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Biomedical subjects

L T Skovgaard

Publications and source records attributed to L T Skovgaard.

At least 37 records · Page 2Linked to original sources
PubMed2000

Seasonal and biological variation of blood concentrations of total cholesterol, dehydroepiandrosterone sulfate, hemoglobin A(1c), IgA, prolactin, and free testosterone in healthy women.

BACKGROUND: Concentrations of physiological response variables fluctuate over time. The present study describes within-day and seasonal fluctuations for total cholesterol, dehydroepiandrosterone sulfate (DHEA-S), hemoglobin A(1c) (HbA(1c)), IgA, prolactin, and free testosterone in blood, and estimates within- (CV(i)) and between-subject (CV(g)) CVs for healthy women. In addition, the index of individuality, prediction intervals, and power calculations were derived. METHODS: A total of 21 healthy female subjects participated in the study. Using a random effects analysis of variance, we estimated CV(g) and total within-subject variation (CV(ti)), i.e., the combined within-subject and analytical variation, from logarithmically transformed data. Analytical variation was subtracted from CV(ti) to give CV(i). CV(i) was estimated from samples taken monthly during 1 year (CV(iy)), weekly during 1 month (CV(im)), and six times within 1 day (CV(id)). RESULTS: A cyclic seasonal variation was demonstrated for total cholesterol, DHEA-S, HbA(1c), prolactin, and free testosterone. Within-day variation was shown for prolactin and free testosterone. The overall mean values for the group and the variability (CV(iy) and CV(g)) were: 5.1 mmol/L, 13% [corrected], and 12% [corrected] for total cholesterol; 6.6 micromol/L, 20% [corrected], and 49% [corrected] for DHEA-S; 30% [corrected], 7.0% [corrected], and 7.5% [corrected] for HbA(1c)/hemoglobin(total); 2.1 g/L, 5.9%, and 13% for IgA; 136 mIU/L, 58% [corrected], and 63% [corrected] for prolactin; and 5.4 pmol/L, 55% [corrected], and 68% [corrected] for free testosterone. CONCLUSIONS: Collecting samples at specific hours of the day or times of the year may reduce high biological variation. Alternatively, the number of individuals may be increased and a paired study design chosen to obtain adequate statistical power.

Adult↗
PubMed1999

A randomized clinical trial of alpha(1)-antitrypsin augmentation therapy.

We have investigated whether restoration of the balance between neutrophil elastase and its inhibitor, alpha(1)-antitrypsin, can prevent the progression of pulmonary emphysema in patients with alpha(1)-antitrypsin deficiency. Twenty-six Danish and 30 Dutch ex-smokers with alpha(1)-antitrypsin deficiency of PI*ZZ phenotype and moderate emphysema (FEV(1) between 30% and 80% of predicted) participated in a double-blind trial of alpha(1)-antitrypsin augmentation therapy. The patients were randomized to either alpha(1)-antitrypsin (250 mg/kg) or albumin (625 mg/kg) infusions at 4-wk intervals for at least 3 yr. Self-administered spirometry performed every morning and evening at home showed no significant difference in decline of FEV(1) between treatment and placebo. Each year, the degree of emphysema was quantified by the 15th percentile point of the lung density histogram derived from computed tomography (CT). The loss of lung tissue measured by CT (mean +/- SEM) was 2.6 +/- 0.41 g/L/yr for placebo as compared with 1.5 +/- 0.41 g/L/yr for alpha(1)-antitrypsin infusion (p = 0.07). Power analysis showed that this protective effect would be significant in a similar trial with 130 patients. This is in contrast to calculations based on annual decline of FEV(1) showing that 550 patients would be needed to show a 50% reduction of annual decline. We conclude that lung density measurements by CT may facilitate future randomized clinical trials of investigational drugs for a disease in which little progress in therapy has been made in the past 30 yr.

Double-Blind Method↗
PubMed1998

Quantification of iliac artery stenoses: a methodological comparative study between intravascular ultrasound, arteriography and duplex scanning.

