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Biomedical subjects

M B Jensen

Publications and source records attributed to M B Jensen.

At least 19 recordsLinked to original sources
PubMed2006

Metabolic effects of caffeine ingestion and physical work in 75-year old citizens. A randomized, double-blind, placebo-controlled, cross-over study.

OBJECTIVE: Whereas caffeine has been demonstrated to impact substantially on the metabolic response to exercise in healthy young subjects, this issue remains to be addressed in healthy elderly subjects. DESIGN AND PATIENTS: The metabolic response to caffeine ingestion (6 mg/kg) and exercise in healthy elderly citizens at 70 years was examined in a randomized, double-blind, placebo-controlled, cross-over study. We included 30 subjects attending for driver license renewal at their general practitioner. Participants abstained from caffeinated drinks and food for 48 h and were randomized to receive placebo-caffeine or caffeine-placebo with 1 week between sessions. MEASUREMENTS: A cycling endurance test at 65% of the expected maximal heart rate was performed 1 h after intervention. Blood samples were taken before intervention, before cycling, after 5 min of cycling, and at exhaustion. Analysis was by intention-to-treat and P < 0.05 was regarded as significant. RESULTS: Caffeine significantly increased the concentration of plasma epinephrine (by 42%, 39%, and 49%), serum-free fatty acids (by 53%, 44%, and 50%), and plasma lactate (by 46%, 36%, and 48%), and insulin resistance (homeostasis model assessment-IR) (by 21%, 26%, and 23%) during rest, after 5 min of cycling, and at exhaustion. At exhaustion, the concentration plasma norepinephrine was elevated by 29%. A decrease was seen with caffeine treatment in blood potassium after 5 min of cycling and at exhaustion (by 3% and 2%, respectively). CONCLUSIONS: Caffeine treatment increased epinephrine, fatty acids, lactate and norepinephrine at different times during test session and led to insulin-resistance. Hence, caffeine ingestion elicits a similar metabolic response in elderly participants at 70 years old to that seen in younger subjects.

Administration, Oral↗
PubMed2006

Postoperative physical training following colorectal surgery: a randomised, placebo-controlled study.

BACKGROUND AND AIMS: Major surgery is often followed by fatigue and reduced physical function. We wished to study if postoperative physical training reduced fatigue and improved physical function. MATERIAL AND METHODS: Randomised, placebo-controlled, single-blinded study. Participants were unselected patients > or = 60 years undergoing elective colorectal surgery without disseminated cancer or inflammatory bowel disease. Group A trained muscular strength and work capacity. Group B performed relaxation exercises and received hot wrappings and massage. Main outcome measures were: fatigue (visual analogue scale), muscular strength, walking speed, physical performance test, and physical function questions (SF-36). RESULTS: Preoperatively the two groups were similar except that A was more fatigued than B. By postoperative day seven fatigue had increased compared to preoperatively, more in B than A, but by day 30 and 90 there were no significant differences between groups. All indices of physical function decreased postoperative day seven and were at the preoperative level day 90 with no significant differences between groups in change in function. Day seven the change in knee extension strength tended to be lower in B than A but by day 30 changes were similar in both groups. CONCLUSION: Postoperative training did not improve physical function, but reduced fatigue in hospital.

Aged↗
PubMed2006

Computer-controlled milk feeding of group-housed calves: the effect of milk allowance and weaning type.

Calves fed by computer-controlled milk feeders are often weaned gradually by reducing the size of the milk portions. However, reducing the number of milk portions instead may lower calves' occupation of the milk feeder and stimulate their concentrate intake, especially when they are offered a high milk allowance. Before weaning, but not during weaning, the calves on low milk allowance occupied the milk feeder more, consumed more concentrates, and had a lower daily gain. There was no interaction between milk allowance and weaning type. Weaning by reducing the number of milk portions resulted in more unrewarded visits to the milk feeder, but less time ingesting a similar amount of milk. The effect of milk allowance on milk feeder occupancy before weaning was not found when this allowance was halved during weaning.

