Search PubMed⌕ Search

Biomedical subjects

R Andersson

Publications and source records attributed to R Andersson.

At least 109 records · Page 6Linked to original sources
PubMed1998

Differences in injury mortality between the Nordic countries--with special reference to differences in coding practices.

The aims of the study are to analyse the incidence and patterns in injury mortality in the Nordic countries, and to assess the extent to which any differences found can be explained in terms of either variation in statistical validity or the existence of genuine differences. The study considers the entire injury panorama, and is performed between certain categories of injuries. Analysis is applied to all ages, and also to certain specific age categories. Finland appears as the Nordic country with the highest injury mortality. While examining potential source of errors, nothing was found to merit an adjustment of Finland's rate. All potential correction would bring the rates of the other Nordic countries closer to that of Finland. Poisoning was found to be a diagnosis that varies in application between the Nordic countries. Falling is the diagnosis with the greatest problems of sensitivity, and cannot be recommended for comparative purposes.

Adolescent↗
PubMed1998

Virulence factors of Staphylococcus aureus strains causing infective endocarditis--a comparison with strains from skin infections.

The objective was to study potential bacterial virulence factors in S. aureus endocarditis. S. aureus strains isolated from patients with well-classified episodes of infective endocarditis (IE) (n=26) were compared with control S. aureus strains from consecutive patients with skin infections (n=30). The potential virulence factors studied were Staphylococcal enterotoxin A-D (SEA, SEB, SEC, SED) and toxic shock syndrome toxin-1 (TSST-1) production and binding capacity to the extracellular matrix proteins: fibronectin, collagen type I, collagen type II and bone sialoprotein (BSP). None of the potential virulence factors studied was more prevalent among the IE strains. BSP binding was more often found in the control group with skin infections. Endocarditis patients with previous damage of the heart valves were more often infected by strains not producing any enterotoxin. No correlation was found between the potential bacterial virulence factors studied and IE. Concerning the toxins known to act as superantigens (SEA-E and TSST-1), the tendencies in this and other studies indicate that a larger study group might identify them as pathogenic factors in a subgroup of staphylococcal endocarditis.

Adolescent↗
PubMed1998

Is maternal malnutrition associated with a low sex ratio at birth?

The low male/female ratio at birth in African populations has been attributed to a variety of genetic, behavioral, and environmental factors. A low sex ratio at birth has been associated with maternal malnutrition in mammals, but this issue has not been studied in humans. In this study we analyzed the relation between maternal nutritional status and sex ratio at birth in 3282 children born to 684 women from a rural African society. Short maternal stature and obesity were independently related to a low sex ratio at birth. These results are consistent with animal experiments that indicate an adverse effect of maternal malnutrition on male fetuses. The results warrant further research in this area.

Adolescent↗
PubMed1997

The serum albumin-binding region of streptococcal protein G: a bacterial fusion partner with carrier-related properties.

In this study, we have explored the use of the serum albumin-binding region (BB) from streptococcal protein G (SpG) as a bacterial fusion partner for production of peptide immunogens. The fusion protein BB-M3, containing BB and repeated structures from the Plasmodium falciparum malaria antigen Pf155/RESA, was efficiently purified from Escherichia coli culture supernatants by affinity chromatography using BB as an affinity tag. Rabbits immunized with BB-M3 in Freund's adjuvant produced high levels of antibodies which reacted with both M3 and BB in ELISA and stained intact Pf155/RESA in the membrane of infected erythrocytes. These antibody levels were sustained for more than 30 weeks. BB-M3 also induced antibody responses to M3, BB and intact Pf155/RESA in a number of mouse strains, including several strains which are non-responders to the malaria sequences. In the latter mice, however, BB-M3 only activated BB-specific T cells, suggesting that BB has ability to provide carrier-related T cell help for antibody production. Moreover, the minimal albumin-binding motif of SpG, containing only 46 amino acids, was immunogenic in both B10.BR, B10.D2 and C57BL/6 mice (H-2k, H-2d and H-2b, respectively). These results indicate that BB has both affinity tag and carrier-related properties and suggest that fusion proteins containing BB can be efficient tools for the generation of antibody responses to peptides which are weak immunogens.

