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Biomedical subjects

S Hansen

Publications and source records attributed to S Hansen.

At least 271 records · Page 15Linked to original sources
PubMed1984

Emergence of displacement activities in the male rat following thwarting of sexual behavior.

The present study revealed the emergence of displacement drinking and hindlimb scratching in noncopulating castrated male rats and in rats with medial preoptic (mPOA) lesions in tests with sexually attractive stimulus females. By contrast, sexually quiescent rats in the postejaculatory refractory period showed no evidence of displacement activity, and anestrous female rats displayed only moderate increments in drinking and scratching, compared with copulating estrous females. In both castrated and mPOA-lesion males, the amount of displacement activity was inversely related to strength of masculine sexual behavior, and in the former, displacement behavior was entirely suppressed by the subcutaneous implantation of a testosterone-filled Silastic capsule. When no stimulus female was present, no difference in drinking and scratching by control, castrated, and mPOA-lesion individuals could be discerned. Sexually inactive females elicited less displacement activity in castrated rats than did females in estrus. On the other hand, unreceptive stimulus females frequently elicited displacement behaviors in normal sexually active males. The results are discussed in relation to current concepts of the psychological organization of masculine sexual behavior, and it is suggested that the emergence of displacement behavior in castrated and mPOA-lesion males, and in normal males paired with anestrous females, may be due to the thwarting of sexual motivation.

Animals↗
PubMed1984

The importance of the peripeduncular nucleus in the neuroendocrine control of sexual behavior and milk ejection in the rat.

Electrocoagulations situated in the lateral midbrain tegmentum cause severe deficits in sexual behavior and lactational performance of rats. In this study we determined the extent to which these effects could be reproduced by axon-sparing lesions using the excitotoxin, ibotenic acid; in another group of rats, 6-OHDA was infused in the same area to degenerate the mesencephalic catecholamine neuronal elements affected by the electrocoagulations. It was found that ibotenic acid, but not 6-OHDA, reproduced most of the effects produced by electrolytic lesions. Thus, female rats bearing ibotenic acid lesions showed little sexual receptivity and proceptivity in response to estrogen and progestin treatment, and the milk ejection reflex appeared nonfunctional following the lesion. Ibotenic acid-infused male rats failed to ejaculate on most postoperative observations, though they continued to mount he estrous female. Examination of the lesions with immunohistochemical visualization of tyrosine-hydroxylase- and substance P-positive neurons, and thionine staining, revealed that the neurotoxins exhibited the intended selectivity, though the ibotenic acid lesions were associated with loss of substance P-immunoreactive nerve terminals in the substantia nigra and the peripeduncular region. It is suggested that the peripeduncular nucleus plays an important role in the neuroendocrine control of male and female copulatory behavior, as well as in the regulation of the milk ejection reflex.

Animals↗
PubMed1984

Neurochemical abnormalities in a patient with ataxia-telangiectasia.

We describe biochemical abnormalities found in autopsied brain of a patient with ataxia-telangiectasia. Neuropathologic changes were limited to the cerebellum and spinal cord. The atrophic cerebellum showed marked loss of Purkinje's and granule cells, and moderate loss of stellate and basket cells. Glutamic acid content was markedly reduced, and taurine content somewhat reduced in the cerebellar cortex, while gamma-aminobutyric acid (GABA) content was greatly reduced in the dentate nucleus. GABA receptor binding was reduced by 70% in cerebellar cortex. Phosphoethanolamine content was greatly reduced in the cerebellar cortex and inferior olivary nucleus. This compound was also deficient in 10 other brain regions and was the only extracerebellar neurochemical abnormality observed.

Ataxia Telangiectasia↗
PubMed1983

5-Hydroxytryptamine-thyrotropin releasing hormone interactions in the spinal cord: effects on parameters of sexual behaviour in the male rat.

In the studies of sexual behaviour in male rats reported here, intrathecal administration of 5-hydroxytryptamine (5-HT) together with thyrotropin releasing hormone (TRH) caused a marked and specific increase in mount and intromission latencies. In contrast, injection of either of the two compounds alone elicited only minor effects. These findings are discussed in relation to the co-existence of 5-HT and TRH in nerve endings in the ventral horn of the spinal cord originating in supraspinal, medullary nuclei.

