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PubMed1980

Quantitative analysis of peroxides in restorative resins.

It has been demonstrated previously by other authors that the quantity of benzoyl-peroxide influences the properties of restorative resins. The purpose of the present work was to analyse quantitatively peroxides in commercial restorative resins. The analysis was performed by iodometric titration. Sixteen brands were investigated, and it was found that the amount of peroxide varied between 0.3% and 2.6% by weight of the monomer. It is possible that the information obtained will lead to a better understanding of the nature of restorative resins.

Benzoyl Peroxide↗
PubMed2005

Local irradiation prior to stem cell harvest has no influence on CD34+ yield: a quantitative analysis.

In patients with multiple myeloma, irradiation of bone marrow prior to mobilization of autologous peripheral blood progenitor cells (PBPCs) may lead to a reduced yield of CD34+ cells. Quantitative effects have not been sufficiently assessed. We retrospectively performed a multivariate analysis in 114 patients (67 men, 47 women) with multiple myeloma, of whom 53 (47%) patients had been irradiated prior to mobilization chemotherapy. High-dose cyclophosphamide followed by granulocyte colony-stimulating factor was used for mobilization in 84% of patients. In addition to previous chemotherapy, we quantitatively evaluated the dose and fractionation of prior irradiation, the volume of the irradiated bone marrow, and the time interval between radiation therapy and mobilization of PBPCs. The median volume of irradiated bone marrow was 9% (range 1-30%) of the estimated total hematopoietic bone marrow. The irradiated bone marrow volume and the number of CD34+ cells per kilogram of body weight in the first leukapheresis product showed no correlation. However, the time between irradiation and mobilization seemed to influence the yield of CD34+ cells. A comparison of irradiated patients with nonirradiated patients revealed no differences with respect to the CD34+ cell counts. We did not find a significant influence of the extent or the total dose of irradiation on the yield of CD34+ cells in the first leukapheresis product in patients with multiple myeloma. However, there may be an inverse correlation between the time elapsed since the last irradiation and the number of mobilized CD34+ cells.

Adult↗
PubMed1998

Quantitative analysis of luciferase activity of viral and hybrid promoters in bovine preimplantation embryos.

This study was conducted to investigate quantitatively the luciferase activity of gene constructs with viral and hybrid enhancers and promoters in bovine preimplantation embryos by using firefly luciferase reporter genes. In Experiment I, to examine the stability of the luciferase, bioluminescence intensity of bovine embryos injected with the luciferase gene driven by the SV40 early promoter and enhancer (SVEluc) was measured with a luminometer at 2 days after microinjection. The results indicated that the bioluminescence could be analysed at any time within 30 min because the luciferase activity was constant during the measurement period from 5 to 30 min. In Experiment II, the luciferase expression of fertilized oocytes injected with four gene constructs (TKEluc, TK6WEluc, SVEluc, and Miwluc) was analysed by using a photon imaging system at 2 or 6 days following microinjection. The results from Experiment II indicated that the reporter gene governed by the Miw promoter (RSV LTR and chicken beta-actin promoter) was expressed more intensively in bovine morulae and blastocysts than three other gene constructs. In Experiment III, the effect of SV40 enhancer was investigated when fused downstream to the luciferase cDNA of the Miwluc vector. The results showed that SV40 enhancer further activated the luciferase activity of the Miw promoter in bovine preimplantation embryos. It was concluded, therefore, that the Miw promoter together with the SV40 enhancer would confer the strongest expression of the firefly luciferase reporter gene among the gene constructs tested in preimplantation bovine embryos.

Animals↗
PubMed1982

Quantitative analysis of plasma nicotine using selected ion monitoring at high resolution.

A highly sensitive and specific method for the quantitative determination of nicotine in plasma is described. Using simple one-step work-up technique and (5',5'-2H2) nicotine as internal standard, the analytical procedure is based on combined capillary column gas chromatography and high resolution selected ion monitoring. Incorporation of a specially designed gas chromatograph/mass spectrometer interface allowing introduction of the eluent by a fused silica capillary via the direct inlet port into the ion source brings the detection level for nicotine in an alcoholic solution down to below 100 fg. The discriminatory nature of the method also makes it well suited for studying ambiguities of instrumental nicotine assay and some of these are discussed.