Animals↗
PubMed1997

Results of adjuvant therapy in resected pancreatic cancer.

After an apparently curative resection, most patients develop local recurrence within the resection bed. In addition, almost all develop liver metastases. This implies that the surgical resection, even if extended, seldom is enough, and that an adjuvant treatment must be effective not only against systemic spread, but also against local recurrence. However, the time schedule may be different for different types of recurrence, resulting in different time frames for the adjuvant treatment. Although extended radical operations may increase the proportion of patients who can undergo resections, the incidence of local recurrences seems unchanged. There are, however, no randomized studies yet comparing the "Standard Whipple" with more extended resection. Intraoperative radiation (IORT) has failed to demonstrate a difference in long-term survival, but there have been reports of a decreased frequency of local progression at the site of the primary tumor. Therefore, it is encouraging that IORT seems to diminish the local recurrences after radical resections. However, randomized studies are also missing for this procedure. These are today only three published studies of adjuvant chemotherapy after radical pancreaticoduodenectomy, but a few more will be finished shortly. Still, the results have not convincingly shown that modern chemotherapy with or without radiotherapy prolongs the life of the patients, and there is little evidence for improving the quality of life. However, since the results are far from satisfactory after resection, more efforts should be made to find better treatment modalities, including adjuvant protocols.

Chemotherapy, Adjuvant↗
PubMed1997

Function of reduced-size liver transplant in the rat.

We have studied the function of partial orthotopic liver transplantation in the rat by evaluating prothrombin time (PT), liver blood flow, basal and glucose-stimulated insulin secretion and glucose tolerance, and the reticuloendothelial function (RES) in hepatectomized rats subjected to partial liver transplantation. A graft corresponding to 68% of a normal liver was transplanted to totally hepatectomized rats. Comparison was made between control rats and rats subjected to 32% liver resection. PT was not significantly different in the transplanted group compared with liver-resected and control rats. Laser Doppler flowmetry showed that at 28 days after surgery, blood flow had increased in the transplanted livers. Furthermore, on the third day after transplantation, basal plasma insulin was increased and the plasma insulin response to glucose was exaggerated, suggesting reduced insulin action and impaired insulin degradation. Finally, uptake of radioactive-labeled E. coli bacteria, as a measure of RES function, was not compromised in transplanted animals. Based on these results, we conclude that reduced-size liver transplant in out-bred rats results in fast normalization of liver function after surgery although, immediately after surgery, glucose intolerance is seen.

Animals↗
PubMed1997

Development of a preferential relationship with the mother by the newborn lamb: importance of the sucking activity.

Lambs develop a preferential relationship with their mothers within 24 h after birth. In a first experiment, we attempted to determine whether neonatal sucking was a potent reinforcer in the establishment of this preference by temporarily covering the udders of ewes after parturition. Lambs were assigned to one of three treatments: they had free access to the udder (group 1) or were prevented from sucking either between birth and 6 h afterward (group 2) or between 12 and 18 h after birth (group 3). Measurements of cholecystokinin plasma levels at birth and at 6 and 18 h showed that all lambs ingested some colostrum when the udder was made accessible. When tested in a two-choice test situation at 24 h of age, lambs from group 1 spent significantly more time near their mothers than near the alien ewes, those from group 2 did not show any discrimination, and lambs from group 3 clearly preferred the alien ewes. At 2 days of age, lambs from groups 1 and 3 showed a strong preference for their mothers, whereas those from group 2 still displayed no preference. In a second experiment, we attempted to determine whether sucking also had a reinforcing value in the maintenance of this preference. Lambs were assigned to one of three treatments: they had free access to the udder (group 1) or were prevented from sucking for 6 h either at birth (group 2) or at the age of 3 days (group 3). Lambs from group 2 did not discriminate between their own and alien dams when tested at 24 h of age, unlike those of groups 1 and 3. When a second test was performed at 4 days of age, all the lambs showed a strong preference for their dams. We concluded that sucking has strong rewarding properties in the establishment of a preferential relationship with the mother by the lamb. On the other hand, the maintenance of this preference does not rely on sucking as strongly.

