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PubMed1997

[Are low back pain and radiological changes during puberty risk factors for low back pain in adult age? A 25-year prospective cohort study of 640 school children].

Recent reports have stated that low back pain (LBP) among children is a common problem comparable with that in adults. This 25-year prospective cohort study confirms that 11% of the cohort have had a history of LBP in adolescence with an 84% lifetime prevalence of LBP in these subjects as adults compared with 70% in the rest of the cohort. LBP was associated with increased morbidity and decreased working capacity. Thirteen percent of the cohort had radiological abnormalities, mainly Scheuermann changes, in the thoracic and lumbar spine as adolescents, with no positive correlation to LBP in this period. Unlike other reports our results did not show any association between X-ray changes in the lower spine in adolescents and a higher prevalence of LBP in adults. Stepwise logistic regression analyses showed that LBP in the growth period and familial occurrence of back disease are important risk factors for LBP later in life, with an observed probability of 88% if both factors are present. Preventive measures in the school period seem to be of great importance.

Adolescent↗
PubMed1996

Back-to-back "one-pot" [18F]FDG syntheses in a single Siemens-CTI chemistry process control unit.

Simple changes in the chemistry, plumbing, and programming of the Siemens-CTI chemistry process control unit (CPCU) effectively double its output by enabling two back-to-back "1-pot" syntheses of 2-[18F]fluoro-2-deoxy-D-glucose in a single unit. Replacement of Kryptofix 2.2.2 with tetramethylammonium carbonate and elimination of diethyl ether from the procedure shorten synthesis time to 48 min, improve process and end-product safety, and increase end-of-synthesis yields from 37% to 52% by minimizing steps and transfer losses.

Animals↗
PubMed1997

Colonoscopic miss rates of adenomas determined by back-to-back colonoscopies.

BACKGROUND & AIMS: The miss rate of colonoscopy for neoplasms is poorly understood. The aim of this study was to determine the miss rate of colonoscopy by same day back-to-back colonoscopy. METHODS: Two consecutive same day colonoscopies were performed in 183 patients. The patients were randomized to undergo the second colonoscopy by the same or a different endoscopist and in the same or different position. RESULTS: The overall miss rate for adenomas was 24%, 27% for adenomas < or = 5 mm, 13% for adenomas 6-9 mm, and 6% for adenomas > or = 1 cm. Patients with two or more adenomas at the first examination were more likely than patients with no or one adenoma detected at the first examination to have one or more adenomas at the second examination (odds ratio, 3.3; 95% confidence interval, 1.69-6.46). Right colon adenomas were missed more often (27%) than left colon adenomas (21%), but the difference was not significant. There was evidence of variation in sensitivity between endoscopists, but significant miss rates for small adenomas were found among essentially all endoscopists. CONCLUSIONS: Using current colonoscopic technology, there are significant miss rates for adenomas < 1 cm even with meticulous colonoscopy. Miss rates are low for adenomas > or = 1 cm. The results suggest the need for improvements in colonoscopic technology.

Adenoma↗
PubMed1998

Leuprolide acetate depot and hormonal add-back in endometriosis: a 12-month study. Lupron Add-Back Study Group.

OBJECTIVE: To evaluate the efficacy and safety of a GnRH agonist, leuprolide acetate depot, alone and in combination with three hormonal add-back regimens in the management of endometriosis-associated pelvic pain. METHODS: Two hundred and one patients were enrolled in this multicenter, randomized, double-blind, 1-year trial. All patients were given an intramuscular injection of leuprolide acetate depot 3.75 mg every 4 weeks. Patients were assigned to one of four treatment groups: Group A received placebos for progestin and estrogen, group B received norethindrone acetate 5 mg daily and placebo for estrogen, group C received norethindrone acetate 5 mg and conjugated equine estrogens 0.625 mg daily, and group D received norethindrone acetate 5 mg and conjugated equine estrogens 1.25 mg daily. Pelvic pain scores were assessed monthly, and bone density was measured after 24 and 52 weeks. RESULTS: By week 8, all four groups showed significant improvement in pelvic pain scores compared with baseline levels. A higher proportion of group D patients terminated the study prematurely due to a lack of improvement in symptoms. Group A experienced a 6.3 +/- 2.3% (P < or = .001) loss in bone density after 52 weeks of treatment, whereas bone density was preserved in all three add-back groups. CONCLUSION: The use of leuprolide acetate depot in combination with norethindrone acetate 5 mg alone, or with norethindrone acetate and conjugated equine estrogens 0.625 mg, provides effective suppression of pelvic pain symptoms associated with endometriosis while protecting against bone loss.

