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Biomedical subjects

T Martinsson

Publications and source records attributed to T Martinsson.

At least 109 records · Page 6Linked to original sources
PubMed1991

Number of remaining teeth among adults in communities with optimal and low water fluoride concentrations.

The aims of this study was to compare the dental health status measured as the number of remaining teeth, also considering local fluoride administration in two sociologically equal communities with optimal and low drinking water fluoride concentrations. The study is based on self-answer enquiries and clinical examinations. To be part of the study the subjects were required to have used a drinking water with a fluoride concentration representative of the community for all their lives. The participants were 30-40 years old: 320 met the criteria in the optimal fluoride concentration community compared to 284 in the low fluoride community. Of these 18% did not turn up to the clinical examination. The results of the study show no differences in the number of still remaining teeth between optimal and low fluoride communities respectively. There were also no statistically significant differences as to the reasons for toothloss. The number of remaining teeth were neither influenced by local fluoride administration in the two groups. Removable dentures were only present in 0.9% with no differences between optimal and low fluoride communities.

Adult↗
PubMed1990

An estimation of dental treatment needs in two groups of refugees in Sweden.

The aim of this study was to estimate dental treatment need in groups of Chilean and Polish refugees in Sweden. Of the Nordic countries, Sweden accepts the greatest number of refugees. An average of 5000 refugees arrived annually in 1981-85, increasing to 15,000 during 1986-87. Refugees and their families now comprise 93% of non-Nordic immigration. In 1981-83 a sample of 193 Chilean and 92 Polish refugees in the county of Stockholm was selected for this study. Dental treatment needs were calculated in accordance with CPITN and the working study of Swedish dentistry, which formed the basis for the Swedish scale of dental fees for the National Dental Insurance Scheme. The estimated mean treatment time (+/- SD) in the Chilean sample was 6.9 +/- 2.3 h and in the Polish group 8.4 +/- 3.0; in comparison with estimated treatment needs in a Swedish material, both would be classified as extreme risk groups. There was no correlation between the number of months in Sweden and the estimated treatment needs. The results indicate a cumulative, unmet need for dental care in these groups. Barriers to ensuring adequate health care for immigrants persist; special outreach programmes, conducted by dental health personnel, may be an effective means of introducing immigrants to the Swedish dental care system.

Adult↗
PubMed1990

Effects of the new undergraduate dental curriculum of 1979.

A new curriculum for dental education was introduced in Sweden in 1979. Among other things the basic training was cut down from 10 to 9 semesters and a preregistration year in the Public Dental service was added. In this study two cohorts of dentists, one having studied under the old and one under the new curriculum, having 1 to 3 years practical experience of the dental profession, were asked to evaluate their undergraduate education as seen from a practising dentist's point of view. The results showed that the dentists trained under the new curriculum regarded their theoretical knowledge, clinical skills, and the relevance of their training generally higher than those trained under the old curriculum. However, the correlations between the old and the new curriculum with respect to the rankings of the individual subjects were high, indicating that no radical changes had occurred in the preference orders of the subjects. The self-estimated importance of different subjects for the dental profession may reflect the dentists' present working situation, e.g. the Public Dental Service or private practice.

Adult↗
PubMed1990

Dental students' views on their education and study circumstances in Nordic countries.

The curricula at the Nordic dental schools are similar in their content but may vary in the placement of different subjects and the way of teaching them. The aim of this study was to analyse Nordic dental students social background, and their reasons for choosing dentistry, their opinions on the course, and their future professional plans. A combination of an open-ended and structured questionnaire was given to final year dental students at the dental schools in Aarhus, Bergen, Kuopio and Stockholm. The response rate as 83%. The main reasons for choosing dentistry were its combination of theory and practice (29%), and a wish to work with people (20%), whereas only 4% mentioned the "high status" of the profession. Regular day-time work was emphasized by female students. Most students considered the teaching load heavy. The time devoted to the different subjects was considered sufficient, except for behavioural science and medicine, where the time was too short. There was general dissatisfaction with the teachers pedagogical skills, and there was a feeling that teaching was regarded as secondary to research. Most students planned to become private practitioners. Between 25-55% of the students wanted to specialize, and oral surgery was the most popular specialization.

Adult↗
PubMed1989

Chromosome 1 deletions in human neuroblastomas: generation and fine mapping of microclones from the distal 1p region.

