Biomedical subjects

E Jansson

Publications and source records attributed to E Jansson.

At least 19 recordsLinked to original sources

PubMed2005

Gastrointestinal bacteria generate nitric oxide from nitrate and nitrite.

Denitrifying bacteria in soil generate nitric oxide (NO) from nitrite as a part of the nitrogen cycle, but little is known about NO production by commensal bacteria. We used a chemiluminescence assay to explore if human faeces and different representative gut bacteria are able to generate NO. Bacteria were incubated anaerobically in gas-tight bags, with or without nitrate or nitrite in the growth medium. In addition, luminal NO levels were measured in vivo in the intestines in germ-free and conventional rats, and in rats mono-associated with lactobacilli. We show that human faeces can generate NO after nitrate or nitrite supplementation. Lactobacilli and bifidobacteria generated much NO from nitrite, but only a few of the tested strains produced NO from nitrate and at much lower levels. In contrast, Escherichia coli, Bacteroides thetaiotaomicron, and Clostridium difficile did not produce significant amounts of NO either with nitrate or nitrite. NO generation in the gut lumen was also observed in vivo in conventional rats but not in germ-free rats or in rats mono-associated with lactobacilli. We conclude that NO can be generated by the anaerobic gut flora in the presence of nitrate or nitrite. Future studies will reveal its biological significance in regulation of gastrointestinal integrity.

Adult↗

PubMed2005

VEGF-A splice variants and related receptor expression in human skeletal muscle following submaximal exercise.

VEGF-A contributes to muscle tissue angiogenesis following aerobic exercise training. The temporal response of the VEGF-A isoforms and their target receptors has not been comprehensively profiled in human skeletal muscle. We combined submaximal exercise with and without reduced leg blood flow to establish whether ischemia-induced metabolic stress was an important physiological stimuli responsible for regulating the VEGF-A system in humans. Nine healthy men performed two 45-min bouts of one-leg knee-extension exercise, with and without blood flow restriction. Muscle biopsies were obtained at rest and 2 and 6 h after exercise. Expression (mRNA) of the VEGF-A splice variants and related receptors [VEGF receptor (VEGFR)-1, VEGFR-2, and neuropilin-1] was determined by using qPCR. VEGF-A(total) expression increased more robustly after exercise with reduced blood flow, and initially this principally reflected an increase in VEGF-A(165). Six hours after exercise, there was a relatively greater increase in VEGF-A(189), and this response was not influenced by blood flow conditions. VEGFR-1 mRNA expression increased 2 h after exercise, and neuropilin-1 expression was transiently reduced, while all three receptors increased by 6 h. There was no evidence for the expression of the inhibitory VEGF-A(165B) variant in human skeletal muscle. Our study, reflecting both VEGF-A ligand and receptors, implicates metabolic perturbation as a regulator of human muscle angiogenesis and demonstrates that VEGF-A splice variants are distinctly regulated. Our findings also indicate that all three receptor genes exhibit different pretranslational regulation, in response to exercise in humans.

Adaptation, Physiological↗

PubMed2005

Expression of oestrogen receptor alpha and beta is higher in skeletal muscle of highly endurance-trained than of moderately active men.

AIM: Two known oestrogen receptors (ERs), ERalpha and the recently cloned ERbeta, are expressed in the human skeletal muscle of both males and females. The effects of oestrogen and the role of ERs in skeletal muscle tissue are not well known. Oestrogen receptors and some of their target genes are involved in angiogenic processes. It was hypothesized that ERs are expressed at a higher level in a group with higher oxidative capacity, and that such an enhanced expression would parallel expression of the angiogenic factor -- vascular endothelial growth factor (VEGF). METHOD: Muscle biopsies were taken from vastus lateralis in 10 highly endurance-trained males and 10 moderately active males and analysed for the expression of ERs and VEGF. RESULTS: The major findings in the present study were the higher mRNA levels of ERalpha, ERbeta and VEGF in the highly endurance-trained than in the moderately active group. CONCLUSION: These data suggest that the greater mRNA expression of ERalpha and ERbeta and the oestrogen-associated angiogenic factor VEGF support the hypothesis of an involvement of ERs in the adaptation of skeletal muscle to endurance training.