Adult↗
PubMed2004

Mononuclear and binuclear wirelike ruthenium(II) complexes with oligo-diethynyl-thiophene bridged back-to-back terpyridine ligands: synthesis and electrochemical and photophysical properties.

The syntheses, structural features, electrochemical behavior, absorption spectra, and photophysical properties of five mononuclear complexes [(terpy)Ru(terpy-DEDBT(n)-terpy)](2+), RuT(n), and five binuclear complexes [(terpy)Ru(terpy-DEDBT(n)-terpy)Ru(terpy)](4+), RuT(n)Ru, are reported, where n varies from 1 to 5 so that the metal-metal distance is estimated to be 42 A for the largest binuclear complex, RuT(5)Ru (terpy is 2,2':6',2"-terpyridine and DEDBT is 2,5-diethynyl-3,4-dibutylthiophene). The metal-centered oxidation potentials for the mononuclear and binuclear species are slightly more positive than for the reference [Ru(terpy)(2)](2+) complex, owing to the withdrawing nature of the back-to-back terpyridine ligands incorporating the repeat diethynyl-thiophene units. Comparison of the reduction potentials for the mononuclear and binuclear complexes reveals that the reduction steps are localized either at the terpy fragments of the T(n) ligands or at the terpy peripheral ligands. The spectroscopic results (absorption spectra at room temperature, luminescence spectra and lifetimes at room temperature and at 77 K) in acetonitrile solvent are consistent with the establishment of electronic delocalization within the oligomeric diethynyl-thiophene fragments (DEDBT(n)) of the T(n) ligands; however, the results also indicate that the terpy units of these ligands and the DEDBT(n)fragments are not strongly coupled. Both at room temperature and at 77 K, the (3)metal-to-ligand charge-transfer luminescence of RuT(n) and RuT(n)Ru complexes is strongly depressed in the larger species with respect to what happens for n < or = 2 (where the luminescence quantum yield is phi approximately 10(-4)); this is discussed in terms of the possible intervention of triplet levels localized at the oligothiophene DEDBT(n)(fragments.

Journal Article↗
PubMed2005

Synthesis and complexation of "back-to-back" capped bis-dioxocyclams.

Pyridine-capped 5,12-dioxocyclams were coupled "back-to-back" directly, with one or two intervening phenyl groups, an ethynyl group, or a diazo group via Suzuki, Sonogashira, or reductive coupling of the 4-nitropyridine monocyclam. These bis-dioxocyclams linked through extended pi-conjugated systems were complexed to copper(II) and cobalt(III), producing bis-metal complexes which were characterized spectroscopically and electrochemically. These studies gave little evidence for electronic communication between metal centers across the pi-conjugated linkers.

Copper↗
PubMed1998

Executive function in treated phenylketonuria as measured by the one-back and two-back versions of the continuous performance test.

The executive dysfunction hypothesis in treated phenylketonuria was investigated by means of the one-back and two-back versions of the continuous performance test. Eleven non-retarded, primary school-age children with classical phenylketonuria who had been treated early and continuously were indistinguishable from healthy, matched controls on the measures and test performance was not predicted by historical or concurrent plasma phenylalanine concentrations. Mean lifetime phenylalanine concentrations for the phenylketonuric subjects were within ranges currently recommended as dietary optima in the United Kingdom. The negative neuropsychological test findings add weight to the rationale for this policy.

