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Biomedical subjects

S Einarsson

Publications and source records attributed to S Einarsson.

At least 73 records · Page 4Linked to original sources
PubMed1995

Hormone profiles around weaning in cyclic and anoestrous sows.

Peripheral plasma patterns of LH, cortisol, corticosteroid-binding globulin (CBG) and beta-endorphin were studied around weaning in sows that resumed cyclicity and those that remained anoestrus after weaning. Average LH concentration in both groups of sows, and basal LH concentration, LH pulses/6 h and the sum of LH pulses and peaks/6 h in the cyclic sows, increased from the day before weaning to significantly higher (P < 0.05) levels on the days after weaning. Overall, average and basal LH concentrations were higher (P < 0.05) in the sows that resumed cyclicity than in those that remained anoestrus. Cortisol and beta-endorphin concentrations were high before weaning and on the day of weaning in both groups of sows. Cortisol in the cyclic sows, and beta-endorphin in both groups of sows, decreased (P < 0.05) after weaning. CBG levels were unchanged until the second day after weaning when there was an increase (P < 0.05) in both groups of sows. Before and even after weaning cortisol, CBG and beta-endorphin levels tended to be higher in the sows that remained anoestrus compared with those that resumed cyclicity. Findings in the present study show higher levels of cortisol, CBG and beta-endorphin before weaning that persisted even after weaning, and lower LH concentrations around weaning in sows that failed compared with those that resumed oestrous activity.

Animals↗
PubMed1995

Ovulation as determined by transrectal ultrasonography in multiparous sows: relationships with oestrous symptoms and hormonal profiles.

Twenty-four cross-bred multiparous sows in their second and fourth parities were studied during two consecutive oestruses after weaning. Careful oestrous control was done on the animals and ovulation was monitored by transrectal ultrasonography. Blood for analysis of LH and E2 contents was collected through an indwelling catheter. The sows were mated/inseminated once approximately 18 h before expected ovulation in their second oestrus. The interval between weaning and ovulation varied from 86 h-204 h (153 +/- 26). Onset of standing oestrus to ovulation was found to be longer in sows with long oestruses and ovulation occurred within a mean of 68% of the oestrous period. Duration of the first pro-oestrus was significantly shorter than the second pro-oestrus (40 h and 71 h, respectively). There was no significant difference within sows for the intervals from onset of oestrus to ovulation during the first and second oestrus after weaning (37 h and 39 h, respectively). The diameter of the largest follicles at onset of oestrus and at ovulation had very small variation between animals. The mean intervals from E2 peak to onset of oestrus and to ovulation were 1 h (range -10-(+)22 h) and 44 h (range 34-54 h) respectively, and from LH peak to onset of oestrus and to ovulation 12 h range -10-(+)32 h) and 35 h (range 27-48 h), respectively. The present study indicates that repeated ultrasonographic examination of ovaries during one oestrus can be used to predict the time of ovulation during the subsequent oestrus.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Ultrastructure of the secretory endometrium during oestrus in young maiden and foaled mares.

Cyclical accumulation of uterine fluid occurs during oestrus and is often seen in excessive volumes in mares considered susceptible to endometritis. Since the mechanisms behind the formation of free uterine fluid remain to be clarified, the fine structure of the secretory equine endometrium was studied in biopsies collect during videoendoscopy from 14 endometritis-free, 4-9-year-old mares during oestrus. A distinct oedema of the tunica mucosa was evident. The surface epithelium had both ciliated and nonciliated cells and, particularly at the uterine body, often presented intra-epithelial macrophages. The epithelial cells of the gland duct were similar to the surface epithelium, except that the nonciliated cells lacked secretory vesicles in the non ciliated cells. This glandular epithelium presented clear signs of secretory activity with conspicuous secretory vesicles holding electron-dense granula in the adluminal cytoplasm and a well developed supranuclear Golgi apparatus. Secretory products as well as cell debris were commonly found in the lumen of the glands. No clear signs of apocrine secretion were found and it seemed therefore, that the mechanism of secretion is merocrine, i.e. by exocytosis. The endometrial oedema and intense secretory activity, both under oestrogenic influence, contribute to the building up of the uterine fluid during oestrus. No differences in morphology of the secretory endometrium could be noticed between nulliparous mares and mares that had had 1 or 2 foals.