Animals↗
PubMed2006

The effects of milk feeding method and group size on feeding behavior and cross-sucking in group-housed dairy calves.

This study investigated the effect of teat feeding and group size on cross-sucking and competition for milk in dairy calves. Ninety-six Holstein-Friesian male and female calves were allocated to either pairs or groups of 6 and fed milk either from a bucket or via a teat. Calves fed via a teat spent more time ingesting the milk. They spent time sucking the empty teat after milk intake and they spent less time cross-sucking compared with calves fed from buckets. The results show that teat feeding reduces cross-sucking in groups of 6 calves. Calves in groups of 6 ingested the milk faster than calves housed in pairs, which suggests that the competition for milk was greater than in pairs. Teat-fed calves changed to another teat more often than bucket-fed calves changed to another bucket during milk intake. Thus, the use of teat feeding did not reduce the competition for milk as compared with bucket feeding and future studies should focus on improving teat-feeding methods so that they reduce competition for milk in group-housed calves.

Animals↗
PubMed2005

Caffeine improves endurance in 75-yr-old citizens: a randomized, double-blind, placebo-controlled, crossover study.

This study investigated the effect of caffeine on physical performance in healthy citizens aged > or =70 yr. The randomized, double-blind, placebo-controlled, crossover study was conducted in 15 men and 15 women recruited by their general practitioner. Participants abstained from caffeine for 48 h and were randomized to receive one capsule of placebo and then caffeine (6 mg/kg) or caffeine and then placebo with 1 wk in between. One hour after intervention, we measured reaction and movement times, postural stability, walking speed, cycling at 65% of expected maximal heart rate, perceived effort during cycling, maximal isometric arm flexion strength, and endurance. Analysis was by intention to treat, and P < 0.05 was regarded as significant. Caffeine increased cycling endurance by 25% [95% confidence interval (CI): 13-38; P = 0.0001] and isometric arm flexion endurance by 54% (95% CI: 29-83; P = 0.0001). Caffeine also reduced the rating of perceived exertion after 5 min of cycling by 11% (95% CI: 5-17; P = 0.002) and postural stability with eyes open by 25% (95% CI: 2-53; P = 0.03). Caffeine ingestion did not affect muscle strength, walking speed, reaction, and movement times. At the end of the study, 46% of participants correctly identified when they received caffeine and placebo. Caffeine increased exercise endurance in healthy citizens aged > or =70 yr, but the participants' reasons for stopping the test may have varied between subjects, as the cycling test was done at approximately 55% of maximal oxygen consumption. Further studies are required to investigate whether caffeine can be utilized to improve the physical performance of elderly citizens.

Administration, Oral↗
PubMed2005

RNA polymerase IV directs silencing of endogenous DNA.

Plants encode subunits for a fourth RNA polymerase (Pol IV) in addition to the well-known DNA-dependent RNA polymerases I, II, and III. By mutation of the two largest subunits (NRPD1a and NRPD2), we show that Pol IV silences certain transposons and repetitive DNA in a short interfering RNA pathway involving RNA-dependent RNA polymerase 2 and Dicer-like 3. The existence of this distinct silencing polymerase may explain the paradoxical involvement of an RNA silencing pathway in maintenance of transcriptional silencing.

Amino Acid Sequence↗
PubMed2005

Little effect of physical training on body composition and nutritional intake following colorectal surgery--a randomised placebo-controlled trial.

