Biomedical subjects

Erik Larsson

Publications and source records attributed to Erik Larsson.

26 records · Page 2Linked to original sources

PubMed2002

Developmental expression of HERV-R (ERV3) and HERV-K in human tissue.

The human endogenous retroviruses (HERVs), ERV3 (HERV-R) and HERV-K, are both known to be transcriptionally active in human placenta. In the case of ERV3 there is also indirect evidence for its participation in cellular differentiation. In this study we examined the expression of ERV3 (HERV-R) and HERV-K in human normal fetal tissues by in situ hybridization. The highest level of ERV3 env expression was detected in primitive adrenal cortex. Elevated levels of expression were also found in the following developing tissues: kidneys (tubules), tongue, heart, liver, and central nervous system. Tissue-specific expression was found for HERV-K rec (former cORF) but not for pol/int transcripts. The highest rec expression was found in placenta and levels slightly higher than sense control were found in the rest of the tissues examined. Pol/Int was not possible to quantitate. It appears that ERV3 is expressed in an organ-specific way during embryogenesis and might suggest a possible role in the development and differentiation of human tissues.

Adrenal Cortex↗

PubMed2002

BORIS, a novel male germ-line-specific protein associated with epigenetic reprogramming events, shares the same 11-zinc-finger domain with CTCF, the insulator protein involved in reading imprinting marks in the soma.

CTCF, a conserved, ubiquitous, and highly versatile 11-zinc-finger factor involved in various aspects of gene regulation, forms methylation-sensitive insulators that regulate X chromosome inactivation and expression of imprinted genes. We document here the existence of a paralogous gene with the same exons encoding the 11-zinc-finger domain as mammalian CTCF genes and thus the same DNA-binding potential, but with distinct amino and carboxy termini. We named this gene BORIS for Brother of the Regulator of Imprinted Sites. BORIS is present only in the testis, and expressed in a mutually exclusive manner with CTCF during male germ cell development. We show here that erasure of methylation marks during male germ-line development is associated with dramatic up-regulation of BORIS and down-regulation of CTCF expression. Because BORIS bears the same DNA-binding domain that CTCF employs for recognition of methylation marks in soma, BORIS is a candidate protein for the elusive epigenetic reprogramming factor acting in the male germ line.

Amino Acid Sequence↗

PubMed2002

Quantification of lymphocytes propagating from rat-kidney allografts--a tool to monitor anti-rejection treatment.

BACKGROUND: Morphological evaluation of kidney biopsies applying the Banff Classification is closely correlated to clinical parameters of rejection. However, this classification is insufficient for monitoring the effect of instituted anti-rejection therapy. The objective of the present study was to develop a diagnostic tool enabling rapid assessment of the effects of an attempted anti-rejection treatment. MATERIALS AND METHODS: A kidney allotransplantation model in the rat was applied. All animals were initially maintained on cyclosporine A (CsA). In order to induce an episode of acute cellular rejection, CsA was withdrawn for 5 days. Thereafter, the immunosuppressive treatment was restarted. Core biopsies were taken before, and at various times after, the introduction of anti-rejection therapy. Infiltrating cells were isolated using an in vitro culture system, allowing cells to propagate from the biopsies to culture medium. Propagated cells were counted and analysed for subtype and activation markers using flow cytometry. The results were compared with immunohistochemical and morphological analyses of the grafts. RESULTS: By applying the in vitro culture system it was possible to demonstrate a reduction in outgrowth of mononuclear cells from core biopsies as early as 2 days after the start of anti-rejection therapy. At this time-point, as well as 2 days later, morphological and immunohistochemical analyses of biopsies showed ongoing acute cellular rejection, with no differences between biopsies taken before and after restart of CsA-therapy. The percentage of propagating T lymphocytes expressing the activation markers CD25 or MHC class II did not differ between grafts with ongoing rejection and grafts obtained from CsA-treated rats, neither did the ratio of CD4/CD8-positive cells. CONCLUSION: Our findings indicate that the ex vivo propagation method could function as a complement to routine histology, not only in the diagnosis of cellular rejection but also in order to rapidly reveal a failure of an anti-rejection therapy to halt the rejection process.

Animals↗

PubMed2002

Transverse dental and dental arch depth dimensions in the mixed dentition in a skeletal sample from the 14th to the 19th century and Norwegian children and Norwegian Sami children of today.

Secular changes in transverse dental arch dimensions and dental arch depth were studied. Four cohorts with mixed dentitions were selected. The skull group comprised 48 skulls dating from the 14th to the 19th century and belonging to The Schreiner Collection at the Department of Anatomy, University of Oslo. The 1980s Sami group was comprised of 39 boys and 34 girls born in 1987 and living in the northern part of Norway. The 1960s Oslo group was comprised of 31 boys and 30 girls born in 1963 and living in the southern part of Norway. The 1980s Oslo group was comprised of 32 boys and 26 girls born in 1983 and living in the same area in southern Norway as the previous Oslo group. Sex was unknown in the skeletal sample, and the groups were analyzed with the sexes pooled; separate descriptive values are presented for the modern groups. The mandibular intercanine distance was smaller in the skulls compared with the modern groups. The transverse intermaxillary difference between the molars was larger in the skull group than in the 1980s Oslo group. The difference between the maxillary and mandibular intercanine distances was larger in the skulls compared with the modern groups, although the small number of measurements in the skull group impeded further analysis. The arch depth was smaller in the skull group compared with the modern groups; the 1960s Oslo group deviated because of a higher prevalence of caries in the second deciduous molars. The overjet was smaller among the skulls. The arch form measured as the angle between the left and right molar tooth rows was more acute in the skulls than in the modern groups. It was concluded that smaller arch depths are found in skeletal samples at early ages and that attrition does not explain the more upright incisors found in skeletal samples. A secular trend was found in the intermaxillary relation, which indicated that children in the 1980s Oslo group were at greater risk of developing a posterior cross-bite than children born in the 14th to 19th centuries.