Animals↗
PubMed1995

A field study on group housing of lactating sows with special reference to sow health at weaning.

Four farms that group-housed sows from 2 weeks of lactation until weaning (G-farms) and 3 farms that kept the sows individually penned throughout the 5 to 6-week-long lactation period (C-farms), were compared in terms of sow health. All sows were crossbred Swedish Yorkshire x Swedish Landrace. The daily food ration was similar on all farms except during the group-housing period, when G-farm sows were fed ad libitum. Sows were grouped in the breeding section and kept grouped on deep litter in the dry sow section on all farms. Individual health examinations were performed at the time of weaning (+/- 4 days) on 179 G-farm sows and on 167 C-farm sows. Teat- and udder skin wounds occurred less frequently (p < 0.001) in G-farm sows than in C-farm sows. In addition, preweaning atrophy of all mammary glands occurred in 6.6% of the G-farm-sows but not in a single C-farm sow (p < 0.001). This indicates that sow-piglet interactions decrease when sows are group housed. However, these differences did not occur in primiparous sows, suggesting that the relation between the primiparous sow and her litter is not affected. Mastitis frequency was the same in the 2 systems. Moreover, the frequency of locomotor disorders was the same in the 2 groups, and hoof overgrowth was common in both systems. These similarities could be due to the fact that all farms group housed dry sows on deep litter. A strong relation (p < 0.001) between hoof overgrowth and locomotor disorders was evident. Low access to food due to low rank among primiparous group-housed sows was indicated by a lower (p < 0.05) backfat thickness compared with multiparous sows, and a higher (p < 0.001) frequency of skin wounds compared with individually housed primiparous sows.

Animal Husbandry↗
PubMed1995

Ovarian activity at naturally attained oestrus in the sow. An ultrasonographic and LH study.

In 6 multiparous crossbred sows (2nd to 4th parity, Swedish Landrace x Swedish Yorkshire), 15 proosestrous-oestrous periods during 2 oestrous cycles were studied after weaning. The animals were controlled for oestrus, and the follicular growth and ovulation in their ovaries were followed by transrectal ultrasonography. Blood was sampled through indwelling catheters for analyses of LH and progesterone (P4). The duration of oestrus (standing reflex) was 47 +/- 12.4 h, and the interval from onset of standing reflex until the end of ovulation was 39 +/- 12.4 h (range 20-64 h). The LH peak concentration was 3.7 +/- 0.8 microgram/l, and the interval from LH peak level until ovulation was 23 +/- 8.4 h (range 8-32 h). The onset of standing reflex occurred in average 13 h before the LH peak level (range -4 - +36 h). The peripheral plasma concentration of P4 showed a normal cyclic pattern in all animals. Low levels (mean levels, 1.1-1.3 nmol/l) were seen during prooestrus and oestrus, high mean levels were found on days 10-16 (45-75 nmol/l) in the oestrous cycle. It was concluded that for an accurate determination of ovulation, each animal has to be examined repeatedly. Ultrasonography is a most valuable tool for this purpose.

Animals↗
PubMed1994

Age specific prevalence of antibodies against Chlamydia pneumoniae in Iceland.

Chlamydia pneumoniae is a newly recognized common cause of respiratory tract infections. The aim of this study was to examine its prevalence in Iceland. The study was based on 1020 serum samples from individuals 0-99 years old. The samples were divided into 10-year age groups. IgG and IgM antibodies were determined with microimmunofluorescence assay. An IgG titer > or = 32 and IgM titer > or = 16 were considered positive. The prevalence of positive IgG titer in the study population was 53 +/- 16% (mean +/- SD, age group range 14-66%). Neither seasonal nor gender-based difference in IgG antibody prevalence was demonstrated. It was lowest in the youngest group, 0-9 years old (p < 0.001), but rose linearly to age 70 (p < 0.005). 34 samples were IgM positive on initial testing; most from the older age groups. 12 were rheumatoid factor positive as well. After treatment with caprine antihuman IgG antibodies all became negative. The prevalence of C. pneumoniae infections is high in Iceland according to these results and similar to that in neighbouring countries. The presence of IgM rheumatoid factor may cause false positive tests for pathogen-specific IgM by immune complex binding with pathogen-specific IgG, thereby requiring its removal before testing.

