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Biomedical subjects

D Hansen

Publications and source records attributed to D Hansen.

At least 19 recordsLinked to original sources
PubMed1992

[Kleine-Levin syndrome].

The Kleine-Levin syndrome is a rare and probably underdiagnosed syndrome. It is characterized by periodic attacks of the triad: hypersomnia, vegative disturbances such as hyperphagia and hypersexuality, psychopathological changes in the level of consciousness and control of emotions. Boys and young men in the age group 10-20 years are most commonly affected. Spontaneous remission with a tendency to remission is observed and the disease "burns out" after a prolonged period of years. The etiology and pathogenesis are unknown. Theories have been propounded suggesting dysfunction of the hypothalamus. No pathognomonic findings have been observed in the early phase of sleep during the daylight hours. Central stimulating drugs have been reported to have some effect on the hypersomnia. The diagnosis is based on the clinical picture. Frequently, a long period can elapse before the diagnosis is established and some cases are never diagnosed. The literature is reviewed and is illustrated by two case reports.

Adolescent↗
PubMed1992

Structural analysis of the operator binding domain of Tn10-encoded Tet repressor: a time-resolved fluorescence and anisotropy study.

An engineered Tn10-encoded Tet repressor, bearing a single Trp residue at position 43, in the putative alpha-helix-turn-alpha-helix motif of the operator binding domain, was studied by time-resolved fluorescence and anisotropy. Fluorescence intensity decay data suggested the existence of two classes of Trp-43, defined by different lifetimes. Analysis of anisotropy data were consistent with a model in which each class was defined by a different lifetime, rotational correlation time, and fluorescence emission maximum. The long-lifetime class had a red-shifted spectrum, similar to that of tryptophan zwitterion in water, and a short rotational correlation time. In contrast, the spectrum of the short-lifetime class was blue-shifted 10 nm compared to that of the long-lifetime class. Its correlation time was similar to that of the protein, which showed that Trp in this class was entirely constrained. Trp in this latter class could not be quenched by iodide, whereas most of the long-lifetime class was easily accessible. Presence of disruptive agents, such as 1 M GuCl or 3 M KCl, did not alter markedly the lifetimes but increased the weight of the short-lifetime component. In the same time, the rotational correlation time of this component was dramatically reduced. Taken together, our data suggest that the long-lifetime class could correspond to the tryptophan residues exposed to solvent whereas the short-lifetime class would correspond to the tryptophan residues embedded inside the hydrophobic core holding the helix-turn-helix motif. Destabilization of hydrophobic interactions would lead to an increase in the weight of the latter class for entropic reasons. Analysis of the fluorescence parameters of Trp-43 could provide structural information on the operator binding domain of Tet repressor.

DNA Transposable Elements↗
PubMed1992

Bacterial endocarditis in children: trends in its diagnosis, course, and prognosis.

In a population-based study of 41 children with bacterial endocarditis (BE), diagnosed in the period 1970 through 1989 in eastern Denmark, we analyzed trends in the diagnosis of BE and in mortality, and searched for possible prognostic factors. During this period the delay in diagnosis from first symptom to treatment did not change, but the delay from admission to treatment was significantly prolonged from 0 to 3 days, despite the introduction of echocardiography (ECHO). There was a significant improvement in the prognosis, the mortality rate having decreased from 40 to 0% [95% confidence limits: 12-74 vs. 0-26 (0.01 less than p less than 0.02)]. The improved prognosis was not explained by changes in the etiology or pattern of antibiotic resistance and may reflect a milder course of BE in children. Children with "mild anomalies"--such as bicuspid aortic valve (n = 5), coarctation of the aorta (n = 2), and prolapse of the mitral valve (n = 2)--had a significantly poorer prognosis than children with other forms of congenital heart disease (CHD) (p = 0.004), a reminder of the importance of suspecting BE in all children with unexplained long-lasting or intermittent fever, because some may have unrecognized "mild" CHD.

Child↗
PubMed1992

Aneurysm of the ductus arteriosus in the neonate: three case reports with a review of the literature.

