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Biomedical subjects

S Hansen

Publications and source records attributed to S Hansen.

At least 235 records · Page 13Linked to original sources
PubMed1987

Brain glutamate deficiency in amyotrophic lateral sclerosis.

Amino acid contents were measured in autopsied brains of eight patients with the sporadic form of amyotrophic lateral sclerosis (ALS) and in brains of control subjects dying without neurologic or psychiatric disease. Glutamic acid content was reduced in most brain regions and in the cervical cord in the ALS patients, while glutamine contents were normal. Taurine contents were increased, and gamma-aminobutyric acid contents were decreased in some brain regions in the ALS patients. The brain glutamate deficiency in ALS is unexplained, but insufficient production or release of this excitatory neurotransmitter might have important secondary effects on motor neurons.

Amino Acids↗
PubMed1987

Sexual activity increases plasma concentrations of cholecystokinin octapeptide and offsets hunger in male rats.

Male rats deprived of food for 48 h ignored food pellets immediately after ejaculating with a sexually receptive female rat as did males tested 5 min after i.p. injection of 5 micrograms cholecystokinin octapeptide (CCK-8) or males which had consumed food pellets for 1 h. The concentration of CCK-8 in plasma was increased to comparable levels (10.1 +/- 3.8 (S.E.M.); 11.3 +/- 3.7 and 7.2 +/- 0.5 pmol/l respectively, compared with 1.2 +/- 0.3 pmol/l for NaCl-injected controls) under each of these conditions, whereas the concentration of gastrin increased only after food consumption (18.4 +/- 3.8; 17.7 +/- 5.4 and 54.3 +/- 7.0 pmol/l respectively, compared with 21.5 +/- 2.1 pmol/l for NaCl-injected controls). The effect of ejaculation on the latency to starting to eat was partially reversed by i.p. injection of 50 mg of the CCK-8 antagonist proglumide, but neither treatment with proglumide or CCK-8 nor consumption of food affected the display of sexual behaviour. The results support the suggestion that CCK-8 is a 'satiety peptide' in the rat.

Animals↗
PubMed1987

Distribution of fibre types in thirty-seven muscles of Didelphis virginiana.

The proportions of Type I and II fibers were determined in 37 muscles of Didelphis virginiana, representing 9 body regions. There was a distinct cranial/caudal gradation in the distribution of Type II fibers throughout the trunk musculature. Muscles of the fore- and hind-limbs showed a gradation of Type II fiber across the width of the muscle, being more prominent at the surface. The type II fibers in the tip of the tail showed peculiar staining properties in which the core of each fiber stained much more lightly than did the periphery.

Adenosine Triphosphatases↗
PubMed1986

Noradrenaline-serotonin interactions in the control of sexual behavior in the male rat: DSP4-induced noradrenaline depletion antagonizes the facilitatory effect of serotonin receptor agonists, 5-MeODMT and lisuride.

The present communication reports how depletion of central noradrenaline neurons of DSP4 treatment antagonizes the facilitatory actions of 5-MeODMT and lisuride on male rat sexual behavior. In males with intact noradrenaline, 5-MeODMT facilitated sexual behavior by reducing the number of intromissions required for ejaculation; inhibitory actions were also noted, since 5-MeODMT prolonged intromission and ejaculation latencies. In DSP4-pretreated animals the inhibitory effect of 5-MeODMT remained unchanged, whereas its facilitatory action was abolished. Consistent with previous research, lisuride also reduced intromission frequency prior to ejaculation. This facilitation of sexual behavior was not observed in DSP4-treated animals. In the male rat, ejaculations following the first have a lower latency and are preceded by a lower number of intromissions. This naturally occurring facilitation of sexual behavior was not prevented by DSP4-induced noradrenaline depletion. Our results suggest that serotonin and noradrenaline interact in the control of sexual behavior in the male rat.

Animals↗
PubMed1986

Food intake, aggression, and fear behavior in the mother rat: control by neural systems concerned with milk ejection and maternal behavior.

Mother rats eat more, are more aggressive, and show less fear behavior (freezing) than during other stages of the reproductive cycle. Electrolytic lesions in the peripeduncular area of the lateral midbrain made nursing mother rats eat less and interact peacefully with male intruders. This midbrain area forms part of the ascending milk-ejection pathway, so it seems plausible that the suckling stimulus maintains hyperphagia and aggression in mother rats. Because no alteration in fear behavior was observed in mothers with lesions, it was predicted that the reduction in freezing was related primarily to maternal responsiveness to pup cues other than suckling. In line with this hypothesis, it was found that the experimental induction of maternal behavior in ovariectomized, hormone-treated females was associated with a significant decrease in fear behavior, with no concomitant changes in food intake or aggression.

Afferent Pathways↗
PubMed1986

Effects of bicuculline infusions in the ventromedial hypothalamus and amygdaloid complex on food intake and affective behavior in mother rats.

