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Biomedical subjects

P K Hansen

Publications and source records attributed to P K Hansen.

At least 19 recordsLinked to original sources
PubMed1996

A comparison of two control-display gain measures for head-controlled computer input devices.

We compared two gain measures: One, defined as angle/angle (A/A) gain, is the ratio between the angle subtended by displacement of the cursor and the corresponding angle of head extension/flexion or rotation. The alternative measure, defined as displacement/angle (D/A) gain, is the ratio between the linear displacement of the cursor on the screen and the corresponding angle of head extension/ flexion or rotation. A discrete target acquisition task using circular targets was used to compare control-display gain measures. Operator performance was evaluated for three viewing distances and three gain settings of each measure. Average movement time and root mean squared (RMS) cursor deviation from a straight line path increased as viewing distance increased for A/A gain settings 0.75 and 1.0. That no significant distance effect was observed for any of the D/A gain settings indicated that it might be more suitable to fix D/A gain rather than A/A gain for head-controlled computer input devices. Minimum movement time occurred for D/A gain settings of 0.5 cm/degree and 0.67 cm/degree. One explanation for the observed insensitivity of performance to changes in viewing distance with a fixed D/A gain may be that both angular head movement and the accompanying kinesthetic feedback do not change for a specified cursor displacement as viewing distance is changed.

Adult↗
PubMed1994

[Treatment of episiotomy wound infections. Incision and drainage versus incision, curettage and sutures under antibiotic cover--a randomized trial].

Conventional, "open" treatment of episiotomy wound infections was compared to incision, curettage and primary suture under antibiotic cover in a prospective, randomized study. During the period 1.5.1986-31.12.1988 there were 4154 vaginal deliveries with episiotomy, of which 20 (0.48%) became infected. Seventeen of these patients consented to enter the study. Median time for healing was 12 days following suture and 19 days after "open" treatment (not significant). Hospitalization time was the same in the two groups. No re-infections were seen. A need for vaginal plastic repair was found in three of nine of the conventionally treated patients and in none of the patients in the suture group (not significant). It is concluded that treatment of episiotomy wound infections with incision, curettage and primary suture under antibiotic cover is an attractive, safe ad convenient alternative treatment.

Adult↗
PubMed1993

Dissection of the DNA-binding domain of Xenopus laevis TFIIIA. Quantitative DNase I footprinting analysis of specific complexes between a 5 S RNA gene fragment and N-terminal fragments of TFIIIA containing three, four or five zinc-finger domains.

Recombinant zinc finger proteins corresponding to N-terminal fragments of Xenopus laevis transcription factor IIIA (TFIIIA) comprising three, four and five fingers produced in Escherichia coli as cleavable hybrid proteins were shown to form specific stoichiometric complexes with DNA fragments containing the internal control region (ICR) of a 5 S RNA gene. The ordered set of DNase I footprints of each of the three proteins on the ICR comprise a nested set of footprints extending upstream from its 3' end (position +96 relative to start of the mature transcript) 20 bp, 20 bp or 34 bp into the ICR, respectively. Quantitative analysis of the footprinting data provided firm evidence that the DNase I footprint, and hence the structure, of the authentic TFIIIA:ICR complex in this region is fully and precisely accounted for by the N-terminal three fingers binding within the +77 to +96 region plus the pair of fingers 4 and 5, both required to extend the footprint upwards from the +77 to the +63 position. A structural interpretation of this set of new footprinting data in view of previous results and data is presented and discussed in terms of a refined model in which the protein-DNA interaction between the ICR and the three N-terminal fingers corresponds closely to that observed in the homologous three-finger zif268:DNA complex, whereas the basic mode of protein-DNA interaction, in which the pair of fingers 4 and 5 is engaged in forming the TFIIIA:ICR complex is of an entirely different, albeit not yet understood nature. To allow assessment of our model in terms of potential specificity-determining H-bonding patterns, a molecular model of the complex between the three-finger TFIIIA fragment and the ICR was constructed, using the zif268:DNA co-ordinates. Eight out of the nine amino acid residues, which according to our model are suitably located for forming hydrogen bonds with the bases, are potential H-bond acceptors or donors.

