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Biomedical subjects

R T Lie

Publications and source records attributed to R T Lie.

At least 73 records · Page 4Linked to original sources
PubMed1994

Ultrasound screening for developmental dysplasia of the hip in the neonate: the effect on treatment rate and prevalence of late cases.

OBJECTIVE: To assess the effect of ultrasound screening on primary diagnosis, management, and prevalence of late cases of developmental dysplasia of the hip (DDH). DESIGN: A randomized, controlled trial, including 11,925 newborn infants who were allocated to receive either general, or selective or no ultrasound screening in addition to the clinical examination. In the selectivity screened group only infants with risk factors or clinical findings of DDH received an ultrasound examination. The infants were at least 27 months old at the conclusion of the study. Those with risk factors for DDH had a radiograph examination of the hips at 4.5 months of age. RESULTS: The three study groups did not differ in terms of sex distribution or positive Barlow/Ortolani tests. General ultrasound screening resulted in a higher treatment rate than in either the selective or in the no ultrasound screening groups (3.4% vs 2.0% and 1.8%, P < .0001). For infants not subjected to treatment, ultrasound screening resulted in a higher follow-up rate because of nonconclusive early findings (13%, 1.8%, 0%, respectively; P < .0001). The prevalence of late subluxation or dislocation was lower for subjects assigned to general ultrasound screening than for those subjected to selective or no ultrasound screening, but the differences were not statistically significant (0.3, 0.7, 1.3 per 1000, respectively; P = .11, test for trend). CONCLUSION: The effect of ultrasound screening in reducing the prevalence of late DDH was at best marginal despite a considerable increase in diagnostic and therapeutic efforts.

Hip Dislocation, Congenital↗
PubMed1994

Maximum likelihood estimation of the proportion of congenital malformations using double registration systems.

Since 1970, epidemiological surveillance of congenital malformations has been carried out in Norway on the basis of data in the nationwide Medical Birth Registry. A separate local registry of cases occurring in the county of Hordaland was established in 1985 to clarify problems inherent in the reporting. This paper deals with double sampling estimators of the prevalence at birth of various malformations, utilizing joint data from two such registries. Particular examples include Down's syndrome, malformations of the central nervous system (CNS), cleft lip or cleft palate, and hypospadias. The methods applied also allow estimation of the probabilities of ascertainment of the different malformations in each registry. Expressions are derived for the variances of the asymptotic distributions of the double sampling estimators, and the possibility of using these values to detect true changes in disease prevalence when ascertainment is uncertain is discussed. The merits of double sampling are assessed comparing the crude estimator based on the Medical Birth Registry alone with the double sampling estimators. Finally, some fully parameterized alternatives to the double sampling models are introduced to evaluate some of the assumptions involved.

Biometry↗
PubMed1993

[Apparent decrease in the occurrence of anencephalus in Norway 1967-90].

The occurrence of anencephalus as reported to the Norwegian Medical Birth Registry has fallen from 4.9 per 10,000 births in 1967-71 to 2.7 in 1987-90. The decrease is particularly noticeable for births with a gestational length of 28 weeks or more. On the other hand, there has been a significant increase in the number of cases of anencephalus with a gestational age less than 28 weeks. The occurrence of meningomyelocele has remained relatively stable throughout the same period. Ascertainment error could explain these contrasting trends, since cases of anencephalus detected on ultrasound screening may lead to early termination of pregnancy without notification to the Medical Birth Registry. Better routines for notification of malformations are needed to improve the basis for surveillance in Norway.

Anencephaly↗
PubMed1993

Prognostic value of plasma atrial natriuretic factor, norepinephrine and epinephrine in acute myocardial infarction.

