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PubMed2002

Comparing injuries of spin bowling with fast bowling in young cricketers.

OBJECTIVE: To compare the incidence and anatomic distribution of injuries sustained in spin and fast bowling in young cricketers. DESIGN: A prospective cohort study. Physical characteristics and retrospective data (sporting involvement and previous injuries) from young cricketers were recorded. The cohort of young cricketers was divided according to style of bowling into a group of spin bowlers and a group of fast bowlers. Data from the spin bowler group was compared with the data from the fast bowler group to assess whether these groups were matched. A prospective study of injuries sustained by the bowlers was then undertaken. Data regarding cricket played and injuries sustained were collected by telephone questionnaire every 6 weeks for 6 months from each bowler. SETTING: Bowlers were recruited from young cricketers training at Centers of Excellence of 3 "First Class" Counties in England in January 1998. PARTICIPANTS: There were 42 spin bowlers and 70 fast bowlers. The mean age was 14.9 years (range 9 to 21 years). MAIN OUTCOME MEASURES: Injuries caused by bowling and interfering with bowling are included in incidence data. The number of deliveries bowled in matches and practice is used as the denominator for the reported incidence. RESULTS: Telephone follow-up was achieved when planned on 98.2% of occasions. There were 29 injuries meeting the criteria above. The incidence of injury in spin bowlers was 0.066 per 1,000 balls and 0.165 per 1,000 balls in fast bowlers (p = 0.097 Wilcoxon rank sum test). The incidence of injury (per 1,000 balls) at various anatomic sites in fast bowling was knee 0.057, ankle 0.043, low back 0.029, and shoulder 0.007. In spin bowlers, the site incidence was shoulder 0.055 and low back 0.011. The percentage with injuries at ankle, knee, and shoulder was significantly different (95% confidence intervals) for fast and spin bowlers. A significant difference was not found for lower back injuries. CONCLUSIONS: Incidence of injuries in fast bowling is greater than in spin bowling (but this was not a significant difference within the limits of this study). Low back injuries in fast bowlers have been the subject of published research. However, injuries in spin bowling have not previously been described, and this study indicates that shoulder injuries in wrist spinners merit further study.

Adolescent↗
PubMed2004

Randomized comparison of chromic versus fast-absorbing polyglactin 910 for postpartum perineal repair.

OBJECTIVE: We conducted a randomized trial to evaluate the healing characteristics of chromic versus fast-absorbing polyglactin 910. METHODS: Laboring women were randomly assigned to chromic or fast-absorbing polyglactin for perineal repairs. Subjects were evaluated at 24-48 hours, 10-14 days, and 6-8 weeks to assess perineal and uterine pain, analgesic use, presence of residual suture, and wound dehiscence. RESULTS: Between April 2002 and January 2003, 1,361 subjects were randomly assigned. Two thirds of women in each group (459 fast-absorbing polyglactin and 449 chromic) required sutures for perineal repairs. Women were evaluated according to randomization assignment. Overall, 794 (87%) of subjects received the appropriate allocated suture to repair a perineal laceration (399 of 459, 86.9% fast-absorbing polyglactin 910; 395 of 449, 88% chromic catgut). At 24-48 hours, there was a statistically significant reduction in uterine cramping pain (25% versus 34%; P =.006) in subjects randomly assigned to fast-absorbing polyglactin. At 10-14 days, there were no statistically significant differences between the groups. At 6-8 weeks there was, again, a statistically significant reduction in uterine cramping pain (1% versus 4%; P =.017) and a statistically significant decrease in analgesic use (5% versus 10%; P =.048) in subjects randomly assigned to fast-absorbing polyglactin. Finally, at 6-8 weeks postpartum there was no difference in residual suture (2 of 175 versus 2 of 134; P =.802) or wound breakdowns (4 of 175 versus 3 of 134; P =.959) for fast-absorbing polyglactin 910 and chromic catgut, respectively. CONCLUSION: Our data suggest that fast-absorbing polyglactin 910 and chromic elicit similar postpartum perineal discomfort. In contrast to previous studies evaluating standard polyglactin, our trial demonstrated that fast-absorbing polyglactin rarely requires late removal and has a similar wound breakdown profile as compared with chromic. LEVEL OF EVIDENCE: I

Catgut↗
PubMed2006

Fast-track failure after cardiac surgery: development of a prediction model.