Two morphological methods for quantifying the degree of stenoses in the iliac arteries, intravascular ultrasound (IVUS) and arteriography, were compared with duplex scanning, a method of evaluating the haemodynamic importance of the stenosis. A total of 38 patients, 20 women and 18 men, median age 66 y, admitted for either PTA (n=18) or femoro-femoral crossover bypass surgery (n=20), were examined by IVUS, single plane arteriography and duplex scanning. The predictive value, sensitivity, specificity and kappa value of IVUS were higher than the corresponding values for arteriography. Logistic regression analysis found that IVUS had a predictive value (p=0.0003) for diagnosing significant stenosis as defined by duplex scanning, but arteriography did not (p=0.1). However, this difference in usefulness as predictors did not reach significance. The agreement between arteriography and IVUS was relatively good. The conclusion is that IVUS seems to be superior to single-plane arteriography in predicting hemodynamically significant stenoses as defined by duplex scanning.

Adult↗
PubMed1998

Long-range correlations of serial FEV1 measurements in emphysematous patients and normal subjects.

In obstructive lung disease the annual change in lung function is usually estimated from serial measurements of forced expiratory volume in 1 s (FEV1). Frequent measurements in each patient may not improve this estimate because data are not statistically independent; i.e., the measurements are autocorrelated. The purpose of this study was to describe the correlation structure in time series of FEV1 measurements. Nineteen patients with severe alpha1-antitrypsin deficiency (phenotype PiZ) and moderate to severe emphysema and two subjects with normal lungs were followed for several years with daily self-administered spirometry. FEV1 measurements fulfilling standard criteria were detrended, and the autocorrelation profile and the power spectrum were calculated. On average the subjects were followed for >3 yr and performed >1,000 acceptable spirometries. The autocorrelation of FEV1 measurements in the emphysematous patients was approximately 0.35 for short intervals and decreased almost exponentially with a half time of 38 days. Between 3 and 4 mo, the autocorrelation function became negative. It reached a minimum of -0.1 at approximately 8 mo and then increased toward zero over the following 12 mo. The autocorrelation function in the two normal subjects showed a similar pattern, but with a faster decay toward zero. In the patients, the power spectrum had a peak at 1 cycle/wk and showed a 1/f pattern, where f is frequency, with a slope of -0.88 at lower frequencies. We conclude that serial spirometric measurements show long-range correlations. The practical implication is that FEV1 need not be measured more often than once every 3 mo in studies of the long-term trends in lung function.

Adult↗
PubMed1997

Comparison of the pattern of agenesis in the primary and permanent dentitions in a population characterized by agenesis in the primary dentition.

The first aim of this study was to collect a large sample of radiographs from children with congenitally missing teeth (CMT) in the primary dentition and to analyse the local relationship between agenesis of a primary tooth and the presence/absence of its permanent successor. The second aim was to compare, in the same sample, the pattern of agenesis in the primary dentition with the developmental pattern seen in the permanent dentition. 124 dentists from 72 municipalities contributed to the investigation of a total of 213 children. The dentists were asked to lend existing radiographic material from patients with agenesis in the primary dentition. The analysis of the local occurrence of agenesis showed that agenesis of a primary incisor was often but not always followed by agenesis of the succedaneous tooth. In the molar region, agenesis of a primary tooth was in all cases but one followed by agenesis of the succedaneous tooth. Comparison of the pattern of CMT in the primary dentition with the pattern of tooth presence/absence in the permanent dentition in a group of 33 patients, for whom complete radiographic material was available showed that agenesis always occurred in the permanent dentition and that the pattern of agenesis in the permanent dentition differed from that in the primary dentition. Incisors were most frequently missing in the primary dentition and premolars in the permanent dentition. The number of congenitally missing teeth was substantially larger in the permanent dentition that in the primary dentition. Also, permanent teeth that are very rarely congenitally missing were missing in this sample, characterized by the occurrence of agenesis in the primary dentition.

Adolescent↗
PubMed1997

Progress of emphysema in severe alpha 1-antitrypsin deficiency as assessed by annual CT.

PURPOSE: To assess serial CT as a measure of the progress of emphysema in patients with severe alpha 1-antitrypsin deficiency (phenotype PiZ). MATERIAL AND METHODS: In a randomized placebo-controlled study of alpha 1-antitrypsin augmentation therapy, 22 patients with moderate emphysema were followed for 2-4 years with an annual lung CT. The images were analysed by means of semiautomatic lung detection, and the degree of emphysema was quantitated by the density-mask and the percentile methods. The influence of lung volume was standardised by a regression model. RESULTS: A highly significant decline in Hounsfield units (HU) was found in low-density areas, corresponding to a mean (SE) annual loss of lung tissue of 2.1 (0.4) g/l lung volume. Analysis of a single slice at 5 cm below the level of the carina gave comparable results: 2.4 (0.4) g/l. CONCLUSION: Serial CT is a sensitive measure of the progress of emphysema in patients with severe alpha 1-antitrypsin deficiency.

