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At least 109 records · Page 6Linked to original sources
PubMed2006

Rapid methylation on carbon frameworks useful for the synthesis of 11CH3-incorporated PET tracers: Pd(0)-mediated rapid coupling of methyl iodide with an alkenyltributylstannane leading to a 1-methylalkene.

The Pd(0)-mediated rapid coupling of methyl iodide with an excess of alkenyltributylstannane was examined with the aim of incorporating a short-lived 11C-labeled methyl group into a biologically significant organic compound with a 1-methylalkene unit for the synthesis of a PET tracer. Four sets of reaction conditions (A-D) were used, all performed in DMF at 60 degrees C for 5 min. Condition B, using CH3I/stannane/Pd2(dba)3/P(o-tolyl)3/CuCl/K2CO3 (1:40:0.5:4-6:2:5), works well in almost all cases. Condition D, using CH3I/stannane/Pd2(dba)3/P(o-tolyl)3/CuX (X = Br, Cl, or I)/CsF (1:40:0.5-5:2-20:2-20:5-50), shows the best results with regard to general applicability to tin substrates, affording the corresponding methylated product in >90% yield based on consumption of methyl iodide. P(t-Bu)2Me was less effective than P(o-tolyl)3, particularly for alpha,beta-unsaturated carbonyl substrates. No regio- or stereoisomerization occurred under these reaction conditions. The efficiency of the protocol was demonstrated by synthesis of an 11C-methylated compound.

Alkenes↗
PubMed2004

A comparison of the effects of rapid maxillary expansion and fan-type rapid maxillary expansion on dentofacial structures.

The aim of this study was to evaluate and compare the sagittal, transverse, and vertical effects of rapid maxillary expansion (RME) and fan-type RME on dentofacial structures. The study group consisted of 34 patients, 14 boys and 20 girls (average age 12.5 years), selected without considering their skeletal class and sex. The fan-type RME group comprised 17 subjects, who had an anterior constricted maxilla with a normal intermolar width. The RME group comprised 17 other subjects, who had a maxillary transverse discrepancy with a posterior crossbite. The records obtained for each patient included a lateral and a frontal cephalometric film, upper plaster models, and occlusal radiograph obtained before treatment (T1), after expansion (T2), and immediately after a three-month retention period (T3). The data obtained from the evaluation of the records before and after treatment, after treatment and after retention, and before treatment and after retention were compared using paired t-test. Further comparisons between the groups were made using Student's t-test. There was significantly greater expansion in the intercanine than in the intermolar width in the fan-type RME group as compared with the RME group. Downward and forward movement of the maxilla was observed in both groups. The upper incisors were tipped palatally in the RME group, but they were tipped labially in the fan-type RME group. There was significantly greater expansion in the nasal cavity and maxillary width in the RME group as opposed to the fan-type RME group.

Biomechanical Phenomena↗
PubMed2006

Surgically assisted rapid maxillary expansion compared with orthopedic rapid maxillary expansion.

The objective of this study is to evaluate and compare the dental and skeletal changes occurring during orthopedic rapid maxillary expansion (RME) and surgically assisted RME during the active phase of treatment. The study was divided into two groups. The first group of 10 patients (six males, four females; mean age, 15.51 years) received orthopedic RME. The second group of 10 patients (seven males, three females; average age: 19.01 years) received surgically assisted RME (SARME). All patients underwent maxillary expansion with occlusal-coverage Hyrax-type expanders activated two turns a day (0.25 mm per turn). Preexpansion and postexpansion lateral and posteroanterior cephalograms were obtained for each patient. Statistically significant differences between the SARME and RME groups were found in the N-ANS, SN/ PP (P < .01) and SNA, SNB, mandibular dentoalveolar, and maxillary bony base (P < .05) measurements. Clinically, there is no difference in patient response between the RME and SARME groups. The only difference between the groups was their indication for RME or SARME, which is based on the age and skeletal maturation of the patient.

Adolescent↗
PubMed1994

XMAP from Xenopus eggs promotes rapid plus end assembly of microtubules and rapid microtubule polymer turnover.