OBJECTIVE: Risk factors for unsuccessful fast-tracking of cardiac surgery patients have not been collectively defined in the literature. The aim of this study was to determine risk factors for fast-track failure and incorporate them into a predictive fast-track failure score. DESIGN: Prospective observational study. SETTING: Cardiothoracic Department of St Mary's Hospital, London. PATIENTS: Data were collected from April 2003 to April 2005 including 1,084 patients undergoing heart surgery who were admitted into the fast-track unit. INTERVENTIONS: Multifactorial logistic regression was used to develop a propensity score for estimating the likelihood of fast-track failure. MEASUREMENTS AND MAIN RESULTS: One hundred and sixty-nine patients failed fast-track management (15.6%). Independent predictors for fast-track failure were impaired left ventricular function with or without recent acute coronary syndrome (odds ratios 2.89 and 1.65 respectively), re-do operation (one, two, or more vs. none, odds ratio 1.75, 7.98), extracardiac arteriopathy (odds ratio 2.63), preoperative intra-aortic balloon pump (odds ratio 3.09), raised serum creatinine in micromol/L (120-150, >150 vs. <120, odds ratio 1.57, 11.24), and nonelective (odds ratio 3.43) and complex surgery (odds ratio 2.70). Model validation showed very good discrimination (area under the curve = 0.815) and calibration (ĉ statistic = 8.527, p = .129). CONCLUSIONS: The fast-track failure score incorporates several preoperative factors and has been successfully internally validated; after undergoing external validation and possible recalibration it may be used as a tool to facilitate planning and flow of cardiac surgery patients, based on the predicted probability of failure. Application of this score may limit fast-track failure rates and help to reduce morbidity and cost.

Aged↗
PubMed1997

Fast (mainly 30-100 Hz) oscillations in the cat cerebellothalamic pathway and their synchronization with cortical potentials.

1. Intracellular recordings from 216 thalamocortical (TC) neurones in the ventrolateral (VL) nucleus of intact-cortex and decorticated cats under ketamine-xylazine anaesthesia revealed spontaneously occurring fast oscillations (mainly 30-100 Hz) in 86% of investigated cells. The fast depolarizing events consisted of excitatory postsynaptic potentials (EPSPs), giving rise to fast prepotentials (FPPs) in 22% of neurones, which eventually lead to full-blown action potentials. The frequency of fast events changed by factors of 2-5 in periods as short as 0.3-1.0 s. 2. The spontaneous oscillations were similar to responses evoked in VL relay neurones by stimuli to the afferent cerebellofugal axons in brachium conjunctivum (BC) and were strikingly reduced or abolished after electrolytic lesion of BC axons. 3. The amplitude and duration of fast depolarizing events were significantly reduced during the descending phase of the inhibitory postsynaptic potentials (IPSPs) in TC cells, related to spontaneous spindles or evoked by local thalamic stimulation. 4. Averaged field potentials recorded from motor cortex and triggered by EPSPs and/or action potentials of intracellularly recorded VL cells demonstrated that both spontaneous and BC-evoked fast depolarizations in VL relay neurones were coherent with fast rhythms in cortical area 4. 5. These results show that, in addition to the thalamic and cortical generation sites of the fast (so-called gamma) oscillations, prethalamic relay stations, such as deep cerebellar nuclei, are major contributors to the induction of fast rhythms which depend on the depolarization of thalamic and cortical neurones and which represent a hallmark of brain activation patterns.

Action Potentials↗
PubMed1988

A comparison of fast and slow depolarizations evoked by 5-HT in guinea-pig coeliac ganglion cells in vitro.

