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Biomedical subjects

K Petersson

Publications and source records attributed to K Petersson.

At least 37 records · Page 2Linked to original sources
PubMed1998

A TCR alpha chain transgene induces maturation of CD4- CD8- alpha beta+ T cells from gamma delta T cell precursors.

The proportion of CD4- CD8- double-negative (DN) alpha beta T cells is increased both in the thymus and in peripheral lymphoid organs of TCR alpha chain-transgenic mice. In this report we have characterized this T cell population to elucidate its relationship to alpha beta and gamma delta T cells. We show that the transgenic DN cells are phenotypically similar to gamma delta T cells but distinct from DN NK T cells. The precursors of DN cells have neither rearranged endogenous TCR alpha genes nor been negatively selected by the MIsa antigen, suggesting that they originate from a differentiation stage before the onset of TCR alpha chain rearrangements and CD4/CD8 gene expression. Neither in-frame V delta D delta J delta nor V gamma J gamma rearrangements are over-represented in this population. However, since peripheral gamma delta T cells with functional TCR beta gene rearrangements have been depleted in the transgenics, we propose that the transgenic DN population, at least partially, originates from the precursors of those cells. The present data lend support to the view that maturation signals to gamma delta lineage-committed precursors can be delivered via TCR alpha beta heterodimers.

Animals↗
PubMed1998

The Malmö model: a problem-based learning curriculum in undergraduate dental education.

A new undergraduate dental curriculum was introduced in Malmö in 1990 which is based on problem-based learning (PBL). The principles of PBL are strongly influenced by evidence from cognitive psychology and they form the educational strategy throughout the whole curriculum. Two further essential principles underpin the curriculum: a holistic attitude to patient care, and the promotion of oral health. Basic sciences and clinical dentistry are integrated within a structure based on oral conditions prevalent in the community. Students are encouraged to build their new knowledge, understanding and skills into the context of what they have already learned. This approach is facilitated by the presentation of conceptual models, one of which, The Oral Ecosystem is described in detail. The educational programme also gives students opportunities to learn in the clinical context from an early stage, and we endeavour to promote a scientific attitude from the very beginning of the programme. This paper describes the curriculum at three organisational levels (whole curriculum, single course, individual week).

Curriculum↗
PubMed1997

Parental education as viewed by nurses. An interview study.

This interview study of nurses in three health centres in Växjö municipality in Sweden sought to find out how they perceived their work with parental education. The aim was to study the possibilities of and any obstacles to achieving the goals of good parenthood training on equal terms for all people. The results showed areas where further development is needed. It appears to be difficult to achieve the goals. Parents' needs for educational measures differed depending on social, cultural, and gender differences. Young single mothers rarely took part in the parents' groups. They belonged to a minority whose needs and problems differed from those of the majority of parents. Also immigrant parents rarely participated in parents' groups. According to the nurses, this may have been due to cultural differences in child care and difficulties with the Swedish language. To give fathers more scope and opportunity to take part, it was suggested that special fathers' groups should be set up. To sum up, families with specific needs should be given more individual education and guidance by nurses. This study, confined to one geographical area, has only shed light on a few nurses' perceptions of parental education, so the findings merely serve to indicate a trend. More general knowledge would require further research-oriented trial projects with the focus on the parents' perspective.

Adult↗
PubMed1997

Direct digital radiography for the detection of periapical bone lesions: a clinical study.