Adolescent↗

PubMed2005

Low physical activity among adolescents in practical education.

The aim of this study was to investigate physical activity levels and factors related to physical activity among 16-year-old girls and boys in secondary school practical and theoretical programs. An additional aim was to identify factors contributing to differences in physical activity patterns between the educational programs. Sixteen-year-old students in the first year of secondary school in Sweden (n=585) were systematically selected and 93% agreed to complete a questionnaire. Compared with students in theoretical programs, those in practical programs spent less time and energy per day in physical activity. Girls in practical programs were the least physically active, and boys in theoretical programs the most physically active students. Statistical analysis showed that, among students in practical programs, the influence of educational program on physical activity level was explained by lower socio-economic level, less parental support, lower perceived health level, and negative attitudes toward outdoor physical activities. These data suggest that promotion of physical activity should focus on students, especially girls, in practical programs. Because the difference in physical activity levels between educational programs was partly an effect of less positive parental influence, school-based programs may be especially influential in increasing physical activity levels among secondary school students.

Adolescent↗

PubMed2004

Measurement of the activated clotting time during cardiopulmonary bypass: differences between Hemotec ACT and Hemochron Jr apparatus.

BACKGROUND: Measurement of the activated clotting time (ACT) represents a standard method for coagulatory assessments. The test employs specific agents to trigger the coagulation process. The present study aimed to compare kaolin (Hemotec) versus a combination of silica, kaolin and phospholipid (Hemochron Jr) ACTs. METHODS: Hemotec and Hemochron Jr ACT monitors were compared by simultaneous measurement of paired arterial blood samples (n = 114) with respect to precision and bias during clinical conditions of cardiopulmonary bypass (CPB). The influence of haemodilution on the ACT was tested in an ex-vivo model. RESULTS: The precision of Hemotec and Hemochron Jr ACT measurements attained 21 +/- 2.6 s versus 27.0 +/- 2.6 s (p = 0.126) during CPB and 2.5 +/- 2.2 s versus 9.4 +/- 6.9 s (p = 0.000) after protamine administration, respectively. The Hemochron Jr monitor was associated with a bias of -102 +/- 13.7 s compared to the Hemotec ACT monitor (p = 0.000) during CPB and -6.9 +/- 2.9 s after protamine (p = 0.025). Linear regression analysis of ACT readings between monitors reached r = 0.526 (p = 0.000). Hemochron Jr ACT values correlated with the erythrocyte volume fraction r = 0.379 (p = 0.000). Ex-vivo data indicated that the Hemotec ACT monitor was associated with relatively higher ACT readings after haemodilution. CONCLUSION: The ACT is not a standardized measure. Test results are strongly associated with the specific compounds used to initiate the coagulation process.

Aged↗

PubMed2004

Influence of pericardial suction blood retransfusion on memory function and release of protein S100B.

BACKGROUND: To study the influence of pericardial suction blood (PSB) on postoperative memory disturbances and release patterns of protein S100B during and after cardiopulmonary bypass (CPB). METHODS: Sixty male patients admitted for coronary artery bypass surgery were prospectively randomized to receive PSB either by using conventional cardiotomy suction retransfusion or after cell-saver processing. RESULTS: The concentration of S100B rose during the period of CPB from 0.065 +/- 0.004 to 0.24 +/- 0.001 microg/L (p < 0.001). PSB contained 18.0 +/- 1.7 microg/L of S100B. Direct retransfusion from the cardiotomy reservoir made the systemic level increase to 1.42 +/- 0.19 microg/L compared to 0.25 +/- 0.02 microg/L using a cell-saver. Signs of postoperative memory dysfunction ( > 1 SD) were discovered in one of three tests, but were unrelated to technique of retransfusion. No associations were found between serum concentrations of S100B and memory function. CONCLUSION: In this study, retransfusion of PSB during cardiac surgery appeared not to cause memory disturbances. PSB contained high concentrations of protein S100B making its use as a marker of cerebral injury unsuitable.

Blood Transfusion, Autologous↗

PubMed2003

Bone formation after 4 weeks around blood-plasma-modified titanium implants with varying surface topographies: an in vivo study.