OBJECTIVE: Postoperatively patients have a reduction in nutritional intake and body weight. We studied the effect of postoperative physical training on nutritional intake and body composition. METHODS: Patients > or =60 y admitted for elective colorectal surgery were randomised to train muscular strength (group A) or to nonstrengthening exercises (group B) for 3 months. Fat mass (FM) and lean body mass (LBM) were assessed with bioimpedance preoperatively, 7, 30, and 90 days postoperatively. Nutritional intake was registered in a subpopulation. RESULTS: Of 119 included patients, 60 were randomised to group A and 59 to B. The changes in LBM at postoperative day 7 were a mean (s.d.) of 0.4 (2.1) kg in group A compared to -0.7 (2.0) kg in B. The difference between groups of 1.2 (0.5) kg at day 7 was statistically significant (P=0.03). At no other time was observed difference between groups in weight, LBM, or FM. The energy and protein intake rose during postoperative day 1-7 and rose further after discharge. At no time were differences between groups. CONCLUSION: Physical training had little effect on body composition following abdominal surgery. The nutritional intake in well-nourished patients did not increase by training.

Aged↗
PubMed2004

Determinants of weak femoral artery pulse in dogs with mitral valve prolapse.

In three substudies encompassing 247 dogs from two breeds predisposed to myxomatous mitral valve disease (MMVD), femoral artery pulse strength was palpated and related to potential explanatory factors, including quantitative echocardiographic measures of MMVD, aortic and femoral artery diameter and wall thickness and blood pressure. In addition, in 109 Cavalier King Charles Spaniels (of which 61 were included in the three substudies mentioned above), the relation between femoral artery pulse strength and presence of thrombocytopenia was investigated. In 26% of the dogs, a pulse </=50% of normal strength was detected; six dogs (2.0%) had an absent pulse unilaterally or bilaterally. Mitral valve prolapse severity, degree of obesity, heart rate and age all influenced femoral artery pulse strength negatively. Weak femoral artery pulses were not related to clinical signs or to decreased pulse pressure or stroke volume. A weak femoral artery pulse reflected reduced artery diameter and/or distension rather than occlusion. In conclusion, weak femoral artery pulses in dogs with MMVD seem to be associated with regional/local reductions in blood flow and not arteriosclerosis or platelet count.

Animals↗
PubMed2004

Transthoracic echocardiography for cardiopulmonary monitoring in intensive care.

BACKGROUND AND OBJECTIVE: To evaluate the feasibility of an abbreviated focus assessed transthoracic echocardiographic protocol, consisting of four standardized acoustic views for cardiopulmonary screening and monitoring. METHODS: The protocol was applied in 210 patients in a 20-bed multidisciplinary intensive care unit in a university hospital. When inconclusive, an additional transoesophageal echocardiographic examination was performed. Diagnosis, indication, acoustic window, position and value were recorded. Significant pathology, load, dimensions and contractility were assessed. RESULTS: Two-hundred-and-thirty-three transthoracic and four transoesophageal echoes were performed. The protocol provided usable images of the heart in 97% of the patients, 58% subcostal, 80% apical and 69% parasternal. Images through one window were obtainable in 23%, through two windows in 41% and through three windows in 34%. In 227 patients (97.4%) the focus assessed echo protocol contributed positively. In 24.5% of cases the information was decisive, in 37.3% supplemental and in 35.6% supportive. CONCLUSIONS: By means of an abbreviated, focus assessed transthoracic echo protocol it is feasible to visualize the haemodynamic determinants for assessment and optimization. One or more useful images are obtainable in 97% of critically ill patients.

Adult↗
PubMed2004

Computer-controlled milk feeding of dairy calves: the effects of number of calves per feeder and number of milk portions on use of feeder and social behavior.

One hundred ninety-two calves (Holstein-Friesian, Danish Red, and Jersey) were allocated to either groups of 24 calves or groups of 12 calves with one computer-controlled milk feeder per group. Within group, one-half of the calves were offered the daily milk allowance in either 4 or 8 milk portions. In groups with 24 calves, there was a higher level of competition for access to the feeder than in groups with 12 calves. Calves waited longer for access, and while occupying the feeder, they were more often disturbed by other calves attempting to access the feeder. The increased level of competition resulted in a higher rate of milk ingestion among calves in groups of 24 and, as a result, a lower duration of time spent ingesting the milk and a lower occupation of the feeder per calf. The number of calves per feeder did not affect the amount of milk ingested, but the high level of disturbance and the increased feeding rate with 24 calves per feeder suggest that these calves were subject to social constraint. Offering the same milk allowance in 4 rather than 8 milk portions lowered the occupancy of the feeder. The number of portions did not affect the duration of ingesting milk, but the duration of occupying the feeder just after milk ingestion was lower with 4 than with 8 milk portions. Thus, fewer and larger portions may lower competition for access during the activity periods if all other factors remain equal.