Ductus arteriosus aneurysm was demonstrated in three neonates by echocardiography. One case was already diagnosed in utero. One patient needed surgical resection, whereas in one case the aneurysm of the ductus arteriosus regressed spontaneously. In the third case the patient died of associated lesions. In a review of the literature, 61 previous cases of ductus aneurysm in infants less than 2 months were found. Ductus arteriosus aneurysm may be diagnosed by echocardiography both pre- and postnatally. A ductus aneurysm should be monitored closely by echocardiography. Since a high incidence of complications is reported, surgical resection is indicated if the aneurysm does not regress within a few days.

Adult↗
PubMed1992

Laboratory assessment of feeding behavior in bulimia nervosa and healthy women: methods for developing a human-feeding laboratory.

We have designed a human-feeding laboratory to be used to study feeding behavior in patients with eating disorders. Twenty-one normal-weight bulimic subjects consumed 29.711 +/- 39.940 MJ (range 0.862-178.632 MJ; 7101 +/- 9546 kcal, range 206 to 42,694 kcal) in 24 h. In comparison, 11 healthy volunteer women, when instructed to eat ad lib for 48 h, ate 7.715 +/- 2.590 MJ (1844 +/- 619 kcal) during the first 24 h and 7665 +/- 1828 MJ (1832 +/- 437 kcal) during the second 24 h. Bulimics and control subjects had a similar number of eating intervals (6.6 +/- 2.6 vs 5.0 +/- 1.7); 72% of the bulimic subjects' meals were similar in size to the meals of the controls [167-4100 kJ (40-980 kcal)] but these meals were higher in carbohydrate and lower in fat in bulemic patients. Excessive caloric intake by bulimic subjects was because 28% of their meals were very large [range 4.427-28.150 MJ (1058-6728 kcal)]. Data gathered in a laboratory setting appears to be a reasonable replication of naturalistic feeding and suggest that such a laboratory may prove useful for future studies of feeding behaviors in humans.

Adult↗
PubMed1992

Growth during treatment of familial hypercholesterolemia.

Treatment of hypercholesterolemic children with restriction of dietary saturated fat may result in an inadequate supply of energy for normal somatic growth. We examined the growth of 30 children with familial hypercholesterolemia, some of whom were also treated with colestipol, a bile acid-binding resin. The median duration of treatment was 8.5 years in 13 patients on diet only, and 5.5 years + 3.5 years in 17 patients treated with diet followed by diet and colestipol. Statistically significant reductions in serum total cholesterol were obtained in both groups. The SD scores for both height/age and weight/age decreased by approximately 0.4 during dietary treatment (p < 0.05), but were not affected by treatment with colestipol. These results document the risk of growth retardation during dietary treatment of children with familial hypercholesterolemia.

Child↗
PubMed1992

A time-course study of the effects of pentobarbital, fentanyl, and morphine chloralose on myocardial mechanics.

Cardiovascular physiological studies in anesthetized animals may be confounded by the hemodynamic actions of the anesthetic agents themselves. To identify an anesthetic regimen that does not significantly influence cardiovascular physiology, the hemodynamic responses of 28 dogs were studied. Animals were equally divided among groups with 1) no anesthesia (i.e., trained conscious preparation), 2) pentobarbital sodium, 3) fentanyl citrate, and 4) a combination of morphine sulfate and alpha-chloralose. Anesthesia was maintained for 3 h. Data were acquired with the use of ultrasound imaging of the heart in conjunction with invasive pressure measurements. Left ventricular ejection phase indexes and end-systolic force-velocity relations were used to evaluate the effects of each anesthetic agent on overall systolic performance and myocardial contractility. Compared with the conscious animals, pentobarbital profoundly depressed systolic performance (P less than 0.05 vs. control) because of a reduction in myocardial contractility (P less than 0.01) and an increase in left ventricular afterload (end-systolic wall stress, P less than 0.05). Fentanyl increased myocardial contractility (P less than 0.05) but also tended to increase afterload with the net result that overall systolic performance remained unchanged. Morphine-chloralose did not affect overall ventricular systolic performance or its individual determinants. Pentobarbital and fentanyl also caused progressive time-dependent deteriorations in all parameters of systolic function during prolonged anesthesia. In contrast, cardiac function was stable for greater than or equal to 3 h after induction of morphine-chloralose anesthesia. The hemodynamic profile of dogs anesthetized with morphine-chloralose most closely resembled that of the conscious animals. Morphine-chloralose is recommended when prolonged anesthesia is required for studies of cardiovascular physiology.