Gas Chromatography-Mass Spectrometry↗
PubMed1983

Quantitative analysis of albuterol in human plasma by combined gas chromatography chemical ionization mass spectrometry.

A highly sensitive and specific quantitative assay for the determination of albuterol in human plasma, based on selected ion monitoring gas chromatography chemical ionization mass spectrometry, has been developed. The [MH]+ ions from the tri-TMS derivatives of albuterol (m/z 456) and the internal standard (2H3)albuterol (m/z 459), were assayed simultaneously by selected ion monitoring. The lower limit of quantitation is 0.25 ng ml-1 and the average assay precision (CV) for albuterol concentrations ranging from 0.25 ng ml-1 to 25 ng ml-1 is approximately 4%. This method is currently being employed for the routine quantitation of albuterol in plasma following the administration of doses therapeutically effective to man.

Albuterol↗
PubMed2002

Quantitative analysis of adiabatic fast passage for steady laminar and turbulent flows.

Adiabatic fast passage (AFP) is used in noninvasive quantitative perfusion experiments to invert (or label) arterial spins. Continuous arterial spin labeling (CASL) experiments conducted in vivo often assume the inversion efficiency based on the labeling field and steady flow conditions, without direct verification. In practice, the labeling field used in CASL is often amplitude- and duty cycle-limited due to hardware or specific absorption rate constraints. In this study, the effects of the labeling field amplitude and duty cycle, and flow dynamics on the inversion efficiency of AFP were examined under steady flow conditions in a saline flow phantom. The experimental results were in general agreement with models based on Zhernovoi's theory except at high labeling field amplitudes, when the spin inversion times are at least half of the duration of the labeling pulse. The nonlinear relation observed between the inversion efficiency and the labeling duty cycle implies that the practice of linear derating the inversion efficiency with the labeling duty cycle may be prone to significant error. A secondary finding was that the T1 of the flowing fluid could be calculated based on the flow dynamics after varying the flow rate.

Blood Flow Velocity↗
PubMed2005

Quantitative analysis of myocardial glucose utilization in patients with left ventricular dysfunction by means of 18F-FDG dynamic positron tomography and three-compartment analysis.

PURPOSE: Myocardial glucose utilization (MGU) is altered in various heart diseases. The aim of this study was to quantitatively assess regional myocardial glucose utilization in patients with left ventricular (LV) dysfunction by dynamic( 18)F-fluorodeoxyglucose positron emission tomography (FDG PET). METHODS: A total of 18 subjects were studied, including ten with LV dysfunction (seven with idiopathic dilated cardiomyopathy and three with aortic regurgitation; NYHA II in 8 and III in 2) and eight healthy normal volunteers. Patients with diabetes mellitus were excluded. A dynamic PET study was performed for 40 min following the injection of 370 MBq of FDG after 50-g glucose loading. On the basis of a three-compartment model, MGU, K1, k2, and k3 were computed on a pixel by pixel basis to generate LV myocardial parametric maps. FDG standardized uptake value (SUV) was also calculated using static images obtained 40 min after FDG injection. These metabolic values were compared with myocardial flow distribution (%Flow), LVEF, LV volumes, and LV wall thickening (WT) determined by gated myocardial single-photon emission computed tomography using QGS software in eight myocardial segments. RESULTS: MGU correlated positively with LV volumes and negatively with LVEF. K(1) was significantly higher in the segments of the patients than in those of the normal volunteers (0.082+/-0.055 vs 0.041+/-0.017 ml min(-1) g(-1), p<0.05), although there was no difference in MGU between the groups. On the other hand, SUV, k2, and k3 did not differ significantly between the groups. Among the patients, the K1 values were significantly higher in the areas with impaired WT (%WT<17%) (0.109+/-0.063 vs 0.069+/-0.062 ml min(-1) g(-1), p<0.05) and in the areas with flow reduction (%Flow<71%) (0.112+/-0.076 vs 0.071+/-0.046 ml min(-1) g(-1), p<0.05). CONCLUSION: These results indicate that glucose utilization was preserved in the patients with LV dysfunction, mainly due to an increase in glucose transport, particularly in the regions with severely impaired LV function. Thus, the quantitative assessment of myocardial glucose utilization by FDG dynamic PET may provide useful information for assessing the regional myocardial metabolic status in patients with LV dysfunction.