1. 5-Hydroxytryptamine (5-HT) was applied by pressure ejection to coeliac ganglion cells of the guinea-pig maintained in vitro and responses measured intracellularly. 2. Cells responded in one of three ways to 5-HT: by (a) a fast, transient depolarization (43%), (b) a fast transient followed by a slow depolarization (biphasic response, 30%) or (c) a slow sustained depolarization (25%). 3. Fast depolarizations (response (a) above] were graded according to the duration of the ejection pulse. Maximal responses had a mean amplitude of 12 +/- 0.8 mV, a duration of 6.4 +/- 1.0 s, a latency of 0.4 +/- 0.1 s, were associated with a fall in membrane input resistance, increased in amplitude by hyperpolarization and probably mediated by an increased conductance to Na and K. The estimated reversal potential was -22.8 +/- 2.4 mV (n = 14). The maximal fast response seen in biphasically-responding cells (b) appeared similar to fast response (a). 4. Fast depolarizations (a) showed marked tachyphylaxis and were abolished by superfusion of the ganglion with 5-HT (100 microM). They were reduced in amplitude by tubocurarine (10-100 microM, pIC50 4.4), MDL 72222 (1-5 microM, pIC50 5.8), quipazine (1 microM reduced responses by 65 +/- 15%, n = 3), ICS 205-930 (1 microM reduced responses by 64 +/- 14%, n = 7) and metoclopramide (10 microM reduced responses by about 45%), but were unafected by methysergide (up to 1 microM) or hexamethonium (up to 1 mM). 5. Slow depolarizations (c) varied in amplitude with the duration of the ejection pulse. Maximal responses had a mean amplitude of 6.4 +/- 0.7 mV, a duration of 62 +/- 6 s, a latency of 3.5 +/- 0.8 s and were reduced in amplitude by methysergide (0.1-1 microM, pIC50 6.5) but not by MDL 72222 (1 microM). The maximal slow component in biphasically-responding cells (b) was similar in amplitude and duration to slow response (c), was partially blocked by methysergide (1-5 microM) in 4 of 6 cells and was enhanced by tubocurarine (50 microM) which reduced the fast component. 6. Slow depolarizations (b,c) were associated with either a small reduction or no change in membrane input resistance depending on the cell studied. Hyperpolarization had variable effects on slow depolarization amplitude. 7. It was concluded that the fast, phasic depolarization is mediated by an ionic mechanism and by receptors both of which are distinct from those involved in the slow depolarization. The receptor mediating the fast depolarization is a 5-HT3 receptor while that mediating the slow depolarization has yet to be identified.

Animals↗
PubMed1999

Heritability of percentage of fast myosin heavy chains in skeletal muscles and relationship with performance.

The purpose of this study was to determine the percentage of fast myosin heavy chains (fast MHCs = MHC 2A + 2B) in 2 propelling muscles to estimate the heritability and to identify any relationship with performance. The gluteus medius and the biceps femoris muscles were biopsied in 100 related French Anglo-Arabian horses. The percentages of slow and fast myosin heavy chains were measured using an ELISA technique. The heritability (s.e.) of the fast MHCs percentage was estimated at 13% (0.1) using a restricted maximum likelihood resolution of a mixed animal model. There were significant (P < 0.05) correlations between the performance level and the fast MHCs percentage of the gluteus medius and biceps femoris muscles: 0.47 and 0.34 respectively. An analysis of variance revealed a significant (P < 0.05) effect of performance level in gallop racing and show jumping on the fast MHCs percentage of the gluteus medius muscle. The good performers in gallop racing (75.5 > 69.6% fast MHCs) and show jumping (74.1 > 67.8% fast MHCs) had a higher percentage of fast MHCs in the gluteus medius than poor performers (P < 0.05). This muscular analysis could be one of the interesting physiological traits to measure for early selection of gallop racing and show jumping horses.

Analysis of Variance↗
PubMed1968

Effects of nerve cross-union on fast-twitch and slow-graded muscle fibres in the toad.