The aim of the present study was to investigate and compare the stability and bone ingrowth capacity to screw-shaped titanium implants with five different surface treatments. The implants were: (1) standard turned with a thin blood plasma coat (TP), (2) NaOH-etched dito with pore size 0.2-0.3 microm (E), (3) NaOH-etched with pore size 0.2-0.3 microm and a thin blood plasma coat (EP), (4) electrochemically oxidised with pore size 1-2 microm (O), (5) electrochemically oxidised with pore size 1-2 microm and a thin blood plasma coat (OP). A total of 66 implants were divided into the above-described five groups and inserted for 4 weeks into tibia and femur of 11 rabbits. The implants were evaluated by resonance frequency (RF) measurements at the time of insertion and removal, and analysed histomorphometrically at removal. The RF measurements showed that the implant stability was lower in soft bone compared to dense and increased with time. No significant differences were observed between the different surface modifications. The histomorphometric analysis revealed no statistically significant differences between the implants regarding bone-to-metal contact (BMC) and bone area inside the threads (BA). The above results indicate that thin blood plasma-coated and non-coated screw-shaped titanium implants with turned, NaOH-etched and electrochemically etched surface profiles integrate similarly to bone at 1 month of implantation.

Bone Development↗

PubMed2003

Secular trends in body dimensions and physical fitness among adolescents in Sweden from 1974 to 1995.

AIM: To investigate changes over time in body dimensions, and muscular and aerobic fitness in a representative sample of 16-year-old-girls and boys in secondary schools in Sweden from 1974 to 1995 (n = 855). METHOD: Height and weight were measured and five tests were performed: run-walk, two-hand-lift, Sargent jump, sit-ups, and bench-press. RESULTS: In 1995, girls and boys had higher body mass index (BMI) than in 1974. Girls and boys performed less well in bench-press, sit-ups, and run-walk-tests in 1995. Boys, but not girls, performed better in Sargent jump in 1995 than in 1974. Girls and boys performed better in two-hand-lift in 1995 than in 1974. However, after adjustment for body dimensions, there were no differences in performance in two-hand-lift or run-walk-tests between 1974 and 1995. CONCLUSION: There was a decreased aerobic fitness and an increased maximal static strength among adolescents in Sweden between 1974 and 1995. These changes were partly due to increased BMI. However, decreased daily physical activity level cannot be excluded as a contributing factor to the decreased aerobic fitness. The reduced performance in muscular endurance in 1995 was not related to increased BMI. Instead, it is suggested that it is to be related to a specific decrease in hip flexion and arm muscle endurance.

Adolescent↗

PubMed2003

Oestrogen receptor beta is expressed in adult human skeletal muscle both at the mRNA and protein level.

AIM: There are two known oestrogen receptors (ER), oestrogen receptor alpha (ERalpha) and the recently cloned oestrogen receptor beta (ERbeta). ERalpha mRNA has been detected in mouse, rat, bovine and human skeletal muscle. ERbeta mRNA has been detected in bovine skeletal muscle. To our knowledge, no study has investigated the expression of oestrogen receptor beta in human skeletal muscle. Therefore, the primary aim of the present investigation was to study ERbeta mRNA and protein expression in human skeletal muscle. In addition the ERalpha expression was also studied. METHODS: Muscle biopsies were taken from vastus lateralis in six healthy adults (three women and three men). mRNA expression was detected with real-time PCR (TaqMan) and protein localization by immunohistochemistry. RESULTS: A clear expression of ERalpha and ERbeta mRNA was seen in skeletal muscle in all subjects. The ERalpha mRNA expression was 180 fold higher compared with that of ERbeta mRNA. Immunohistochemistry demonstrated positive staining for ERbeta, but not for ERalpha, with localization to the nuclei of skeletal muscle fibres. On average, 70% of all nuclei were ERbeta-positive. CONCLUSION: The present study shows for the first time ERbeta mRNA and protein expression in human skeletal muscle tissue in both males and females.

Adult↗

PubMed2003

Secular trends in sports: participation and attitudes among adolescents in Sweden from 1974 to 1995.

