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Biomedical subjects

K Larsson

Publications and source records attributed to K Larsson.

At least 325 records · Page 18Linked to original sources
PubMed1980

Sperm morphology and in vitro viability in diluted semen in relation to fertility of AI boars.

Examination of sperm morphology and assay of in vitro sperm viability by use of a thermoresistance test, incubation with ouabain and assay of ASAT-release was performed in 10 ejaculates from each of 10 boars during a 7-month period. The boars were routinely used for AI during the period and the results of the various laboratory assays were related to the fertility of the boars.

Animals↗
PubMed1979

Prolongation of the ejaculation latency in the male rat by thioridazine and chlorimipramine.

Thioridazine (3 mg/kg) and chlorimipramine (1.5-6.0 mg/kg) prolonged the ejaculation latency and increased the number of mounts but did not change the number of intromissions preceding ejaculation. Blockade of peripheral and central noradrenaline receptors by phentolamine and phenoxybenzamine respectively resulted in a suppression of all aspects of the sexual behavior with increasing doses. DL-5-HTP (25-100 mg/kg) in combination with an inhibitory of peripheral 5-HTP decarboxylase (benserazide, 25 mg/kg) produced, like chlorimipramine and thioridazine, a prolongation of ejactulation latency and an increase in the number of mounts preceding ejaculation. Selective inhibition of 5-HT reuptake however, by zimelidine (0-20 mg/kg) or alaproclate (0-20 mg/kg) did not affect the mating behavior. At higher doses of these drugs some animals failed to initiate sexual activities. There was an increase in the postejaculatory interval but not change in the ejaculatory latency. It is concluded tha the prolonged ejaculation latencies observed following treatment with thioridazine or chlorimipramine is not due to a blockade of central or peripheral adrenergic alpha-receptors.

5-Hydroxytryptophan↗
PubMed1979

Effects of gonadectomy and hormone replacement on brain monoamine synthesis in male rats.

The synthesis of catecholamines and serotonin in the brains of castrated male rats was analyzed at either various times after castration or at various ages. It was found that (a) castration of rats at 50 days or later causes an increase in brain monoamine synthesis, and (b) this phenomenon was not observed until 20 days after castration. The increase in brain monoamine synthesis following castration was counteracted by treatment with testosterone, thus relating the biochemical consequences of castration with changed hormonal conditions of the animal. It is suggested that testosterone exerts an inhibitory influence on monoamine synthesis.

5-Hydroxytryptophan↗
PubMed1979

PCPA potentiates the effects of specific copulatory experience on the sexual behavior of the pudendectomized male rat.

The interactional effects of bilateral pudendectomy and sexual experience were studied on the sexual behavior of male rats. In Experiment 1, limited sexual experience in terms of mounts, intromissions or ejaculations was provided prior to the operation. The sexual behavior was then tested before and after treatment with PCPA, a drug known to increase the sexual activity of male rats. In Experiment 2, massive sexual experience was provided the animals prior to pudendectomy, and the sexual behavior was tested with or without PCPA treatment. No variety of limited sexual experience differentiated the effects of pudendectomy. After PCPA treatment, however, the intromittive and ejaculatory capacity of all experienced animals improved significantly. In animals with massive sexual experience the behavioral dysfunctions after pudendectomy were even more dramatically counteracted by PCPA treatment.

Animals↗
PubMed1979

Father-infant interaction at the first contact after delivery.

The behavior exhibited by human fathers at their first contact with the young was studied on 15 fathers of full-term infants delivered by cesarean section. The naked infant was presented to the father approximately 15 min after delivery, and photographs were taken every second during the first 7 min of contact. An orderly progression of behavior was observed: the father began touching the extremities, and then proceeded to touch the infant with his fingers and fingertips, then to use his palms and finally the dorsal side of his fingers. An increase in eye-to-eye contact over time was observed. It was concluded that the father displayed a very similar behavior, in his first contact with the young, as has been described previously for the mother.

Adult↗
PubMed1979

Rat strain differences in copulatory behavior after para-chlorophenylalanine and hormone treatment.

The potentiation of masculine copulatory behavior in castrated male rats following systemic para-chlorophenylalanine (PCPA) treatment was found to be dependent upon the strain of rat and the recency of castration. Wistar (W) and Sprague-Dawley (SD) males displayed a decline in behavioral responsiveness to PCPA treatment following castration, the W males retaining their behavioral responsiveness longer than SD males. Castrated W males were also behaviorally more responsive to androgen replacement than were SD males. Ovariectomized W and SD females receiving estrogen replacement displayed a strain difference in hormonal sensitivity. In tests for feminine copulatory behavior, ovariectomized W females were behaviorally more sensitive to estrogen treatment than SD females. Ovariectomized and estrogen-primed females of both strains displayed potentiated lordotic behavior following chronic PCPA treatment. Concomitant treatment with dexamethasone to reduce adrenal steroid output abolished the potentiation of lordotic behavior found with PCPA treatment.