1. A method is described for resolving isometric tetanic tension developed by fast-twitch and slow-graded components of heterogeneous toad muscles. This makes use of the difference in threshold for excitation of low threshold nerve fibres which normally innervate the fast-twitch muscle fibres and high threshold nerve fibres which innervate slow-graded muscle fibres.2. The sartorius muscle contains only fast-twitch muscle fibres whereas the posterior semitendinosus (PST) contains both fast-twitch and slow-graded muscle fibres, the latter contributing 10-15% of the maximum isometric tetanic tension.3. Following surgical cross-union of nerve to sartorius and PST muscles, both the fast-twitch and slow-graded muscle fibre components of the PST are reinnervated by low threshold nerves originally innervating sartorius fast-twitch fibres, and sartorius fast-twitch muscle fibres are reinnervated by both low threshold and high threshold nerves formerly supplying the fast-twitch and slow-graded muscle fibre components of the PST.4. The characteristic mechanical responses of fast-twitch muscle fibres and slow-graded muscle fibres were not transformed up to 134 and 200 days respectively following nerve cross-union.5. PST nerve partially innervated the sartorius muscle whereas sartorius nerves completely innervated the PST muscle. Isometric tetanic tension declined markedly during repetitive indirect stimulation of cross-innervated sartorius muscles, whereas the tetanic contractions of cross-innervated PST showed a plateau of tension and resembled the response of normal muscles.6. Normal, cross-innervated and self-innervated PST muscles gave sustained contractures in the presence of acetylcholine whereas PST muscles denervated for 120 days gave phasic contractures similar to those of normal, cross-innervated and self-innervated sartorius muscles.

Journal Article↗
PubMed2005

Molecular mechanisms of regulation of fast-inactivating voltage-dependent transient outward K+ current in mouse heart by cell volume changes.

The K(v)4.2/4.3 channels are the primary subunits that contribute to the fast-inactivating, voltage-dependent transient outward K(+) current (I(to,fast)) in the heart. I(to,fast) is the critical determinant of the early repolarization of the cardiac action potential and plays an important role in the adaptive remodelling of cardiac myocytes, which usually causes cell volume changes, during myocardial ischaemia, hypertrophy and heart failure. It is not known, however, whether I(to,fast) is regulated by cell volume changes. In this study we investigated the molecular mechanism for cell volume regulation of I(to,fast) in native mouse left ventricular myocytes. Hyposmotic cell swelling caused a marked increase in densities of the peak I(to,fast) and a significant shortening in phase 1 repolarization of the action potential duration. The voltage-dependent gating properties of I(to,fast) were, however, not altered by changes in cell volume. In the presence of either protein kinase C (PKC) activator (12,13-dibutyrate) or phosphatase inhibitors (calyculin A and okadaic acid), hyposmotic cell swelling failed to further up-regulate I(to,fast). When expressed in NIH/3T3 cells, both K(v)4.2 and K(v)4.3 channels were also strongly regulated by cell volume in the same voltage-independent but PKC- and phosphatase-dependent manner as seen in I(to,fast) in the native cardiac myocytes. We conclude that K(v)4.2/4.3 channels in the heart are regulated by cell volume through a phosphorylation/dephosphorylation pathway mediated by PKC and serine/threonine phosphatase(s). These findings suggest a novel role of K(v)4.2/4.3 channels in the adaptive electrical and structural remodelling of cardiac myocytes in response to myocardial hypertrophy, ischaemia and reperfusion.

Action Potentials↗
PubMed1989

Effect of ganglionic stimulating and blocking agents on the fast components of colonic myoelectrical activity in the rat.

The presence of two types of fast myoelectrical activities, medium fast activity and fast activity, has been demonstrated previously in the electromyogram of colon in normal children and in the rat by the authors. An absence of medium fast activity in Hirschsprung's disease and in experimental aganglionosis of colon in the rat has also been described. In the present study the fast components of colonic myoelectrical activity were analysed during the procedures affecting ganglionic transmission. It was observed that ganglionic stimulants, such as balloon inflation, and intra-arterial injections of acetylcholine and small amounts of nicotine, increased the spike activity and the frequency of medium fast activity without affecting fast activity. The intra-arterial injections of ganglionic blocking agents, such as nicotine in large amounts and pentolinium tartrate, completely abolished the medium fast activity. These observations suggest that the ganglionic activity is responsible for the genesis of medium fast activity and that the absence of cholinergic ganglionic transmission is the most important single factor for the reported altered electromyogram pattern in aganglionosis.

Acetylcholine↗
PubMed1997

Rotator cuff: evaluation with fast spin-echo versus conventional spin-echo MR imaging.