The aim was to compare the observer performance of direct digital radiography, with and without image processing, with that of conventional radiography, for the detection of periapical bone lesions. For 50 patients, a conventional periapical radiograph using E-speed film was taken. Then, a direct digital image of the same area was made. The images presenting the periapical bone tissue of 59 roots were assessed by seven observers using a 5-point confidence scale. The digital images were first presented as original images, with default contrast and brightness set by the computer system. Following this, the observers were allowed to use the processing facilities for greyscale treatment. The results for original and processed direct digital images and for conventional radiographs were compared by Receiver Operating Characteristic (ROC) analysis. The area under the ROC curve, calculated as P(A) value, was 0.88 for conventional film, 0.82 for original digital images and 0.78 for processed images. Corresponding Az values were slightly higher, 0.89, 0.84 and 0.81. Statistically significant differences between ROC areas calculated as P(A) values for the methods were found. Comparison between Az values showed no significant differences between conventional radiographs and original digital images, whereas the difference between Az values for original and processed digital images was still significant. It was concluded that conventional film radiography performed slightly better for the detection of periapical bone lesions than direct digital radiography and that image processing did not improve the observer performance.

Alveolar Bone Loss↗
PubMed1997

Self-image, self-values and interpersonal values among newly graduated nurses.

This longitudinal study (1994-1996) used the Gordon Personality Inventory to measure nursing students' self-image (Gordon A), self-values (Gordon B) and interpersonal values (Gordon C). It was performed with students from three colleges of health in the south of Sweden: Jönköping (n = 54), Växjö (n = 24) and Kristianstad (n = 38). The null hypothesis of the study was that the new academic three-year programme did not have the power to change significantly the students' self-image and professional values. The hypothesis was tested by paired sample Student's t-test. The result was that, at Jönköping, self-image changed and increased significantly in the dimensions of 'cautiousness' and 'personal relations', and decreased in 'sociability', and increased in the self-value 'order'. At Växjö the self-image dimensions of 'original thinking' and 'personal relations' increased, and, at Kristianstad, the students increased their self-image scores in 'responsibility'.

Adult↗
PubMed1993

Endodontic status of mandibular premolars and molars in an adult Swedish population. A longitudinal study 1974-1985.

The purpose of the investigation was to study the incidence of endodontic treatment and the progression of periapical disease in an adult Swedish population. A random sample was selected in 1974 and offered a clinical and radiographic examination. In 1985, 345 of the original 1302 persons received a follow-up examination. The present study was based on information obtained from radiographs of the mandibular premolar and molar regions at the two examinations. The highest increase in people with endodontically treated teeth from 1974 to 1985 and the highest increase in people with periapical lesions were found in the youngest age-group, born between 1945 and 1954. New endodontic treatment, received between 1974 and 1985, was mostly found among those who already had endodontically treated teeth in 1974. New periapical lesions also appeared more often in persons with endodontic disorders in 1974.

Adult↗
PubMed1991

Distribution of mercury in rabbits subchronically exposed to low levels of radiolabeled methyl mercury.

The metabolism of methyl mercury (MeHg) has been studied in rabbits administered 203Hg-labeled methyl mercuric chloride, 0.125 mumol/kg body weight, twice a week for 9 weeks, by intravenous injection. Twelve weeks after cessation of treatment, about 54% of the administered dose had been excreted in faeces and 5% in urine. After one week, the highest concentration of 203Hg was found in fur (8.6 nmol Hg/g). Substantially lower concentrations were found in kidney (2.5 nmol/g), liver (0.9 nmol/g), brain (0.4 nmol/g), muscle (0.3 nmol/g) and blood (0.1 nmol/g). The rate of elimination of 203Hg from brain, muscle and blood was faster (t1/2 about 12 days) than that from kidney and liver (t1/2 about 28 days). The relative amount of inorganic Hg in kidney and liver increased with time after cessation of treatment. The highest fractions were 85 and 70%, respectively. In brain, no significant demethylation of MeHg could be detected.

Animals↗
PubMed1991

Follow-up study of endodontic status in an adult Swedish population.

The purpose of this study was to examine changes in the endodontic status of selected teeth in a population over time, in order to get a long-term perspective of endodontically treated teeth. A random sample of the adult Swedish population was selected in 1974 and offered a clinical and radiographic examination. Eleven years later 351 of the selected persons attended a follow-up examination (1985). In radiographs, covering the mandibular premolar and molar regions, the status of 1974 was directly compared, tooth by tooth, with the status of 1985. The results showed that a number of endodontically treated teeth with an apical periodontitis healed during the observation period. During the same period, approximately the same number of endodontically treated teeth presented with a new apical periodontitis. This finding suggested that cross-sectional studies could provide reliable information on the long-term success rate of endodontic treatment at the population level. The periapical lesions that persisted or developed during the observation period were strongly related to incomplete root canal obturation, which is in agreement with observations in follow-up studies from teaching and specialist clinics.