Neurohumoral activation in acute myocardial infarction (AMI) may reflect the degree of hemodynamic compromise, contribute to the progression of heart failure and augment to the risk of serious ventricular arrhythmias. Consequently, assessment of neurohumoral variables may provide an index of prognostic value in AMI. Plasma levels of atrial natriuretic factor (ANF), norepinephrine and epinephrine were determined in 145 patients on day 3 after AMI. During the 360-day follow-up period 17 patients died. In univariate analysis, all 3 neurohormones were significantly related to 1-year mortality rates (ANF, p < 0.001; norepinephrine, p = 0.009; epinephrine, p = 0.048). After correction for age, sex, anamnestic, biochemical and clinical variables including signs of clinical heart failure in a multivariate model, ANF remained independently related to mortality. The association between plasma norepinephrine and survival failed to reach statistical significance after introduction of clinical heart failure in the model. Comparison of patients subdivided according to median hormone levels (ANF, 30.3 pmol/liter; norepinephrine, 2.29 nmol/liter) demonstrated a significantly increased mortality rate in patients with elevated ANF (p < 0.001), but not elevated norepinephrine levels. These results suggest that early plasma ANF levels are related to survival in patients with AMI, independently of signs of clinical heart failure.

Aged↗
PubMed1993

A new sequential procedure for surveillance of Down's syndrome.

A new method is proposed for the surveillance of Down's syndrome among newborn. Despite the strong dependence of overall risk of Down's syndrome on maternal age, it has been suggested that an environmentally induced increase in risk may be additive over all maternal ages. The surveillance method introduced here is specifically designed to detect such changes. The method is based on registry data for successive periods for a given population. It is assumed that the number of Down's syndrome cases as well as the total number of births are known in all maternal age groups. Tables of average run lengths until an alarm (ARLs) are calculated for a total sample size of 14,500 in each period, the approximate number of births in a three-month period in Norway. Comparison with the Poisson cusum shows that the new surveillance method can detect moderate additive increases significantly faster. Applied retrospectively to quarterly data from the Medical Birth Registry of Norway for 1978-89, the proposed method was close to an alarm in 1985 and actually signalled a strong alarm in 1986, reflecting a previously reported increase in risk in this period. The cusum method was not so sensitive to the aberration in Down's syndrome risks in 1985 and 1986.

Adult↗
PubMed1993

Prognostic significance of N-terminal pro-atrial natriuretic factor (1-98) in acute myocardial infarction: comparison with atrial natriuretic factor (99-126) and clinical evaluation.

OBJECTIVE: To evaluate the prognostic significance of plasma N-terminal pro-atrial natriuretic factor (1-98) concentrations measured in the subacute phase after acute myocardial infarction, and to compare the predictive value of measurement of N-terminal pro-atrial natriuretic factor (1-98) with the measurement of atrial natriuretic factor (99-126) and with clinical assessment of the degree of heart failure. DESIGN: Prospective observational. SETTING: Norwegian central hospital. PATIENTS: 139 patients (mean (SD) age 66.9 (11.1) years, 71.2% males) with acute myocardial infarction. Patients in cardiogenic shock or with severe heart failure (New York Heart Association class IV) were excluded. MAIN OUTCOME MEASURE: Cardiovascular death within 12 months. RESULTS: During the follow up period 15 patients died. In a univariate Cox proportional hazards model N-terminal pro-atrial natriuretic factor (1-98) was significantly related to mortality (p = 0.0003). In a multivariate model the prognostic value of N-terminal pro-atrial natriuretic factor (1-98) was better than that of atrial natriuretic factor (99-126) and clinical assessment of heart failure (N-terminal pro-atrial natriuretic factor (1-98), p = 0.0003; atrial natriuretic factor (99-126), p = 0.4513; heart failure, p = 0.0719). The odds ratio estimate of patients in whom plasma concentrations of N-terminal pro-atrial natriuretic factor (1-98) were greater than 2000 pmol/l was 25 (95% confidence interval 2.8-225.0) compared with patients with plasma concentrations less than 1000 pmol/l. CONCLUSIONS: These results suggest that determination of plasma N-terminal pro-atrial natriuretic factor (1-98) in the subacute phase of myocardial infarction may provide clinically relevant prognostic information that is superior to that obtained from atrial natriuretic factor (99-126) measurements and clinical evaluation.

Aged↗
PubMed1993

Bubble-induced aggregation of platelets: effects of gas species, proteins, and decompression.