PURPOSE: To determine if fast spin-echo (SE) magnetic resonance (MR) imaging can provide similar information to that of conventional SE imaging for evaluation of the rotator cuff. MATERIALS AND METHODS: One hundred twenty-six patients underwent MR imaging with conventional SE and non-fat-suppressed fast SE sequences (65 patients) or conventional SE and fat-suppressed fast SE sequences (61 patients). Two radiologists independently graded the rotator cuff with separate and side-by-side assessment of the fast SE and conventional SE images. RESULTS: For detection of full-thickness tears, agreement between non-fat-suppressed fast SE and conventional SE images was 93.8% (kappa = 0.78 [good]) and 95.4% (kappa = 0.82 [very good]) for the two readers, respectively, and agreement between fat-suppressed fast SE and conventional SE images was 98.4% (kappa = 0.96 [very good]) and 91.8% (kappa = 0.73 [good]) for the two readers, respectively. Rotator cuff grading was similar for fast SE and conventional SE: weighted kappa = 0.77 (good) and 0.68 (good) for non-fat-suppressed and weighted kappa = 0.83 (very good) and 0.67 (good) for fat-suppressed fast SE images for the two readers, respectively. CONCLUSION: Fast SE sequences yield similar interpretations as those obtained with a conventional SE sequence for evaluation of the rotator cuff.

Adolescent↗
PubMed2004

Alpha-1 adrenoceptor agonists generate a "fast" NMDA receptor-independent motor rhythm in the neonatal rat spinal cord.

Noradrenaline, a potent activator of rhythmogenic networks in adult mammals has not been reported to produce functional rhythmic patterns in isolated spinal cords of newborn rats. We now show that a "fast" (cycle time: 1-4 s) transient rhythm was induced in sacrococcygeal (SC) and rostral-lumbar spinal segments of the neonatal rat by bath-applied noradrenaline. The fast rhythm was blocked by 1 microM of the alpha1-adrenoceptor antagonist prazosin but not by 1-20 microM of the alpha2-adrenoceptor blocker yohimbine, it could be initiated and maintained by alpha1-adrenoceptor agonists, and it was accompanied by a slow nonlocomotor rhythm. Transection at the lumbosacral junction abolished the fast-thoracolumbar (TL) rhythm while the fast-SC and slow-TL rhythms were unaffected. The N-methyl-d-aspartate (NMDA) receptor antagonist 2-amino-5-phosphonopentanoic acid (AP5) abolished the slow- and did not interrupt the fast rhythm. Thus alpha1-adrenoceptor agonists induce an NMDA receptor-independent rhythm in the SC cord and modulate NMDA receptor-dependent rhythmicity in TL segments. Injection of current steps into S(2) and flexor-dominated L(2) motoneurons during the fast rhythm revealed a 20-30% decrease in input-resistance (R(N)), coinciding with contralateral bursting. The R(N) of extensor-dominated L(5) motoneurons did not vary with the fast rhythm. The rhythmic fluctuations of R(N) in L(2) motoneurons were abolished, but the alternating left-right pattern of the fast rhythm was unchanged in midsagittally split TL cords. We suggest that the locomotor generators were not activated during the fast rhythm, that crossed-inhibitory pathways activated by SC projections controlled the rhythmic decrease in R(N) in L(2) motoneurons, and that the alternating pattern of the split TL cord was maintained by excitatory SC projections.

2-Amino-5-phosphonovalerate↗
PubMed1976

Fast and slow pyramidal tract neurons: an intracellular analysis of their contrasting repetitive firing properties in the cat.

1. Intracellular recordings were made from an estimated 500 neurons in the sensorimotor cortex of barbiturate-anesthetized cats. Of those which were antidromically identified from the medullary pyramids, 70 were selected which also exhibited steady repetitive firing to steps of current injected through the recording electrode; 81% were "fast" (conduction velocity greater than 20 m/s) and 19% were "slow". 2. As shown by earlier workers, the spike duration is a function of conduction velocity; a spike duration of 1.0 ms is the dividing line between fast and slow. 3. Of the 57 fast pyramidal tract neurons (PTNS), 14 exhibited double spikes during otherwise rhythmic firing patterns to a step of injected current. These very short interspike intervals (usually 1.5-2.5 ms) were first seen interspersed in a rhythmic discharge (e.g., 50-ms intervals) but, with further increases in current strength, would come to dominate the firing pattern; e.g., double spikes every 40 ms. Further increases in current would typically shorten only the long intervals; e.g., 40-30 ms, but some fast PTNS developed triple spikes, etc. 4. The extra spike appears to arise from a large hump which follows most spikes in fast PTNS; while this humplike "depolarising after-potential" can also be seen in slow PTNS, it is small. Extra spikes were seen only in fast PTNS with large postspike humps; in perhaps half of the fast PTNS, extra spikes probably contributed to "adaptation." 5. Slow PTNS often had frequency-current curves which were not repeatable; a "hysteresis" phenomenon could often be seen, where the proportionality constant relating current to firing rate decreased following high firing rates. 6. The B spike was distinguishable from the A spike in differentiated antidromic spikes in 77% of the slow PTNS, in only 14% of the fast PTNS which later exhibited double spikes during current-induced repetitive firing, and in 53% of the other fast PTNS. 7. The antidromic spike heights of doublet PTNS were not significantly different from those of other repetitively firing PTNS.

