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Biomedical subjects

L Iversen

Publications and source records attributed to L Iversen.

At least 19 recordsLinked to original sources
PubMed1999

Orthodontics at the turn of the century. A discussion of some relevant aspects.

Some changing paradigms, that might influence orthodontics in the future, are being discussed: economic problems related to our welfare systems; development of the media societies; concepts of normality; future changes as regards the type of treatment records; evaluation of treatment outcome; "exaggerated orthodontics?"; orthodontics and facial aesthetics; Newtonian paradigms and scientific revolution; the growth of knowledge; phenomenology; tacit knowledge; decision making.

Esthetics, Dental↗
PubMed1999

The long-term biological variability of fasting plasma glucose and serum fructosamine in healthy Beagle dogs.

The aim of this study was to estimate the long-term (month-to-month) between-dog, within-dog and analytical components of variance for fasting plasma glucose and serum fructosamine in healthy dogs to assess the usefulness of a single measurement of these analytes in a single dog. Fasting plasma glucose and serum fructosamine were measured in blood samples collected every month for 9 months from 23 clinically healthy dogs, and the results were subjected to nested analysis of variance. The between-dog variation, the within-dog variation, and the analytical variation were 3.8%, 9.5% and 3.7%, respectively, for plasma glucose and 4.2%, 11.1% and 2.8%, respectively, for serum fructosamine. The maximum allowable analytical imprecision, analytical inaccuracy and difference between analytical methods were 4.8%, 2.6% and 3.2%, respectively, for plasma glucose and 5.6%, 3.0% and 3.7%, respectively, for serum fructosamine. The index of individuality, 2.7 for both analytes, indicated that the test results from single dogs can be compared usefully to the corresponding population-based reference intervals. The number of samples required to estimate the true individual mean value +/-5% for a single dog was 16 for fasting plasma glucose and 20 for serum fructosamine. The one- and two-sided critical differences expressing the difference needed for two serial results from the same dog to be significantly different at a 5% level was 24% and 28%, respectively, for plasma glucose and 27% and 32%, respectively, for serum fructosamine.

Animals↗
PubMed1999

Evidence of nuclear PKC/MAP-kinase cascade in guinea pig model of epidermal hyperproliferation.

In order to delineate the biochemical events in the nuclear compartment of an in vivo proliferating epidermis, we produced a model of hyperproliferative epidermis by topical application of docosahexaenoic acid (22:6n-3) on guinea pig skin. Employing this model we demonstrated: (i) that protein kinase C (PKC)-a and atypical PKC-zeta are the two major PKC isozymes in the normal epidermal nuclear membrane, in contrast to PKC-alpha and PKC-beta in the epidermal plasma membrane; (ii) that topical application of docosahexaenoic acid induced epidermal hyperproliferation and enhanced total nuclear PKC, particularly nuclear PKC-alpha and the atypical PKC-zeta isozymes. The increase in the nuclear PKC isozymes paralleled a marked increase in the expression of nuclear mitogen-activated protein-kinase. These data suggest that epidermal hyperproliferative activity is accompanied by the upregulation of nuclear PKC/mitogen-activated protein-kinase signaling pathway.

Animals↗
PubMed1998

Development and validation of an improved enzyme-linked immunosorbent assay for the detection of thyroglobulin autoantibodies in canine serum samples.