Animals↗
PubMed1997

Predominance of H-2d- and H-2k-restricted T-cell epitopes in the highly repetitive Plasmodium falciparum antigen Pf332.

Genetic restriction of immune responses to malaria antigens is an important issue for a better comprehension of malaria immunity as well as for development of subunit vaccines. To experimentally define the major histocompatibility complex restriction of immune responses to the highly repetitive Plasmodium falciparum high-molecular-weight antigen Pf332, H-2-congenic mice were immunized with EB200, a recombinant fragment of Pf332 consisting of degenerate repeat motifs. Strong B- and T-cell responses were elicited in H-2d and H-2k mice whereas responses in H-2b, H-2q and H-2s mice were of lower magnitude. The T-cell specificity elicited by EB200 was defined by in vitro proliferative responses to a panel of overlapping peptides spanning EB200. Dominant epitopes were identified for H-2d and H-2k mice, respectively, and an additional epitope was recognized by all five mouse strains. Selected EB200-derived peptides were further investigated for their ability to elicit T-cell help when injected as multiple antigen peptides. Defined H-2d- and H-2k-restricted T-cell epitopes generated high antibody levels in the respective mouse strains, as did several peptides lacking defined epitopes indicating the presence of additional H-2d- and H-2k-restricted, cryptic or subdominant T-cell epitopes in EB200. The biased H-2 restriction pattern of T-cell epitopes in Pf332 and, as previously reported, in structurally related repeats in the malaria antigens Pf11.1 and Pf155/RESA may be explained by a shared motif for H-2d and H-2k class II-restricted T-cell epitopes, as revealed by alignment of these sequences.

Amino Acid Sequence↗
PubMed1997

Peripheral blood T cell expansions in patients with Behcet's disease.

Behçet's disease (BD) is a chronic multisystemic inflammatory disorder characterized mainly by recurrent oral and genital aphthous ulcerations and uveitis. Etiology and pathogenesis of BD remain unknown. T cell receptor (TCR) V alpha/V beta gene product expression as well as Jbeta gene segment expression in peripheral blood of BD patients were analysed to investigate the possible role of T lymphocytes in the etiopathogenesis of BD. Flow cytometry with 12 TCR V-specific MoAbs was used for TCRV analyses. Jbeta gene segment usage by T cell populations expressing certain V betas was determined by polymerase chain reaction (PCR) technique with V beta- and C beta-specific primers, Southern blotting of PCR products, and subsequent hybridization with radiolabelled Jbeta gene segment-specific probes. Although 13 of the 23 BD patients exhibited increases in expression of one or more TCR V-gene products, only expansions among the CD4+ T cell subset were significantly more frequent in BD patients (7/23) compared with healthy controls (0/15) (P = 0.019). Six out of eight cases followed for up to 20 months had at least one expansion correlated with disease activity. A strict preference for particular Jbeta gene segments implicating clonality was apparent in all analysed T cell expansions and correlated well with disease activity. These results suggest a possible involvement of antigen-specific T lymphocytes in the pathogenesis of BD.

Adolescent↗
PubMed1997

The role of intravenous administration of dextran 70 in enteric bacterial translocation after partial hepatectomy in rats.

The aim of this study was to assess the effect of intravenous dextran on bacterial translocation and intestinal vascular endothelial and epithelial barrier function after experimental partial hepatectomy. We determined systemic arterial pressure, enteric bacterial growth (proximal and distal small intestine and colon) and bacterial translocation (BT) to mesenteric lymph nodes (MLN), liver, lungs, spleen, kidneys and blood, as well as intestinal vascular endothelial and epithelial barrier permeability, after sham operation or partial hepatectomy (50% and 90%) with preoperative intravenous administration of saline, albumin or dextran 70. Subtotal hepatectomy induced a significant decrease in arterial pressure and an increase in the number of Escherichia coli in the distal small intestine. BT was not observed in sham-operated animals or in rats with 50% hepatectomy administered dextran. The number of positive cultures of enteric bacteria was significantly increased after hepatectomy, whereas dextran treatment decreased the number of animals with BT. Increased permeability of the intestinal vascular endothelial and epithelial barriers was noted in hepatectomized animals, while dextran prevented hepatectomy-induced vascular endothelial barrier injury. Enteric bacterial translocation occurred following partial hepatectomy in the rat, associated with bacterial overgrowth in the distal small intestine. Intravenous administration of dextran 70 prevented bacterial overgrowth and translocation, at least in part, by maintaining gut vascular endothelial barrier integrity

Animals↗
PubMed1997

The ineffectiveness of cyclical oral clodronate on bone mineral density in glucocorticoid-treated patients with giant-cell arteritis.