AIM: To study the secular trend (time changes) in participation in leisure-time sports activities and in attitudes towards sports activities and physical education in a representative sample of Swedish adolescents between 1974 and 1995. METHODS: A questionnaire was distributed to 16-y-old girls and boys (n = 395 in 1974, n = 542 in 1995) to assess participation in leisure-time sports activity, attitudes towards sports activities and attitudes towards physical education at school. Height and weight were measured and body mass index (BMI) was calculated. RESULTS: Compared with 1974, more subjects in 1995 answered that they were engaged in leisure-time sports activities, and that they were members of sports clubs. BMI increased from 1974 to 1995. By 1995, adolescents participated in and had become more interested in individual sports activities, including keep-fit activities (e.g. strength training and aerobics) compared with 1974. A gender difference in the feeling of anxiety towards physical education, with more girls experiencing it, appeared in 1995, but not in 1974. CONCLUSION: Although more adolescents participated in leisure-time sports activity in 1995 than in 1974, the lifestyle of adolescents between sports training sessions may have become more sedentary. This is negative in a health perspective, since the benefits of physical activity on health are largely correlated to the total energy expenditure. However, the increased interest in keep-fit activities is important, since these activities have the potential to be continued into adulthood.

Adolescent↗

PubMed2002

Increased expression of vascular endothelial growth factor in human skeletal muscle in response to short-term one-legged exercise training.

The effects of short-term exercise training on vascular endothelial growth factor (VEGF) and one of its regulatory transcription factors, the hypoxia inducible factor 1 (HIF-1) subunit, were studied in eight healthy males. Muscle and blood samples were obtained before the 1st, and 24 h after the 7th training session. VEGF and HIF-1 mRNA were analysed using RT-PCR, VEGF mRNA localization with in situ hybridization and VEGF protein with ELISA. Concurrent increases in VEGF mRNA and protein levels were observed in skeletal muscle, and the mRNA was expressed within the skeletal muscle fibres and in cells in the interstitium. These data support the idea of a pretranslational regulation of exercise-induced changes in VEGF mRNA, and indicate that increased VEGF protein expression is an early event in skeletal muscle adaptation to training. Furthermore, different cell types may act as sources for the production of angiogenic factors in response to exercise. The levels of HIF-1 mRNA subunits did not change, suggesting no change in HIF-1 mRNA transcript levels in the regulation of training-induced VEGF expression. In contrast to increased tissue VEGF expression, the arterial and femoral venous plasma levels of VEGF were decreased by training, which may indicate an exercise-induced enhancement of the peripheral uptake of VEGF.

Adult↗

PubMed2002

Ultrasound-guided percutaneous biopsies of the semitendinosus muscle following ACL reconstruction--a methodological description.

PURPOSE: To evaluate whether the ultrasound-guided biopsy technique could be used to analyse the histochemical profile of m. semitendinosus following ACL reconstruction with autologous semitendinosus tendon graft. MATERIAL AND METHODS: Sixteen patients were included in the study. During ACL surgery, specimens from m. semitendinosus were obtained via open biopsy. Ultrasound-guided biopsies from m. semitendinosus were performed 7 - 11 months postoperatively from operated leg (n = 16) and non-operated leg (n = 8). RESULTS: Two biopsy samples were pooled and formed a specimen of approximately 150 fibres. For fibre type composition, there was correlation between open biopsy and ultrasound-guided biopsy data, (P = 0.003, r = 0.89). The r-value for mean fibre area was 0.72 (P = 0.06). The methodological error for fibre type 1 % and mean fibre area was 9 %. Postoperatively, no significant differences were found in fibre type composition or fibre type areas between the operated and non-operated leg. CONCLUSION: Ultrasound-guided biopsy is an easy and safe technique that can be used for scientific studies and in clinical practice where biopsy from small muscles or from special location in muscles, such as in ruptures, scars or others is needed.

Adolescent↗

PubMed2002

Use of heparin-bonded circuits in cardiopulmonary bypass improves clinical outcome.