Child, Preschool↗
PubMed2003

Back-to-back correlations of high-p(T) hadrons in relativistic heavy-ion collisions.

We investigate the suppression factor and the azimuthal correlation function for high p(T) hadrons in central Au+Au collisions at sqrt[s(NN)]=200 GeV by using a dynamical model in which hydrodynamics is combined with explicitly traveling jets. We study the effects of parton energy loss in a hot medium, intrinsic k(T) of partons in a nucleus, and p (perpendicular) broadening of jets on the back-to-back correlations of high p(T) hadrons. Parton energy loss is found to be a dominant effect on the reduction of the awayside peaks in the correlation function.

Journal Article↗
PubMed2003

Wide angle colonoscopy with a prototype instrument: impact on miss rates and efficiency as determined by back-to-back colonoscopies.

OBJECTIVE: Polyps are missed during conventional colonoscopy, even with meticulous technique. The aim of this study was to investigate whether a prototype wide angle colonoscope is associated with a reduced miss rate for polyps. METHODS: Two studies were performed. In study 1, a total of 50 patients underwent back-to-back, same-day colonoscopy by a single examiner with the prototype wide angle colonoscope and with a standard colonoscope, with the order of scopes randomized. In study 1, an attempt was made to keep examination time with the two colonoscopes equal. In study 2, a total of 20 patients were examined, 10 by the same colonoscopist who performed study 1 and 10 by a second colonoscopist. In study 2, examiners tried to perform the examinations as quickly as accuracy would allow. RESULTS: In study 1, the miss rate for all polyps was lower with the wide angle colonoscope (20% vs 31%; p = 0.046), although the mean examination time with the wide angle instrument was shorter (6.75 min vs 7.64 min; p = 0.0005). There was no significant difference in detection of adenomas. Polyps, including adenomas, were missed in the peripheral endoscopic field more frequently with the standard colonoscope. In study 2, wide angle colonoscopy was associated with reductions in examination time of 25% and 30% for the two examiners, respectively. Miss rates were the same for one colonoscopist but were higher for the other colonoscopist when the wide angle instrument was used. CONCLUSION: A prototype wide angle colonoscope did not eliminate polyp miss rates. Wide angle colonoscopy has the potential to reduce examination time and improve visualization of the periphery of the endoscopic field of view, but improvements in resolution are needed.

Adult↗
PubMed2005

The role of high-magnification-chromoscopic colonoscopy in hereditary nonpolyposis colorectal cancer screening: a prospective "back-to-back" endoscopic study.

BACKGROUND: In hereditary nonpolyposis colorectal cancer flat and diminutive adenomas occur, particularly in the right colon. Such lesions may assume a high risk of malignant transformation. Interval cancers are known to occur in this group. Chromoscopic colonoscopy enhances detection in patients assuming a moderate to high lifetime risk of colorectal cancer. AIM: To prospectively assess the efficacy of high-magnification-chromoscopic colonoscopy for the detection of neoplastic lesions in patients undergoing hereditary nonpolyposis colorectal cancer screening. METHODS: Twenty-five asymptomatic patients fulfilling modified Amsterdam criteria underwent "back-to-back" colonoscopy. Conventional colonoscopy with targeted chromoscopy was performed initially followed by pan-colonic chromoscopic colonoscopy. Diagnostic extubation times and volumes of normal saline and indigo carmine (IC) were controlled. RESULTS: Using conventional colonoscopy and targeted chromoscopy 24 lesions were detected in 13 patients (20 exophytic/4 flat). Pan-colonic chromoscopy identified a further 52 lesions in 16 patients (17 exophytic/35 flat). Pan-chromoscopy identified significantly more adenomas than conventional colonoscopy (p= 0.001) and a significantly high number of flat adenomas (p= 0.004). CONCLUSIONS: Pan-colonic chromoscopic colonoscopy improves detection of significant neoplastic lesions in hereditary nonpolyposis colorectal cancer screening. Pan-chromoscopy may help better stratify colorectal cancer "risk" in this cohort and aid planning of surveillance colonoscopic follow-up.