OBJECTIVES AND DESIGN: The aim of the present study was to determine whether cyclic oral administration of clodronate, a bisphosphonate, every second month prevents rapid bone loss during the first year of glucocorticoid treatment in patients with giant-cell arteritis (GCA). The trial was designed as a prospective double blind study, assessing total body mineral content (BMC) and bone mineral density (BMD) using DXA technique. Supplementation of calcium was given to both groups of patients. SETTING: The outpatient clinics of the rheumatic and infectious diseases of Sahlgren University Hospital of the city of Göteborg on the west coast of Sweden. SUBJECTS: Twenty-seven patients with confirmed GCA were consecutively included during a 15-month period. RESULTS: An early influence on bone turnover was found with a temporary decrease in BMC after six months of glucocorticoid treatment, which was normalized after 12 months in both study groups. No significant differences between the patients given clodronate and calcium and the controls, who got supplementation with calcium alone, was observed at any assessment point. However, there was a significant and prolonged depression of the osteocalcin levels in the clodronate-treated patients. CONCLUSIONS: Oral administration of clodronate in a moderately high dose given cyclically every other month had no additive effect on BMD compared with calcium supplementation alone during the first year of glucocorticoid treatment. A larger material might have revealed some differences between the categories. In most patients with GCA, however, the BMD seems to recover after one year of glucocorticoid treatment, provided there is good control of the inflammation and patients are kept physically active. It needs to be elucidated whether there are subsets of patients who might benefit from bone sparing agents: women near menopause with a high turnover rate of bone, individuals who have low BMD from the start of glucocorticoid treatment or patients requiring high doses of glucocorticoids during a long period of time.

Administration, Oral↗
PubMed1997

T-cell receptor BJ gene segment expression in human umbilical cord blood CD4+ and CD8+ T-cell subsets.

By employing RT-PCR-based technology, followed by Southern-blot analysis, patterns of relative TRC BJ gene segment usage in human CD4+ and CD8+ umbilical cord blood T cells (UCT) from ten children were determined in relation to seven recombined TCR BV gene (sub) families (BV 3, 5S1, 6S1-3, 8, 9, 12 and 18). Normal frequency of usage of individual BJ members was observed to be extremely nonrandom. BJ usage in association with each BV was ranked and mean ranking values were calculated for individual BJs. Moreover, BJ family usage and family ranges as well as individual BJ over-representations were determined. In all these aspects of BJ exon expression, CD4+ and CD8+ UCT displayed similar distribution patterns. Comparisons of BJ usage in UCT subpopulations and in the adult peripheral blood lymphocyte (PBL) counterparts were performed and many similarities were observed. However, discrepancies in two parameters were recorded; contrary to observations in PBL, individual BJ over-representations were virtually absent in UCT, and significantly less wide BJ family ranges were demonstrated in CD8+ UCT relative to CD8+ PBL T cells. These differences support the notion that UCT are in a less dynamic state than are PBL T cells. Hence, despite the fact that PBL T cells are subjected to continuous antigenic challenge, the striking resemblance of PBL and UCT with regard to the overall individual relative usage, ranking, mean ranking and family utilisation of BJ gene segments, irrespective of the choice of recombined BV exons, may suggest a relatively nondiscriminatory role for the BJ gene product in antigen recognition as compared to those encoded by the BV, (N) and BD gene segments.

Blotting, Southern↗
PubMed1997

Maternal nutrition and socio-economic status as determinants of birthweight in chronically malnourished African women.