Adolescent↗
PubMed1993

Nitrous oxide elimination and diffusion hypoxia during normo- and hypoventilation.

We studied the elimination rate of nitrous oxide in 36 patients undergoing orthopaedic surgery. They were allocated randomly to one of six groups which differed in time of nitrous oxide exposure and mode of ventilation. In order to simulate recovery conditions, nitrous oxide administration was discontinued after 30, 60 or 120 min of exposure. Either normoventilation or hypoventilation was used. The mean excretion rate was 1 litre min-1 at 1 min, declining to 100 ml min-1 at 30 min, with relatively small effects of different modes of ventilation and times of exposure. In spite of an FIO2 of 0.30, there were significant decreases in SpO2 during both normo- and hypoventilation. The smallest end-tidal oxygen concentrations were reached at 10-15 min in the groups with hypoventilation, after 1 or 2 h of nitrous oxide exposure.

Adolescent↗
PubMed1993

The post-antibiotic effect of antimicrobial combinations in a neutropenic murine thigh infection model.

The post-antibiotic effect (PAE) may allow for more widely spaced dosing of antibiotics than is currently employed without loss of efficacy. Antimicrobial combinations are widely used in clinical medicine. However, dosing schedules are usually based on pharmacological profiles of the drugs used alone. Previously we have demonstrated significant prolongation of the PAE induced by antimicrobial combinations in vitro as compared to PAEs induced by the agents alone. We examined this issue further in vivo in a neutropenic mouse thigh infection model, by exposing Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae to several antimicrobials, either singly or in combination. The PAE in vivo was defined as the difference in time needed for the organisms in the treated animals to grow 1 log10 as compared with controls after serum drug concentrations had fallen below the MIC. Drug concentrations exceeded the MIC for 1.2-3.2 h, but bactericidal activity occurred mainly during the first hour. When the agents were used singly a negative PAE was produced by ceftazidime against P. aeruginosa, a PAE of approximately 0 h by imipenem against E. coli and K. pneumoniae, a PAE of 2-4 h by cefazolin against S. aureus, gentamicin against E. coli and K. pneumoniae, and imipenem and tobramycin against P. aeruginosa, and a PAE of 6-7 h by gentamicin against S. aureus and rifampicin against P. aeruginosa. The beta-lactam/aminoglycoside combinations when used against S. aureus and P. aeruginosa prolonged the PAE by 1.0-3.3 h, compared with the longer of the individual drug PAEs, but no prolongation was observed against E. coli and K. pneumoniae. Ceftazidime reduced the PAE when used with tobramycin against P. aeruginosa. The long PAE of rifampicin against P. aeruginosa was 'carried over' to the combination, thus prolonging the growth suppression achieved by imipenem and tobramycin alone or in combination by 5.5-8.0 h. This effect on the PAE was additive only, and synergy was not observed. In conclusion, a potentially significant prolongation of the PAE by combination of drugs was observed in vivo, but only if both (or all) agents induced a PAE when used alone. The impact of this observation needs to be examined further in studies involving multiple and different dosing regimens in an infection model.

Animals↗
PubMed1993

Effects of insulin administration at weaning on hormonal patterns and reproductive performance in primiparous sows.