Animals↗
PubMed1997

Two types of ACh receptors contribute to fast channel gating on mouse skeletal muscle.

Single-channel recordings from mouse C2 myotubes indicate that maturation of skeletal muscle is accompanied by the appearance of two types of fast acetylcholine (ACh) receptor channels that are each functionally distinct from the embryonic receptor type present at early stages of differentiation. The embryonic receptor type has a low conductance (45 pS) and long channel open time, rendering slowly decaying synaptic currents. One fast channel type that appears during muscle maturation is distinguished from the embryonic receptor type on the basis of both higher conductance (65 pS) and shorter open time. However, single-channel recordings from differentiated mouse skeletal muscle cell line (C2) point to the existence of a second fast receptor type, which has a conductance similar to the embryonic receptor type (45 pS), yet significantly reduced mean channel open time. Analyses of individual channel function at high ACh concentrations directly demonstrate the coexistence of two kinetically distinct types of 45 pS ACh receptors. Openings by fast type and slow embryonic type of 45 pS receptors occurred in bursts, allowing distinction on the basis of both mean open time and open probability for individual receptors. The embryonic type of 45 pS receptor has an open time approximately twofold longer than the fast-receptor counterpart. Additional differences were reflected in the open probability distributions for fast and slow 45 pS receptor types. Both types of 45 pS receptor were kinetically distinguishable from the 65 pS receptor. We found no support for the idea that the slow and fast 45 pS receptor types result from the interconversion of dual gating modes involving the same receptor protein. Our results are consistent with the idea that the acquisition of fast synaptic current decay, required at mature neuromuscular synapses, is the result of the up-regulation of two distinct fast types of nicotinic ACh receptors during skeletal muscle development.

Animals↗
PubMed1996

Modulation of putrescine transport in rat intestinal brush-border membrane vesicles by fasting and refeeding.

Fasting and refeeding dramatically alter small intestinal mucosal growth which is greatly dependent on polyamine biosynthesis and transport. The aim of this study was therefore to examine the uptake of the diamine putrescine by brush-border membrane vesicles from the small intestine of rats fasted for 3 days or refed a standard diet after a PERIOD OF FASTING. WHILE THE MICHAELIS-MENTEN CONSTANT KM WAS essentially unaltered, the maximum velocity (Vmax) for putrescine uptake was 1.85-fold higher in fasted animals than in ad libitum-fed controls. Refeeding fasted rats for 24 h caused a 31% decrease in the Vmax value that, however, remained 1.27-fold higher than in control RATS, WHILE THE KM VALUE WAS STILL UNCHANGED. FASTING RATS OR refeeding rats after a period of fasting caused only a 13 or 17% increase, respectively, in the value of the constant for the nonsaturable component (P) of putrescine transport relative to the corresponding control condition. Our study also confirms that both the mucosal polyamine biosynthesis and intestinal content are altered by fasting. We suggest that an increased uptake activity may have a conservative role by preventing a substantial loss of tissue polyamines during fasting.

Animals↗
PubMed2006

Are fast food restaurants an environmental risk factor for obesity?