Adult↗
PubMed2001

Evaluation of the EMG activity of the long back muscle during induced back movements at stance.

In this study we investigated the activity of the main back muscle (Musculus longissimus) by surface electromyography (EMG) during induced extension and lateral flexion at stance. Measurements were taken of 15 horses (age 5-20 years, 450-700 kg bwt) without signs of back pain. Reflecting markers were placed on the head, spinous processes of T5, T12, T16, L3 and on 2 of the sacral bones. The surface EMG electrodes were situated on the Musculus longissimus on both sides of the dorsal spinous processes of T12, T16 and L3. In all horses and all movements (extension, lateral flexion to the left and right), the EMG on both sides of the dorsal spinous process of T12 had the highest, and the EMG on both sides of the spinous process of L3, the lowest amplitude (30% of T12). At T16 the amplitude of the EMG signal was 60% of that at T12. There was no time shift between the EMG signals at the different locations (T12, T16, L3). There was a very high correlation between motion and amplitude of the EMG signal of extension, with correlation coefficients of 0.78 at L3, 0.80 at T16 and 0.75 at T12. The correlation of the lateral flexion between amplitude of the EMG and motion was lower, with 0.38 at L3, 0.43 at T16 and 0.39 at T12. This investigation showed that the EMG of the Musculus longissimus during spinal reflexes should be derived on both sides of T12, because this is important for the clinical use of surface EMG.

Animals↗
PubMed1985

A back-to-back zig-zag model for higher order chromatin structure.

The evidence for the next level of chromatin structure above the 'zig-zag' is examined and a system of large, uncoiled, 'hair-pin' loops, folded until the zig-zags are back to back, is proposed as being more compatible with the evidence than coiling models. The loop model suggests a simple way for the base sequences on the DNA to control the higher order folding of chromatin, and is also strongly suggestive of a simple mechanism ensuring homologous alignment of nucleofilaments at synapse.

Animals↗
PubMed2005

Effects of chronic low back pain on trunk coordination and back muscle activity during walking: changes in motor control.

Low back pain (LBP) is often accompanied by changes in gait, such as a decreased (preferred) walking velocity. Previous studies have shown that LBP diminishes the normal velocity-induced transverse counter-rotation between thorax and pelvis, and that it globally affects mean erector spinae (ES) activity. The exact nature and causation of these effects, however, are not well understood. The aim of the present study was to examine in detail the effect of walking velocity on global trunk coordination and ES activity as well as their variability to gain further insights into the effects of non-specific LBP on gait. The study included 19 individuals with non-specific LBP and 14 healthy controls. Gait kinematics and ES activity were recorded during treadmill walking at (1) a self-selected (comfortable) velocity, and (2) sequentially increased velocities from 1.4 up to maximally 7.0 km/h. Pain intensity, fear of movement and disability were measured before the experiment. The angular movements of thorax, lumbar and pelvis were recorded in three dimensions. ES activity was recorded with pairs of surface electrodes. Trunk-pelvis coordination and mean amplitude of ES activity were analyzed. In addition, invariant and variant properties of trunk kinematics and ES activity were studied using principal component analysis (PCA). Comfortable walking velocity was significantly lower in the LBP participants. In the transverse plane, the normal velocity-induced change in pelvis-thorax coordination from more in-phase to more antiphase was diminished in the LBP participants, while lumbar and pelvis rotations were more in-phase compared to the control group. In the frontal plane, intersegmental timing was more variable in the LBP than in the control participants, with additional irregular movements of the thorax. Rotational amplitudes were not significantly different between the LBP and control participants. In the LBP participants, the pattern of ES activity was affected in terms of increased (residual) variability, timing deficits, amplitude modifications and frequency changes. The gait of the LBP participants was characterized by a more rigid and less variable kinematic coordination in the transverse plane, and a less tight and more variable coordination in the frontal plane, accompanied by poorly coordinated activity of the lumbar ES. Pain intensity, fear of movement and disability were all unrelated to the observed changes in coordination, suggesting that the observed changes in trunk coordination and ES activity were a direct consequence of LBP per se. Clinically, the results imply that conservative therapy should consider gait training as well as exercises aimed at improving both intersegmental and muscle coordination.