Acute Disease↗
PubMed1997

Analysis of anaesthesia in patients suspected to be susceptible to malignant hyperthermia before diagnostic in vitro contracture test.

BACKGROUND: It is well known that patients susceptible to malignant hyperthermia (MH) do not always develop clinical signs of MH at their first anaesthetic. Large material concerning this epidemiological problem do not exist. Therefore, we undertook the present investigation at the Danish Malignant Hyperthermia Register. METHODS: Retrospective analysis of anaesthetics given to 371 patients before in vitro contracture test (IVCT) for susceptibility to MH or before death of MH. Patients (or relatives in the case of a dead patient) gave information about previous anaesthetics and anaesthetic charts were collected and reviewed. RESULTS: Fifteen patients died of clinical MH, 112 patients survived an episode of suspected MH, and 244 patients were relatives of the above. Of the 127 patients with clinical signs of MH, 37% had received anaesthesia before, and trigger agents (potent inhalational agents and/or suxamethonium) were used in 98% of patients with no statistical difference between MH-susceptible (MHS) and non-susceptible (MHN) patients. Emergency anaesthesia was more frequent in patients with fulminant MH compared to those with abortive forms of MH (P < 0.01). Of the 244 relatives, 48% had received anaesthesia before MH was suspected in the family and trigger agents were used in 44% of the anaesthetics without statistical difference between MHS and MHN relatives. In 17 cases, trigger agents were used for anaesthesia after MH was suspected in the family, but before IVCT. CONCLUSION: The clinical expressivity of the MHS phenotype was found to be 34%-54%.

Adolescent↗
PubMed1997

Residual neuromuscular block is a risk factor for postoperative pulmonary complications. A prospective, randomised, and blinded study of postoperative pulmonary complications after atracurium, vecuronium and pancuronium.

BACKGROUND: After anaesthesia involving pancuronium a high incidence of both residual neuromuscular block and postoperative pulmonary complications (POPC) has been reported. The aim of this study was to compare the incidence of POPC following the use of pancuronium, atracurium, and vecuronium, and to examine the effect of residual neuromuscular block on the incidence of POPC. METHODS: A total of 691 adult patients undergoing abdominal, gynaecological, or orthopaedic surgery under general anaesthesia were randomised to receive either pancuronium, atracurium, or vecuronium. Perioperatively, the response to train-of-four (TOF) nerve stimulation was evaluated manually. Postoperatively, the TOF ratios were measured mechanomyographically, and through a 6-day follow-up the patients were examined for pulmonary complications. RESULTS: The incidence of residual block, defined as a TOF ratio < 0.7, was significantly higher in the pancuronium group (59/226: 26%) than in the atracurium/vecuronium groups (24/450: 5.3%). In the pancuronium group, significantly more patients with residual block developed POPC (10/59: 16.9%) as compared to patients without residual block (8/167: 4.8%). In the atracurium/vecuronium groups, the incidence of POPC was not significantly different in patients with (1/24: 4.2%) or without (23/426: 5.4%) residual block. Multiple regression analysis indicated that abdominal surgery, age, long-lasting surgery, and a TOF ratio < 0.7 following the use of pancuronium were potential risk factors for the development of POPC. CONCLUSION: Postoperative residual block caused by pancuronium is a significant risk factor for development of POPC.

Adult↗
PubMed1997

Growth in the external cranial base evaluated on human dry skulls, using nerve canal openings as references.

The purpose of this investigation was to measure on human dry skulls the postnatal widening and lengthening of the external cranial base, including the hard palate, using nerve canal openings as references. Forty-five Indian dry skulls were examined, 36 from children and 9 from adults. The age evaluation was made on the basis of dental development. The dimensions of the external cranial base were determined by direct measurements on the skulls and by measurements from photographs of the skulls. The study showed that growth in width of the external cranial base followed two distinct patterns. The two regions represent different embryologic developmental fields. The study points out that different growth patterns in these fields ought to be taken into account in future investigations of normal and pathologic craniofacial growth.