Cephalometry↗

PubMed2002

Protective effect of insulin on ischemic renal injury in diabetes mellitus.

BACKGROUND: An exceptional susceptibility to unilateral renal ischemia/reperfusion (I/R) injury resulting in inflammation, fibrosis, atrophy of the kidney, and end-stage renal disease (ESRD) has been demonstrated in the diabetic rat. The aim of this study was to examine whether insulin treatment would reduce I/R injury in diabetic kidneys. METHODS: Diabetes mellitus (DM) was induced in male Wistar rats by streptozotocin. I/R was achieved by clamping the left renal artery for 30 minutes. Treatment with long acting insulin was started 7 to 14 days before or one day after I/R. Short acting insulin was administrated 2 to 6 hours before the injury. Apoptosis was evaluated six hours after ischemia with the TUNEL-method. Four weeks after the clamping inulin clearance was measured and kidneys were removed for histopathological evaluation. RESULTS: In DM animals renal I/R caused massive induction of apoptosis in the renal medulla after six hours as well as inflammation, fibrosis, renal atrophy and anuria within four weeks. Treatment with long acting insulin before I/R resulted in decreased cell death and an almost complete protection of both renal function and histomorphology. Treatment with short acting insulin before I/R also decreased the loss of renal function. In contrast, insulin treatment after I/R did not protect the kidney from damage. CONCLUSIONS: This study shows that insulin treatment with a subsequent improved metabolic control before renal I/R protected kidneys from ESRD.

Animals↗

PubMed2002

Dental arch space and permanent tooth size in the mixed dentition of a skeletal sample from the 14th to the 19th centuries and 3 contemporary samples.

Dental arch space and permanent tooth size in the mixed dentition were studied in 4 cohorts: (1) 48 skulls from the 14th to the 19th centuries from The Schreiner Collection in the Department of Anatomy, University of Oslo; (2) 39 boys and 34 girls of Sami origin born in the 1980s living in northern Norway; (3) 31 boys and 30 girls born in the 1960s living in southern Norway; and (4) 32 boys and 26 girls born in the 1980s living in the same part of southern Norway as the previous group. The sexes were unknown in the skeletal sample, and the groups were analyzed with the sexes pooled. The crown sizes of the permanent teeth in the mixed dentition of the Norwegian children who had lived between the 14th and the 19th centuries were smaller than those of contemporary children living in the same country. Probable reasons for this increase in tooth size include improved nutrition and reduced morbidity, because this study ruled out attrition as a major cause of the discrepancy in tooth size. The relative space (arch perimeter minus tooth size) in the group born in the 1960s deviated from that in the other 3 groups, indicating a greater degree of crowding in this group. The relative space in the skulls did not differ significantly from that in the groups born in the 1980s. This means that the improved caries situation during the last decades has changed the dental arch space in these populations. The irregularity index of the 4 mandibular permanent incisors was larger in the skulls than in the modern samples.

Analysis of Variance↗

PubMed2002

Bond failure of a no-mix adhesive during orthodontic treatment.

Bond failure of a no-mix adhesive was evaluated in 320 patients followed longitudinally during orthodontic treatment. Factors evaluated were the patient's gender, the complexity of the appliance, the bond site location, initial crowding, and caries development. The overall bond failure rate was 7.2%. Bond failures were significantly higher in the mandible, with the second premolars showing the highest prevalence (23%) (P <.001). There were significantly higher bond failure rates in boys than in girls (P <.05). There was a significant negative correlation between initial crowding and bond failure. Increased white spot lesions during treatment and complex appliance design were significantly correlated with high bond failure rates.

Acrylic Resins↗

PubMedDate not supplied

Feeding, artificial sucking habits, and malocclusions in 3-year-old girls in different regions of the world.

PURPOSE: The way babies and young children are reared is important to their health and development. Extensive breast-feeding has also been shown to reduce the development of artificial sucking habits like digit or pacifier-sucking. The aim of this study was to determine feeding methods, artificial sucking habits, and the presence of malocclusions in 3-year-old girls living in different regions of the world. METHODS: Children from the following countries were involved in the present study: (1) Brazil (Porto Alegre); (2) Japan (Niigata); (3) Mexico (Mexico City); (4) Norway (Oslo); (5) Sweden (Falköping); (6) Turkey (Istanbul); (7) and the United States (Iowa City, Iowa). During the interview and examination, the following variables were evaluated and registered: (1) breastfeeding and bottle-feeding; (2) duration and frequency; (3) sucking habits; (4) posterior and anterior crossbites; and (5) other malocclusions/normal occlusion. RESULTS: The prevalence of breast-feeding was very high in all groups, ranging between 78% and 98%. The prevalence of bottle-feeding in the different areas was also high. Except for Iowa City, the prevalence of digit-sucking was relatively low. Pacifier-sucking is fairly popular in most areas, with the exception of Niigata. The prevalence of normal occlusion in different cities ranged from 38% to 98%. CONCLUSIONS: There are considerable differences in feeding, as well as artificial sucking habits, in different areas of the world and at different periods.

Bottle Feeding↗