The birthweight is the most important determinant of mortality and morbidity in the neonatal period and may have an influence on health in adult life. The high rate of low birthweight in developing countries is therefore a major health problem. Maternal malnutrition is usually assumed to be a causal factor but other environmental factors are also involved. In this study we analysed maternal nutritional and socio-economic factors as determinants of birthweight in term infants from a rural African society characterised by a high rate of chronic malnutrition. Relations of maternal weight, gestational weight gain, parity, socio-economic status and infant sex with birthweight were analysed in 1,477 women and child pairs. The selected women were followed from early pregnancy and had an uncomplicated delivery at term of a living singleton child. The gestational weight gain was 5.6 (SD 6.0) kg and the mean birthweight 2.933 kg (SD 408). Maternal weight, representing the maternal long-term nutritional situation, was the most important independent determinant of birthweight, accounting for 13.0% of the variance in birthweight. The weight gain, representing the short-term nutritional situation, explained only 5.6% of the variance. Birthweight increased by 20 g (CI 18-23) for each kg maternal weight and by 15 g (CI 12-18) for each kg gestational weight gained. The socio-economic difference in birth-weight was 153 g (CI 109-196) 88 of which (CI 48-128) remained unexplained after adjustment for differences in maternal weight, parity and gender. Improved long-term nutritional situation and living conditions seems to be the most important prerequisites to counteract low birthweight in developing countries.

Birth Weight↗
PubMed1997

The influence of circulatory and gut luminal challenges on bidirectional intestinal barrier permeability in rats.

BACKGROUND: The endothelial and epithelial barriers are important for maintenance of intestinal barrier function. The present study evaluated the response of these barriers after various challenges. METHODS: Mucosal endothelial and epithelial barrier integrity was evaluated by the leakage of human serum albumin, labeled with different isotopes, from the circulation to the interstitium and the intestinal lumen, or from the intestinal lumen to the interstitium and the circulation, in rats with endothelial or epithelial challenge. RESULTS: Epithelial barrier dysfunction and alterations in epithelial microvillous ultrastructure showed a pattern dependent on the dose of the intraluminal detergents, whereas only higher doses induced an increase in endothelial barrier permeability. Intravenous challenge with CHAPS or Triton caused a dose-dependent increase in both endothelial and epithelial barrier permeability. The development of endothelial barrier dysfunction was related to a decrease in blood pH values. CONCLUSIONS: The results indicate that capillary endothelial barrier integrity may play an important role in maintaining intestinal barrier function and that endothelial injury may initiate or at least be involved in the development of intestinal barrier failure.

Acetic Acid↗
PubMed1997

Role of macrophage overactivation in the development of acute pancreatic injury in rats.

BACKGROUND: An increase in systemic inflammatory mediators from stimulated leucocytes and macrophages has been noted during acute pancreatitis. The role of cytolytic inflammatory macrophages and potential mechanisms in the development of acute pancreatic injury and endothelial barrier dysfunction are less well defined. METHODS: Rats were challenged by an intraperitoneal injection of cytolytic or non-cytolytic inflammatory macrophage stimulators at various concentrations. The effects of oxygen free radicals, prostaglandin and extracellular calcium influx on macrophage-associated pancreatic endothelial compromise, measured by pancreatic intravascular plasma volume, pancreatic interstitial fluid volume, and the pancreatic extravascular human serum albumin distribution volume, were explored. RESULTS: Zymosan-induced overactivation of cytolytic inflammatory macrophages resulted in the development of acute pancreatic endothelial dysfunction in a dose- and time-dependent pattern. An increase in pancreatic water content and interstitial fluid volume was observed following a higher dose (0.5 mg/g) of concanavalin A without alteration in plasma lipase level, while thioglycollate medium did not compromise pancreatic endothelial barrier function. Oxygen free radicals, but also prostaglandins and extracellular calcium influx, seemed to be involved in macrophage overactivation-induced pancreatic injury. CONCLUSION: Overactivation of cytolytic macrophages plays a role in the pathogenesis of pancreatic injury by initiating the development of endothelial barrier dysfunction. Multiple inflammatory mediators from overactivated macrophages act as intercellular signals between macrophages and the endothelium during acute pancreatic injury.

Animals↗