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Biomedical subjects

K Larsson

Publications and source records attributed to K Larsson.

At least 217 records · Page 12Linked to original sources
PubMed1989

Experimentally induced testicular alterations in boars: histological and ultrastructural findings.

Nine mature boars (8 experimental and one control) were used to study the effects of elevated testicular temperature. The scrotum was covered by a textile-aluminium foil insulation for 100 hours. The boars were divided into 4 groups and were slaughtered at the end of scrotal insulation (group I), 10 days (group II), 20 days (group III) and 40 days (group IV) after scrotal insulation. In groups I and II changes were seen among primary spermatocytes and spermatids, although the changes in group II were more severe. In group III the changes were restricted to the spermatids and in group IV most of the tubules were normal. The epididymal spermatozoa showed slight changes in group I, severe changes in groups II and III and were normal in group IV. The results indicated that spermatogonia were not affected, whereas primary spermatocytes seemed to be the most susceptible germ cell type. Scrotal insulation produced restricted damage that was reversible when the insulation was removed and turned out to be a suitable method to study regeneration processes in the testis of boars.

Animals↗
PubMed1989

Clinical, endocrinological and spermatological studies after endotoxin in the ram.

Eight rams were injected intravenously with endotoxin from Salmonella typhimurium. Blood plasma was analysed for the contents of 15-ketodihydro-PGF2 alpha, LH, testosterone, calcium and total amount of white blood cells. Semen was examined for motility, concentration, volume and morphological appearance. After castration at 4 or 16 weeks the testes were examined histologically. The total white blood cells and the calcium levels as well as LH and testosterone decreased and the levels of 15-ketodihydro-PGF2 alpha rose after the endotoxin administration. The examination of the semen showed a significant decrease in motility and a significant increase in abnormal sperm heads. The histological examination showed a slight degeneration in the seminiferous epithelium in the rams castrated at 4 weeks after the endotoxin administration; this degeneration was not seen in the rams castrated at 16 weeks. The present results indicate that endotoxin seems to exert a negative effect on the genital functions of the ram; the changes in LH and testosterone are very similar to those seen after heat induced stress. The histological changes indicate a short-lasting mild degeneration in the seminiferous epithelium.

Animals↗
PubMed1989

Characteristics of alveolar cells and soluble components in bronchoalveolar lavage fluid from non-smoking aluminium potroom workers.

Aluminium potroom workers have been reported to develop severe pneumoconiosis and bronchial hyperreactivity. The influence of inhalation of aluminium oxide and fluorides on the alveolar milieu was studied by bronchoalveolar lavage (BAL) in 14 male non-smoking potroom workers; 28 non-smoking healthy volunteers served as controls. The total numbers, concentrations, and proportions of various alveolar cells did not differ between the groups. The concentrations of albumin and fibronectin in BAL fluid were significantly higher (p less than 0.01 for both) in the exposed workers, reflecting an increased alveolar capillary permeability and an activation of alveolar macrophages (AMs). The concentration of angiotensin converting enzyme, another AM marker, was, however, decreased (p less than 0.01) in the workers. The concentration of hyaluronan, a fibroblast marker, did not differ between the groups. AMs from workers had a decreased capacity (p less than 0.05) to interact with yeast C3b particles but not to ingest them. The expression of HLA-DR and OKM1 on the cell surfaces of AMs were equal in the two groups. The BAL findings were not accompanied by restrictive lung disease in the workers. The fact that only a discrete alveolitis was found in the potroom workers may be due to a low grade of exposure to alumina and fluorides and to frequent use of respiratory protection equipment.

Adult↗
PubMed1989

Banding studies and synaptonemal complex analysis of an X-autosome translocation in the domestic pig.

In a litter of nine domestic pigs, a translocation between the X-chromosome and chromosome 13 was found in six individuals: four males and two females. The translocation was presumed to have originated in the dam. Banding studies indicated that the breaks preceding the translocation had occurred in a distal GTG-negative band of the long arm of the X, 15-30% of the length of Xq from the telomere, and proximally in chromosome 13, 15-25% from the centromere. The normal X of the females invariably replicated its DNA late. Synaptonemal complex analysis of spermatocytes demonstrated a quadrivalent in 75 of 85 analyzable cells (88.2%), and in 10 cells (11.8%) one trivalent and one univalent were found. Extensive nonhomologous pairings were visualized in the pachytene stage by applying an 'overlap' test measuring the sex chromosomes and collating their pairings. An arrest in male meiosis was verified histologically; no meiotic stages later than pachytene developed. This resulted in sterility, with considerable testicular hypoplasia. The records of female fertility were available only for the dam and did not show any deviations from the average of the herd.

Animals↗
PubMed1989

Increased fracture risk in hypercalcemia. Bone mineral content measured in hyperparathyroidism.