Amino Acid Sequence↗
PubMed1991

Sequence-specific binding of the N-terminal three-finger fragment of Xenopus transcription factor IIIA to the internal control region of a 5S RNA gene.

An N-terminal fragment of Xenopus TFIIIA, containing domains 1-3, (TF 3), was expressed in E. coli. High yields of recombinant zinc finger protein was isolated, and its DNA binding activity for the internal control region (ICR) of the Xenopus 5S RNA gene, was demonstrated by band-shift experiments and DNase I footprinting analysis. TF 3 protects 20 bp of ICR against DNase I digestion. The limits of protection are from +77 to +96 on both coding and noncoding strand. This protection pattern is identical to the protection pattern obtained with TFIIIA in the overlapping region, showing that the 3-finger fragment accounts fully for the protein-DNA interactions in TFIIIA-5S RNA gene over this region.

Amino Acid Sequence↗
PubMed1987

Estimation of fetal weight in the third trimester by ultrasound.

A method to estimate the intrauterine fetal weight by use of ultrasound measurements of the fetal biparietal diameter (BPD) and the abdominal diameter (AD) is presented. From a consecutive series of single pregnancies the 238 pregnancies (3% of the hospital population) with ultrasound measurements obtained within 4 days before delivery were used in the estimation of birth weight. In addition, the estimated formula was applied on a test material consisting of 100 similarly selected pregnancies from the same hospital. To evaluate the expected selection effects, the birth weight for gestational age in the study group was compared with birth weight for gestational age in the total population. The weight could be estimated as 0.0351 X AD1.65 X BPD0.69 X exp(0.00196 X gestational age). Thus, the actual birth weight was within 83-120% of the estimated weight (95% prediction limits), with a residual coefficient of variation of about 9%. The gestational age could be omitted without major influence on the weight prediction. When applying the formula on the test material, 70% of the actual weights deviated less than 10% from the estimated fetal weight, but a tendency towards a slight overestimation of the weight for light for gestational age infants was found.

Birth Weight↗
PubMed1987

Interaction between non-formylated initiator Met-tRNA(fMet) and the ribosomal A-site from Escherichia coli.

We report studies in vitro of the interaction between non-formylated initiator Met-tRNA(fMet) and 70S ribosomes. The binding of Met-tRNA(fMet) to ribosomes carrying fMet-tRNA(fMet) in the P-site is strongly stimulated by elongation factor EF-Tu:GTP in the presence of (AUG)3. The enzymatically bound Met-tRNA(fMet) does not react with puromycin. The bound Met-tRNA(fMet) can accept formylmethionine from P-site-bound fMet-tRNA(fMet). These results demonstrate a functionally active binding at the ribosomal A-site. Partial ribonuclease digestion (footprinting) was used to study the sites in Met-tRNA(fMet) which are involved in the interaction with the ribosomal A-site. The results show that a large part of the tRNA molecule is protected by the ribosome against ribonuclease digestion. In addition to the protection found in the amino acid region and the anticodon arm, protection is seen in the D-loop and in the extra arm. No region within the bound tRNA is found to be more accessible for RNases than in the free Met-tRNA(fMet). The reported enhancement of ribonuclease cuts in the D- and T-arms of A-site-bound Phe-tRNAPhe is thus not found in A-site bound Met-tRNA(fMet).

Base Sequence↗
PubMed1987

Plasma fibronectin concentration in normal pregnancy and pre-eclampsia.