Twelve primiparous sows were grouped into six pairs. One sow from each pair (T) received subcutaneous injections of porcine insulin as follows: pairs 1 and 2, 0.5 IU/kg at 07.00 h; pairs 3 to 6, 0.5 IU/kg at 07.00 and 15.00 h. Insulin administration was started one day before weaning and continued until the last day of post-weaning oestrus. Control sows (C) received physiological saline solution as a sham treatment. Blood samples were collected every 3 h from 09.00 to 21.00 h and, additionally, at 07.00 h during the period of insulin treatment. Additional blood samples were collected at 15-min intervals for 6 h for 2 days before and for 3 days after weaning, and for 12 h on the day of weaning (D35 of lactation). Exogenous treatment with insulin increased plasma levels of insulin (53 v 36 mU/l, P < 0.001) and decreased plasma levels of glucose (4.6 v 5.5 mmol/l, P < 0.001) in T-sows as compared to C-sows. During the treatment period, the average levels of cortisol (31 v 35 nmol/l, P < 0.001) and non-esterified fatty acids (0.13 v 0.16 mmol/l, P < 0.01) were lower in T-than in C-sows. No differences in glucagon or urea levels were observed between the two groups. Plasma levels of LH were higher in T- than in C-sows both before and during the treatment period. However, no differences in number of LH pulses/6h were found between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Body weight loss during lactation in relation to energy and protein metabolism in standard-fed primiparous sows.

After 5 weeks of lactation 14 standard-fed primiparous sows were divided into a low weight-loss group (L-gr, loss < 25 kg, n = 7) and a high weight-loss group (H-gr, loss > or = 25 kg, n = 7). Body weights of the sows and their litters were recorded on days 2, 7, 14, 21, 28 and 35 of lactation. Blood samples were collected before the morning feeding on each weighing day. Samples were analysed to determine concentrations of insulin, glucagon, glucose, triglycerides, non-esterified fatty acids (NEFA), urea and creatinine. The H-gr sows lost weight throughout lactation, whereas the L-gr sows gained weight during the last week. Weight loss was higher in the H-gr than in the L-gr during weeks 2, 3 and 5 of lactation. Litter size and litter weight gain were higher in the H-gr than in the L-gr. Significant changes in levels of insulin, glucagon, glucose, triglycerides and creatinine were observed over lactation. No significant differences in concentrations of any of the parameters were found between the two groups, except for insulin and cholesterol which were higher in the L-gr. Catabolism of adipose tissue and muscle protein was observed in both groups during the first week of lactation. This catabolic state was more pronounced and tended to be prolonged in the H-gr. Concentrations of all parameters seemed to be stable in both groups during the last two weeks of lactation.

Animals↗
PubMed1993

Patterns of release of oxytocin, prolactin, insulin and LH in lactating sows, studied using continuous blood collection technique.

To describe the patterns of release of oxytocin, prolactin, insulin and LH in relation to suckling and to investigate relationships between them, blood was collected continuously from four sows at a rate of 1 ml per min for 12 h (0900-2100 h) on day 10 (D10) and day 20 (D20) of lactation. The 12-h period was divided into four smaller periods: P1 (0900-1200 h), P2 (1200-1500 h), P3 (1500-1800 h) and P4 (1800-2100 h). The number of nursings occurring during a 12-h period tended to decrease between D10 (17.3 +/- 0.3) and D20 (16.0 +/- 0.3). About 40-50% of all sucklings induced a significant rise in plasma oxytocin, while prolactin gradually increased following each suckling. Decrease in the levels of oxytocin (14.1 +/- 0.4 vs 7.1 +/- 0.4 pmol/l, P < 0.001), prolactin (12.9 +/- 0.3 vs 7.9 +/- 0.1 micrograms/l, P < 0.001) and insulin (24.8 +/- 1.7 vs 14.4 +/- 1.7 mU/l, P < 0.001) were observed between D10 and D20. Average and basal levels of LH and the number of LH pulses increased (P < 0.01) between D10 and D20. A negative correlation between number of sucklings and number of LH pulses was demonstrated on D20 (r = -0.59, P = 0.07). There was a positive correlation between levels of LH and oxytocin on D10 (r = 0.54, P = 0.001) and between prolactin and insulin levels on D20 (r = 0.34, P = 0.05).

Animals↗
PubMed1993

Plasma oxytocin, prolactin, insulin and LH after 24 h of fasting and after refeeding in lactating sows.

