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Biomedical subjects

J Nielsen

Publications and source records attributed to J Nielsen.

At least 361 records · Page 20Linked to original sources
PubMed1988

Tobacco smoking and twinning.

In a case-control study an association was found between mothers' smoking habits and the frequency of dizygotic twinning. As cases were included all twins born in Denmark in 1984 and 1985. A random sample of 1.5% of mothers to singletons, born in the same period were selected as controls. Only live-borns, conceived after no hormonal treatment, were included in the study. The finding may be due to the well-known anti-estrogen effect of smoking.

Cross-Sectional Studies↗
PubMed1988

IgG antibodies against polyisocyanates in car painters.

A group of thirty car painters exposed to vapours and aerosols of paint containing prepolymer andmonomer of hexametylene diisocyanate (HDI) was investigated. Specific antibodies against monomer HDI and prepolymerized HDI were analysed with RAST (IgE) and ELISA (IgG) assays after conjugation of the haptens with human serum albumin. There was no significant increase of serum IgG antibodies against HDI monomer, nor of specific IgE antibodies against HDI monomer or prepolymer. Specific IgG antibodies against prepolymerized HDI were significantly increased, as compared with non-exposed referents (medians 0.11 vs 0.03 absorbance (A]. Six car painters were found to have specific IgG antibodies of subclass 4 against HDI prepolymer, four also against HDI monomer. This shows an association between exposure and specific IgG antibodies. Thirteen subjects had suffered symptoms of rhinitis and/or conjunctivitis, and ten had symptoms from the bronchi (two asthma). There was no significant association between symptoms and levels of specific antibodies. Most of the symptoms were slight and unspecific, probably due to irritative effects of the exposure.

Adult↗
PubMed1988

Follow-up of 30 Klinefelter males treated with testosterone.

Thirty Klinefelter males treated with testosterone were studied by a follow-up examination carried out an average of 3.6 years after treatment began. The age of the men averaged 25.5 years at the time of the follow-up. Seventy-seven per cent of the men were judged to have benefited from testosterone treatment. They showed better mood, less irritability, more energy and drive, less tiredness, more endurance and strength, less need for sleep, better concentration ability and better relations with others during testosterone treatment. The beneficial effects of testosterone persisted in some of the men after cessation of treatment. The findings show that Klinefelter males given testosterone for the first time as adults can benefit from such treatment, even though it is preferable to start treatment at the age of 11-12 years.

Adaptation, Psychological↗
PubMed1988

[Psychomotor seizures in infants and young children].

off authors analyzed the ictal clinical symptoms (in 6 cases with videotape monitoring) of 12 infants and young children, who had focal epileptic discharges in the temporal regions (fig. 3, 4, 5). The average age was 1 9/12 years with a range of 3 months to 5 years. In 6 cases the seizures were typical "psychomotor" with oral automatisms, aimless movements of the upper extremities and/or tonic versive motor manifestations (fig. 2). In 5 cases the seizures consisted of staring and arrest of any movement. In another case, automatisms of the upper extremities were accompanied by a psychomotor arrest reaction. It is probable that in this age group seizures with sudden arrest of activity ("temporal pseudoabsences") are more frequently the main expression of partial complex seizures than in older children and in adults.

Child, Preschool↗
PubMed1987

[Infectious diarrhea in children. Results of a prospective study concerning various epidemiological and clinical aspects of infectious diarrhea in children].

Over a 3-year period (from October 1981 to September 1984) 352 pediatric patients were treated for infectious diarrhea at the Division for Pediatric Infectious Diseases, Department of Pediatrics, University of Berne, Switzerland. Routine diagnostic tests on stool samples included cultures for Salmonella, Shigella, Campylobacter and Yersinia, and enzyme-linked immunosorbent assay (Rotazyme) for rotaviruses. In selected cases special tests for parasitic pathogens were also performed. The patients were divided into three etiologic groups to compare epidemiological, clinical and laboratory characteristics; group 1 = rotavirus, group 2 = no detectable pathogen, and group 3 = bacterial agents. Specific etiology of diarrhea was established in 210 of the 352 patients (59.5%). Rotaviral gastroenteritis represented the most common diagnosis (42.5%), whereas Salmonella was isolated from fecal cultures in 9% and Campylobacter jejuni in 3%. A parasitic etiology was documented in only 1%. In 5 patients two pathogens were recovered from stools: rotavirus and Salmonella in 4 cases and Salmonella and Campylobacter in 1 case. Relevant features of rotavirus, Salmonella and Campylobacter gastroenteritis in childhood are described in detail.