Animal Nutritional Physiological Phenomena↗
PubMed2002

Enforced mobilization, early oral feeding, and balanced analgesia improve convalescence after colorectal surgery.

OBJECTIVE: A postoperative regimen using a multimodal approach with enforced mobilization and early oral nutrition has been reported to improve convalescence but has not been compared with other postoperative regimens. METHODS: Forty patients undergoing elective colorectal surgery were randomly allocated to an intervention group receiving comprehensive information on the importance of mobilization, balanced anesthesia, and postoperative analgesia including epidural local anesthetics and enforced postoperative mobilization or a control group receiving anesthesia without epidural local anesthetics, postoperative analgesia with epidural morphine, and mobilization without fixed goals. All patients were offered early oral nutrition. The regimens were compared by means of ambulation time and physical activity, voluntary muscle strength, pulmonary function, and body composition. RESULTS: The ambulation time improved substantially within 22 h in the intervention group versus 3 h in the control group on day 1 (P = 0.0004) and within 8 h versus 2 h on day 4 (P = 0.0003). The voluntary strength of the quadriceps muscle decreased by 3% in the intervention group versus 15% in the control group on day 7 (P = 0.04). Two months postoperatively, the difference between groups was the same (P = 0.02). CONCLUSION: This active per- and postoperative regimen based on a multimodal approach improved ambulation time and muscle function during admission and late convalescence.

Aged↗
PubMed2000

[Should all younger patients with breast cancer be offered adjuvant cytotoxic chemotherapy?].

The aim of the study was to investigate whether young age at diagnosis is a negative prognostic factor in primary breast cancer and how stage of disease at diagnosis and treatment may influence such an association. It was conducted as a retrospective cohort study based on a population-based data-base of breast cancer diagnosis with detailed information on tumour characteristics, treatment regimens, and vital status and included 10,356 patients with primary breast cancer less than 50 years of age at diagnosis. The main outcome measures were relative risk of dying within the first ten years after diagnosis according to age at diagnosis, adjusted for effect of known prognostic factors and expected mortality. Overall, young patients with low risk disease who did not receive adjuvant treatment had a significantly increasing risk of dying with decreasing age at diagnosis (adjusted relative risk: 45-49 years: 1 (reference); 40-44 years: 1.12 (0.89-1.40); 35-39 years: 1.40 (1.10-1.78); < 35 years: 2.18 (1.64-2.89). However, a similar trend was not seen in young patients who received adjuvant cytotoxic therapy. We found the same difference as above when comparing women receiving no treatment with those receiving adjuvant cytotoxic therapy within strata of node negative patients and patients with the same tumour size. In conclusion, the negative prognostic effect of young age is almost exclusively seen in women diagnosed with low risk disease not receiving adjuvant cytotoxic therapy, whereas young women who receive adjuvant cytotoxic therapy have the same prognosis as middle-aged women. These results suggest that young women with breast cancer, on the basis of age alone, should be regarded as high risk patients and be given adjuvant cytotoxic therapy.

Adult↗
PubMed2000

IFNgamma enhances microglial reactions to hippocampal axonal degeneration.