In the present study, 39 women with mild hypercalcemia, which had been detected 18 years earlier during a health survey, and presumably caused by primary hyperparathyroidism (HPT), were investigated together with 34 age-matched controls. The bone mineral content (BMC) of the nondominant distal forearm was measured by single-photon absorptiometry, and the occurrence of fractures was recorded. Among women up to the age of 70 years, those with hypercalcemia had lower BMC than the controls (P less than 0.05), whereas among the older women, there was no difference. Twelve of the women with probable primary HPT had suffered a distal radius fracture as compared with 3 of the controls (P less than 0.05). Thus, also mild hypercalcemia is a risk factor for bone loss and distal forearm fractures. The findings constitute arguments in favor of early detection and treatment of primary HPT.

Aged↗
PubMed1989

Lung function and bronchial reactivity in aluminum potroom workers.

Lung function and bronchial reactivity were measured in 38 aluminum potroom workers with no airway symptoms and in 20 healthy referents (office workers). All of the participants were non-smokers. The magnitude of exposure to airborne dust (alumina) and fluorides was determined. The aluminum potroom workers had obstructive lung function impairment with a significant decrease in expiratory flow and an increase in residual volume. Diffusing capacity was found to be lower than in the referents. No bronchial hyperreactivity was found in the aluminum potroom workers. The exposure to inhaled alumina and particulate and gaseous fluorides in the plant was low, 15-20% of the Swedish exposure limits. The finding of only modest lung function alterations with no bronchial hyperreactivity in the aluminum potroom workers is not consistent with the results of other authors. This discrepancy can probably be explained by the fact that the exposure to inhaled contaminants in the investigated aluminum plant was low.

Adult↗
PubMed1988

Preparative high-performance liquid chromatography of peptides on a new reversed-phase packing material, Kromasil C18.

Preparative reversed-phase high-performance liquid chromatography has found wide use in the production of peptides for pharmaceutical formulations. Purity of the substance and overall economy of the chromatographic system are the most important criterias. In this sense optimized, silica particles and production process with capability to separately control parameters important to chromatography, are essential to high-performance chromatography. Kromasil C18 packing material was tested and evaluated in respect of its selectivity, flow and pressure properties, resolution, load capacity, recovery, adsorption effects, mechanical strength and chemical degradation.

Chromatography, High Pressure Liquid↗
PubMed1988

Lipid phase transitions in membranes involving intrinsic periodic curvature.

A conformation of the lipid bilayer of membranes is proposed, with periodic curvature corresponding to the minimal surface structure of cubic lipid phases. Evidence is given indicating that activities of lipid synthesis/modification enzymes embedded in the membrane are controlled by the lateral "packing-pressure", so that the lipid bilayer is close to a transition from the lamellar (L alpha) type of conformation to this periodically curved conformation. Such a phase transition mechanism is assumed to be involved in numerous cooperative membrane functions.

Membrane Lipids↗
PubMed1988

Sexual orientation, proceptivity, and receptivity in the male rat as a function of neonatal hormonal manipulation.

The influence of neonatal androgen on the potential to exhibit feminine sexual behavior was investigated. Male rats castrated on Day 0 but not those castrated on Day 4 or later showed hop/darting, ear wiggling, and lordotic behavior in response to treatment with estrogen and progesterone in adulthood at a frequency equal to that of females. Neonatal treatment with testosterone propionate (1 mg/rat for 4 days) abolished the capacity to show these behaviors. In subsequent experiments, involving castration of male rats at 0 or 4 hr after cesarean delivery, the effect of the postnatal surge of testicular secretions on the expression of female sexual behavior was investigated. No differences were seen in the frequency of hop/darting, ear wiggling, and receptivity between males castrated immediately or 4 hr after delivery. In a preference test where the experimental male could choose between an estrous female and a sexually active male, the neonatally castrated males preferred the company of a male when treated with estrogen and progesterone. The implantation of testosterone resulted in a preference for an estrous female. It was concluded that testicular secretions in the newborn male influence adult sexual orientation and suppress the ability to show proceptive and receptive behaviors.

Animals↗
PubMed1988

Copulatory performance of penile desensitized male rats following the administration of 8-OH-DPAT.

Bilateral transection of the dorsal penile nerve in male rats was followed by reduction of the amount of intromissions in relation to the frequency of mounts and abolishment of the capacity to ejaculate. Treatment with 8-OH-DPAT (0.25 mg.kg-1 -20 min SC) essentially normalized the behavior of the operated animals which showed a normal proportion of mounts to intromissions and which all ejaculated at almost all testing occasions. It was speculated that treatment with 8-OH-DPAT makes central neural mechanisms more responsive to genital stimulation thereby facilitating the development of full penile erection, vaginal insertion and intromission.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1988

Vocal communication between parents and infants.