Plasma fibronectin concentration was determined by electroimmunoassay in 111 normal pregnant women and in 23 pregnant with evidence of pre-eclampsia. The plasma fibronectin concentration during the period of normal pregnancy showed a significant increase. In mild or severe pre-eclampsia patients, the plasma fibronectin concentration was significantly higher than that measured at normal 38-41 weeks of gestation. The present findings suggest that measurement of plasma fibronectin might be of diagnostic value in pre-eclampsia.

Adolescent↗
PubMed1986

Intrapartum fetal heart rate monitoring in a combined low- and high-risk population: a controlled clinical trial.

In a prospective clinical randomized investigation 487 women had the condition of the fetus during labour supervised by means of stethoscope (AUS), while 482 women went through labour under surveillance of electronic fetal monitoring, cardiotocography (EFM). 349 women refused to participate in the investigation (NAI) and had delivery conducted according to the normal procedures of the department (70% AUS, 30% EFM). Significantly more pathological fetal heart rate patterns (FHR) were found in the EFM group compared to the AUS group in both the first and the second stage of labour. As a result significantly more vacuum extractions were performed in the EFM group than in the AUS group, while no statistical difference was found between the groups in the incidence of acute cesarean sections carried out for asphyxia. One case of intrapartum death occurred in the AUS group. No differences were found in Apgar scores after 1 and 5 min or in neonatal morbidity at examination on the 2nd and 5th days after delivery. A tendency towards more biochemically compromised children was found in the AUS group. The specificity for both methods was found to be acceptably high (80%), while the predictive value for both methods was low (50%). More research is therefore urgently needed to evaluate supplementary investigations and parameters for the evaluation of the intrapartum fetal condition.

Acid-Base Equilibrium↗
PubMed1986

Controlled trial of ultrasound screening for light for gestational age (LGA) infants in late pregnancy.

The study included 3311 pregnant women: 1570 in the screened group and 1741 in the unscreened group. In the screened group, ultrasound was offered routinely in the 32nd and 37th week of pregnancy, at which time the fetal biparietal diameter (BPD) and the abdominal mean diameter (AD) were measured. If, after the first ultrasound examination, the estimated weight was less than 85% of the expected mean birthweight, a finding of light for gestational age (LGA) was suspected and the ultrasound examination was repeated in the 34th week. In the screened group 6.5% of the women were at risk at the final ultrasound examination (the sensitivity was 38%) and the predictive values of abnormal and normal weight deviation were 60% and 93%, with a specificity of 97% and a relative risk of 9. Ultrasound was offered to the unscreened group only in cases of clinical concern (23% of the women). In the unscreened group 34% of the 158 LGA infants had ultrasound performed before delivery because of clinical concern. By including pregnancies induced before ultrasound could be performed, 45% of the LGA infants in the unscreened group were suspected before delivery. No significant difference between the rate of induction, instrumental deliveries and caesarean sections was found between the two groups. No benefit in terms of decreased incidence of infants with low Apgar score and acidosis was achieved.

Clinical Trials as Topic↗
PubMed1986

Interaction between initiator Met-tRNAfMet and elongation factor EF-Tu from E. coli.

It has recently been shown that the non-formylated initiator Met-tRNAfMet from E. coli can form a stable ternary complex with the elongation factor EF-Tu and GTP. Using the protection of EF-Tu:GTP against spontaneous hydrolysis of the aminoacylester bond of Met-tRNAfMet, we confirm these results, and show that the protection is specific for the non-formylated form of the initiator tRNA. The ternary complex Met-tRNAfMet:EF-Tu:GTP can be isolated by column chromatography in a way similar to that demonstrated previously with EF-Tu complexed to the elongator Met-tRNAmMet. 32P-labeled Met-tRNAfMet within the ternary complex was analyzed by the footprinting technique. The pattern of initiator tRNA protection by EF-Tu against ribonuclease digestion is not significantly different from the one found previously for elongator tRNAs. These results lead us to suggest that the initiator tRNAfMet, under growth conditions which do not permit formylation, may to some extent function as an elongator tRNA.

Autoradiography↗
PubMed1986

Incidence and aetiological pattern of jaw fractures in Greenland.