Glial reactivity is implicated in CNS repair and regenerative responses. Microglia, the cells responding earliest to axonal injury, produce tumor necrosis factor-alpha (TNFalpha), a cytokine with both cytopathic and neuroprotective effects. We have studied activation of hippocampal microglia to produce TNFalpha in response to transection of perforant path axons in SJL/J mice. TNFalpha mRNA was produced in a transient manner, peaking at 2 d and falling again by 5 d after lesioning. This was unlike other markers of glial reactivity, such as Mac-1 upregulation, which were sustained over longer time periods. Message for the immune cytokine interferon-gamma (IFNgamma) was undetectable, and glial reactivity to axonal lesions occurred as normal in IFNgamma-deficient mice. Microglial responses to lesion-induced neuronal injury were markedly enhanced in myelin basic protein promoter-driven transgenic mice, in which IFNgamma was endogenously produced in hippocampus. The kinetics of TNFalpha downregulation 5 d after lesion was not affected by transgenic IFNgamma, indicating that IFNgamma acts as an amplifier and not an inducer of response. These results are discussed in the context of a regenerative role for TNFalpha in the CNS, which is innately regulated and potentiated by IFNgamma.

Animals↗
PubMed2000

Factors influencing the effect of age on prognosis in breast cancer: population based study.

OBJECTIVE: To investigate whether young age at diagnosis is a negative prognostic factor in primary breast cancer and how stage of disease at diagnosis and treatment influences such an association. DESIGN: Retrospective cohort study based on a population based database of patients with breast cancer containing detailed information on tumour characteristics, treatment regimens, and survival. SETTING: Denmark. SUBJECTS: 10 356 women with primary breast cancer who were less than 50 years old at diagnosis. MAIN OUTCOME MEASURES: Relative risk of dying within the first 10 years after diagnosis according to age at diagnosis after adjustment for known prognostic factors and expected mortality. RESULTS: Overall, young women with low risk disease who did not receive adjuvant treatment had a significantly increased risk of dying; risk increased with decreasing age at diagnosis (adjusted relative risk: 45-49 years (reference): 1; 40-44 years: 1.12 (95% confidence interval 0.89 to 1.40); 35-39 years: 1.40 (1.10 to 1.78); <35 years: 2.18 (1.64 to 2.89). However, no similar trend was seen in patients who received adjuvant cytotoxic treatment. The increased risk in younger women who did not receive adjuvant treatment compared with those who did remained when women were grouped according to presence of node negative disease and by tumour size. CONCLUSION: The negative prognostic effect of young age is almost exclusively seen in women diagnosed with low risk disease who did not receive adjuvant cytotoxic treatment. These results suggest that young women with breast cancer, on the basis of age alone, should be regarded as high risk patients and be given adjuvant cytotoxic treatment.

Adult↗
PubMed2000

Muscular performance and fatigue in primary hyperparathyroidism.

The purpose of this study was to evaluate changes in muscular strength and endurance, work capacity, and subjective fatigue following surgical treatment of primary hyperparathyroidism (pHPT), and to assess whether changes in muscular function were due to changes in activation of the muscles. A prospective consecutive study design was used, and patients surgically treated for nontoxic goiter served as controls. Nineteen female patients with mild to moderate pHPT and 20 controls were included. Maximal isometric handgrip and quadriceps strength, quadriceps endurance (intermittent stimulation), and quadriceps activation (superimposed twitch technique) were used for evaluation of muscular function. All patients were operated on successfully. Knee extension strength increased by 17 +/- 17% (mean +/- SD; p = 0.0004) in the patients, whereas no change was observed in the controls. The relative strength increase correlated positively to patient age at operation (r = 0.52, p = 0.02). Handgrip strength, quadriceps endurance, and general work capacity did not change in any group after operation. Subjective fatigue was preoperatively higher in patients than in controls (p = 0.01), and decreased postoperatively to the level of controls. In conclusion, women with pHPT increase knee extension force after parathyroidectomy as a result of increased force generation capacity of the muscle. If change in physical performance is a determinant for change in subjective fatigue in pHPT after operation, then change in strength of the quadriceps muscle seems to be of primary importance, whereas handgrip strength, muscular endurance, and work capacity do not seem to be important. The cause of the increasing strength benefit with increasing age at operation as found in this study needs further investigation.

Female↗