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Biomedical subjects

S Hansen

Publications and source records attributed to S Hansen.

At least 433 records · Page 24Linked to original sources
PubMed1966

Urinary screening tests in the prevention of mental deficiency.

A substantial number of genetically determined biochemical disorders in infants and young children produce mental deficiency and serious ill health in early life. If these diseases are detected promptly, effective therapy can be instituted to prevent the development of mental defect, or, where no treatment is presently available, the parents can be given appropriate genetic counselling so that the birth of further affected children can be prevented.Eight simple urine screening tests are described which have proved useful in the early detection of metabolic disorders in apparently healthy infants. These tests can easily be performed by a physician or nurse without special training or elaborate equipment. The attention of general practitioners, pediatricians and public health physicians is directed to the real possibilities for preventing some forms of mental deficiency through the routine use of screening tests on urine and on blood.

Blood↗
PubMed1966

Homolanthionine excretion in homocystinuria.

Patients with homocystinuria excrete in their urine small amounts of an amino acid indistinguishable from authentic L-homolanthionine. This compound could be formed from homocysteine and homoserine by a condensation analogous to that normally leading to cystathionine. The only other known occurrence of homolanthionine in nature is in a methionine-requiring mutant strain of Escherichia coli.

Adolescent↗
PubMedDate not supplied

The neurophysiologic investigation of small fiber neuropathies.

We have applied our technique for the measurement of thermal thresholds to 25 patients referred with symptoms and signs of small fiber peripheral neuropathy in whom conventional electrophysiological indices were individually within the range of normal values for our laboratory. Vibration threshold determinations were also within normal range. Significant abnormalities of thermal thresholds were noted in all patients. The results indicate that the technique provides an accurate, easily performed and reproducible index of function in small A delta and C groups of nerve fibers.

Adult↗
PubMedDate not supplied

A small angle X-ray scattering study of the binding of cyclosporin-A to calmodulin.

Small angle X-ray scattering (SAXS) was applied to the binding of the immunosuppressant drug cyclosporin-A to the protein calmodulin. Guinier analysis of the SAXS profiles yielded a radius of gyration, Rg, of 19.7 +/- 0.3 A for the native protein and 16.9 +/- 0.3 A for the drug/protein complex. Maximum entropy (maxent) methods of data analysis were used to calculate the distance distribution function, p(r). From this analysis, the Rg for the native protein is 20.9 +/- 0.1 A and that for the complex 16.7 +/- 0.1 A. The measured SAXS profiles and the derived p(r) for calmodulin agree with profiles calculated from the crystallographic structure of calmodulin. Major structural changes are induced in calmodulin on binding cyclosporin-A. A model consistent with the observed scattering profiles is an ellipsoid with major axes 55 and 36 A. Molecular modeling of the calmodulin molecule suggests that bond rotation in the flexible alpha-helix linker region produces models consistent with the above observations.

Animals↗
PubMedDate not supplied

Intraocular penetration of fusidic acid with topical Fucithalmic.

Fucithalmic is a newly developed 1% microcrystalline suspension of the antistaphylococcal antibiotic fusidic acid. Penetration into the eye was investigated in twenty patients about to undergo cataract extraction. A single dose produced median antibiotic levels in the aqueous humour of 0.3 mcg/ml, maintained for at least 12 hours. Repeated doses produced significantly higher levels, median 0.8 mcg/ml, indicating some cumulative effect. The results show that fusidic acid passes the corneal aqueous barrier, and twice daily administration of Fucithalmic gives aqueous concentrations comparable with or higher than those seen after recommended systemic administration.

Aqueous Humor↗
PubMedDate not supplied

In quest for a possible association between heightened social aggression and excessive alcohol drinking in the rat.

Many clinical studies show that a sizeable proportion of male alcoholics are also inclined to act violently and aggressively. Given this association in humans, we asked whether a relationship exists between ethanol intake and aggressive behaviour in laboratory rats. In a first test of the hypothesis, we measured ethanol intake in male rats made aggressive by periodic contacts with sexually active females. Although the males became significantly more aggressive, there was no concomitant enhancement of alcohol consumption. In another experiment, observations of ethanol drinking in lactating rats exhibiting maternal aggression revealed no alteration in ethanol intake relative to nonlactating control females. However, because water intake was substantially elevated in the maternal rats, there was a net decrease in ethanol preference. The final experiment examined aggressiveness in chronically food-restricted male rats. In line with previous studies, this procedure increased ethanol drinking, but it did not enhance aggressive behaviour. It is concluded that, in our rats, there is no apparent association between the level of social aggression and the voluntary intake of ethanol in a two-bottle choice paradigm. The possibility remains, though, that alcohol drinking is better related to other forms of aggression, such as defensive or predatory aggression.