We have used video-enhanced DIC microscopy to examine the effects of XMAP, a Mr 215,000 microtubule-associated protein from Xenopus eggs (Gard, D.L., and M. W. Kirschner. 1987. J. Cell Biol. 105:2203-2215), on the dynamic instability of microtubules nucleated from axoneme fragments in vitro. Our results indicate that XMAP substantially alters the parameters of microtubule assembly at plus ends. Specifically, addition of 0.2 microM XMAP resulted in (a) 7-10-fold increase in elongation velocity, (b) approximately threefold increase in shortening velocity, and (c) near elimination of rescue (the switch from rapid shortening to elongation). Thus, addition of XMAP resulted in the assembly of longer, but more dynamic, microtubules from the plus ends of axonemes which upon catastrophe disassembled back to the axoneme nucleation site. In agreement with previous observations (Gard, D.L., and M. W. Kirschner. 1987. J. Cell Biol. 105:2203-2215), the effects of XMAP on the minus end were much less dramatic, with only a 1.5-3-fold increase in elongation velocity. These results indicate that XMAP, unlike brain MAPs, promotes both polymer assembly and turnover, and suggests that the interaction of XMAP with tubulin and the function of XMAP in vivo may differ from previously characterized MAPs.

Animals↗
PubMed1997

Father-to-mother-to-infant transmission of HIV-1: clonally transmitted isolate of infant mutates more rapidly than that of the mother and rapidly loses reactivity with neutralizing antibody.

The sequences of the V3 loop and surrounding regions of human immunodeficiency virus type-1 from a father-to-mother-to-infant trimmer were studied and the horizontal and vertical transmissions compared. The father's virus was variable for reactivity with neutralizing antibody and sequences of the V3 loop central core sequence. In contrast, the mother's viral sequences were much less diverse and reacted with a virus neutralizing antibody. The infant's viral sequences were also less diverse than those of the father, and N-glycosylation sites were conserved. By phylogenetic analysis, the major clone, of which V3-peptide reacted with the neutralizing antibody, was found to be transmitted from the mother to her infant; however, the mutated minor clones did not bind to the antibody. These findings suggest that both horizontal and vertical virus transmission were selective, and that the clonally transmitted virus in infants mutates more rapidly than viruses in the mother, to whom the virus was horizontally transmitted.

Amino Acid Sequence↗
PubMed1997

Variation of electroencephalographic activity during non-rapid eye movement and rapid eye movement sleep with phase of circadian melatonin rhythm in humans.

1. The circadian pacemaker regulates the timing, structure and consolidation of human sleep. The extent to which this pacemaker affects electroencephalographic (EEG) activity during sleep remains unclear. 2. To investigate this, a total of 1.22 million power spectra were computed from EEGs recorded in seven men (total, 146 sleep episodes; 9 h 20 min each) who participated in a one-month-long protocol in which the sleep-wake cycle was desynchronized from the rhythm of plasma melatonin, which is driven by the circadian pacemaker. 3. In rapid eye movement (REM) sleep a small circadian variation in EEG activity was observed. The nadir of the circadian rhythm of alpha activity (8.25-10.5 Hz) coincided with the end of the interval during which plasma melatonin values were high, i.e. close to the crest of the REM sleep rhythm. 4. In non-REM sleep, variation in EEG activity between 0.25 and 11.5 Hz was primarily dependent on prior sleep time and only slightly affected by circadian phase, such that the lowest values coincided with the phase of melatonin secretion. 5. In the frequency range of sleep spindles, high-amplitude circadian rhythms with opposite phase positions relative to the melatonin rhythm were observed. Low-frequency sleep spindle activity (12.25-13.0 Hz) reached its crest and high-frequency sleep spindle activity (14.25-15.5 Hz) reached its nadir when sleep coincided with the phase of melatonin secretion. 6. These data indicate that the circadian pacemaker induces changes in EEG activity during REM and non-REM sleep. The changes in non-REM sleep EEG spectra are dissimilar from the spectral changes induced by sleep deprivation and exhibit a close temporal association with the melatonin rhythm and the endogenous circadian phase of sleep consolidation.