An enzyme-linked immunosorbent assay to detect thyroglobulin autoantibodies (TGAB) in canine serum was developed and validated. The test result for each sample was derived from the optical density readings (OD) and expressed as an Ab-score(%) calculated from three in-house calibrators. The assay specifically detected TGAB as judged from lack of response in the assay after samples had been incubated with specific antigen. Intra- and interassay coefficients of variation ranged from 2.0-4.9% and 4.6-9.9%, respectively. The detection limit, an Ab-score of 5.6%, was close to the median Ab-score of 10% observed in healthy dogs (n = 132). The median Ab-score of dogs with primary hypothyroidism and lymphocytic thyroiditis (n = 11), skin diseases (n = 35), and non-thyroidal diseases (n = 63) was 340%, 12%, and 8%, respectively. The prevalence of TGAB in hypothyroid dogs with lymphocytic thyroiditis (sensitivity) was 91% (95% confidence limits: 59%-99%). In dogs with dermatological diseases without lymphocytic thyroiditis the prevalence of TGAB was 3% corresponding to a specificity of 97% (95% confidence limit: 85%-100%). In dogs with non-thyroidal diseases and healthy dogs the prevalence of TGAB was 5% and 6%, respectively. The diagnostic accuracy of serum TGAB was evaluated by subjecting the data from 11 dogs with lymphocytic thyroiditis and 35 control dogs without lymphocytic thyroiditis to receiver-operating characteristic curve analysis. The area under the receiver-operating characteristic curve (W = 0.966; 95% confidence limit 87%-100%) was significantly higher than that of a worthless test (0.5) (P < 0.0001), thereby indicating that serum TGAB measurements distinguished between dogs with and without lymphocytic thyroiditis.

Animals↗
PubMed1998

Upregulation of nuclear PKC and MAP-kinase during hyperproliferation of guinea pig epidermis: modulation by 13-(S)-hydroxyoctadecadienoic acid (13-HODE).

13-(S)-Hydroxyoctadecadienoic acid (13-HODE), the lipoxygenase metabolite of linoleic acid, has been shown to reverse the epidermal hyperproliferation induced by topical application of docosahexaenoic acid (DNA, 22:6 n-3) on guinea pig skin. Our initial studies demonstrated that 13-HODE exerts a selective inhibition of the membrane-bound PKC-beta activity in the hyperproliferative skin. To delineate the antiproliferative effects of 13-HODE, we investigated the nuclear events associated with this process. Our data demonstrated that the major PKC isozymes in the epidermal nuclear fraction are alpha and zeta. Epidermal hyperproliferation induced by DHA caused an increase in nuclear total PKC and atypical PKC activities, and this was accompanied by an increase in the two nuclear isozymes, alpha and zeta (P < 0.05). This increase was reversed after topical application of 13-HODE. Similarly, 13-HODE suppressed elevated nuclear MAP-kinase. Taken together, these data suggest that nuclear signalling events in the epidermis involve PKC-MAP-kinase pathway.

Animals↗
PubMed1998

Effects of naturally-occurring flavonoids and biflavonoids on epidermal cyclooxygenase and lipoxygenase from guinea-pigs.

Although there have been numerous topical applications of plant extracts having flavonoids known as anti-inflammatory compounds, only a few studies were reported concerning effects of flavonoids on epidermal cyclooxygenase/lipoxygenase. In this investigation, effects of naturally occurring flavonoids on epidermal cyclooxygenase/lipoxygenase were studied using five selected derivatives: flavanone, apigenin (flavone), quercetin (flavonol), amentoflavone and ginkgetin (biflavone) because eicosanoids generated in the epidermis are believed to be involved in various biological activities of the skin. Microsomal and cytosolic fractions were obtained from guinea-pig epidermal homogenate by centrifugation and used as a source for cyclooxygenase and lipoxygenase. It was found that quercetin inhibited both cyclooxygenase and lipoxygenase, being more potent against lipoxygenase, while flavanone and apigenin did not show any inhibition. Amentoflavone, one of the biflavones tested, showed potent and selective inhibitory activity on cyclooxygenase (IC50 = 3 microM) which was comparable to indomethacin (IC50 = 1 microM). In contrast, structurally similar ginkgetin possessed weak inhibitory activity on cyclooxygenase. The in vivo effects of these flavonoids on the normal and diseased skin remain to be studied.

Animals↗
PubMed1998

Evaluation of the analytical performance of an enzyme immunometric assay (EIA) designed to measure endogenous thyroid-stimulating hormone (TSH) in canine serum samples.