Aggression↗
PubMedDate not supplied

An instrument for measurement of thermal thresholds in man.

Routine clinical electrophysiological techniques assess function in the large diameter, motor and sensory nerve fibres, but not in the smaller diameter fibres subserving pain, thermal sensation and autonomic function. The instrument we describe measures thermal sensation thresholds to both cooling and warming thus providing an index of function in the small diameter thinly myelinated A delta fibres and unmyelinated C fibers respectively. A commercial version, the Thermal Threshold Tester (TRIPLET) provides a portable instrument for routine clinical use. It has a particularly important role in the sequential and quantitative monitoring of small nerve fibre function as for example in diabetic neuropathy. It can also be applied to the study of small nerve fibre function in persons exposed to potentially neurotoxic substances either as medication or in industry.

Biosensing Techniques↗
PubMedDate not supplied

Taste reactivity to ethanol in rats: influence of adrenalectomy or ipsapirone.

The affective mimetic responses of male Wistar rats with prior access to 6% ethanol in their home cages were observed during intraoral infusions of an equivalent alcohol solution. Ethanol preference in the home cage appeared unrelated to measures of aversion and ingestion in the taste reactivity tests in normal rats. Adrenalectomy, which significantly reduced home cage ethanol preference, failed to influence the taste reactions elicited by ethanol or water. On the other hand, treatment of intact rats with the 5-HT1A receptor agonist ipsapirone (2.5 mg/kg), a drug that also decreases ethanol drinking in two-bottle intake tests, did increase the duration of aversive groomings, whereas measures of ingestion remained unaffected. These results suggest that ipsapirone, but not adrenalectomy, may alter the palatability of ethanol; this perceptual change may partly underlie the ability of ipsapirone to reduce home cage alcohol drinking in the rat.

Adrenalectomy↗
PubMedDate not supplied

Effects of ibotenic acid lesions of the ventral striatum and the medial prefrontal cortex on ethanol consumption in the rat.

The purpose of this study was to to assess the effect on ethanol drinking of ibotenic acid lesions in the medial prefrontal cortex and the ventral striatum of female rats with continuous access to water and a 6% ethanol solution. Ibotenic acid infusions in the prefrontal cortex did not affect ethanol intake at any time, but a significant increase in water intake was observed on the third postoperative week. Ventral striatal lesions significantly increased ethanol intake during the first 2 postoperative weeks. On the third week consumption was not significantly different from vehicle-infused controls. Apparently, then, severe excitoxic injury to the ventral striatum is compatible with normal, or increased, intake of ethanol; in contrast, similar lesions reduce the intake of other drugs of abuse such as psychostimulants and opioids.

Alcohol Drinking↗
PubMedDate not supplied

Amphetamine-induced hyperactivity: differences between rats with high or low preference for alcohol.

This study determined the relationship between ethanol intake and spontaneous and amphetamine-induced locomotor activity. Locomotion was studied in high-preferring (HP; > 70% of total fluid intake consumed as alcohol) and low-preferring (LP; < 20% of total fluid intake consumed as alcohol) male Wistar rats with free access to water and a 6% (v/v) ethanol solution for 3 weeks. Following an alcohol-free 3-week period, the animals were tested for spontaneous motor activity for 1 h. One week later, locomotion was recorded in the same activity boxes following a subcutaneous injection with d-amphetamine sulfate (1 mg/kg). For determination of plasma levels of corticosterone, blood samples were taken immediately after each of the two tests for locomotor activity. There was no difference between HP and LP rats with regard to spontaneous locomotor activity. Neither were there any differences in plasma levels of corticosterone between the groups. Amphetamine stimulated locomotion in both HP and LP rats, but to a significantly greater extent in HP animals. Both groups had higher blood levels of corticosterone after the amphetamine test than after the drug-free test, but the corticosterone increase was significantly larger in the HP than in the LP rats. These data indicate that the same neural substrate (e.g., the mesocorticolimbic dopamine system) may mediate important aspects of both ethanol drinking and amphetamine responsiveness. Individual differences in the properties of this substrate may account for the finding that ethanol drinking and amphetamine responsiveness covary. A possible explanation for this association may be that prior consumption of ethanol sensitizes the neural substrate responsible for amphetamine-induced hyperactivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol Drinking↗