Human neuroblastomas show a high incidence of deletions in the distal region of the short arm of chromosome 1. In pursuit of a molecular analysis of these deletions, we have generated a microclone bank from microdissected 1p35-pter chromosomal fragments. To allow a rapid localization of the microclones, we have also generated a panel of (human x mouse) hybrid cell lines through microcell-mediated chromosome transfer. The hybrid cells contained different portions of the human chromosome 1 on a murine background. A total of 20 randomly chosen single or low-copy microclones were localized by Southern analysis on DNA of the hybrid panel: All probes were derived from chromosome I. Sixteen mapped in region 1p36.1-pter, two in 1p22-p36.1, and another two in 1cen-qter. The mapping of ten of these microclones was further refined by in situ hybridization. Cells of the neuroblastoma line GI-ME-N carry two types of chromosome 1, one cytogenetically normal and another with a translocation reported to be in 1p36.2, i.e., a t(1;?) (p36.2;?) marker. Using cell hybridization, we separated the two chromosome 1 types of GI-ME-N into different hybrid cell clones. Southern hybridization of three microclones from distal Ip to DNA of the hybrid cell clones revealed that the breakpoint in the translocated chromosome I was located in 1p36.1.

Bacteriophage lambda↗
PubMed1989

Neuroblastoma consensus deletion maps to 1p36.1-2.

At least 70% of human neuroblastomas display cytogenetically visible aberrations in the short arm of chromosome 1. We have used a panel of probes detecting polymorphic DNA loci, most of which were derived from a library of microdissected distal 1p chromosome fragments, to compare the hybridization pattern of DNA on nine different tumors and the corresponding normal tissue. In eight of the neuroblastomas allelic loss was observed with at least two probes. The deletions were of different size. Since a consensus deletion in all eight tumors included the segment 1p36.1-2, we conclude that genetic information related to neuroblastoma tumorigenesis is located within this approximately 10 megabase segment. Previous studies have revealed the amplification of MYCN in neuroblastomas. Our study did not provide evidence for a correlation between MYCN amplification and the 1p deletion, suggesting that the two genetic alterations result from molecular mechanisms that are not directly related to each other.

Alleles↗
PubMed1989

Precision of computerized measurement of marginal alveolar bone height from bite-wing radiographs.

The digitizer technique has previously shown good precision when applied to measurements of alveolar marginal bone height on unstandardized periapical radiographs of adults. In this study the precision of the digitizer technique was evaluated for direct measurement of alveolar bone height on unstandardized bite-wing radiographs of young subjects with intact cemento-enamel junctions. Measurements of the distance between the cemento-enamel junction and the alveolar crest at 432 sites gave an agreement of 96.5% within a margin of error of 0.3 mm. The T-test showed no significant difference between repeated measurements of the same site. Regression analysis showed that the order of magnitude of the distance between the landmarks did not influence the results. The mean difference between repeated readings of the same site was 0.09 mm at a confidence limit of 99.9%. The study confirms that the digitizer technique is a reliable method for measurement of alveolar bone height on unstandardized bite-wing radiographs of young subjects.

Adolescent↗
PubMed1988

Swedish and Finnish dental practitioners' opinions of their undergraduate education.

Recently qualified dentists from a dental school in Stockholm, Sweden (n = 259) and the dental school in Kuopio, Finland (n = 103) were sent a questionnaire designed to obtain information concerning the perceived relevance of their undergraduate education to the practice of dentistry. The response rate was 71% for Stockholm and 82% for Kuopio. Except for minor differences, probably mainly due to economic resources and traditions in choice of treatment, the graduates in the two countries had comparable views of their basic education. In general, clinical dental subjects were highly valued, while basic science subjects but also subjects in medical and behavioral sciences were given low values. Our results indicate that, although prevention and behavioral sciences are stressed more and more in undergraduate education, the practice of clinical dentistry remains essentially unchanged and restorative dentistry is still very highly valued among recent graduates of these two dental schools.

Adult↗
PubMed1988

Dental health status in two groups of refugees in Sweden.