Anesthetics↗
PubMed1992

Mixing does not improve mechanical properties of all bone cements. Manual and centrifugation-vacuum mixing compared for 10 cement brands.

Contemporary mixing methods--centrifugation, vacuum mixing with or without precompression--were compared with manual mixing by testing strength characteristics in accordance with a proposed revision of the international standard for bone cements as applied to 10 cement brands. Simplex brands and low-viscosity cements were the strongest, and were not improved by any of the vacuum-mixing procedures. Centrifuging was found unsuitable for low-viscosity cements. Without attaining the strength of the former, the cements best suited for auxiliary mixing methods were CMW-1 and Palacos brands, which improved 6-11 percent by either of the methods. The Sterivac system was generally found unacceptable, because about 20 percent of a cement package was retained in the mixing gear, and the application of precompression had no additional effect on compressive and bending strengths.

Acrylic Resins↗
PubMed1992

Mesenteric microcirculatory changes in nonlethal hemorrhagic shock: the role of resuscitation with balanced electrolyte or hypertonic saline/dextran.

Class I and II hemorrhage has been routinely treated clinically with 2-2.5 times the volume of shed blood as balanced electrolyte solution. Although this regimen has been shown to adequately restore arterial pressure in trauma patients, it is not clear that it uniformly restores regional perfusion. Since it is becoming apparent that the gut plays a major role in the development of the posttraumatic septic state, we studied the effects of graded doses of balanced electrolyte resuscitation on the mesenteric microcirculation. Regimens consisting of one (1 x LR), two (2 x LR), or three (3 x LR) times the volume of shed blood as lactated Ringer's (LR) solution or 7.5% hypertonic saline and 6% dextran (HSD) equal to one seventh the volume of shed blood were given to groups of anesthetized (urethane-chloralose) male Sprague-Dawley rats after 30 minutes of hemorrhage to 50% of baseline mean arterial blood pressure. The microcirculation of the distal ileum was observed using an in vivo video microscope. Mean arterial pressure and ileal A1 diameters returned to baseline values with HSD within 20 minutes following this moderate hemorrhage. Additionally, A1 diameters returned to baseline in the 2 x LR and 3 x LR groups. A1 vessels remained significantly constricted in the 1 x LR group. Mean arterial pressure remained significantly lower than the baseline value in all of the LR groups. We conclude that in this model, HSD is superior to LR for restoration of blood pressure. In restoring A1 diameters, LR is equivalent to HSD only when volumes of balanced electrolyte two and three times shed blood volume are given.

Animals↗
PubMed1992

Additional mechanical tests of bone cements.

A revision of the ISO-standard for bone cement testing has been proposed to include compressive strength after 24 hours in air and 4-point bending testing after 50 hours in a 37 degrees water bath. Nine commercially available bone cements were tested in accordance with the new program. Compressive strength varied from 78 to 100 MPa, bending strength from 48 to 74 MPa and bending modulus from 2.2 to 2.8 GPa. The highest strengths, but also the highest stiffness, were encountered with Simplex brands and low-viscosity cements.

Acrylic Resins↗
PubMed1992

[Psychosocial consequences of screening programs in children].

Owing to improved possibilities of early diagnosis, there has been increasing interest in screening children, particularly newborns. However, in the event of false-positive results or certain hereditary risk factors there is a danger of adverse psychosocial consequences, especially negative stigmatization (both of children and their families). Accordingly, except where neonatal screening may be essential for medical reasons, such screening programmes should preferably be scheduled for a later stage in life when the parents are less prone to anxiety about anything that might be interpreted as a threat to the well-being of their offspring.

Anxiety↗
PubMed1991

Abnormal caloric requirements for weight maintenance in patients with anorexia and bulimia nervosa.