Adolescent↗
PubMed1987

Mechanistic studies on the phosphoramidite coupling reaction in oligonucleotide synthesis. I. Evidence for nucleophilic catalysis by tetrazole and rate variations with the phosphorus substituents.

Tetrazole catalyzed reactions of a series of phosphoramidites, 5'-O-DMTdT-3'-O-P(OR1)NR2(2) (1a-h), with 3'-O-SiButPh2-6-N-benzoyl-dA (2a) in acetonitrile solution have been studied. It is found that the coupling rate depends very much on whether tetrazole is added before or after 2a, and that dialkylammonium tetrazolide salts are inhibitors. These and other facts are evidence that the reactions are subjected to nucleophilic catalysis by tetrazole, in addition to acid catalysis. The rate variations with phosphorus substituents of 1a-h are NEt2 greater than NPri2 greater than N(CH2CH2)O greater than NMePh, and OMe greater than OCH2CH2CN greater than OCHMeCH2CN greater than OCMe2CH2CN much greater than OC6H4Cl. The inhibitor properties of dialkylammonium tetrazolides have practical consequences for the efficiency of DNA syntheses, when in situ prepared phosphoramidites are used; the same would apply for segmented, simultaneous syntheses or syntheses where recycling is performed.

Indicators and Reagents↗
PubMed1987

Follow-up 20 years later of 34 Klinefelter males with karyotype 47,XXY and 16 hypogonadal males with karyotype 46,XY.

A 20-year follow-up study of 50 hypogonadal males has been made. Of these 34 had Klinefelter's syndrome with the karyotype 47,XXY and 16 had the karyotype 46,XY. These males have been examined at mean ages of 27 and 37 and in the present study at a mean age of 47. At the first examination the following conditions were found in the Klinefelter males to a significantly higher degree than in the hypogonadal males with 46,XY: immaturity, below average school performance, few or no friends, previous mental illness, little energy and initiative, few or no spare time interests, occupation as an unskilled labourer. Psychological testing showed a full scale IQ of 103 in the Klinefelter males and 115 in the hypogonadal males. The follow-up studies have shown that in spite of these findings the Klinefelter males have managed far better than could have been expected at the time of the first investigation. The improvement in a number of conditions such as mental health, working capacity, social adjustment, relations with other people, and activity level was considerable between the ages of 27 and 37. The present examination shows a further improvement at the age of 47 with the only significant difference between the Klinefelter males and the hypogonadal males with 46,XY being a higher frequency of single Klinefelter males. The present examination also showed that there was no significant difference between the two groups in occupation, working capacity, social adjustment, mental and physical disorders or criminality. The results of the examination at the mean age of 27 would probably have been considerably more favourable for the Klinefelter males if diagnosis had been made in childhood, and information, counselling, support and hormone treatment had been given from an early age. The fact that the great majority of the Klinefelter males have managed quite well in spite of this and that no remarkable differences were found between them and a control group is of great importance for genetic counsellers, especially for prenatal counsellers. Up until now, in 75% of cases in which sex chromosome abnormalities, including Klinefelter's syndrome, have been diagnosed prenatally in Denmark abortion has been induced. We believe this is mainly due to insufficient information about the many positive aspects of the development of individuals with sex chromosome abnormalities.

Adoption↗
PubMed1987

Mitogenic reactivity of mononuclear cells isolated from thymus, spleen and umbilical cord blood of pig foetuses.