Adult↗
PubMed1996

The gap between back pain patients' prior knowledge and scientific knowledge and its evolution after a back school teaching programme: a quantitative evaluation.

This study presents a method for quantitative evaluation of the congruence between patients' representations and teachers' scientific knowledge, which is used as the standard of assessment. First, the patients' knowledge and the teachers' scientific concepts before a back school (BS) programme were compared (T0). Then the evolution of patients' knowledge at 1 month (T1) and 1 year (T2) after the teaching was evaluated. Patients' knowledge was assessed blind by a multidisciplinary panel of nine independent judges. Mean scores were computed for each set of data (T0,T1,T2); these scores were then submitted to an analysis of variance. The results showed an important gap between patients and teachers before BS with an improvement after the teaching. Knowledge referring to know-how and/or attitudes evolved differently when compared to theoretical knowledge.

Adolescent↗
PubMedDate not supplied

The Nordic back pain subpopulation program: can patient reactions to the first chiropractic treatment predict early favorable treatment outcome in nonpersistent low back pain?

OBJECTIVE: To investigate whether 3 distinct patterns of reactions to chiropractic care can predict early favorable treatment outcome in patients with nonpersistent low back pain (LBP). DESIGN: Multicenter practice-based predictive validity study. STUDY SUBJECTS: Sixty private practice chiropractors in Sweden recruited a maximum of 20 consecutive patients with LBP each, with a duration of less than 2 weeks at the time of consultation and a maximum of 30 days totally over the past year. METHODS: Chiropractic management was decided on by the treating chiropractor. The outcome variable was self-reported "definite improvement" at the fourth visit. The predictor variables included 3 hypothesized prognostic groups (best, intermediate, and least favorable) on the basis of clinical information collected at baseline and at the second visit. The covariates included age, sex, pain intensity during the past 24 hours, description of disability, duration and pattern of pain during the present attack, and duration and pattern of pain during the past 12 months. The 3 predictor groups were cross-tabulated against the outcome variable and the other covariates. Backward stepwise logistic regression was performed to test for confounding or modification from relevant covariates. RESULTS: Information was provided on 708 patients, of which 674 questionnaires were valid. Of the 223 patients in the hypothesized best prognostic group, 91% (95% CI, 79-100) reported to be "definitely improved" by the fourth visit, vs 76% (72-80) of the 420 patients in the intermediate prognostic group, and 36% (19-53) of the 31 patients in the least favorable prognostic group. These results were not altered after controlling for the covariates. CONCLUSION: For chiropractic patients with nonpersistent LBP, these findings show that it is possible to predict already by the second visit which patients may or may not report improvement at the fourth visit.

Adult↗
PubMedDate not supplied

The Nordic Back Pain Subpopulation Program: validation and improvement of a predictive model for treatment outcome in patients with low back pain receiving chiropractic treatment.