We show that bubbles containing different gases (N2, He, Ne, Ar, or an O2-CO2-N2 mixture) are equally potent platelet agonists. The synergistic effect of different platelet antagonists does not seem to be affected by the type of gas in the bubbles. In contrast to aggregation in platelet-rich plasma (PRP), bubbles cause only a weak response in gel-filtered platelets (GFP), i.e., comparison of aggregation in protein-rich and protein-poor platelet suspensions may shed light on the role of different plasma proteins. Extracellular fibrinogen promotes bubble-induced platelet aggregation similar to known physiologic agonists, whereas albumin counteracts this aggregation. Bubble-induced aggregation is inhibited in GFP-fibrinogen by 2-deoxy-D-glucose plus antimycin A, suggesting dependency on ATP generation in the platelets and evidence for direct exposure of the "cryptic" fibrinogen receptor by bubbles. Hyperbaric compression and subsequent rapid, inadequate decompression of PRP caused little change in the aggregation response to gas bubbles and epinephrine at 1 bar, but reduced the response to ADP. Bubbles tended not to form before the surface film was broken. Pressure-induced aggregation was apparently metabolically active and not due to passive agglutination; electron microscopic studies and PRP with added glutaraldehyde did not show platelet activation, clumping, or reduced platelet count. In contrast to aggregation caused by pressure, bubble-induced aggregation in PRP at 1 bar (after treatment in the pressure chamber) was nearly completely inhibited by theophylline, a phosphodiesterase inhibitor that increases intracellular platelet cyclic AMP.

Adenosine Diphosphate↗
PubMed1992

Birth defects in Norway by levels of external and food-based exposure to radiation from Chernobyl.

In Norway, external doses of radiation resulting from fallout from the Chernobyl nuclear accident were estimated from detailed measurements, including soil deposition patterns. Internal doses were estimated from measurements of radioactive cesium in meat and milk supplies. The doses were calculated as average monthly doses for each of 454 municipalities during 36 consecutive months after the accident in spring 1986. Prospectively collected data on all newborns listed in the Medical Birth Registry of Norway who were conceived in the period May 1983-April 1989 were used to assess possible dose-response relations between estimated external and food-based exposures and congenital malformations and some other conditions. A positive association was observed between total radiation dose (external plus food-based) and hydrocephaly, while a negative association was observed for Down's syndrome. However, an important conclusion of the study was that no associations were found for conditions previously reported to be associated with radiation, i.e., small head circumference, congenital cataracts, anencephaly, spina bifida, and low birth weight. Potential sources of bias, including exposure misclassification and incomplete ascertainment of cases, are discussed.

Abnormalities, Radiation-Induced↗
PubMed1992

Ultrasound in the early diagnosis of congenital dislocation of the hip: the significance of hip stability versus acetabular morphology.

Recent studies have suggested that ultrasound examinations may improve diagnostic accuracy in congenital dislocation of the hip, but there is differing opinion whether ultrasound diagnosis should be based on morphology or stability. Ultrasound was added to the routine clinical screening in 1503 newborns (1291 girls and 212 boys). Hip morphology was classified according to Graf (type 1-4), while sonographic stability was based on a modified Barlow maneuver, and classified as stable, elastic deflection (normal finding), unstable (provocating a gap between the femoral head and the acetabulum) and dislocated. Among 80 morphologically dysplastic hips, 73 (91%) were sonographically unstable or dislocated, while seven dysplastic hips were stable. On the other hand, in 49% of the sonographic unstable hips (69 out of 142) the acetabulum was either normal or just physiologically immature. 38 of these hips were left untreated and normalized spontaneously. There was a close correlation between sonographically and clinically determined hip stability (gamma = 0.95). Our study shows that the majority of morphologically dysplastic hips is sonographically unstable or dislocated, but also that morphologically dysplastic hips may be stable. Morphologically normal hips showing minor sonographic instability do probably not require treatment, and thus morphology seems to be an important diagnostic criterion.

Acetabulum↗
PubMed1992

The influence of the host on the course of gastric carcinoma.