Adult↗
PubMed1983

Comparison of a new rapid plasma reagin card test with the standard rapid plasma reagin 18-mm circle card test and the venereal disease research laboratory slide test for serodiagnosis of syphilis.

The rapid plasma reagin (RPR) card test manufactured by Beckman Instruments, Inc., was compared, qualitatively and quantitatively, with the Venereal Disease Research Laboratory (VDRL) slide test and the standard RPR 18-mm circle card tests for the serodiagnosis of syphilis. Sera from 638 individuals were used in this study. Two pilot lots and two production lots of antigen were submitted by Beckman Instruments, Inc., for evaluation. Qualitative agreement among the three RPR card tests was 98.1%; between the Beckman RPR card and the VDRL slide tests, 95.0%; and between the reference RPR card and the VDRL slide tests, 95.5%. The Beckman RPR card test was 95.3% specific, whereas the specificities of the reference RPR card and the VDRL slide tests were 98.8% and 96.1%, respectively. Sensitivities of the three nontreponemal tests were: Beckman RPR card test production lots, 94.7%; reference RPR card test, 96.8%; and VDRL slide test, 90.6%. Quantitative agreement +/- 1 dilution among the three RPR card tests was 93.0%, whereas quantitative agreement was approximately 40% when both RPR card tests were compared with the VDRL slide test. We found the Beckman RPR card test comparable to the standard RPR card tests. Therefore, the decision of which test to use for the serodiagnosis of syphilis is at the discretion of the user.

Antibodies↗
PubMed2003

A laboratory evaluation of the level 1 rapid infuser (H1025) and the Belmont instrument fluid management system (FMS 2000) for rapid transfusion.

UNLABELLED: In this investigation I compared the heating capabilities, infusion rates, and air management system of the new FMS 2000 and the Level 1 infusion systems. A rollerhead pump was placed at the position of the IV bag spikes on the Level 1 disposable set and used to match the flow of the rollerhead pump of the FMS 2000. Infusate temperature was measured at 250 and 500 mL/min by using packed red blood cells (PRBC) at the infusate supply and distal end of the disposable tubing. Tubing lengths were equal for both systems. Devices were set at maximum flow while temperatures were measured as described previously. Flow was measured with a graduated cylinder and stopwatch. Air management was evaluated with a 10-mL air bolus injected proximal to the heat exchanger at maximum flow. Air passing through the system was collected and measured. At 250 mL/min, both devices provided infusate at >or=37 degrees C. At 500 mL/min, only the FMS 2000 provided PRBC at >or=37 degrees C. PRBC infusate temperature decreased over time with the Level 1 device. The FMS 2000 delivered PRBC at its maximum flow rate of 500 mL/min. The Level 1 attained a maximum flow of 575 mL/min of PRBC with a temperature of 32 degrees C. Air (10 mL) was recovered from the distal tubing of the Level 1. No air was recovered from the tubing of the FMS 2000. In this laboratory investigation, the FMS 2000 performance was superior with respect to providing PRBC at physiologic temperatures (at 500 mL/min) and with respect to air detection and elimination compared with current widely used pressure-infuser technology. IMPLICATIONS: The FMS 2000 and Level 1 H1025 warming capabilities were similar at metered flows of 500 mL/min. At more rapid flow rates, which are achieved by the H1025, fluid warming decreases dramatically. The air-detection and -elimination system of the FMS 2000 is superior to that of the H1025.

Blood Transfusion↗
PubMed1999

The sleep supine position has a major effect on optimal nasal continuous positive airway pressure : relationship with rapid eye movements and non-rapid eye movements sleep, body mass index, respiratory disturbance index, and age.

