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Biomedical subjects

R Jensen

Publications and source records attributed to R Jensen.

At least 91 records · Page 5Linked to original sources
PubMed1997

Comparison of vancomycin and teicoplanin for prophylaxis of sepsis with coagulase negative staphylococci (CONS) in very low birth weight (VLBW) infants.

A prospective randomized study was performed to evaluate the efficacy of a low dose (5 mg/kg/day bid) vancomycin compared with a low dose (5 mg/kg/day once daily) teicoplanin therapy to prevent CONS sepsis in VLBW-infants. All infants received this therapy after their 4th day of life or after an eventual therapy of early onset sepsis as long as an i.v. line was in place or 1500 g body weight. Twenty-seven infants were treated with vancomycin (birth weight 1103 +/- 286 g, gest. age 28.8 +/- 1.9 weeks), 28 with teicoplanin (birth weight 1133 +/- 226 g, gest. age 29.04 +/- 2.2 weeks). The infants were observed for clinical and laboratory signs of sepsis. On day 4 of therapy and every 3rd day during therapy serum creatinine levels, tracheal aspirates, stool cultures and vancomycin/teicoplanin peak and trough levels were obtained. We could not detect any case of blood culture positive sepsis and 1 case of suspected sepsis (neg. blood cultures) in both groups, as compared with a former CONS sepsis rate of 24% in our institution's VLBW infants without antibiotic prophylaxis. Nine patients in the vancomycin and five in the teicoplanin group had tracheal colonization with CONS. In both groups peak and trough levels of antibiotics were in the bactericidal range. Serum creatinine was not normal in both groups. We conclude that teicoplanin is preventing CONS sepsis as well is vancomycin. The minimal inhibitory concentrations of both antibiotics against grampositive isolates in units using this strategy have to be observed carefully to detect emerging resistance.

Anti-Bacterial Agents↗
PubMed1997

Basal serum pancreatic polypeptide is dependent on age and gender in an adult population.

This study is the first epidemiologically based study of basal levels of serum pancreatic polypeptide (s-PP). The basal level of serum PP has become a field of interest mainly due to the role of PP as an endocrine tumour marker, and as a marker of pancreatic neuroendocrine function after pancreas transplantation and in the case of diabetic autonomic neuropathy. The study population consisted of primarily Caucasian adults representative of a general population living around Copenhagen. Serum pancreatic polypeptide was measured in random serum samples from fasting persons (n = 623), aged 25-64 y, using a monospecific radioimmunoassay. Fasting serum pancreatic polypeptide depended on age and gender. The results demonstrated that fasting pancreatic polypeptide levels increase exponentially with age. Fitted separately for each sex, basal serum pancreatic polypeptide was found to increase by approximately 3% per year of age. Males had higher concentrations of pancreatic polypeptide in serum compared to age-matched females. Normal range and 95% reference intervals are given. The lower limit for the reference interval of the normal range was close to detection limit. We conclude that discrepancies among earlier reports on the fasting levels of serum pancreatic polypeptide are most likely due to lack of adjustment for age and gender. Thus, variation due to age and gender should be considered in evaluating fasting levels of serum pancreatic polypeptide. Whether similar considerations are important when evaluating stimulated serum pancreatic polypeptide levels remains to be elucidated.

Adult↗
PubMed1997

Comparison of two methods of bedside blood glucose screening in the NICU: evaluation of accuracy and reliability.

Bedside whole blood glucose screening in the NICU has been an accepted method of care for several years. Meters or visually read reagent strips are used in bedside screening, but the reliability and accuracy of these methods are not always established before they are implemented as routine practice in the NICU. A study was conducted to determine which method of bedside whole blood glucose screening was the more accurate: visually read Chemstrip bG reagent strips or the One Touch II meter method. The values obtained were compared with lab analysis of serum glucose, and a correlation study was performed to compare the accuracy and reliability of the values produced by the two methods. One hundred samples were obtained from 38 NICU infants; 63 percent of the 100 samples were compared with lab values. Results revealed that the One Touch II method was more reliable (r = .92) than the Chemstrip bG method (r = .87). Furthermore, the One Touch II results correlated better with lab values when the meter was not operated in the neonatal mode. This study revealed that the One Touch II method appears to provide safe and accurate screening of bedside blood glucose in a high-risk neonatal population.