Animals↗
PubMed1983

Role of descending monoaminergic neurons in the control of sexual behavior: effects of intrathecal infusions of 6-hydroxydopamine and 5,7-dihydroxytryptamine.

The present study concerns the possible participation of descending monoamine pathways in the control of sexual behavior. Male and female rats received micro-injections of the neurotoxins, 6-hydroxydopamine (6-OHDA) or 5,7-dihydroxytryptamine (5,7-DHT), in the spinal subarachnoid space, which were found to deplete spinal synaptosomal uptake of radiolabeled noradrenaline and serotonin to 46.7% and 34.5%, respectively. Whereas intrathecal 5,7-DHT did not affect sexual behavior appreciably, female 6-OHDA-treated rats showed less sexual receptivity and proceptivity when exposed to constant estradiol; similarly treated males had prolonged post-ejaculatory refractory periods and were more sensitive than controls to androgen deprivation.

5,7-Dihydroxytryptamine↗
PubMed1983

The recovery cycle of the pattern visual evoked potential in normal subjects and patients with multiple sclerosis.

The recovery cycle of amplitude and latency of the P100 of the chequerboard pattern reversal visual evoked response was studied in 16 normal subjects and 20 patients with multiple sclerosis. There was no clear-cut pattern of recovery with respect to amplitude but at interstimulus intervals of less than 40 msec the latency of the test response P100 tended to be significantly delayed, the magnitude of this delay being virtually constant at intervals of 20 msec or less. Only 8 of 40 eyes from the 20 multiple sclerosis patients showed a pattern of recovery of latency significantly different from the normal subjects. Possible mechanisms for these observations are discussed with particular reference to current concepts of the pathophysiology of multiple sclerosis.

Electroencephalography↗
PubMed1983

Karyotype 47,XXY,18p--in a newborn child with holoprosencephaly.

This may be the first reported case of a 47,XXY,18p--("Klinefelter-de Grouchy I syndrome"), in a post-term male neonate. The child had a dysmorphic facies, a small nose with a single orifice, cranial malformations and an alobar holoprosencephaly. These symptoms corresponded with the known phenotypic variants of the simple 18p--anomaly. The karyotypes of both parents were normal.

Abnormalities, Multiple↗
PubMed1983

Current status of statewide school health education programs in Michigan.

This study surveyed all Michigan public school principals regarding the current status of comprehensive school health education being provided in Michigan public schools. A 32-item survey was developed, pretested, revised and mailed to all public school principals in Michigan. Followup letters were sent to nonrespondents. A phone survey was conducted to nonrespondent principals after the cut-off date to verify survey responses. All data was analyzed by elementary, junior high school and high school population. The areas of professional preparation, inservice education, application and utilization of the Essential Performance Objectives for Health Education in Michigan, the content and time allotted for health education, and the lack of a well-developed organizational structure for health education have been articulated as deficit areas in the current status of comprehensive school health education. This survey provided much information for future consideration by educators, public and private health organizations, and other individuals and groups interested in school health in Michigan.

Adolescent↗
PubMed1983

Mechanisms regulating hormone release and the duration of dioestrus in the lactating rat.

Lactation in rats nursing seven pups was associated with a period of dioestrus lasting for 3 weeks, reduced LH secretion, hyperprolactinaemia and increased serum progesterone levels. Removal of the litter resulted in increased LH secretion, a prompt return of oestrus and termination of the prolactin-dependent luteal phase. Administration of domperidone (2.5 mg/day), a dopamine receptor antagonist, to rats deprived of their litters on day 1 or 9 post partum maintained hyperprolactinaemia and delayed the reappearance of oestrus. Administration of bromocriptine (0.5 mg/day), a dopamine receptor agonist, to lactating rats with suckling pups suppressed prolactin secretion and advanced oestrus, females in the middle of lactation being considerably more sensitive to prolactin suppression than those in the early post-partum period. Cross-fostering experiments revealed that the greater sensitivity to bromocriptine of mothers in late lactation was due to their lactational age rather than to the age of the offspring. Similarly, the length of lactational dioestrus was not affected either by giving newborn pups to females in the middle of lactation or by giving 9-day-old pups to newly parturient females.

Animals↗
PubMed1983

Evidence that prolactin does not affect the induction of sexual behaviour by oestradiol and progesterone in ovariectomized rats.