The effects of 24 h of fasting and refeeding on the release of oxytocin, prolactin, insulin and LH in three lactating sows were investigated. The sows were starved, but supplied with water ad libitum, from 09.00 h on day 27 of lactation until 15.00 h on day 28 of lactation, when they were refed. Blood samples were collected continuously, using an automatic collection system, at a rate of 1 ml min-1 from 09.00 to 21.00 h on day 28 (P1 = 6 h period after the 24 h fast, P2 = 6 h period after refeeding). For both P1 and P2 the mean number of nursings was 7.0 +/- 1.0. Plasma insulin and glucose decreased to very low levels during fasting and increased (P < 0.001) after refeeding (insulin, 2.5 +/- 0.7 vs. 28.9 +/- 0.7 mU l-1; glucose, 2.6 +/- 0.3 vs. 6.4 +/- 0.3 mmol l-1). Following fasting, levels of prolactin were low (2.8 +/- 0.1 micrograms l-1), and sucking did not induce significant release of prolactin. However, prolactin increased rapidly after refeeding (5.4 +/- 0.1 micrograms l-1, P < 0.001). Neither the 24 h fast nor refeeding had a marked effect on basal levels of oxytocin, the percentage of sucklings with an oxytocin peak or the size of oxytocin peak. LH release (average and basal levels and number of pulses/6 h) during fasting was similar to that measured after refeeding. Plasma CCK increased significantly after feeding. The results indicate that the release of prolactin is also regulated by feed intake.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Production of Rhizobium Inoculants for Lupinus nootkatensis on Nutrient-Supplemented Pumice.

The use of the legume Lupinus nootkatensis as a pioneer plant to fight soil erosion and to reclaim eroded soils in Iceland has been under development for a few years. Production of a robust, low-cost bacterial inoculant was therefore a prerequisite for the extended use of this plant. Volcanic pumice is a naturally expanded mineral which is available in vast amounts in Iceland. It was tested as a carrier for solid fermentation of Rhizobium lupini. Nutrient-supplemented pumice containing a small percentage of peat and diatomaceous earth and kept in sterile plastic bags promoted good growth of the bacteria. Viable-colony counts remained stable at 10 to 10/g for at least 35 weeks when the carrier was stored at 22 degrees C. The pumice-based inoculant had good storage and handling properties and could be mixed directly with the seeds during the sowing process. When seeds of L. nootkatensis were sown manually into nutrient-poor eroded sandy soils, about 56% of the first-year plants were successfully nodulated.

Journal Article↗
PubMed1993

Effects of nutrition on pregnant and lactating sows.

It has been suggested that the long-term reproduction of the sow is best served by minimizing weight and fat loss in lactation. Such a strategy would require only a minimal restoration of weight in the following pregnancy, which would be beneficial, since the greater feed intake and weight gain in pregnancy, the greater the weight loss in lactation. Feeding ad libitum should be practised during lactation while gestation feed intake must be held low. A relationship between feed intake and embryo survival has been demonstrated in several studies, but the data are sometimes difficult to interpret. High energy feeding during the premating period and during early pregnancy, however, are often associated with increased embryo mortality. A short-term starvation in lactation decreased prolactin to post-weaning concentrations, and insulin and glucose to very low concentrations. Prolactin increased very rapidly after refeeding indicating that a neural mechanism might be involved. The increasing levels of cholecystokinin after refeeding and the neural reflex triggered might be related to this increase in prolactin. No changes in LH release were observed during the periods of starvation or refeeding. The catabolic rate during the first week of lactation is higher in sows with higher backfat thickness than in late gestation. As lactation progresses a more balanced metabolism is achieved regardless of backfat thickness before parturition. High-weight-loss primiparous sows need a longer recovery period from their negative energy balance during lactation than do low-weight-loss primiparous sows or multiparous sows. Several investigations have demonstrated that sows losing excessive amounts of body weight have extended weaning to oestrous intervals and an increase in anoestrus. Sows with low body-weight loss during lactation have higher plasma insulin and lower cortisol around weaning than do sows with high body-weight loss. What remains undefined is the degree of weight or condition loss below which an extension in the remating interval will occur and the level of dietary energy intake required to prevent this extension.

Animal Nutritional Physiological Phenomena↗
PubMed1993

Intraluminal pressure variations in the isthmus of the porcine oviduct after intrauterine insemination with saline, oestrogen solution or boar seminal plasma.