Aged↗
PubMed1991

Study of the influence of left bundle branch block on the signal-averaged electrocardiogram: a qualitative and quantitative analysis.

UNLABELLED: To study the influence of left bundle branch block (LBBB) on the signal-averaged electrocardiogram (SAECG), quantitative and qualitative analyses of SAECG parameters were undertaken in 48 patients with electrocardiographic evidence of intrinsic LBBB and in 39 patients with a "normal" surface QRS duration (less than 120 msec) who underwent right ventricular pacing-induced LBBB. We assumed pacing of the right ventricular apex to be a suitable model of this conduction defect. Sustained monomorphic ventricular tachycardia (SMVT) was inducible in 16 of 48 patients with intrinsic LBBB and in 23 of 39 patients with pacing-induced LBBB. Utilizing a filter setting of 25 to 250 Hz, late potentials were defined as a total filtered QRS duration greater than or equal to 120 msec, a root mean square voltage in the terminal 40 msec (RMS 40) of less than or equal to 25 microV, and the duration of signals less than 40 microV (LAS 40) of greater than or equal to 38 msec. Only RMS 40 and LAS 40 criteria were used in patients with LBBB. Prolongation of LAS 40 and fragmentation of signals in the terminal portion of the filtered QRS were characteristic of all patients with LBBB aberration. Of those patients with intrinsic LBBB, the mean total filtered QRS duration, RMS 40, and LAS 40 for inducible and noninducible patients were significantly different (170 +/- 28, 16 +/- 10, 55 +/- 24, and 153 +/- 18 msec, 25 +/- 10 microV, 33 +/- 16.9 msec; p = 0.04, 0.009, and 0.007, respectively). Noninducible patients with a normal QRS duration demonstrated a 60% decrement in the mean RMS 40 value during pacing-induced LBBB. These changes resulted in a 59% false positive incidence of late potentials during pacing-induced LBBB. This correlated with a similarly low mean RMS 40 value in patients with intrinsic LBBB and no inducible SMVT, hence giving rise to a false positive incidence of late potentials of 63%. Since "standard" RMS 40 and LAS 40 criteria resulted in low specificity and positive predictive value, new parameters were selected and analyzed. The combination of RMS 40 less than or equal to 17 microV plus LAS 40 greater than or equal to 55 msec yielded the best overall statistical result, with a sensitivity, specificity, and total predictive accuracy of 69%, 81%, and 77%, respectively. IN CONCLUSION: (1) A reduction of RMS 40, prolongation of LAS 40, and fragmentation of signals in the terminal portion of the filtered QRS are characteristics of LBBB.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1986

Quantitative analysis of a polysulfated xylan (SP54) in urine using gas-liquid chromatography.

A sensitive analytical method for the quantitation of a polysulfated xylan (SP54) in urine has been developed. SP54 and urinary glycosaminoglycans have been isolated from urine using cetylpyridinium chloride. This method removes all glycosaminoglycans with molecular weights less than 3000 Da. Following isolation, SP54 and urinary glycosaminoglycans have been selectively hydrolyzed under conditions (0.5 M HCl/105 degrees C/30 min) which produce an efficient yield of xylose from SP54 but not from the glycosaminoglycans. Xylose derived from SP54 has subsequently been determined using gas-liquid chromatography. Levels of SP54 down to 10 micrograms/ml have been determined using this technique.

Chromatography, Gas↗
PubMed1989

Quantitative analysis of peptide levels and neurogenic extravasation following regeneration of afferents to appropriate and inappropriate targets.