Adolescent↗
PubMed1996

Validation of the Danish Birth Registration.

We assessed validity and reliability of data on four serious pregnancy complications and gestational age in two national registers, the Medical Birth Register (MBR) and the National Register of Hospital Discharges (NRHD). From a cohort of all women in Denmark who gave birth to their first and second singleton infant in 1982-1987, a review was made of a selected sample of 1662 medical records. Regarding registration of pregnancy complications, there was good agreement (kappa above 0.6) between medical records and the registers, and between the registers. However, there was a tendency toward understatement evidenced by low sensitivity of three of four pregnancy complications. The level of agreement (43%) for length of gestation was disappointing. The number of systematic and nonsystematic errors indicate that there was about 52% more singleton preterm deliveries in Denmark in 1982 than previously reported (6.9% instead of 4.5%). It is concluded that the validity of the Danish birth registers should be improved by explicit definitions, increased use of raw data, and data collection by motivated professionals at birth.

Denmark↗
PubMed1996

Estimation of otitis media in ancient populations. A study of past and present Greenlandic Inuit.

Examination of disease patterns in the past has often been difficult due to lack of morphological evidence. This study presents a new unbiased method for estimation of occurrence of infectious middle ear disease (IMED) in childhood. The method is based on the relation between IMED in childhood and small or asymmetric pneumatized cell areas in the temporal bones as seen on standardised X-rays. A polychotomous logistic regression model was applied on 434 pneumatized cell areas in temporal bones from 34 adult living Greenlandic Inuit, 56 adult crania from the 18th to the 19th century, A.D. and 127 adult Inuit crania from the pre-European colonization period (before A.D. 1721) of Greenland. The occurrence of IMED as designated by the model was eight out of 34 (23.5 per cent) in living Inuit, 10 out of 56 (17.9 per cent) in crania from the 18th to 19th century and six out of 127 (4.7 per cent) in crania from the pre-colonization period. These frequencies differed significantly (p < 0.002). The mean area size also differed significantly, thus indicating a change in occurrence of IMED and a decrease in area sizes from past to present in Greenland.

Adolescent↗
PubMed1996

Timing of tracheal intubation: monitoring the orbicularis oculi, the adductor pollicis or use a stopwatch?

The most suitable time for tracheal intubation, following vecuronium 0.1 mg kg-1, was estimated in 120 patients. The trachea was intubated at cessation of the visually observed response of the orbicularis oculi muscle to facial nerve stimulation (group 1; n = 30), or of the manually detected response of the adductor pollicis to ulnar nerve stimulation (group 2; n = 30), or after waiting 3 min (group 3; n = 30), or 4 min (group 4; n = 30). There were no significant differences in intubation scores between the four groups of patients. Loss of response to train-of-four stimulation occurred significantly sooner in group 1 (orbicularis oculi) than in group 2 (adductor pollicis) P = 0.021). However, intubating conditions were poor in four patients (14%) in group 1, compared with none in group 2 and one in groups 3 and 4, respectively. Thus, contrary to expectations, the cessation of the response of the orbicularis oculi muscle did not guarantee good or even satisfactory intubating conditions. The results suggest that in fit adult patients it is as good to wait 3 min after injection of vecuronium 0.1 mg kg-1 before tracheal intubation, as to use a nerve stimulator.

Adolescent↗
PubMed1996

Good clinical research practice (GCRP) in pharmacodynamic studies of neuromuscular blocking agents.

Based on an international consensus conference held in Copenhagen in the autumn of 1994, a set of guidelines for Good Clinical Research Practice (GCRP) in pharmacodynamic studies of neuromuscular blocking agents are presented. The guidelines are intended to be a help for people working in this research field, and it is hoped that the guidelines will assist researchers, editors, and drug companies to enhance the quality of their pharmacodynamic studies of neuromuscular blocking agents.

Clinical Trials as Topic↗
PubMed1995

Anchorage of TiO2-blasted, HA-coated, and machined implants: an experimental study with rabbits.