The aim of this study was to determine dental health status in two separate groups of Chilean and Polish refugees in Sweden. In Scandinavia, Sweden has the largest number of immigrants--1 million out of a population of 8.3 million. Since 1975, most immigrants have been refugees and their families. During 1978-82 Sweden granted residency to 20,000 refugees, the two largest groups being Chileans and Poles. In 1981-83 a sample of 193 Chilean and 92 Polish refugees in the county of Stockholm were selected for this study. The investigation consisted of a questionnaire followed by clinical examination, including roentgenograms. The average age was 34.0 years in the Chilean group and 34.8 years in the Polish group. The Chileans had been in Sweden for 17.3 months on an average and the Poles for 16.0 months. The Chileans had an average of 10.0 carious surfaces, D(s), and the Poles 11.3. Gingivitis was recorded in 87% of the total number of sites examined in the Chilean group. The corresponding figure in the Polish group was 79%. Of the Chileans 36.5% and of the Poles 32.5% had periodontal pockets measuring more than 5 mm. The results indicate that, when compared with Swedish individuals of a corresponding age, the refugee groups have a high prevalence of caries and periodontal disease.

Adolescent↗
PubMed1988

Tumorigenicity of SEWA murine cells correlates with degree of c-myc amplification.

Previous studies have shown that cells of the SEWA mouse tumor contain amplified copies of the proto-oncogene c-myc in the aberrant chromosomal structures of double minutes (DMs), homogeneously staining regions (HSRs) and C-bandless chromosomes (CMs). DMs, and to a lesser degree CMs, tend to disappear from the cells grown in vitro and again reappear after transfer back in vivo, as if DNA amplification confers a growth advantage upon the tumor cells. We have now isolated five in vitro clones that exhibit different degrees of c-myc amplification. When we inoculated cells of the different clones into compatible hosts, we found that there was a positive correlation between degree of c-myc amplification, level of c-myc RNA, and tumorigenicity. Our results lend further support to the idea that gene amplification contributes to the higher malignant phenotype, and to progression of tumors.

Animals↗
PubMed1987

Novel cytogenetic expression of gene amplification in actinomycin D-resistant somatic cell hybrids: transfer of resistance by centric chromatin bodies.

SEWATC13 mouse cells, resistant to 0.1 microgram/ml of actinomycin D (AMD), were fused to AMD-sensitive cells of the Chinese hamster ovary cell line (CHO). Twenty-two hybrid clones were isolated and put into serial culture in the selective medium. Unexpectedly, identifiable mouse chromosomes were found only in one of the hybrids. All the others had only hamster chromosomes and, in addition, numerous chromatin bodies (CBs), mostly small and irregularly shaped, but also larger, more chromosome-like ones. The CBs were distinctly C-band positive and a mouse satellite probe hybridized strongly to them. The AMD resistance of the murine parental cells had previously been attributed to gene amplification in two large homogeneously staining regions (HSR-AMD1 and 2). They were not observed in the hybrid cells but had supposedly reappeared in the guise of the CBs. It was established by Southern DNA blot analysis that amplified DNA sequences, localized to the HSR-AMD1 and 2 of the SEWA parent were present in multiple copies in the hybrids. It was also established by in situ hybridization that they were located in the CBs. Unlike double minutes (DMs) the CBs were all centric.

Animals↗
PubMed1987

Localization of the multidrug resistance-associated 170 kDa P-glycoprotein gene to mouse chromosome 5 and to homogeneously staining regions in multidrug-resistant mouse cells by in situ hybridization.

This report describes the localization of the 170 kDa P-glycoprotein gene(s) to mouse chromosome 5, subbands A2 or A3. Overproduction of P-glycoprotein is associated with multidrug resistance (MDR). MDR cell lines derived from the SEWA mouse tumor carry multiple copies of the P-glycoprotein gene. These were found to reside in homogeneously staining regions, situated in different locations in different sublines.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1987

A retrospective study on the relevance of the dental curriculum in general practice.

The undergraduate dental curriculum in Swedish dental schools has recently been changed. The aim of this study was to estimate the opinions of recently qualified dentists concerning their undergraduate education received according to the old curriculum. A questionnaire was mailed to all graduates who qualified from the dental school in Huddinge between 1981-1983. The response rate was 71%. The respondents indicated that their theoretical knowledge was in general better in subjects closely related to clinical dentistry compared with basic biological subjects or behavioural science subjects. In most subjects clinical competence was closely related to the level of theoretical knowledge. The results of this study suggest that the "old" dental curriculum was successful in imparting knowledge concerning traditional dental subjects and preventive dentistry, but less successful in imparting knowledge concerning basic and medical sciences, behavioural subjects and in relating theoretical and practical skills.

Adult↗