Immunoglobulins (Ig) and some complement components (C) were quantified in sera from patients with gastric carcinoma before surgery and at regular intervals during a 5-year follow-up. The preoperative concentrations of C1-INH and C4 were higher (P < 0.0005 and P < 0.005) and IgG lower (P < 0.0005) in 50 patients with recurrence than in 46 5-year survivors. The prognostic significant of C1-INH was superior to that of the extent of disease (F-values 37.1 and 26.1). The preoperative immune data classified 76% of the patients correctly as to recurrence and no recurrence. Also, the preoperative C1-INH concentration had a highly significant effect on time to recurrence of cancer (P = 0.0007), adjusting for age and disease extent. After surgery the mean IgG concentrations were within normal range and without difference between the two groups. On the other hand, the concentrations of C1-INH and C4 in the individual patients in both groups remained the same from before to after surgery and throughout the observation period (P = 0.34). Apparently, the serum levels of C1-INH and C4 do not reflect the bearing of cancer. We therefore suggest that these variables represent an independent immune state that is appropriate to the host. A comparison of our variables with those of healthy individuals seems to support this idea. This immune state has a significant influence on whether a resected gastric cancer will recur, and also on how soon recurrence may be manifest.

Adult↗
PubMed1992

Congenital dislocation of the hip: a prospective study comparing ultrasound and clinical examination.

Screening for congenital dislocation of the hip by standard clinical methods and ultrasound was compared prospectively in 1503 newborns (1291 girls and 212 boys). A total of 82.8% of the hips (78.8% of the infants) had well developed acetabulae, 14.5% (17.2% of the infants) were shallow (immature) and 2.7% (4.1% of the infants) were dysplastic. Within 1-3 months 96.7% of the infants with clinically stable, but immature hips normalized, while 3.3% did not improve or worsened, and therapy was therefore initiated. Indications for treatment included dysplastic and/or clinically unstable hips, and a higher number of newborns were treated during the study period than in 1982-85 (31.2 vs 19.7 per 1000, p = 0.0002). Thirty-seven percent of the patients had both clinical and ultrasound findings compatible with congenital dislocation of the hip, while the decision to treat was based on clinical findings alone in 25.0% and on ultrasound findings in 38.0%. Infants born during the study period of nine months had a low incidence of late congenital dislocation of the hip compared with our earlier reported results from 1982-85 (0.9 vs 3.5 per 1000, p = 0.012). The study demonstrated major discrepancies between clinical and ultrasound evaluation of hips in the newborn, and the role of ultrasound in the screening for congenital dislocation of the hip requires further evaluation.

Acetabulum↗
PubMed1991

Microbubble-induced serotonin secretion in human platelets.

The effect of nitrogen (N2) microbubbles on platelets resembles that of common platelet agonists with respect to aggregation (Thorsen T et al., Undersea Biomed Res 1986; 13: 289-303). In the present study we examined the effect of microbubbles on platelet secretion of preloaded 14C-serotonin. We demonstrate that stirring of platelet-rich plasma with N2-microbubbles causes a loss of single platelets that is associated with secretion. However, secretion did not increase above baseline values until after 20 min of microbubble exposure, when platelet aggregation had reached 40%. After that time the secretion rate increased. There was no correlation between secreted serotonin and the degree of platelet aggregation. Although no 14C-serotonin secretion occurred in presence of acetylsalicyclic acid (ASA), microbubble-induced platelet aggregation was only marginally reduced. Epinephrine alone caused significant platelet aggregation but no 14C-serotonin secretion and it enhanced N2-microbubble-induced platelet aggregation and secretion; ASA completely prevented secretion under these circumstances but failed to abolish the enhancement of aggregation compared with microbubbles alone. Earlier studies have shown that platelets adhere to the bubble surfaces (Thorsen T et al., Undersea Biomed Res 1987; 14: 45-59). The results in the present study indicate that non-adhering platelets in the bulk phase are not activated by means of autocrine stimulation through dense granule material.

Blood Platelets↗
PubMed1991

A temporary increase of Down syndrome among births of young mothers in Norway: an effect of risk unrelated to maternal age?