The in vitro mitogenic reactivity of mononuclear cells from the thymus, spleen and umbilical cord blood of Danish Landrace pig foetuses ranging in gestational age (GA) from 48 to 112 days was monitored by means of a microculture lymphocyte transformation test (LTT). Dose-response profiles for concanavalin A (Con A), pokeweed mitogen (PWM) and leucoagglutinin (LAG) were set up for the various age-groups and the results showed that the onset and development of mitogenic reactivity in the pig foetus is age-related. The results indicate the occurrence of mitogen responsive cells in the thymus and cord blood at 48 days GA and in the spleen at 54 days but statistically significant reactivity (p less than 0.01) for the various tissues could only be demonstrated at later stages of gestation. Thymus cells from all foetuses ranging in GA from 54 to 112 days exhibited significant reactivity to Con A, PWM and LAG. While the first detectable definite response of spleen cells was seen at 60 days GA when 50% of the foetuses exhibited significant reactivity to the 3 mitogens, spleen cells from all foetuses beyond that age responded significantly. Cord blood cells from only 50% of the foetuses of 60 and 70 days GA responded significantly to Con A and PWM but after this stage, cord blood cells from all foetuses did. The first significant response of cord blood cells to LAG was seen at 70 days GA but only in 50% of the foetuses and it was not until 100 days GA that significant reactivity to LAG was detected in all foetuses.

Animals↗
PubMed1987

Transient ischemic dilation of the left ventricle on stress thallium-201 scintigraphy: a marker of severe and extensive coronary artery disease.

On exercise thallium-201 scintigraphy, it has been noted that the size of the left ventricle is sometimes larger on the immediate poststress image than on the 4 hour redistribution image; this phenomenon has been termed transient ischemic dilation of the left ventricle. The angiographic correlates of this finding were assessed in 89 consecutive patients who underwent both stress-redistribution thallium-201 scintigraphy and coronary arteriography. A transient dilation ratio was determined by dividing the computer-derived left ventricular area of the immediate postexercise anterior image by the area of the 4 hour redistribution image. In patients with a normal coronary arteriogram or nonsignificant coronary stenoses (less than 50%), the transient dilation ratio was 1.02 +/- 0.05 and, therefore, an abnormal transient dilation ratio was defined as greater than 1.12 (mean + 2SD). The transient dilation ratio was insignificantly elevated in patients with noncritical coronary artery disease (50 to 89% stenosis) (1.05 +/- 0.05) and in patients with critical stenosis (greater than or equal to 90%) of only one coronary artery (1.05 +/- 0.05). In contrast, in patients with critical stenoses in two or three vessels, the transient dilation ratio was significantly elevated (1.12 +/- 0.08 and 1.17 +/- 0.09, respectively; p less than 0.05 compared with all other patient groups). An abnormal transient dilation ratio had a sensitivity of 60% and a specificity of 95% for identifying patients with multivessel critical stenosis and was more specific (p less than 0.05) than were other known markers of severe and extensive coronary artery disease, such as the presence of multiple perfusion defects or washout abnormalities, or both.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Transcultural study of Turner's syndrome.

A transcultural questionnaire study was made of 111 girls with Turner's syndrome aged 17 to 30 from Belgium, Canada, Denmark, France, the FRG and Hungary. The study reveals that there is still too much secrecy and ignorance concerning Turner's syndrome, and the diagnosis should be made and presented together with full information much earlier than at present, preferably at birth. More and better information concerning Turner's syndrome is needed in all participating countries, but more in some countries than in others. The study further shows that there is a great need for the establishment of Turner's syndrome societies or Turner contact groups so that such groups are available in all countries. The study also shows that in spite of personality profiles with characteristics such as happy, active, extroverted, realistic, talkative, and good contact abilities, far too many girls with Turner's syndrome suffer from anxiety, loneliness and inferiority feelings, especially in certain countries. This is definitely due to environmental factors that ought to be changed and can be changed by an increase in the level of information and research, together with establishment of Turner contact groups in all countries.

Adolescent↗
PubMed1987

Spontaneous abortion following mid-trimester amniocentesis. Clinical significance of placental perforation and blood-stained amniotic fluid.