Blood Glucose↗
PubMed1997

A study of the effects of exposure on cleanup workers at the Chernobyl nuclear reactor accident using multiple end points.

Blood samples were collected from 192 exposed workers who participated in the cleanup after the April 26, 1986, nuclear reactor accident at Chernobyl, Ukraine. These samples, together with samples from 73 individuals living in Russia but not involved in Chernobyl cleanup activities, were collected during September 1991 to May 1996 and shipped to the U.S. for evaluation by three bioassays: cytogenetic analysis based on chromosome painting, HPRT mutation analysis and glycophorin A (GPA) variant analysis. Univariate statistical analyses of the results of each bioassay (including adjustments for age, smoking status and estimated precision of the bioassay) found greater frequencies of chromosome translocations and HPRT mutant T lymphocytes among the exposed individuals compared to the controls (P < or = 0.01). GPA analyses showed no significant difference for exposed compared to controls for either hemizygous, N/O, or homozygous, N/N, variant cell frequency. Multivariate analysis of variance of the subset of 44 exposed and 14 unexposed individuals with measurements from all three bioassays found elevated frequencies of chromosomal translocations and HPRT mutants, and reduced frequencies for both GPA end points among the exposed persons compared to the controls. However, none of these differences, considered singly or in combination, was statistically significant (although statistical power is low due to small sample sizes). Mean estimated dose, based on cytogenetic response, for those exposed was 9 cGy (range 0 to 51 cGy) and was less than that estimated by physical dosimetry (25 cGy). Correlation between the end points of the bioassays and estimated physical dosimetry was low (r < 0.2); the only significant correlation found was for physical dose estimate and dates worked at Chernobyl (r = 0.4, P < 0.01), with those working soon after the accident receiving greater estimated doses.

Adolescent↗
PubMed1996

Hepatocyte growth factor (HGF)/NK1 is a naturally occurring HGF/scatter factor variant with partial agonist/antagonist activity.

Hepatocyte growth factor/scatter factor (HGF/SF) stimulates cell proliferation, motility, and morphogenesis by activation of its receptor, the c-Met tyrosine kinase. HGF/SF is structurally related to plasminogen, including an amino-terminal hairpin loop, four kringle domains, and a serine protease-like region. A truncated HGF/SF isoform, designated HGF/NK2, which extends through the second kringle domain and behaves as a competitive HGF/SF antagonist, was previously shown to be encoded by an alternative HGF/SF transcript. In this study, we describe a second naturally occurring HGF/SF variant, HGF/NK1, consisting of the HGF/SF amino-terminal sequence and first kringle domain. This product is encoded by a 2-kilobase alternative transcript containing intronic sequence that was contiguous with exon K1b. Analysis of baculovirus-expressed HGF/NK1 revealed that this isoform possesses the heparin binding properties of HGF/SF and modest mitogenic and scattering activity relative to HGF/SF. However, at a 40-fold molar excess, HGF/NK1 inhibited HGF/SF-dependent DNA synthesis. HGF/NK1 stimulated tyrosine phosphorylation of Met, and covalent affinity cross-linking demonstrated a direct HGF/NK1-receptor interaction. These findings establish that the HGF/SF gene encodes multiple alternative products, which include not only a mitogenic agonist (HGF/SF) and a pure antagonist (HGF/NK2) but also a molecule with partial agonist/antagonist properties.

Amino Acid Sequence↗
PubMed1996

Decreased pain detection and tolerance thresholds in chronic tension-type headache.