Injection of 2.5 mg of the dopamine receptor antagonist domperidone raised serum prolactin concentrations within 3 h and high prolactin levels were maintained for 12 h in ovariectomized rats pretreated with 2 micrograms oestradiol benzoate (OB). This dose of domperidone stimulated the display of sexual behaviour in ovariectomized OB-treated rats within 3 h of administration. The behavioural effect of domperidone, but not its effect on serum prolactin concentrations, was blocked by adrenalectomy. Daily treatment with domperidone had no inhibitory effect on the subsequent induction of sexual behaviour by OB and progesterone in ovariectomized rats. A slight facilitation of the behaviour was noticed in OB-treated rats given daily domperidone injections, but this effect was cancelled by adrenalectomy. The results suggest that an acute increase in serum prolactin levels has no effect on the induction of sexual behaviour by OB in itself, but can stimulate the secretion of an adrenal product, perhaps progesterone, which facilitates the behaviour. Similarly, constant high levels of prolactin by themselves have no effect on the subsequent induction of sexual behaviour by OB and progesterone.

Adrenalectomy↗
PubMed1983

Inhibition of sexual behaviour in lactating rats.

Treatment with oestradiol benzoate (OB; 2-250 micrograms) and progesterone (0.5-25 mg) failed to induce sexual behaviour in lactating rats 6 days after parturition. Removal of pups permitted the induction of sexual behaviour by OB and progesterone and the inhibitory effect of the presence of pups was proportional to the number present. Ovariectomy of lactating rats or reduction of serum prolactin levels in intact lactating rats by daily treatment with the dopamine receptor agonist bromocriptine (0.5 mg/day) permitted the induction of sexual behaviour despite the presence of suckling pups. Removal of pups from lactating rats and subsequent maintenance of high prolactin levels by daily treatment with the dopamine receptor antagonist domperidone (2.5 mg/day) maintained the state of refractoriness to the behavioural effects of OB and progesterone provided that the ovaries remained in situ. Inhibition of sexual behaviour in lactating rats could be maintained after ovariectomy by implantation of progesterone-filled, but not androgen-filled implants at the time of ovariectomy. Removal of the pups or reduction of prolactin levels by bromocriptine treatment permitted the induction of sexual behaviour by OB in ovariectomized progesterone-implanted lactating rats. Inhibition of the behaviour in ovariectomized progesterone-implanted lactating rats could be maintained after pup removal by daily domperidone treatment. Continuously raised serum progesterone or prolactin levels have no effect on the induction of sexual behaviour in female rats but the present data suggest that during lactation progesterone and prolactin act in synergy to inhibit the behaviour.

Animals↗
PubMed1983

Hyperasparaginemia in a schizophrenic patient.

A man with a chronic schizophrenia-like psychotic disorder had fasting plasma asparagine concentrations that were consistently 4 to 8 SD above the normal level. Asparagine levels were also high in his cerebrospinal fluid (CSF) and erythrocytes. Ornithine, proline, and glutamate concentrations were irregularly high in fasting plasma, and gamma-aminobutyric acid (GABA) concentrations were elevated in CSF. Whether or not these biochemical abnormalities were related to the psychotic disorder is unclear. However, increased asparagine concentrations, possibly due to an enzymatic deficiency of asparaginase, could lead to deregulation of polyamine biosynthesis and to excessive production of GABA from putrescine. These biochemical changes could in turn cause disordered brain function. A search in mentally ill patients for metabolic abnormalities involving asparagine, or other amino acids, might hasten elucidation of the biochemical basis of the schizophrenias.

Adult↗
PubMed1983

Tarsal coalitions: long-term results of surgical treatment.

We reviewed 40 patients who had undergone 57 operations for tarsal coalition between 1965 and 1980. Ten patients were treated for talocalcaneal coalitions. Four had successful resections and the remainder had successful single or combination arthrodesis. Thirty patients had 39 calcaneonavicular resections and five primary triple arthrodeses. In the entire series only two patients had a poor end result due to either technically poor surgery or failed calcaneonavicular resection because of advanced degeneration. Polytomography, computed tomography, or both were valuable in determining if talocalcaneal coalition resection was feasible. Care must be taken in evaluating the talonavicular joint for degenerative changes. The talar "beak" is not necessarily a degenerative spur, but rather a traction process occurring secondary to increased motion.

Adolescent↗