The Medical Birth Registry of Norway carries out a population-based surveillance of birth defects on a routine basis. An increased proportion of newborn with Down syndrome was seen among children of young mothers during 1985-1986. Three alternative explanations were considered: a first representing a maternal age specific effect, a second based on a general increase in a subgroup of cases caused by factors not related to maternal age, and a third based on the assumption that a particular birth cohort of young women was carrying a high risk. As 1987 and 1988 showed very low proportions in all age groups, the last explanation was considered less likely. Statistical modeling was used to explore which of the two remaining explanations of the temporary increase was the more likely. The observed changes were compatible with a change in the occurrence of a group of maternal age-independent Down syndrome cases, from 4.59 per 10,000 in 1973-1984 and again in 1987-1988 to a temporary high of 7.68 per 10,000 in 1985-1986. However, the possibility of an age specific change only among young mothers could not be ruled out.

Adolescent↗
PubMed1991

Pregnancy outcome in Norway after Chernobyl.

Pregnancy outcome has been studied in terms of legal abortions, early spontaneous abortions and total number of pregnancies (in an ad hoc study covering 6 counties) as well as various perinatal health problems (on the basis of routinely recorded data for epidemiological surveillance from the Medical Birth Registry of Norway). Apparently, no effects were observed in terms of an increased occurrence of legal abortions, while spontaneous abortions increased from 7.2% of all pregnancies during the last 12 months before the accident to 8.3% after the accident [corrected]. At the same time, the total number of pregnancies somewhat decreased. Based on monthly measurements in each municipality of external and internal (food-based) doses, dose-response associations were assessed for a number of perinatal health problems. No associations were observed.

Abortion, Legal↗
PubMed1991

The influence of age on the growth and spread of gastric carcinoma.

A twelve year series of 375 patients with gastric carcinoma has been studied. Patients were divided into TNM Groups. Tumours were classified as intestinal-type and diffuse. The patients with T1-3NOMO diffuse tumour were ten years younger than the patients with T1-3NOMO intestinal-type tumour. The mean age increased from T1 through T2 to those with T3 tumour. The age differences between the T-stages were the same in both groups, which indicate that once started, the diffuse and the intestinal-type tumours infiltrate the gastric wall at about the same rate. Among the patients with intestinal-type tumour, those with lymph node or distant metastases were three to seven years younger than the patients without metastases. On the other hand, the patients with diffuse tumour and metastases were as many years older than the patients without metastases. Apparently, tumour spread is age dependent and different between the two types of gastric carcinoma. The ill repute of the diffuse gastric carcinoma may therefore be explained by the advanced stage of that tumour at the time of treatment as compared to the intestinal-type tumour. The diffuse tumour seems to be clinically more silent and to give symptoms at a later stage than the intestinal-type tumour.

Adult↗
PubMed1991

Age and sex distribution of intestinal type and diffuse gastric carcinoma.

A twelve-year series of 375 patients with gastric carcinoma has been studied. Primary tumours were classified as intestinal type (58%) or diffuse (26%), whereas 16% were unclassifiable. The relative age and sex incidence rates of intestinal type and diffuse gastric carcinoma were estimated using the age and sex distribution of individuals in Norway as the basis for calculation. There was no difference in the rates of diffuse gastric carcinoma between the sexes. On the other hand, the rate of men with intestinal type carcinoma was more than twice as high as that of women. This difference was consistent within each age group from adolescence to senescence. The findings indicate that Laurén's two types of gastric carcinoma are aetiologically different. The rates of both types increased with age up to the 70-79 age group, whereas the rates in octogenarians tended to be lower than in septuagenarians. A comparison of our data with the data of incidence of gastric cancer in Norway indicates that some of the older patients do not come for surgery.

Adult↗
PubMed1991

Age-related differences in chemical composition of rat femur as determinants for strain.

We have explored previous findings of remarkably stable in vivo strain at the femoral surface in rats at different ages, and at the same time increased bone stiffness. The rate of collagen synthesis (14C-hydroxyproline/total hydroxyproline ratio) decreased with age, whereas mineralization (calcium/hydroxyproline ratio) increased. Smaller amounts of immature collagen, caused by reduced synthesis, and increased mineralization both probably produce a less flexible material. These chemical alterations support the observed increase in structural stiffness and strength with age. Both mineralization and configurations separately seemed to have effects on in vivo strain. However, none of these variables seemed to be the major determinant for strain.

Aging↗