OBJECTIVE: To study nociceptive processing in patients with chronic tension-type headache. METHODS: Forty patients with chronic tension-type headache and 40 healthy controls were examined. Pericranial tenderness was recorded by manual palpation, pressure pain detection and tolerance thresholds were recorded with an electronic pressure algometer, and the relative (pain detection minus sensory detection) electrical pain threshold was recorded with a constant current stimulator. RESULTS: Patients were considerably more tender than controls at all the locations examined by manual palpation (P<.001). Pressure pain detection and tolerance thresholds recorded in the finger were significantly lower in patients than in controls (P<.001). A nonsignificant similar trend was observed in the temple (P < or =.12). Detection and tolerance thresholds were decreased to a similar degree in patients compared with controls, and pain thresholds recorded in the finger and in the temple were highly correlated (r=.84, P<.001). The relative electrical pain threshold recorded at the labial commissure was significantly decreased in patients compared with controls (P=.03). All of the examined pain thresholds were significantly correlated to the pericranial tenderness recorded by palpation (r=-.35 to -.53, P < or = .03). CONCLUSION: The present finding of a general hypersensitivity to pain stimuli in chronic tension-type headache indicates that central factors play an important role in the pathogenesis of this disorder.

Adult↗
PubMed1996

A comparison of tension-type headache in migraineurs and in non-migraineurs: a population-based study.

The prevalence, sex-ratio and clinical characteristics of tension-type headache were analyzed in 4000 people from the general population. The one-year-period prevalence of tension-type headache was not significantly different in people with migraine without aura (83%), in people with migraine with aura (75%) and in people who had never had migraine (76%). The male/female ratio varied from 1:1.19 to 1:1.23 and was not significantly different in the three subgroups. Tension-type headache was significantly more frequent within the last year and lasted longer in migraineurs than in people who had never had migraine. The pain characteristics and accompanying symptoms were very similar in the three subgroups. Tension-type headache was often precipitated by stress, mental tension and tiredness. Only migraineurs had episodes of tension-type headache precipitated by alcohol, over-matured cheese, chocolate and physical activity. We conclude that tension-type headache and migraine are separate disorders and not part of a continuum of headache disorders. However, migraine may aggravate and precipitate tension-type headache possibly due to convergence of various noxious peripheral input into the trigeminal nucleus.

Adult↗
PubMed1996

Muscular disorders in tension-type headache.

In order to evaluate the diagnostic criteria for muscular disorders in tension-type headache, pericranial muscle tenderness and pressure pain thresholds were studied in a random sample population of 735 adults aged 25-64. In addition, quantitative EMGs were recorded in 547 of these subjects. The correlation between the three diagnostic tests was assessed and the discriminality and cut-off points were analysed using Receiver Operating Characteristics analysis. Local tenderness from the temporal muscles was closely related to the total tenderness scores from 14 pairs of muscles. In chronic tension-type headache, tenderness was positively related to EMG and inversely related to pain thresholds. In the episodic from the total tenderness score was inversely related to pain thresholds, whereas no significant relation to EMG was noted. The Receiver Operating Characteristics curves indicated that tenderness recorded by manual palpation was the most specific and sensitive test, whereas EMG and pain thresholds were of limited diagnostic value. Eighty-seven percent of subjects with the chronic, and 66% of subjects with the episodic form were found to have a "muscular disorder" defined as increased tenderness recorded by either manual palpation or pressure algometry and/or increased EMG levels. However, muscle tenderness increased significantly during pain, so the headache state should be considered in future studies. Suggestions for revision of the present diagnostic criteria for muscular disorders are given.

Adult↗
PubMed1996

Initiating mechanisms of experimentally induced tension-type headache.

To elucidate possible myofascial mechanisms of tension-type headache, the effect of 30 min of sustained tooth clenching (10% of maximal EMG-signal) was studied in 58 patients with tension-type headache and in 30 age- and sex-matched controls. Pericranial tenderness, mechanical and thermal pain detection and tolerance thresholds and EMG levels were recorded before and after the clenching procedure. Within 24 h, 69% of patients and 17% of controls developed a tension-type headache. Shortly after clenching, tenderness was increased in the group who subsequently developed headache, whereas tenderness was stable in the group of patients who remained headache free. Mechanical pain thresholds evaluated by pressure algometry remained unchanged in the group which developed headache, whereas thresholds increased in the group which did not develop headache. Thermal pain detection and tolerance thresholds remained unchanged in both groups. These findings indicate that, although there may be several different mechanisms of tension-type headache, one of them is sustained muscle contraction. A peripheral mechanism of tension-type headache is therefore possible, whereas a secondary segmental central sensitization seems to be involved in subjects with frequent tension-type headache. Finally, the increase in pressure pain thresholds in patients who did not develop headache suggested that clenching activated their antinociceptive system, whereas those developing headache were unable to do so.