All of the cases involving fractures of the mandible and/or maxilla in Greenland were recorded in a 1 1/2 year period beginning 1 July 1981. Further information of aetiological patterns was added from 2 studies of mandibular fractures in Godthåb/Greenland. The incidence of jaw fractures in Greenland (17 to 10,000 per year) was the highest ever reported. In 90% of these cases, the cause of fractures were interpersonal violence. Jaw fractures were encountered in nearly all districts of Greenland, most often in urban areas and the patients were chiefly of Greenlandic descent. The % of patients in the age group of 20-29 years was extremely high (57%) as was the women (36%). 75% of the women were ill-treated by their spouses. In half of the cases, the victims and the assailants were related. Victims unknown to the assailants made up only 20% of the cases. These were trends typical of a small society. Compared to other reports, violence in Greenland was aggravated and involvement of alcohol was seen in 4 out of 5 cases. Regulation and deregulation of alcohol in Greenland had only temporary effects on the occurrence of jaw fractures. Aetiological patterns of jaw fractures changes from one subculture to another depending on social conditions. The figures from Greenland demonstrated this.

Accidents↗
PubMed1986

Birthweight-for-gestational age charts based on early ultrasound estimation of gestational age.

Birthweight-for-gestational age charts were based on the analysis of 3888 consecutive births in which the gestational age was estimated by measuring the fetal biparietal diameter before the 20th week of gestation. The data showed, in contrast to previous studies, a linear relation between gestational age and birthweight without inflection after term. The regression parameters showed a strongly significant difference between girls and boys. Thus, boys were 1.5% heavier than girls at 190 days gestation and 3.6% heavier at 300 days gestation. The linearity in the birthweight-for-gestational age charts could be due to the more reliable gestational age based on early ultrasound.

Birth Weight↗
PubMed1986

Endoscann cell sampling for cytological assessment of endometrial pathology.

Cytological samples of the endometrium obtained by Endoscann were compared with histological preparations from conventional curettage of the uterine cavity (D & C) in 275 women. Indications of D & C were irregular menstrual bleeding, postmenopausal bleeding, or suspected ovarian or cervical neoplasia in women of 50 years or more. The women were consecutively enrolled in the study and had an average age of 60.2 years (range 50-87). The cytological investigation detected all 16 cases of endometrial cancer but none of 6 cases of atypical hyperplasia. Insertion of the Endoscann cell sampler was easily performed in 87% of the patients in whom cervical dilatation was unnecessary. The cytological technique had 11 cases of insufficient material (4%). By D & C, sufficient material for histological evaluation could not be obtained in 32 cases (12%). The predictive value of a positive test with respect to endometrial carcinoma was 0.38, the corresponding sensitivity was 1.00, and the specificity 0.90. A positive cytology should lead to immediate further investigation.

Adult↗
PubMed1986

Cobalamin absorption determined by the stool spot test. Reliability in patients with uremia or disorders of the ileum.

A cobalamin absorption test, the stool spot test (SST), which makes use of radioactive cobalamin and a nonabsorbable isotope, 51Cr-trichloride, has been shown to produce reliable results in patients with pernicious anemia and in healthy controls. The reliability of the SST in patients with bowel disorders and in patients with decreased renal function was investigated by comparing with both whole-body counting and the Schilling test. Fourteen patients with bowel disorders and eight patients with uremia joined the trial. The SST correlated highly significantly with the whole-body counting method. However, the precision of the SST was poor in patients with decreased bowel transit time and inferior to that in the uremic patients. In one of two patients with decreased bowel transit time the two isotopes were shown to have different transit times, thus invalidating the test. In patients with uremia the SST was significantly more reliable than the Schilling test. It is concluded that the SST is reliable also in patients with uremia but may not be reliable in patients with intestinal disorders and decreased bowel transit time. In these patients collection of larger stool samples is recommended.

Feces↗