The purpose of this study was to investigate if an intrauterine deposition of saline, boar seminal plasma, or an oestrogen solution containing 11.5 micrograms oestrogens affected the intraluminal pressure in the isthmus of the oviduct in unrestrained gilts. In order to monitor variations in intraluminal pressure, 2 ultra-miniature pressure sensors, located at 2 different points along the same isthmus were used. After an initial recording period, either saline, boar seminal plasma, or the oestrogen solution was deposited directly into the uterus. Intraluminal pressure recordings were conducted up to 6 h after insemination, and blood samples, for monitoring oestradiol-17 beta and 15-ketodihydroprostaglandin F2 alpha levels, were collected. None of the inseminates had any consistent effect on the intraluminal pressure in the porcine oviduct. After deposition of the oestrogen solution, increases in the circulating levels of both oestradiol-17 beta and 15-ketodihydroprostaglandin F2 alpha were seen.

Animals↗
PubMed1993

A study on the effects of inhibition of prostaglandin biosynthesis with flunixin meglumine and later administration of prostaglandin F2 alpha on the intraluminal pressure variations in the isthmus of the oviduct in unrestrained gilts.

Three gilts were each equipped with 2 ultra-miniature pressure sensors, placed at 2 different points along the same isthmus of the oviduct. Following base recordings of isthmic intraluminal pressure, the gilts were treated with 2.2 mg flunixin meglumine (FM) per kg body weight. After FM treatment, the peripheral plasma levels of 15-ketodihydro-PGF2 alpha, the major metabolite of prostaglandin F2 alpha (PGF2 alpha), decreased within 30 min. The frequency of the phasic pressure fluctuations in the isthmus of the oviduct decreased after FM treatment. Exogenous administration of PGF2 alpha increased the peripheral plasma levels of 15-ketodihydro-PGF2 alpha. When administered at a dose of 0.1 mg, PGF2 alpha produced an increase in the frequency of the phasic pressure fluctuations in the oviductal isthmus. When the PGF2 alpha dose was increased to 0.5 mg, a marked increase in the base and total pressures was seen in addition to the increase in the frequency of the phasic pressure fluctuations.

Animals↗
PubMed1993

Energy metabolism during late gestation and lactation in multiparous sows in relation to backfat thickness and the interval from weaning to first oestrus.

Ten crossbred, fourth or fifth parity sows were divided into 2 groups - high (H) and low (L)- according to their backfat thickness 9 days before parturition. Body weight, backfat thickness and litter weight were recorded repeatedly during a 5 week lactation period. The length of the interval from weaning to first oestrus was also noted. All sows were fed a commercial diet (11.9 MJ/kg, 14.5% crude protein). During gestation, daily food intake was 2.2 kg/sow, while during lactation it was 3.0 kg/sow plus 0.4 kg/piglet. Blood samples were drawn on day 9 before parturition and on days 2, 7, 14 and 21 of lactation. The samples were analysed to determine concentrations of glucose, urea nitrogen, creatinine, triglycerides, free fatty acids and beta-hydroxybutyric acid. In both groups, concentrations of free fatty acids and urea nitrogen were low on day 9 before parturition while those of triglycerides were high, indicating anabolism regardless of backfat thickness. During the first week of lactation, concentrations of free fatty acids increased in the H-group but not in the L-group, and concentrations of urea nitrogen were higher in the H-group. These differences, together with the greater loss of weight observed in the H-group, indicate that catabolism of maternal fat and protein depots was more pronounced in the H-group than in the L-group during this time. On day 14 of lactation, both groups showed equally low concentrations of free fatty acids, decreasing creatinine concentrations and stable triglyceride and urea nitrogen concentrations. Furthermore, weight loss during the second and third weeks of lactation was low in both groups. These facts, taken together, indicate that the catabolic rate was decreasing in both groups during this period. No differences in return to oestrus interval were noted between the groups. The present study indicates that under a restricted feeding regime the catabolic rate during the first week of lactation is higher in sows with higher backfat thickness in late gestation. As lactation progresses, a more balanced metabolism is achieved regardless of backfat thickness, which may tend to reduce differences in return to oestrous interval.

Adipose Tissue↗