OBJECTIVE: The use of heparin-coated surfaces in cardiopulmonary bypass has been shown to decrease the inflammatory response imposed by the contact between blood and artificial surfaces. One would expect this reaction to improve clinical outcome. However, this has been difficult to verify. This investigation is based on an aggregation of two randomized studies from our institution and highlights possible effects of heparin coating on a number of clinically oriented parameters. DESIGN: Departmental analysis of patients subjected to coronary artery bypass surgery using heparin-coated circuits. Cardiopulmonary bypass was employed using either the Carmeda or Duraflo heparin coatings compared with a control. The systemic heparin dose was reduced in the heparin-coated groups (ACT > 250 s) vs control group patients (ACT > 480 s). The effects of heparin coating related to clinical outcome were studied. RESULTS: The use of heparin-coated circuits reduced the mean length of stay in hospital from 7.8 +/- 2.5 to 7.3 +/- 1.8 days (p = 0.040) and postoperative ventilation time from 9.7 +/- 9.2 to 8.2 +/- 8.5 h (p = 0.018), blood loss 8 h post surgery from 676 +/- 385 to 540 +/- 245 ml (p = 0.001), individual perioperative change of haemoglobin loss (p = 0.001), leukocyte count (p = 0.000) and creatinine elevation (p = 0.000), proportion of patients exposed to allogenous blood transfusions 39.2 vs 23.9% (p = 0.001), postoperative coagulation disturbances 4.4 vs 0.4% (p = 0.006), postoperative deviations from the normal postoperative course 47.2 vs 36.7% (p = 0.035), neurological deviations 9.4 vs 3.9% (p = 0.021) and atrial fibrillation 26.4 vs 18.0% (p = 0.041). No effects were found with respect to perioperative platelet count, postoperative fever reaction and 5-year survival. CONCLUSION: Based on several indicators, the use of heparin coating in cardiopulmonary bypass is associated with improved clinical results.

Aged↗

PubMed2001

Lactate concentrations in human skeletal muscle biopsy, microdialysate and venous blood during dynamic exercise under blood flow restriction.

The intramuscular microdialysate lactate concentration during dynamic exercise with various degrees of blood flow restriction and its relation to lactate concentration in skeletal muscle biopsy and venous blood were studied. Nine healthy males performed three one-legged knee extension exercises (Ex 1-3). Blood flow was restricted stepwise by applying supra-atmospheric pressure over the working leg. Microdialysate mean (range) lactate concentrations at the end of the exercise periods were 3.2 (0.5-6.6), 4.4 (1.1-9.8) and 7.9 (1.1-11.6) mmol.l(-1)during unrestricted, moderately restricted and severely restricted blood flow respectively. There was a significant correlation between microdialysate and venous lactate concentrations at the end of all three exercise periods. Microdialysate lactate concentration correlated significantly to skeletal muscle biopsy lactate concentration at the end of Ex 1. In conclusion, microdialysate lactate concentration in the working muscle increased step-wise with increasing blood flow restriction. It showed a better correlation to venous than to muscle biopsy lactate, which is possibly partly explained by the characteristics of diffusion between body compartments and differences in time resolution between the methods used.

Adult↗

PubMed2001

Mitochondrial transcription factor A and respiratory complex IV increase in response to exercise training in humans.

Protein levels of mitochondrial transcription factor A (Tfam) and nuclear- and mitochondrial-encoded subunits of respiratory chain complex IV (COX I and COX IV) as well as citrate synthase activity were analysed in muscle biopsy samples of vastus lateralis in six healthy male subjects before and after 4 weeks of one-legged cycle training. One leg was trained with restricted blood flow. The other leg was trained with the same power profile but with non-restricted blood flow. Tfam, COX I and COX IV levels all increased with training, with no differences observed between the legs. The training-induced increase in citrate synthase activity was greater in the leg trained with restricted blood flow. These findings indicate that changed expression of Tfam protein could be one mechanism of exercise-induced mitochondrial biogenesis. The increases of COX I and COX IV indicate a concurrent increase of nuclear- and mitochondrial-encoded subunits of respiratory enzyme complex IV at the protein level in skeletal muscle in response to increased muscle activity. In this study, it was not possible to demonstrate that the greater energy disturbance induced by reduced blood flow further stimulates the expression of mitochondrial proteins, even though it did cause a greater enhancement of citrate synthase activity in concordance with earlier studies.

Adult↗

PubMed2001

In vitro preparation and ellipsometric characterization of thin blood plasma clot films on silicon.