Adult↗
PubMed1996

Exteroceptive suppression of temporal muscle activity is normal in chronic tension-type headache and not related to actual headache state.

The aim of the present study was to compare the late exteroceptive suppression period (ES2) of temporalis muscle activity between patients with chronic tension-type headache and healthy controls, and to investigate the influence, if any, of actual headache on ES2. ES2 was recorded in 55 patients and in 55 controls with a previously evaluated methodology and analysed by a blinded observer. The first 20 patients were randomly studied on 2 additional days, 1 day with and 1 day without headache. The duration of ES2 did not differ between patients and controls and did not differ on days with headache compared with days without headache. ES2 duration was not related to the frequency of headache, headache intensity, age, pericranial muscle tenderness or electrical pain threshold. Our results strongly indicate that ES2 is normal in chronic tension-type headache and therefore may not be related to the pathophysiology of this disorder.

Adult↗
PubMed1996

A non-selective (amitriptyline), but not a selective (citalopram), serotonin reuptake inhibitor is effective in the prophylactic treatment of chronic tension-type headache.

OBJECTIVES: Although the tricyclic antidepressant amitriptyline is extensively used in the prophylactic treatment of chronic tension-type headache, only few studies have investigated the efficacy of this treatment and the results are contradictory. In addition, the new selective serotonin reuptake inhibiting antidepressants, which are widely used in depression and of potential value in pain management, have never been investigated in a placebo controlled study of tension-type headache. The aim was to evaluate the efficacy of amitriptyline and of the selective serotonin reuptake inhibitor citalopram in chronic tension-type headache. METHODS: Forty non-depressed patients with chronic tension type headache were included in a 32 week, double blind, placebo controlled, three-way crossover study. RESULTS: Thirty four patients completed the trial. Amitriptyline reduced area under the headache curve by 30% compared with placebo (P = 0.002), whereas citalopram had no significant effect (P = 0.68). Explanatory analyses showed that amitriptyline significantly reduced the duration of headache (P = 0.01), headache frequency (P = 0.01), and intake of analgesics (P = 0.02) but not headache intensity (P = 0.12). CONCLUSION: Although amitriptyline did not eliminate the headache, it provided a clinically important reduction of headache in the majority of otherwise treatment resistant patients. The differential effect of amitriptyline and citalopram indicates that mechanisms other than inhibition of serotonin reuptake are involved in the analgesic effect of the tricyclic antidepressants. Amitriptyline, but not citalopram, is valuable in the prophylactic treatment of chronic tension type headache.

Adolescent↗
PubMed1996

Amitriptyline, a combined serotonin and noradrenaline re-uptake inhibitor, reduces exteroceptive suppression of temporal muscle activity in patients with chronic tension-type headache.

Although reflexes in human jaw muscles have been extensively studied, the neurotransmitters involved in the regulation of these reflexes are not well known. The aim of the present study was to investigate whether amitriptyline, a combined serotonin and noradrenaline re-uptake inhibitor, modulates the late exteroceptive suppression period (ES2) of temporal muscle activity in chronic tension-type headache. ES2 was recorded with a previously evaluated method and assessed by a blinded observer in 35 patients with chronic tension-type headache. Thereafter, ES2 was recorded in 27 of these patients during a double-blind, placebo-controlled, 3-way crossover trial investigating the prophylactic effect of amitriptyline, the selective serotonin re-uptake inhibitor citalopram, and placebo. ES2 duration was significantly shorter during treatment with amitriptyline than during placebo, P = 0.02, while ES2 duration only tended to be shorter during treatment with citalopram, P = 0.34. ES2 was not significantly correlated to the prophylactic effect of amitriptyline or to a range of clinical and experimental pain parameters. Our results demonstrate that amitriptyline reduces ES2 and indicate that ES2 is modulated by serotonergic as well as noradrenergic neuronal pathways.