The purpose of this study was to evaluate the histometrical and biomechanical anchorage of TiO2-blasted implants and TiO2-blasted implants coated with hydroxyapatite. The control implants were machined. Twenty-six rabbits had a total of 156 implants placed in the proximal part of the tibia. Each rabbit had a machined, a TiO2-blasted, and a TiO2-blasted, HA-coated implant placed in each tibia. After a healing period of 3 and 12 weeks, respectively, the implants placed in the right tibia were used for removal torque test, and the implants placed in the left tibia were used for histomorphometrical measurements. Preoperatively, implants from the same batches were examined topographically with a TopScan 3D system. The TiO2-blasted implants demonstrated significantly higher removal torque values than the machined implants, and they also had a significantly more irregular surface. Furthermore, significantly higher bone-to-implant contact length fractions were measured adjacent to the TiO2-blasted implants in contrast to the machined implants. The advantages of a TiO2-blasted surface were more pronounced after 3 weeks than after 12 weeks. The results demonstrated that it was possible to influence the anchorage of implants by altering the surface structure morphology. The new method with TiO2 blasting on the titanium surface improves the anchorage of implants but is not yet practicable for HA coating.

Animals↗
PubMed1995

Identification of human plasma cholinesterase variants in 6,688 individuals using biochemical analysis.

In 1973, a Cholinesterase Research Unit was established in Denmark (DCRU). The primary aim was to provide a central service for determining genotypes and activity of plasma cholinesterase (BChE) in patients showing abnormal response after succinylcholine. The purpose of the present study was, on the basis of 20 years experience with this Unit, to establish accurate reference intervals for BChE activity and inhibition values for the different genotypes of BChE. Also we wanted to evaluate the influence of age and sex on the BChE activity in genotypically normal patients. Plasma cholinesterase activity was measured using benzoylcholine as substrate. The genetic variations of the enzyme were identified using differential inhibitors, i.e.: Dibucaine, Sodium Fluoride, Succinylcholine, Urea and Ro-2-0683. We investigated 6,688 patients. The reference values for the 13 genotypes represented agree with previous findings. In genotypically normal patients, no age or sex differences were found in BChE activity in children below the age of 10 years. From the age of 10 years the activity decreased significantly in both males and females, the activity in females being significantly lower than in males. In females the activity was lowest in the age group 30-40 years, returning to prepuberty level at about 60 years of age. In males the activity decreased slightly up to 50-60 years of age. Hereafter the activity was stable or tended to increase slightly. Most genotypes could be recognized using the results of the different inhibition studies. We found the inhibitors Dibucaine, Sodium fluoride, Urea and Ro-2-0683 most helpful, whereas succinylcholine was of less value.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Dose-response relationship for mivacurium in patients with phenotypically abnormal plasma cholinesterase activity.

During thiopentone-fentanyl-nitrous oxide anaesthesia and using a cumulative design, we studied the dose-response relationship of mivacurium in 8 patients: 7 patients phenotypically homozygous for the atypical plasma cholinesterase gene and 1 patient homozygous for the silent gene. The estimated mean ED50 and ED95 were 15 and 20 micrograms.kg.bw-1 in patients homozygous for the atypical gene, and 13 and 16 micrograms.kg.bw-1 in the patient homozygous for the silent gene, respectively. The results indicate that mivacurium is 4-5 times more potent in patients homozygous for the atypical or the silent gene than in patients with normal plasma cholinesterase activity and phenotype.

Adult↗
PubMed1995

Pneumatization and otitis media in Greenlandic Inuit before European colonization.

A total of 127 Greenlandic Inuit crania from before the European colonization of Greenland and deriving from the West (W), Southeast (SE), and Northeast (NE) coast of Greenland were examined for sequelae of infectious middle ear disease (IMED) and for a relationship between the size of the pneumatized cell area in the temporal bones and cranial morphology. IMED was inferred from the area size of the pneumatized cell system as seen on x-rays. The crania were classified into IMED or non-IMED by applying a statistical model on the distribution of areas. The model designated six crania (4.7%, 95% CI: 1.8-10.0%) as having had IMED, four from the W, one from the SE, and one from the NE. This is lower than the present frequency of IMED in Greenland. One cranium revealed pathology resembling that caused by chronic inflammation (e.g., from cholesteatoma or cancer). The area sizes differed significantly between sexes and between regions, as did some of the cranial measures. This indicated a relationship between cranial morphology and the area size. However, in a multiple regression analysis, cranial morphology only explained 5 to 7% (R2) of the variability in the areas.

Archaeology↗