The analytical performance of a commercially available enzyme immunometric assay (EIA) designed to measure endogenous thyroid-stimulating hormone (cTSH) concentration in canine serum samples was evaluated. The precision of the assay was acceptable with intra- and inter-assay coefficients of variation (CV) of 5 and 11%, respectively. The assay maintained linearity under dilution and recovered added cTSH in a linear and proportional manner. The limit of detection (0.03 microgram/L) was well below the values measured in serum from dogs with primary hypothyroidism (median value 1.52 micrograms/L). Further, the assay clearly distinguished dogs with primary hypothyroidism from clinically healthy dogs (P = 0.0004). Based on these findings, it was concluded that the analytical performance of the assay was acceptable.

Animals↗
PubMed1997

[Sensible drinking limits].

A large number of prospective population studies from many countries have described a J- or U-shaped relation between alcohol intake and mortality. Both heavy drinkers and abstainers are at a higher risk of dying from all causes than individuals with light to moderate alcohol intake. This makes information to the public about sensible drinking limits more complex than, eg, that concerning smoking. The present paper aims at identifying upper thresholds for harmless alcohol intake. The review is mainly based on epidemiological evidence concerning somatic morbidity and mortality. It is concluded that the present Danish recommendations--14 drinks per week for women and 21 drinks per week for men--should be maintained. It is emphasized that these limits apply to adults who are at no risk of dependency and that they do not apply to pregnant women. Information about a potentially beneficial effect of a moderate alcohol intake should be reserved for individuals already at risk of coronary events.

Adult↗
PubMed1997

[Development in mortality, incidence and lethality of ischemic heart disease in Denmark 1982-1992].

In Denmark, as in many other Western countries, a decline in mortality from ischaemic heart disease (IHD) has been observed. The present study assesses whether the decline in IHD mortality is due to a decrease in incidence and/or case-fatality, and whether parallel changes occurred in the various manifestations of IHD requiring hospitalization. The National Patient Register of hospital discharges and the Causes-of-Death Register were linked and all cases of first admission for IHD including acute myocardial infarction (AMI) and fatal first manifestation of IHD since 1977 in the entire Danish population were identified. Cases of AMI and IHD were considered as incident cases if no admission for these diagnoses had occurred during the preceding five years for the same person. Sex-specific, age-standardized annual mortality, incidence and case-fatality rates of AMI (ICD8 code 410), narrowly defined IHD (NIHD, ICD8 codes 410-4) and broadly defined IHD (BIHD, ICD8 codes 410-4, 427 & 795-6) were calculated for the period 1982 through 1992. During the entire period the age-standardized mortality of AMI, NIHD and BIHD decreased in both men and women. The incidence of AMI and NIHD decreased, while the incidence of BIHD remained constant. Case-fatality of AMI decreased in both men and women, while case-fatality of NIHD and BIHD decreased in men and in women aged 0-64 years only. The declining mortality from IHD in Denmark may be partly due to declining incidence as well as declining case-fatality, but changes in disease manifestation or a diagnostic drift may also contribute, since more broadly defined diagnostic groups showed less or no decline in incidence.

Adult↗
PubMed1997

Evaluation of the urinary cortisol: creatinine ratio in the diagnosis of hyperadrenocorticism in dogs.

The diagnostic accuracy of the urinary cortisol:creatinine ratio (CCR), with the cortisol being measured by ELISA, was evaluated by subjecting data from 18 dogs with and 20 dogs without hyperadrenocorticism to receiver operating characteristic (ROC) curve analysis. The area under the ROC curve (W 0.93, SE(w) 0.044) was much higher than 0.5, indicating that the CCR did distinguish between dogs with and without hyperadrenocorticism. A cutoff value of about 60 x 10(-6) was associated with the highest sensitivity (1.0) and specificity (0.85). At the disease prevalence rate of the present study (0.47), the positive and negative predictive values were 0.87 and 1.0, respectively. These numbers indicate that canine hyperadrenocorticism may be safely excluded when the CCR is below 60 x 10(-6) but that a test of higher specificity (eg, the ACTH stimulation test) should be used to confirm the diagnosis of canine hyperadrenocorticism when the CCR is above 60 x 10(-6).

Adrenocortical Hyperfunction↗