Adult↗
PubMed1989

Endodontic status and suggested treatment in a population requiring substantial dental care.

The purpose of this study was to analyse endodontic status and treatment suggested for Swedish citizens requiring substantial dental care. According to the Swedish dental insurance system, treatment plans including radiographs have to be submitted for approval if the estimated cost of treatment exceeds a certain level (USD 500 in 1977). A sample of 1094 treatment plans received during 1977 and 1978 was randomly selected. In the radiographs the number of remaining teeth was recorded, periapical condition was evaluated and the quantity and quality of previous endodontic treatment were estimated. In addition, treatment plans concerning the teeth with periapical lesions were studied. The results indicated that patients analysed in this study that needed expensive treatment had more missing teeth, more root-filled teeth and more teeth with periapical lesions than what has been reported in previous studies of samples supposed to accurately represent the Swedish population. However, the technical quality of the root fillings and the frequency of periapical lesions in root-filled teeth were the same as in previous studies, with high frequencies of inadequate root fillings and related unfavourable responses. Thus the patients in this study retained a significant need for endodontic treatment despite having already received a great deal of endodontic care. Further, it was found that nearly half of the observed periapical lesions would not be treated based on the submitted plans.

Adolescent↗
PubMed1988

Nocturnal hypoxaemia in severe scoliosis.

The relationship between spirometry and daytime blood gases on the one hand and hypoxaemia during sleep on the other was studied in 13 patients with severe thoracic scoliosis. Eight patients had hypoxaemia (mean Sao2 less than 90%) during sleep. They were characterized by a lower vital capacity (30 versus 50% of predicted, P less than 0.01) and by a greater fall in vital capacity from sitting to supine (26 versus 7% of sitting VC, P less than 0.05). All patients with hypoxaemia during sleep were hypercapnic during the daytime. The fall in Sao2 with sleep was related to the increase in transcutaneous PCO2, indicating hypoventilation as the main mechanism behind hypoxaemia during sleep in scoliosis patients.

Adult↗
PubMed1986

Tobacco smoke chemistry. 1. A chemical and mass spectrometric study of tobacco smoke alkyl 2-hydroxy-2-cyclopentenones.

A series of alkyl 2-hydroxy-2-cyclopentenones, which comprise biologically and organoleptically active compounds, have been synthesized and subjected to high resolution mass spectrometric studies to clarify structurally significant fragmentation pathways. On the basis of these results, 26 alkyl 2-hydroxy-2-cyclopentenones were identified in the weakly acidic fraction of smoke condensate from American blend type cigarettes, eighteen of which had not been detected in tobacco smoke previously. The utility for identification purposes of the corresponding quinoxaline derivatives, obtained through condensation with o-phenylenediamine, is discussed.

Chemical Phenomena↗
PubMed1981

Structural studies of the capsular polysaccharide elaborated by Haemophilus influenza type d.

The structure of the capsular polysaccharide elaborated by Haemophilus influenzae type d has been investigated, methylation analysis and n.m.r. spectrometry being the principal methods used. It is concluded that the polysaccharide is composed of repeating units having the structure: leads to 4)-beta-D-GlcpNAc-(1 leads to 3)-beta-D-ManpNAcA-(1 leads to. In addition, single residues of L-alanine, L-serine, or L-threonine, in the proportions 2:2:1, are linked, through their amino groups, to C-6 of the 2-acetamido-2-deoxy-beta-D-mannopyranosyluronic acid residues. The degree of substitution (75-85%) varies for different preparations.

Carbohydrate Conformation↗