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Biomedical subjects

L E Holm

Publications and source records attributed to L E Holm.

At least 19 recordsLinked to original sources
PubMed1998

Population structure and gene flow of the Atlantic walrus (Odobenus rosmarus rosmarus) in the eastern Atlantic Arctic based on mitochondrial DNA and microsatellite variation.

The population structure of the Atlantic walrus, Odobenus rosmarus rosmarus, was studied using 11 polymorphic microsatellites and restriction fragment length polymorphism detected in the NADH-dehydrogenase ND1, ND2 and ND3/4 segments in mtDNA. A total of 105 walrus samples were analysed from northwest (NW) Greenland, east (E) Greenland, Svalbard and Franz Joseph Land. Two of the 10 haplotypes detected in the four samples were diagnostic for the NW Greenland sample, which implied that the group of walruses in this area is evolutionary distinct from walruses in the other three areas. One individual sampled in E Greenland exhibited a Pacific haplotype, which proved a connection between the Pacific walrus and walruses in eastern Greenland. The Franz Joseph Land, Svalbard and E Greenland samples shared the most common haplotype, indicating very little differentiation at the mtDNA level. Gene flow (Nm) estimates among the four areas indicated a very restricted exchange of female genes between NW Greenland and the more eastern Atlantic Arctic samples, and a closer relationship between the three samples composing the eastern Atlantic Arctic. The genetic variation at 11 polymorphic microsatellite loci grouped individuals into three populations, NW Greenland, E Greenland and a common Franz Joseph Land-Svalbard population, which were connected by moderate gene flow.

Animals↗
PubMed1998

Radiation-associated thyroid cancer--facts and fiction.

Thyroid cancer is a rare and complex disease and the thyroid contains various cell types from which specific diseases arise. The malignancies range from indolent to extremely aggressive. Several risk factors for thyroid cancers have been suggested, but only ionizing radiation has been found to have a causative effect. With the exception of tobacco, ionizing radiation is probably the most studied carcinogen there is. It is not yet possible to determine whether or not a specific cancer was induced by radiation and epidemiological studies therefore provide the primary data on cancer risk in man after exposure to ionizing radiation. The current epidemiological knowledge on radiation-associated thyroid cancer is reviewed, focusing on the sharply increased risks recently found among children in the Chernobyl area.

Adult↗
PubMed1998

Sunbathing and sunbed use related to self-image in a randomized sample of Swedish adolescents.

In 1996 a randomized sample of 4,020 Swedish adolescents from three birth cohorts were sent a questionnaire consisting of 50 items concerning habitual sun-related behaviours and attitudes, knowledge about melanoma, risk perception and self-image. A total of 2,615 questionnaires were returned. Girls sunbathed and used sunbeds more than boys at all ages. Sunbathing and sunbed use increased with age. Boys who were most satisfied and girls least satisfied with themselves sunbathed most. Those who were least satisfied with themselves used sunbeds most frequently. Girls reported a higher perceived susceptibility to melanoma than did boys. The perception of susceptibility increased with age. Those who were least satisfied with themselves reported feeling most susceptible. The overall main reason for sunbathing was appearance, both for own sunbathing, and to an even higher degree, as a supposed reason for other adolescents' behaviour, and was reported most frequently by girls and the older age groups. The second most 'important' reason for sunbathing was 'feeling warm and comfortable'. Preventive programmes aimed at a change of sun related behaviours among Swedish adolescents have to be tailored to the climate and cultural conditions and must take into account that having a tan, and the warmth of the sun, are highly valued by most adolescents.

Adolescent↗
PubMed1998

Outcome of reproduction in women irradiated for skin hemangioma in infancy.

The possible impact of early gonadal irradiation on the results of future pregnancies is unclear. This study is based on the progeny of 17,393 women who were treated with irradiation for skin hemangiomas at the age of 18 months or less. The mean ovarian dose was 6 cGy, and the maximum was 8.55 Gy. Using Swedish central health registers, the outcome of delivery was studied in these women; 19,494 infants born were identified. The treated women deviated from the general population by having a longer education and by smoking less. This may explain a reduced risk for low birth weight and preterm birth (not related to radiation dose). Women with ovarian doses greater than 1 cGy had fewer infants than women with a lower ovarian dose. An excess of perinatal deaths was evident as well as a slight excess in the rate of malformation, but neither was related to dose. There was a statistically significant trend of an increasing rate of neural tube defects with ovarian dose, possibly a chance result of multiple statistical testing. Cleft lip/palate occurred at levels significantly below expectation. No increase in the rate of infants with Down syndrome or in childhood malignancies was detected. No major adverse results in outcome of delivery were seen after ovarian irradiation in childhood with the possible exception of neural tube defects.

