride) and a heat test (hot gutta-percha). For the electrical test, the Analytic Technology Pulp Tester was used. The examined teeth were 59 teeth with unknown pulpal status in need of endodontic treatment and 16 intact teeth, all with radiographically normal periapical bone structures. In total 46 teeth with vital pulps and 29 teeth with necrotic pulps were tested. This gave a disease prevalence of 39%. The gold standard was established by direct pulp inspection of the 59 teeth in need of endodontic treatment. In the 16 intact teeth the pulp was judged as vital. The number of true positive (TP), false positive (FP), true negative (TN) and false negative (FN) test results was calculated for each method as compared to the gold standard. Based on this, the sensitivity, specificity, positive predictive value and negative predictive value were calculated for each method. The sensitivity was 0.83 for the cold test, 0.86 for the heat test and 0.72 for the electrical test. The specificity was 0.93 for the cold test, 0.41 for the heat test and 0.93 for the electrical test. The positive predictive value was 0.89 for the cold test, 0.48 for the heat test and 0.88 for the electrical test, and the negative predictive value was 0.90 for the cold test, 0.83 for the heat test and 0.84 for the electrical test. This indicated that the probability of a non-sensitive reaction representing a necrotic pulp was 89% with the cold test, 48% with the heat test and 88% with the electrical test. It also indicated that the probability of a sensitive reaction representing a vital pulp was 90% with the cold test, 83% with the heat test and 84% with the electrical test.

Adult↗