OBJECTIVE: The aim of this study was to develop a predictive model for treatment outcome in patients with low back pain (LBP) receiving chiropractic treatment. METHODS: This multicenter practice-based predictive validity study was conducted in private chiropractic practices in Sweden. Of 64 previously compliant chiropractors, 58 recruited a maximum of 30 consecutive patients with LBP each. Information was provided on 1061 patients, of which 1057 questionnaires were valid. Chiropractic treatment was decided by the treating chiropractor. The outcome variable was the self-reported "definite improvement" at the fourth visit. The predictor variables included model 1, 3 hypothesized prognostic groups (best, intermediate, and least favorable) based on clinical information collected at baseline and at the second visit; and 4 additional models based on the following variables: age, sex, pain intensity during past 24 hours, description of disability, duration and pattern of pain during present attack, total duration of pain, and pain pattern during the past 12 months. RESULTS: Three of our factors were best at predicting the absence of improvement by the fourth visit and were able to correctly classify 79% of patients and to cover 74% of the receiver operated characteristics curve. These were (1) no definite overall improvement by the second treatment, (2) presence of leg pain, and (3) the minimum total duration of pain over the last 12 months being 30 days. CONCLUSION: In this study, patients with LBP who also had leg pain and LBP occurring sufficiently frequently or having lasted sufficiently long to add up to at least 30 days in the past year, and who did not report definite general improvement by the second treatment were not good candidates for short-term recovery. It is suggested that patients who fit the criteria of potential nonresponders should be carefully monitored to allow a selective approach of care.

Adult↗
PubMed2005

The Nordic back pain subpopulation program: the long-term outcome pattern in patients with low back pain treated by chiropractors in Sweden.

OBJECTIVES: (1) To describe the low back pain (LBP) pattern at baseline; (2) to describe the long-term outcome pattern; (3) to investigate the presence of distinct subgroups in relation to outcome; (4) to establish whether short-term outcome is a predictor of long-term outcome. METHODS: A 3- to 6- and 12- to 18-month, multicenter practice-based, prospective descriptive study was performed in private chiropractic practices in Sweden. Fifty-eight of 64 previously compliant chiropractors each recruited a maximum of 30 consecutive patients with LBP. Complete baseline clinical information was provided on 1054 patients, of which 93% were interviewed approximately 3 months later, and 57% responded to a questionnaire at approximately 12 months. Chiropractic treatment was decided by the treating chiropractor. Twelve descriptive subgroups were created based on (1) duration of LBP at baseline, (2) duration of LBP in the past year, and (3) LBP pattern in the past year. The predictive value was tested for outcome status at the fourth visit. Information on self-reported LBP status and improvement over the past months were collected. RESULTS: Patients were spread in a U-shaped fashion from benign to severe with the 2 extreme groups being most prevalent. About half the participants reported "no LBP in the past week" at 3 months and somewhat fewer at 12 months. Almost 75% claimed to be definitely better at 3 months, and approximately 50% at 12 months. Specific predictive subgroups can be identified, mainly in relation to the past-year history of LBP. Improvement at the fourth visit is a predictor of long-term outcome. CONCLUSION: Knowledge of specific subgroups may improve the quality of care and the selection of homogeneous study populations in clinical trials.

Adult↗
PubMed2005

Are difficulties perceiving and expressing emotions associated with low-back pain? The relationship between lack of emotional awareness (alexithymia) and 12-month prevalence of low-back pain in 1180 urban public transit operators.

OBJECTIVE: To assess the association of alexithymia (deficit in emotional awareness) with 12-month prevalence of low back pain (LBP) cross-sectionally in a cohort study of 1180 San Francisco transit operators. METHODS: Alexithymia was measured by the Toronto Alexithymia Scale (TAS-20). LBP was assessed in medical histories during drivers relicensing exams. Multivariate logistic regression analyses controlled for demographic, behavioral (smoking, alcohol, coping style), and physical and psychosocial job factors measured by questionnaire and interview. RESULTS: Of all the drivers, 31.4% suffered from LBP. Scoring in the upper quartile of alexithymia summary scores was associated with twofold higher odds of LBP (adjusted odds ratio=2.00, 95% confidence interval: 1.31-3.00). The association was stronger in women (adj. OR=4.35) than in men (adj. OR=1.83). The factor "difficulty identifying feelings" showed the strongest association with LBP (adj. OR=2.23). CONCLUSION: The results support an association between alexithymia and LBP.

Adaptation, Psychological↗