Congenital Abnormalities↗
PubMed1998

Intracranial tumors after exposure to ionizing radiation during infancy: a pooled analysis of two Swedish cohorts of 28,008 infants with skin hemangioma.

The risk of intracranial tumors after exposure to ionizing radiation during infancy has been studied in a pooled analysis of two Swedish hemangioma cohorts (n = 28,008). The mean absorbed intracranial dose was low (7 cGy, range 0-11.5 Gy). The cohorts were followed up in the Swedish Cancer Register for incident intracranial tumors during the period 1958-1993. Eighty-eight tumors were found in 86 individuals compared to 60.72 expected [standardized incidence ratio (SIR) 1.42, 95% confidence interval (CI) 1.13-1.75]. The SIR increased significantly in ascending dose categories (P = 0.02). Dose-response analyses were performed with Poisson regression methods. There was a significant effect of dose, and the dose-effect relationship was negatively modified by age at first treatment. This indicates a higher risk for those exposed earlier in life. A linear dose-response model modified by age at first treatment resulted in the best fit. The excess relative risk (ERR) was 2.7/Gy (95% CI 1.0-5.6). The ERR/Gy was 4.5 if the treatment was given before 5 months of age, 1.5 if it was given at 5-7 months and 0.4 if it was given later. The study thus strongly indicates that there exists a dose-response relationship between absorbed dose in the brain and the subsequent risk of developing an intracranial tumor and that the risk is higher among infants exposed at younger ages.

Adult↗
PubMed1997

A combined DNA-microsatellite and isozyme analysis of the population structure of the harbour porpoise in Danish waters and west Greenland.

One hundred and twenty-four specimens of the harbour porpoise, Phocoena phocoena, occurring in inner Danish waters (IDW), the North Sea and West Greenland were analysed to study subdivision into genetically differentiated subpopulations using PCR-amplified DNA-microsatellites and isozyme markers. Three polymorphic microsatellites, 415/416, 417/418 and Igf-I (insulin-like growth factor I) were detected with nine, eight and 15 alleles, respectively, and from a former study two polymorphic isozymes, Mpi-1 and Pgm, with three and two alleles, respectively, were used in the analysis. Overall deviations from the expected Hardy-Weinberg distribution were only observed in the total sample and at a single locus in the North Sea-summer sample and at two loci in the West Greenland sample. Whenever this occurred a surplus of homozygotes was observed, suggesting a Wahlund effect, a null allele or nonrandom mating. The analysis of the genetical population structure showed that harbour porpoises from West Greenland, the North Sea and IDW were three geographically, genetically differentiated populations even though connected through some degree of gene flow. A tendency for females to be more stationary than males was suggested. Furthermore, the population structure suggested a closer relationship between IDW and the North Sea.

Animals↗
PubMed1997

Late consequences of radioiodine for diagnosis and therapy in Sweden.

With the exception of tobacco, ionizing radiation is probably the most studied carcinogen; however, it is not yet possible to determine whether a specific cancer was induced by radiation. Epidemiologic studies provide the primary data on cancer risk in humans after exposure to ionizing radiation. The present paper reviews the current epidemiologic knowledge on radiation-induced cancer, focusing on exposure to radioiodines, and describes the latest findings from the Swedish iodine cohorts.

Cohort Studies↗
PubMed1996

Breast cancer after radiotherapy for skin hemangioma in infancy.

Between 1920 and 1959, 9675 women were irradiated in infancy for skin hemangioma at Radiumhemmet, Stockholm. They were exposed to low to moderate doses of ionizing radiation. The mean age at first exposure was 6 months and the mean absorbed dose to the breast anlage was 0.39 Gy (range <0.01-35.8 Gy). The breast cancer incidence was analyzed by record linkage with the Swedish Cancer Register for the period 1958-1986. Seventy-five breast cancers were found [standardized incidence ratio = 1.24; 95% confidence interval (CI) 0.98-1.54] after a mean absorbed dose of 1.5 Gy in the breasts with cancer. The analyses showed a significant dose-response relationship with a linear model estimate for the excess relative risk (ERR) of 0.38 at 1 Gy 95% CI 0.09-0.85). This relationship was not modified significantly by age at exposure or by dose to the ovaries. The ERR increased significantly with time after exposure and for > or = 50 years after exposure the ERR at 1 Gy was 2.25 (95% CI 0.59-5.62). The fitted excess absolute risk (EAR) was 22.9 per 10(4) breast-year gray. The breast absorbed dose and time after exposure were important risk determinants for breast cancer excess risk. Forty to 50 years of follow-up was necessary for the excess risk to be expressed. The study confirms previous findings that the breast anlage of female infants is sensitive to ionizing radiation.

Breast Neoplasms↗