The mother rat is hyperphagic, aggressive toward other adults, and less fearful than non-maternal rats. The present experiments were conducted to examine whether GABAergic (gamma-aminobutyric acid) mechanisms in the ventromedial hypothalamus and amygdala participate in the control of these behavioral changes. Unilateral infusions of the GABA receptor blocker bicuculline (60 ng/0.5 microliter) into the ventromedial hypothalamus depressed food intake and lowered aggression. Similar infusions into the amygdaloid complex did not affect eating, but they did reduce aggressive behavior. Freezing behavior, a natural fear response, was not affected by the hypothalamic or the amygdaloid bicuculline infusions. These data support previous evidence suggesting a role for GABA in the regulation of postpartum changes in food intake and affective behavior.

Aggression↗
PubMed1986

Myotonic dystrophy. A reassessment by conventional and more recently introduced neurophysiological techniques.

A series of complementary neurophysiological investigations was carried out on 24 patients with myotonic dystrophy to determine the extent of nervous system involvement. Conventional electromyography and nerve conduction studies, computerized motor unit number estimation and motor unit potential analysis, vibration threshold studies and a recently introduced technique for heat and cold threshold estimations were undertaken in all patients. The results provide unequivocal evidence of widespread nervous system dysfunction. In many patients there is significant involvement of peripheral large diameter motor and sensory fibres and of small diameter sensory fibres either peripherally and/or centrally. In the light of these results and others reviewed in the literature, the concept of myotonic dystrophy as a pure myopathy can no longer be sustained.

Action Potentials↗
PubMed1986

Visualized cyclodialysis--an additional option in glaucoma surgery.

Visualized cyclodialysis was carried out in 16 consecutive cases of operation-demanding glaucoma, where trabeculectomy was considered inexpedient. In 9 cases simultaneous cataract extraction was carried out. At follow-up 2-34 months (median = 15) post-operatively, the IOP had decreased from a median value of 32 mmHg (range 21-44) to a median value of 17 mmHg (range 7-28) in 15 out of 16 eyes. The 16th eye had to be eviscerated because of pain before and after an inefficient cyclodialysis. Five eyes were reoperated upon. Essential complications were 2 cases of central visual field impairment and 1 case of arteriovenous occlusion after cyclodialysis revision. We find visualized cyclodialysis a useful procedure for aphakic glaucoma as well as for re-operations. Frequent post-operative examinations are necessary for 1-2 months post-operatively.

Aged↗
PubMed1986

Selection of a reference lot of Mueller-Hinton agar.

A collaborative study was undertaken to evaluate the performance of currently marketed Mueller-Hinton agars from seven manufacturers by replicate disk diffusion tests with standard quality control strains. Identification of the manufacturers was concealed, and the resulting data were evaluated for the selection of a physical reagent standard against which the performance of future production lots would be tested and made to conform. A medium was selected which was sufficiently close to existing National Committee for Clinical Laboratory Standards quality control limits that current interpretive criteria would require minimum modification. Two of the seven lots were eliminated from further consideration because the final pHs were outside acceptable limits. The remaining four lots had 96% of mean zone diameters less than or equal to 2 mm from those of the chosen lot and 65% of the means were less than or equal to 1 mm from those of the chosen lot for all 28 antimicrobial agent-organism combinations. Manufacturers then attempted to produce new lots of Mueller-Hinton agar which performed within the prescribed limits of the chosen lot. One lot performed in close conformity with the selected standard, but the overall performance of the media was essentially the same as that of the randomly chosen lots in the initial study. It was concluded that one of the original seven lots demonstrated properties which made it a tentative candidate for a physical reagent standard and that the use of a physical reagent standard in evaluating production lots might aid in stabilizing the performance of Mueller-Hinton agar.

Agar↗
PubMed1986

Accessory spleen imaging. Radionuclide, ultrasound and CT investigations in a patient with thrombocytopenia 25 yr after splenectomy for ITP.

A 42-yr-old man presented with thrombocytopenia 25 yr after splenectomy for idiopathic thrombocytopenic purpura (ITP). Preoperative investigations with 99Tc-colloid scan, ultrasound and computed tomography (CT) revealed 2 accessory spleens. The patient recovered completely after splenunculectomy. CT was superior to radionuclide and ultrasonography in describing the exact location of the 2 spleens, thereby facilitating the operative procedure.

Adult↗
PubMed1986

Sensory control of maternal aggression in Rattus norvegicus.

Female rats become aggressive toward adult conspecifics during lactation. This change in social affect is dependent on the presence of the offspring, because maternal aggression disappears when the pups are removed. It was found that a similar decline occurs when the litter is placed in a glass flask while remaining in the home cage. In contrast, maternal aggression persists following placement of the pups in a nylon mesh bag. The pups did not vocalize while being in the mesh bags, so it appears that olfactory cues from the offspring constitute a critical element in the maintenance of maternal aggression in the rat. It has been suggested that the odor not only of the pups but also of the intruder may contribute to eliciting aggressive behavior in lactating rodents. In line with this proposal, it was found that mother rats spend about one third of the time preceding the first attack sniffing the body of the intruder. In contrast to findings in mice, housing of the prospective intruder behind a double wire mesh partition in the lactating female's home cage failed to reduce her aggressiveness toward him. Rats, then, may require more intimate contact with an individual than do mice for the aggression-reducing effect of familiarization to be observed.

Aggression↗