Mothers and fathers of 20 boys and 20 girls representing all social classes were filmed when playing with their 6-month-old infants in a standardized playing situation. The vocal behavior of the parents and their infants was analyzed for sex differences. In addition, vocal activity was compared in parents and infants. Mothers showed a higher vocal activity than fathers together with their infants. Mothers also received more vocal activity from their infants than the fathers did. Fathers took more vocal initiatives towards girls than towards boys. Parents were vocally more active than infants. Comparing the vocal irritability of boys and girls, no differences were found. Fathers and mothers did not differ in vocal responsiveness to vocal irritability. Girls received more vocal initiations from fathers than boys while mothers treated boys and girls vocally equally.

Adult↗
PubMed1988

Exposure to microorganisms, airway inflammatory changes and immune reactions in asymptomatic dairy farmers. Bronchoalveolar lavage evidence of macrophage activation and permeability changes in the airways.

Lung function, bronchial reactivity, serum antibody levels, bronchoalveolar lavage (BAL) fluid and the magnitude of exposure to airborne microorganisms during farm work were studied in 10 healthy farmers with no respiratory symptoms. Lung function and bronchial reactivity were not altered. An increase in the amount of antibodies against several microorganisms could be demonstrated but precipitating antibodies were observed only in two subjects. In the BAL fluid the nonsmoking farmers had elevated proportion of lymphocytes and elevated levels of albumin, fibronectin and angiotensin-converting enzyme while the levels of hyaluronan and procollagen III N-terminal peptide were within normal limits. The lung function, bronchial reactivity, serum antibody levels and BAL findings were not correlated with the exposure to airborne microorganisms. We conclude that healthy farmers, exposed to mold dust, may exhibit signs of alveolitis including albumin leakage, accumulation of inflammatory cells and alveolar macrophage activation.

Adult↗
PubMed1988

Influence of infused adenosine on bronchial tone and bronchial reactivity in asthma.

Adenosine has been found to contract human bronchial smooth muscle in vitro and to induce bronchoconstriction in asthmatic patients when administered by inhalation. The aim of the present study was to investigate if elevation of circulating levels of adenosine influence bronchial tone or bronchial reactivity. Seven patients with bronchial asthma in whom bronchial hyperreactivity had been confirmed in a pretrial bronchial histamine challenge (PC20 FEV1 0.064 to 2.45 mg/ml) received intravenous infusions of adenosine in increasing doses (10, 30 and 50 micrograms/kg/min, 6 min on each dose step) or placebo (saline solution) on two different days in a randomized, single-blind manner. Heart rate, blood pressure and lung function (lung volumes, flow-volume loops and airway conductance) were measured on each dose step. Infusion rate was held constant (at 50 micrograms/kg/min) throughout the trial and a bronchial methacholine challenge was performed during the infusion of adenosine or placebo. Infusions of adenosine and placebo did not influence heart rate, blood pressure or bronchial tone on either day and bronchial reactivity was similar on both days. We conclude that bronchial tone and bronchial reactivity in asthmatic patients are not increased by intravenously administered adenosine at a dose level which, in other studies, has been shown to induce regional effects in the systemic arterial circulation.

Adenosine↗
PubMed1988

Effects of oral N-acetylcysteine on cell content and macrophage function in bronchoalveolar lavage from healthy smokers.

Bronchoalveolar lavage (BAL) was performed in fourteen healthy non-smokers and eleven healthy smokers. In smokers BAL was performed before and after eight weeks' treatment with N-acetylcysteine (NAC; 200 mg t.i.d.). Cell number, composition and viability were determined in the BAL fluid. Alveolar macrophages (AMs) were cultured before examination of their phagocytic capacity and their ability to produce leukotriene B4 (LTB4). BAL fluid from smokers contained more cells than that from non-smokers (p less than 0.001). This was mainly attributable to increases in both proportion and absolute number of AMs (p less than 0.001) and to an increase in absolute number of neutrophils (p less than 0.05). However, there was a decrease in proportion of lymphocytes in BAL fluid from smokers (p less than 0.001). Phagocytic capacity of adherent cells and capacity of AMs to generate LTB4 after stimulation with opsonized zymosan (OZy) were decreased in smokers (p less than 0.05 and p less than 0.01 respectively). NAC treatment of smokers did not affect cell number but resulted in an increased proportion of lymphocytes in BAL fluid (p less than 0.05). The phagocytic capacity of AMs was not significantly altered but was improved in five of eleven smokers after NAC treatment. NAC also enhanced the decreased LTB4 secretion by smokers' AMs (p less than 0.05). We conclude that smoking leads to reduced phagocytic capacity and LTB4 secretion of AMs and that oral NAC treatment may improve the function of AMs.

Acetylcysteine↗