OBJECTIVE: This study tested previous findings that patients with eating disorders who attain normal weight have abnormal caloric requirements for maintaining weight. METHOD: Fifty-three female patients meeting the DSM-III-R criteria for anorexia nervosa and/or bulimia nervosa were divided into four subgroups, and their daily caloric intake was measured over a weight-stable period. Patients with anorexia nervosa (restricting and bulimic subtypes) were studied 4 weeks after refeeding and weight gain, when they had attained 95% of average body weight. Patients with normal-weight bulimia (previously anorexic or never previously anorexic) were studied 1-4 weeks after admission to an inpatient unit. RESULTS: After weight restoration, restricting anorexic patients required significantly more calories per day to maintain weight than did bulimic anorexic patients, as measured with corrections for weight, body surface area, and fat-free mass. Previously anorexic normal-weight bulimic patients required significantly more calories per day to maintain weight than never-anorexic normal-weight bulimic patients, as measured with correction for weight but not with the other factors used to correct caloric intake. CONCLUSIONS: To maintain stable weight after weight restoration, restricting anorexic patients require a significantly higher caloric intake than do bulimic anorexic patients. Differences in caloric needs between normal-weight bulimic patients with and without histories of anorexia may depend on the methods used to correct caloric requirements. Body surface area may be the most precise correction factor across different subgroups of eating disorder patients. Elevated caloric requirements, when coupled with reduced food intake, may particularly contribute to relapse in anorexic patients.

Adolescent↗
PubMed1990

[Acute admissions to the Psychiatric Children's Hospital, Risskov, during 1 January 1982-31 December 1987. A retrospective descriptive study].

During the period concerned, 50 children were admitted as emergencies to the Psychiatric Children's Hospital. These were compared with 90 children over the age of nine years who were admitted in the ordinary manner during the same period. The children admitted as emergencies were aged ten years or more, they were older than the control group and the sex distribution was more uniform. The emergency admissions were, as a rule, instigated by the parents. Half of the families involved had had contact with the Children's Psychiatric Hospital previously. The majority of the children in the control group were referred by school psychologists. The three most important reasons for emergency admission were psychotic symptoms, threats of suicide or attempted suicide and behavioural disorders. Nearly half of the children admitted as emergencies were hospitalized for less than three months and nearly one third were hospitalized for less than one month. Almost all of the children admitted as emergencies and all of the children in the control group had had contact with the social supportive agencies prior to admission. The recommendations on discharge did not differ essentially in the two groups.

Acute Disease↗
PubMed1990

Capillary electrophoresis of proteins under alkaline conditions.

Successful separations of proteins by capillary electrophoresis in uncoated fused-silica capillaries is limited by adsorption and variable rates of electroendosmosis, which can compromise quantitative accuracy and precision. Operation at extremes of pH to minimize these problems is useful in special cases but is not a general strategy for protein separations. Three alternative strategies are described: use of capillaries coated with a linear hydrophilic polymer, the use of acidic solutions to wash the capillary between runs, and the incorporation of additives into the electrophoresis buffer to minimize adsorption during analysis. Applications of these techniques to protein samples is demonstrated.

Animals↗
PubMed1990

[Limited-time admissions for observation at the Psychiatric Hospital for Children in Risskov during the period 1 January 1984-31 December 1986].

The present article describes experience with admissions for observation for limited periods in the Psyciatric Hospital for Children in Risskov. Admissions of this type were introduced in 1984 in Risskov and this is hitherto the only place in Denmark where this is done. The case records of 75 children admitted during the period 1.1.1984-31.12.1986 were reviewed as regards the pattern of referral, the problems on admission and placing on discharge. The durations of these admissions were 4-5 weeks and the structure of these admissions for limited periods is described in this article. The value of this form of hospitalization is emphasized. Maintenance of the child's relationships to the home and school, efficiency of the working routine and improved sorting out of children for long-term hospitalization are emphasized as important arguments. Finally, it is recommended that all departments for child psychiatry with residential units should have the possibility of admitting children for limited periods as part of extended outpatient investigation.

Adolescent↗
PubMed1990

Prechilling and vacuum mixing not suitable for all bone cements. Handling characteristics and exotherms of bone cements.

Nine bone cements were tested for handling characteristics, intrusion, doughing time, setting time, and exothermic temperature. Comparative studies were made of manual mixing and vacuum mixing of cement components stored at room temperature or chilled to 5 degrees C. Vacuum mixing of cement packages stored at room temperature was inapplicable except for the low-viscosity brands, as the cements became too viscous to mold test specimens. Prechilling and vacuum mixing prolonged the setting time and preserved a lower viscosity during the handling period. Palacos R and Palacos G were most suitable for this method, whereas a considerable increase in exothermic temperature was experienced with the other brands. The method might, however, be considered for Zimmer and Cerafix also, as the exotherm was of the same magnitude as for Palacos brands.

Bone Cements↗