STUDY OBJECTIVES: To evaluate the impact of sleep position on optimal nasal continuous positive airway pressure (nCPAP [op-nCPAP]) in obstructive sleep apnea (OSA) patients and to investigate how rapid eye movements (REM) and Non-REM (NREM) sleep, body mass index (BMI), respiratory disturbance index (RDI), and age are related to this effect. DESIGN: Retrospective analysis. SETTING: Sleep Disorders Unit at Loewenstein Hospital Rehabilitation Center. PATIENTS: Eighty-three consecutive adult OSA patients who underwent a complete nCPAP titration. From this group, 60 patients who spent at least 30 min in both the supine (Sup) and lateral (Lat) positions and 46 patients who had data on both positions during REM and NREM sleep were included in the analysis. RESULTS: In most OSA patients (52; 86.7%), the recommended op-nCPAP was obtained when the patients slept in the Sup posture. The mean op-nCPAP was significantly higher in the Sup posture (10.00 +/- 2.20 cm H(2)O) than it was in the Lat posture (7.61 +/- 2.69 cm H(2)O). The op-nCPAP was significantly higher in the Sup position than it was in the Lat position in both REM and NREM sleep, as well as in the severe BMI group (BMI >/= 30) and in the less obese group (BMI < 30). Similarly, in the severe (RDI >/= 40) and less severe groups (RDI < 40), as well as in both age groups (< and > 60 years of age), the op-nCPAP was significantly higher in the Sup posture than it was in the Lat posture. Irrespective of the four parameters mentioned, the actual differences in op-nCPAP between the two body postures were almost identical, ranging between 2.31 and 2.66 cm H(2)O. CONCLUSIONS: For most OSA patients, the op-nCPAP level is significantly higher in the Sup position than it is in the Lat position. This is true for REM and NREM sleep, for obese and nonobese patients, for patients with different degrees of severity, and for young and old OSA patients. Since the op-nCPAP was highest in the Sup posture during REM sleep, no nCPAP titration should be considered complete without the patient having slept in the Sup posture during REM sleep.

Adult↗
PubMed1996

[Detection of rapid eye movement with rapidly adapting neuronal fuzzy systems in imprecise REM syntax].

Both living beings and artificial neuronal networks are capable of 'learning' and behavioural adaptation. But also the fuzzy program designed to detect rapid eye movements (REM) during sleep and described here, can be provided with a self-learning option that provides important information about REM sleep. The algorithm computes REM on the basis of horizontal and vertical EOG. EEG, EMG and actiography signals are employed to optimize the method and eliminate artefacts. In a second step, the fuzzy system learns to detect REM with the aid of a sample data set and a minimal set of syntax rules. From sample data and the actions and reactions of visual scorers, the program extracts additional rules and information, which are then used to build a complete fuzzy structure. Thereafter, the REM detection program optimizes the fuzzy logic structure, independently of visual monitoring, on its own. A direct comparison of the results of the algorithm in a 10-night analysis with those of two experienced visual scorers revealed a better than 95% agreement. Re-analysis with the algorithm showed a 100% concurrence. Complete visual measurement of the eye movements occurring in a single night requires several hours; this compares with only 15 minutes required by the algorithm.

Algorithms↗
PubMed2003

Rapid enhanced tissue culture immunofluorescence: a new, rapid method for detection of viruses.

The detection of a large variety of viruses requires a number of different susceptible cell lines in a shell vial method--currently considered to be the most enhanced method of viral detection. However, this method is unsuitable in its standard form for handling a large volume of specimens. We have developed a time and cost saving new method, named rapid enhanced tissue culture immunofluorescence (RETCIF) and incorporates the attributes of the current methods. It is specific, uses the most sensitive cell lines and monoclonal antibodies and does not require the use of cover slips. The RETCIF method, in our hands, is a time saving procedure, with higher isolation ratio than the shell vial method. We recommend the RETCIF method for busy diagnostic virology laboratories.

Antibodies, Monoclonal↗
PubMed2006

Comparison of the diagnostic accuracy of a rapid immunochromatographic test and the rapid plasma reagin test for antenatal syphilis screening in Mozambique.