The clinical significance of placental perforation and blood-stained amniotic fluid was studied in a group of 7238 Danish women undergoing mid-trimester amniocentesis for prenatal diagnosis under ultrasound guidance. The risk of spontaneous abortion was significantly increased both in pregnancies where the placenta was perforated and in those with blood-stained amniotic fluid. The risk estimate nearly doubled after placental perforation and more than doubled with a bloody tap. It is concluded that for women at relatively low risk of a fetal genetic abnormality, the indication of the amniocentesis should be reconsidered if a placental perforation is unavoidable.

Abortion, Spontaneous↗
PubMed1987

Screening for Down's syndrome using an iso-risk curve based on maternal age and serum alpha-fetoprotein level.

On the basis of the significantly different distributions of maternal serum alpha-fetoprotein (AFP) levels in 86 pregnancies associated with fetal Down's syndrome and in 2018 unaffected pregnancies, an iso-risk curve for Down's syndrome was constructed. An iso-risk curve shows, for women of all ages, which combinations of maternal age and level of maternal serum AFP result in the same risk of carrying a fetus with Down's syndrome. A 1:400 risk of Down's syndrome, corresponding to the risk of a 35-year-old woman, was chosen as the lowest risk indicating referral for amniocentesis. If all women, irrespective of their age, are offered amniocentesis, when their risk of carrying a Down's syndrome fetus is 1:400 or higher, 53% of the affected fetuses can be detected as compared with 28% of the affected fetuses diagnosed at present in women above 35 years of age.

Adult↗
PubMed1987

Reciprocal Ia inhibition between ankle flexors and extensors in man.

1. Reciprocal inhibition between antagonist muscle groups at the ankle has been investigated in sixty healthy subjects. Hoffmann reflexes (H reflexes) in the soleus and tibialis anterior muscles were used to assess changes in reciprocal inhibition evoked by electrical stimulation of antagonist muscle nerves. 2. Inhibition of the soleus H reflex was evoked by a single conditioning stimulus to the common peroneal nerve, and inhibition of the tibialis anterior H reflex was elicited by one conditioning stimulus to the posterior tibial nerve. Symmetrical central connections between the antagonist flexors and extensors were assumed and under this assumption the central delay for the inhibition, in addition to the delay for monosynaptic Ia excitation, was calculated to be about 1 ms. The inhibition was evoked by weak stimuli to the nerves from antagonist muscle groups; the threshold for the inhibition was around 0.6 X threshold for a direct motor response (M-threshold). Furthermore, tendon taps to the Achilles tendon facilitated the soleus H reflex and inhibited the tibialis anterior reflex at short latencies. The short central delay, the low electrical threshold and the.actions of Achilles tendon taps strongly suggest that the early reciprocal inhibition is homologous to the disynaptic Ia inhibition previously studied in animal experiments. 3. With the test soleus H reflex kept at 15-25% of the maximum directly evoked motor response (M-response) and the strength of the conditioning peroneal nerve stimulation kept at 1.0 X M-threshold, the inhibition from the peroneal nerve ranged between 0 and 40% (mean, 14.9%) at rest. 4. Changes in the amount of reciprocal inhibition from the peroneal nerve were studied both during tonic and dynamic dorsi- and plantarflexion. During tonic dorsiflexion there was no significant change of inhibition as compared to rest, while inhibition decreased during tonic plantarflexion. However, during ramp-and-hold dorsiflexion there was a transient increase in reciprocal inhibition of the soleus H reflex. This increase in inhibition from the peroneal nerve could be seen 50 ms prior to the onset of contraction. The increase in inhibition before and at the very beginning of the contraction cannot be due to sensory feed-back during contraction, but must depend on a supraspinal control of the spinal cord. 5. At conditioning-test intervals of 4-6 ms, the inhibition of the soleus H reflex from the peroneal nerve was considerably larger during tonic dorsiflexion than at rest. Thus, tonic dorsiflexion revealed an inhibition with long latency from the peroneal nerve, which was not seen at rest.(ABSTRACT TRUNCATED AT 400 WORDS)

Achilles Tendon↗