The wound-healing process around implants differs from that of a normal healing without the inserted material. In this work, the composition of a natural wound surface was mimicked through clotting of a thin human blood plasma film with approximate ellipsometric thickness of 100 nm onto differently pretreated silicon surfaces. Their stability was investigated by incubations in sodium dodecyl sulphate (SDS) solutions. The enzymatic clot degradation was induced through addition of human tissue plasminogen activator (t-PA) to the plasma and the surface protein remnants after the degradation were analyzed with polyclonal antibodies. The results show that the plasma films were not SDS resistant on hydrophilic silicon. However, stability was obtained after preparation on hydrophobic silicon or when albumin or fibrinogen was immobilized to silicon before the plasma incubations. Different surfaces bound different polyclonal antibodies after the clot film degradation. The methods indicate a simple means to improve or reestablish a normal tissue inflammatory response around biomaterials.

Blood Coagulation↗

PubMed2001

Semitendinosus muscle in anterior cruciate ligament surgery: Morphology and function.

PURPOSE: To evaluate the fate of the hamstring muscles in general and the semitendinosus muscle in particular, after anterior cruciate ligament (ACL) reconstruction with an autologous semitendinosus tendon graft from the ipsilateral side. TYPE OF STUDY: Prospective consecutive case series investigation. METHODS: Included were 16 consecutive patients, 14 male and 2 female, with a mean age of 26 years. The inclusion criterion was chronic unilateral ACL insufficiency with no concomitant knee ligament injuries. ACL reconstruction was performed with a quadruple semitendinosus tendon graft using the EndoButton technique (Acufex, Mansfield, MA). Intraoperatively, muscle specimens were taken from the semitendinosus muscle on the harvested side. Follow-up at a minimum of 6 months included clinical examination, isokinetic strength performance, magnetic resonance imaging (MRI) of the thigh and knee, and ultrasound-guided muscle biopsy procurement from the semitendinosus muscle for histochemical and enzymatic analyses. RESULTS: Of the patients, 75% showed regeneration of their semitendinosus tendons. The neotendons all inserted below the knee joint where they had fused with the gracilis tendon to a conjoined tendon inserting in the pes anserinus. The semitendinosus muscle had a smaller cross-sectional area on the operated side but none showed total atrophy. Less atrophy was present in the patients with a regenerated semitendinosus neotendon compared with those without regeneration (P =.029). In the latter group the semimembranosus muscle seemed to compensate for this with hypertrophy (P =.019). Cross-sectional muscle fiber areas, the relative number of each fiber type and oxidative potential as estimated by citrate synthase activity, showed no significant differences between the operated and nonoperated legs. The isokinetic strength of the hamstrings and quadriceps was significantly lower in the operated leg than in the nonoperated leg. CONCLUSIONS: With this surgical technique, the semitendinosus muscle can recover and the tendon has, according to the MRI images, a great potential to regenerate after its removal.

Adolescent↗

PubMed2001

Neurological and general outcome in low-risk coronary artery bypass patients using heparin coated circuits.

OBJECTIVE: The clinical significance of heparin coating in cardiopulmonary bypass has previously been investigated. However, few studies have addressed the possible influence on brain function and memory disturbances. METHODS: Three hundred low-risk patients exposed to coronary bypass surgery were randomised into three groups according to type of heparin coating: Carmeda Bioactive Surface, Baxter Duraflo II and a control group. Outcome was determined from a number of clinically oriented parameters, including a detailed registry of postoperative deviations from the normal postoperative course. Brain damage was assessed through S100 release and memory tests, including a questionnaire follow-up. RESULTS: Clinical outcome was similar for all groups. Blood loss (Duraflo only), transfusion requirements and postoperative creatinine elevation were reduced in the heparin-coated groups. A lower incidence of atrial fibrillation was noted in the Duraflo group. Heparin coating did not uniformly attenuate the release of S100 or the degree of memory impairment. CONCLUSIONS: Cardiopulmonary bypass (CPB) with heparin coating and a reduced dose of heparin seems to be safe. Clinical outcome and neurological injury seem not to be associated with type of heparin coating used for CPB. However, blood loss and transfusion requirements may be reduced.

Amnesia↗