Adult↗
PubMed1995

Colour Doppler flow imaging ultrasonography versus venography as screening method for asymptomatic postoperative deep venous thrombosis.

OBJECTIVE: To evaluate colour Doppler flow imaging ultrasonography (CDFI), compared with venography, as a screening method for postoperative deep venous thrombosis (DVT) in a clinical trial on thromboprophylaxis. METHODS: Patients undergoing major abdominal or thoracic surgery were prospectively screened for DVT by CDFI. Patients were examined preoperatively, and on post-operative days 1, 3, 7, 14, 21, and 28. When the CDFI was positive venography was performed. Bilateral venography was performed on day 28 in all patients. The study group comprised 82 patients who underwent CDFI and venography on the same day: four because of suspected DVT (positive CDFI), and 78 on day 28 according to protocol. RESULTS: DVT was detected by venography in seven patients, in three of whom CDFI was positive. CDFI was falsely positive in one case. There were two popliteal and five calf DVTs, of which CDFI detected one and two, respectively. The sensitivity of CDFI was 43%, the specificity 99%. The PVpos for CDFI was 75%, and the PVneg 96%. CONCLUSION: Due to low sensitivity, CDFI cannot stand alone as a screening method for asymptomatic postoperative DVT.

Abdomen↗
PubMed1995

Pressure-controlled palpation: a new technique which increases the reliability of manual palpation.

The objective of the present study was to investigate whether the reliability of tenderness evaluation can be increased by using a new technique called "pressure-controlled palpation" (pcp). The technique has been made possible by a newly invented piece of equipment called a palpometer, with which a pressure-sensitive plastic film attached to the index finger records the pressure exerted. In 15 patients with chronic tension-type headache and in 15 healthy volunteers, 2 investigators studied myofascial tenderness using conventional palpation and pressure-controlled palpation. Tenderness was scored on a 4-point scale in each of the examined pericranial regions. The sum of tenderness scores recorded by two observers using conventional palpation differed significantly (p = 0.0003), while results did not differ between observers using pressure-controlled palpation (p = 0.89). During palpation with seven different pressure intensities a positive and linear relation between pressure and pain intensity was found (p = 0.00006). Pain intensity reported by the subjects correlated highly with tenderness scored by the observer (rs = 0.95, p < 0.0001). These results demonstrate for the first time that tenderness scores can be compared between observers if palpation pressure is controlled. Pressure-controlled palpation represents a major improvement on current palpation techniques and should be standard in future research on myofascial pain disorders.

Adult↗
PubMed1994

Automatic fluorescence metaphase finder speeds translocation scoring in FISH painted chromosomes.

A fluorescence metaphase finder was constructed with commercially available hardware and a standard Unix workstation. Its accuracy was measured in terms of the number of false positive and false negative detected metaphases on a variety of different slide preparations. The metaphase finder was used in a translocation scoring experiment in which metaphase preparations of human peripheral blood lymphocytes were hybridized with whole chromosome probes to chromosomes #1, #2, and #4. The automatic finder presented metaphases to the cytogeneticist, centered in the eyepieces at x63. The cytogeneticist's scores of analyzable metaphases and of painted chromosomes involved in rearrangements were recorded. The time for the analysis was recorded and compared to the time to analyze a similar number of cells in a purely visual experiment in which the cytogeneticist scanned for cells and analyzed them, both at x63. The results showed that, neglecting the machine time spent scanning unattended, the amount of time required for the analysis was reduced by a factor of three. Furthermore, in this experiment the metaphase finder found more scorable metaphases than the cytogeneticist found by visual scanning. Machine-assisted scoring had additional, less quantifiable, benefits; notably that digital images of metaphases sometimes assisted the analysis of chromosome rearrangements, that cells could be revisited easily, and that the analysis was much less fatiguing.

Cytogenetics↗