OBJECTIVE: Eating at "fast food" restaurants has increased and is linked to obesity. This study examined whether living or working near "fast food" restaurants is associated with body weight. METHODS: A telephone survey of 1033 Minnesota residents assessed body height and weight, frequency of eating at restaurants, and work and home addresses. Proximity of home and work to restaurants was assessed by Global Index System (GIS) methodology. RESULTS: Eating at "fast food" restaurants was positively associated with having children, a high fat diet and Body Mass Index (BMI). It was negatively associated with vegetable consumption and physical activity. Proximity of "fast food" restaurants to home or work was not associated with eating at "fast food" restaurants or with BMI. Proximity of "non-fast food" restaurants was not associated with BMI, but was associated with frequency of eating at those restaurants. CONCLUSION: Failure to find relationships between proximity to "fast food" restaurants and obesity may be due to methodological weaknesses, e.g. the operational definition of "fast food" or "proximity", or homogeneity of restaurant proximity. Alternatively, the proliferation of "fast food" restaurants may not be a strong unique cause of obesity.

Journal Article↗
PubMed1994

Evaluation of malignant biliary obstruction: efficacy of fast multiplanar spoiled gradient-recalled MR imaging vs spin-echo MR imaging, CT, and cholangiography.

OBJECTIVE: Although CT and cholangiography have proven value in the detection of biliary obstruction, determining the extent of biliary tumors and imaging small pancreatic or ampullar tumors remain problematic. We hypothesized that the superior contrast resolution of MR, coupled with contrast-enhanced breath-hold imaging, might increase the sensitivity for tumor detection and improve the depiction of the point of obstruction in patients with malignant biliary disease. SUBJECTS AND METHODS: Twenty-one MRI studies were performed prospectively in patients with malignant biliary obstruction by obtaining breath-hold contrast-enhanced fast multiplanar spoiled gradient-recalled (FMPSPGR) images at 0 and 10 min, conventional spin-echo T1-weighted images, and fast spin-echo T2-weighted images. Findings on MR images were correlated with findings on CT scans (15 cases) and/or cholangiograms (14 cases) by two observers. All MR images, CT scans, and cholangiograms were reviewed to evaluate tumor detection, visualization of dilated bile ducts, and conspicuity of the obstructing tumor. A four-point scale (1 = excellent tumor depiction and conspicuity, 4 = tumor not detected) was used for evaluation. Contrast-to-noise ratios for tumor and bile were calculated for the three MR pulse sequences. RESULTS: The contrast-enhanced FMPSPGR images and CT scans provided excellent depiction of the dilated biliary tree in 95% and 93% of examinations, respectively, with both techniques superior to fast spin-echo and T1-weighted images (p < .005). Tumor detection was best with the immediate FMPSPGR MR images (20/21), compared with fast spin-echo MR images (16/21) (p = .04), T1-weighted MR images (16/21) (p = .04), CT scans (12/15) (p > .05), and cholangiograms (13/14) (p > .05). Of 13 examinations showing proximal biliary obstruction, the mean score for tumor conspicuity was best with the immediate enhanced FMPSPGR MR images (1.38 +/- .65), compared with T1-weighted MR images (2.38 +/- 1.3) and fast spin-echo MR images (2.08 +/- 1.0) (p < .05), but it was not different from the delayed FMPSPGR MR images (1.75 +/- 1.1) or CT scans (1.9 +/- 0.99) (p > .05). For five of six cholangiocarcinomas, the immediate and delayed enhanced FMPSPGR MR images showed excellent tumor conspicuity owing to their enhancement with gadopentetate dimeglumine. Data for contrast-to-noise ratios of tumor showed that the immediate FMPSPGR MR images (15.8 +/- 10.2) were superior to T1-weighted images (6.3 +/- 3.5, p < .01), but were not different from fast spin-echo images (13.5 +/- 6.7) or delayed FMPSGR images (11.5 +/- 8.9). For eight examinations in patients with distal biliary obstruction, the mean score for tumor conspicuity was greater with the immediate FMPSPGR MR images (1.38 +/- 0.52), compared with fast spin-echo images (3.25 +/- 0.71, p < .005), T1-weighted images (2.63 +/- 1.06, p < .05), and delayed FMPSPGR MR images (2.60 +/- 1.5, p < .05), but was similar to that with CT scans (1.40 +/- 0.89, p > .05). Data for contrast-to-noise ratios of tumor showed an advantage for the immediate FMPSPGR MR images (12.0 +/- 7.7) over T1-weighted images (4.0 +/- 2.6, p < .01) and delayed FMPSPGR images (4.3 +/- 2.6, p < .025), but no difference from fast spin echo images (6.6 +/- 8.8, p = .05). CONCLUSION: Contrast-enhanced FMPSPGR MR imaging is sensitive for the detection of tumors causing biliary obstruction. For proximal obstruction, it may be particularly effective for detecting and defining tumor extent of hilar cholangiocarcinomas because of their enhancement with gadopentetate dimeglumine. For cases of distal obstruction, this technique showed improved tumor detection and conspicuity compared with T1- and fast spin-echo T2-weighted images, but showed no advantage over CT.