Animals↗
PubMed1979

Plate fixation versus conservative treatment of tibial shaft fractures. A randomized trial.

One hundred consecutive patients with displaced fractures of the tibial shaft were randomly assigned to two groups, one treated with AO-plate fixation and the other with conservative methods. Strictly conservative treatment failed in two patients because of the interposition of muscles. Comparison of the groups showed that a longer duration of hospital stay was needed in the AO-plate group, and there were also more complications in that group. However, the median healing time was shorter and the anatomical end results were better than in the conservatively treated patients. Closed longitudinal fractures were found to be suitable and open fractures, unsuitable for AO-plate fixation. In the group that was treated conservatively most fractures that healed in malalignment were located in the distal third of the tibial shaft.

Adolescent↗
PubMed1979

Unimpaired sexual behavior of male rats after complete removal of the prostate and seminal vesicles.

The ventral and dorsolateral prostate, the coagulating glands, and the seminal vesicles were removed in nine male rats. The rats were tested for sexual behavior 3 to 4 weeks after surgery. The sexual performance of the operated rats was quantitatively and qualitatively equal to that of sham-operated control rats. At autopsy 6 weeks after surgery, no prostatic or seminal vesicle tissue could be found. These studies show that the sexual performance of male rats does not depend on the presence of the prostatic lobes and seminal vesicles.

Animals↗
PubMed1978

Metabolism of pentachlorophenol in vivo and in vitro.

Pentachlorophenol has earlier been shown to be metabolized in mammals to tetrachloro-p-hydroquinone. The metabolite possesses pronounced inhibitory activity on bacterial beta-glucuronidase but not on beta-glucuronidase from liver. Indirect evidence for the occurrence of both pentachlorophenol and tetrachloro-p-hydroquinone as conjugates with glucuronic acid in the urine from pentachlorophenol-treated rats is now presented. Bovine liver beta-glucuronidase has been utlizied to split the conjugates present. The in vivo metabolism of pentachlorophenol has also been studied in rats treated with phenobarbital and beta-diethylaminoethylidiphenyl propylacetate (SKF 525-A). In vitro metabolism has been studied using liver microsomes from rats pretreated with pehnobarbital. Quantitative analysis of the compounds occurring in extracts of urine or extracts from the microsomal incubates was performed by means of mass fragmentography. Pretreatment with phenobarbital increased the metabolism of pentachlorophenol to tetrachloro-p-hydroquinone both in vivo and in vitro. SKF 525-A, however, inhibited the metabolism in vitro but enhanced the metabolism in vivo when given less frequently than every 6th h. Dechlorination of pentachlorophenol is mediated by microsomal enzymes that can be induced by phenobarbital. SKF 525-A does not inhibit the dechlorination in vivo but does so in vitro.

Animals↗
PubMed1978

Metabolism of tetrachlorophenols in the rat.

The three isomers of tetrachlorophenol were administrated intraperitoneally to rats and the urinary excretion products studied. Tetrachloro-p-hydroquinone was identified as a major metabolite of 2,3,5,6-tetrachlorophenol, constituting about 35% of the dose given. Trichloro-p-hydroquinone was identified as a minor metabolite of both 2,3,4,5- and 2,3,4,6-tetrachlorophenol. 2,3,5,6-tetrachlorophenol was eliminated within 24 h, 2,3,4,6-tetrachlorophenol within 48 h while only 60% of the given dose of 2,3,4,5-tetrachlorophenol could be recovered within 72 h. The acute toxicity of the tetrachlorophenols and tetrachloro-p-hydroquinone was studied in mice upon oral and intraperitoneal administration. 2,3,5,6-tetrachlorophenol (LD50p.o. 109 mg . kg-1) was the most toxic compound followed by 2,3,4,6- and 2,3.4,5-tetrachlorophenol (LD50p.o. 131 and 400 mg . kg-1, respectively). Tetrachloro-p-hydroquinone proved to have low oral toxicity (LD50p.o. 500 mg . kg-1) but was more toxic than the tetrachlorophenols when administered intraperitoneally. The oral LD50 for pentachlorophenol, under identical experimental conditions was found to be 74 mg . kg-1.

Animals↗
PubMed1978

The development of sexual behavior in the rat: role of preadult nutrition and environmental conditions.

Rats were subjected to pre- and postnatal undernutrition by restricting the food intake of their mothers (U); another group of rats was normally fed (N). Each nutrition group was divided into 3 subgroups by varying the degree of environmental stimulation: animals in the Max group were stimulated by handling and enriched rearing conditions; the Min group rats were subjected to social isolation; rats in the control condition (C) were raised under ordinary laboratory conditions. The onset of sexual activity was not affected in the U-C male rats, but was delayed in both U-Min and N-Min rats. Although no difference existed in the age of puberty between the N-Max and N-C animals, the U-Max rats displayed an advancement of puberty by 7 days in comparison to the U-C rats. Undernutrition did not affect female sexual maturation; however the Max condition delayed this process in both nutrition groups.

Animals↗