OBJECTIVE: Programmes to control syphilis in developing countries are hampered by a lack of laboratory services, delayed diagnosis, and doubts about current screening methods. We aimed to compare the diagnostic accuracy of an immunochromatographic strip (ICS) test and the rapid plasma reagin (RPR) test with the combined gold standard (RPR, Treponema pallidum haemagglutination assay and direct immunofluorescence stain done at a reference laboratory) for the detection of syphilis in pregnancy. METHODS: We included test results from 4789 women attending their first antenatal visit at one of six health facilities in Sofala Province, central Mozambique. We compared diagnostic accuracy (sensitivity, specificity, and positive and negative predictive values) of ICS and RPR done at the health facilities and ICS performed at the reference laboratory. We also made subgroup comparisons by human immunodeficiency virus (HIV) and malaria status. FINDINGS: For active syphilis, the sensitivity of the ICS was 95.3% at the reference laboratory, and 84.1% at the health facility. The sensitivity of the RPR at the health facility was 70.7%. Specificity and positive and negative predictive values showed a similar pattern. The ICS outperformed RPR in all comparisons (P<0.001). CONCLUSION: The diagnostic accuracy of the ICS compared favourably with that of the gold standard. The use of the ICS in Mozambique and similar settings may improve the diagnosis of syphilis in health facilities, both with and without laboratories.

Adolescent↗
PubMed1975

Rapid analysis of the central nervous system stimulants, amphetamines, via gas chromatography-mass spectrometry: rapid acylation in the presence of a mercury catalyst.

A simple, direct, instantaneous, and quantitative acetylating procedure for amphetamines has been developed. The method uses trifluoroacetic anhydride in the presence of mercuric trifluoroacetate as a catalyst. The product was characterized by a gas chromatography-mass spectrometry system. The salient features of this technique are: (a) rapidity of analysis; (b) no previous cleanup to remove adulterants; and (c) detection of amphetamines at the picomole level. We have routinely applied this technique for court samples and law enforcement authorities. The method could prove to be applicable, with minimum amounts of involvement in sample preparation, to the analysis of a variety of compounds containing an acyl displaceable hydrogen.

Acylation↗
PubMed1991

The influence of ev6 on the immune response to avian leukosis virus infection in rapid-feathering progeny of slow- and rapid-feathering dams.

Endogenous virus (EV) locus ev6 encodes only virus envelope glycoprotein. The influence of ev6 on the immune response to contact infection with hatchmates infected with avian leukosis virus (ALV) was compared in replicate hatches. The ALV Subgroup E-resistant, rapid-feathering (RF) female chickens produced by slow-feathering (SF) and RF dams with and without ev6 were exposed at hatch to hatchmates infected with ALV Subgroup A (Strain RPL-40). The RPL-40 viremia, shedding, and virus neutralizing antibodies were measured among pullets from two hatches at 22 wk of age. Although significant (P less than .05) differences between hatches in the immune response to contact infection were noted among ev6+ pullets, significantly fewer ev6+ pullets seroconverted than their ev6- hatchmates. At 22 wk of age, significantly more lymphomas were also found among ev6+ pullets than among ev6- hatchmates. In flocks wherein both parents and progeny were homozygous resistant to Subgroup E virus, there was no deterimental maternal effect on RF progeny from SF dams that carried ev21. These results also confirm that selection for genetic cellular resistance to Subgroup E ALV infection eliminates congenital transmission of EV21.

Animals↗
PubMed2004

Evaluation of the KAT-Quick Malaria Rapid Test for rapid diagnosis of falciparum malaria in Thailand.

In recent years, several rapid diagnostic tests for falciparum malaria have been developed. KAT test results were compared with microscopy on 90 consecutive patients hospitalized at the Hospital for Tropical Diseases, Bangkok, Thailand. Fifty-one patients had P. falciparum infections while 49 had malaria due to other plasmodium species. For a geometric mean +/-SD (Min;Max;range) parasitemia of 11,481 +/- 5.0 (88;713,838;713,750), the sensitivity of the KAT test was 96% (95% CI = 86-99.5), the specificity was 92% (95% CI = 80-99), the accuracy was 94% and the reliability was 85%. These findings suggest that the KAT test is of potential interest in the diagnosis of falciparum malaria in Thailand.

Animals↗