Biliary Tract Neoplasms↗
PubMed2005

Comparison of fast spin-echo versus conventional spin-echo MRI for evaluating meniscal tears.

OBJECTIVE: We compare sensitivities of conventional spin-echo and fast spin-echo sequences in the evaluation of meniscal tears. Furthermore, we reevaluate the results from prior studies comparing these two sequences to understand why there are differing conclusions regarding the efficacy of fast spin-echo sequences as a commensurate replacement for conventional spin-echo sequences. MATERIALS AND METHODS: We used records from a control group of 64 patients (128 menisci) who had undergone arthroscopy to determine the sensitivity of conventional spin-echo sequences for detecting meniscal tears. Two hundred sixteen consecutive patients (432 menisci) were then imaged using conventional spin-echo and fast spin-echo sequences to evaluate for meniscal tears. Both sequences were proton density-weighted with fat suppression. RESULTS: Of the 432 menisci, 170 tears were detected on conventional spin-echo imaging. Only 128 tears were detected on the fast spin-echo sequence. The sensitivities of conventional spin-echo and fast spin-echo imaging were found to be 93% and 80%, respectively. In addition, findings from conventional spin-echo and fast spin-echo sequences were discordant for 72 menisci (17%, p < 0.01). CONCLUSION: The sensitivities of conventional spin-echo and fast spin-echo imaging for detecting meniscal tears have been shown to be greater than 90% and approximately 80%, respectively. However, some authors advocate substituting conventional spin-echo imaging with fast spin-echo imaging. We urge the abandonment of fast spin-echo imaging for evaluating meniscal tears because a loss of greater than 10% in sensitivity is unacceptable.

Adult↗
PubMedDate not supplied

A comparison of MR imaging with fast-FLAIR, HASTE-FLAIR, and EPI-FLAIR sequences in the assessment of patients with multiple sclerosis.

BACKGROUND AND PURPOSE: Fast fluid-attenuated inversion-recovery (FLAIR) sequences are sensitive for detecting lesions in patients with multiple sclerosis (MS). More rapid fast-FLAIR imaging of the brain can be achieved by the concomitant use of half-Fourier acquisition single-shot turbo spin-echo (HASTE-FLAIR) and echo-planar imaging (EPI-FLAIR). The present study was performed in a large cohort of subjects to assess and compare the number and volume of brain lesions detected by the fast-FLAIR, HASTE-FLAIR, and EPI-FLAIR sequences in patients with MS. METHODS: Fast-FLAIR, HASTE-FLAIR, and EPI-FLAIR sequences were obtained from 46 consecutive MS patients. Lesions seen on each type of sequence were counted and classified by consensus by two observers. Lesion volumes were measured using a semiautomated segmentation technique based on local thresholding. RESULTS: The quality of the fast-FLAIR images was significantly better than that of HASTE-FLAIR and EPI-FLAIR images. Fast-FLAIR revealed significantly more lesions and higher lesion volumes than did HASTE-FLAIR and EPI-FLAIR. A similar number of large lesions was detected by the three sequences, but HASTE-FLAIR and EPI-FLAIR showed significantly fewer small and intermediate lesions than did fast-FLAIR. The number of lesions seen on HASTE-FLAIR and EPI-FLAIR images was similar. CONCLUSION: HASTE-FLAIR and EPI-FLAIR sequences revealed as many large MS lesions as fast-FLAIR. Because their acquisition times are only a fraction of that needed for fast-FLAIR sequences, they may be useful for making a rapid diagnosis of MS in uncooperative patients. Their reduced ability to detect smaller lesions indicates that they should not be used as a routine approach to imaging patients with MS.

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