We have studied quantitatively the levels of substance P and calcitonin gene-related peptide in nerves innervating skin and muscle of rats, and examined the effects of cross-anastomosing these nerves so that they regenerate to an inappropriate target. We have also compared the ability of nerves to induce neurogenic extravasation with their peptide content. Peptide was measured by radioimmunoassay in the proximal section of ligated peripheral nerves, and neurogenic oedema was measured by determination of Evans Blue extravasation induced by either systemic capsaicin treatment or topical mustard oil application. The levels of these peptides are higher in cutaneous nerves than muscle nerves. This cannot be explained by differences in the number of fibres in the nerves studied. The levels of peptides fall when cutaneous afferents reinnervate muscle, and rise when muscle afferents reinnervate skin. We suggest that these changes occur because of some tissue-specific trophic influence arising from the tissue innervated. The ability to produce extravasation in skin is highly correlated with the substance P and calcitonin gene-related peptide levels of its innervation, even when this occurs in inappropriate nerves which do not normally produce extravasation.

Anastomosis, Surgical↗
PubMed2006

Quantitative analysis of the effect of cell type and cellular differentiation on protective antigen binding to human target cells.

We quantitatively measured protective antigen (PA) binding to human cells targeted by anthrax lethal toxin (LT). Affinities were less than 50 nM for all cells, but differentiated cells (macrophages and neutrophils) had significantly increased PA binding and endothelial cells demonstrated the most binding. Combined with the function of such cells, this suggests that PA receptors interact with the extracellular matrix and that differentiation increases the number of PA-specific receptors, which supports previously observed differentiation-induced LT susceptibility. Our results quantifiably confirm that the generality of PA binding will complicate its use as a tumor targeting agent.

Animals↗
PubMed2005

Quantitative analysis of the postnatal development of Purkinje neurons in the cerebellum of the cat.

We have studied the postnatal quantitative changes of cortical Purkinje neurons in the cerebellum of the cat at the following postnatal groups of age: P0, P42, P72 and adults. An unbiased counting method, the optical fractionator was used for the estimation of Purkinje cell numbers. A significant increase of Purkinje cell number was found between P0 (1.097 x 10(6)) and P42/P72 (1.805 x 10(6) and 1.895 x 10(6)) declining to 1.429 x 10(6) in the adult, still 30% higher than in the newborn. It was also observed that during the first few postnatal weeks large "gaps" were present in the Purkinje monolayer as revealed by Nissl staining and metabotropic glutamate receptor 1alpha immunocytochemistry. These Purkinje cell gaps were observed most frequently in well-definable areas, especially in the intermediate zone of the neocerebellum. Simultaneously with the numerical increase of Purkinje neurons between the P0 and P72 age groups, these gaps disappeared after the third postnatal week resulting in the completion of the Purkinje monolayer in the whole cerebellum.

Age Factors↗
PubMed2006

Simple pulse-acquire NMR methods for the quantitative analysis of calcium, magnesium and sodium in human serum.

Simple pulse-acquire NMR methods are presented for accurate quantitation of calcium (Ca(2+)), magnesium (Mg(2+)) and sodium (Na(+)) in human serum. Ca(2+) and Mg(2+) can be determined simultaneously by (1)H NMR via their EDTA (ethylenediaminetetraacetic acid) complexes. Spectra are acquired before and after addition of EDTA, and the difference spectrum is used for integration of the signals from the complexes relative to an internal reference. Serum sodium can also be determined through pulse-acquire (23)Na NMR by integration of the free sodium signal relative to a reference signal (Na(+)+EDTA in a coaxial capillary tube). The method shows excellent accuracy and precision for all three metal ions. Slow chemical exchange between complexed and free EDTA at the natural pH of serum does not limit the accuracy of the determination of Ca(2+) and Mg(2+), and the large errors associated with spin-echo spectral editing methods are avoided.

Calcium↗
PubMed1991

Quantitative analysis of lens changes after vitrectomy by fluorophotometry.

We measured the amount of autofluorescence in the lens to evaluate quantitatively lens changes after vitrectomy. Thirteen phakic patients, ranging in age from 12 to 75 years, were studied after unilateral vitrectomy, with a follow-up period of more than two years (range, 26 to 55 months). Autofluorescence in the lens was measured at the center along the ocular axis by fluorophotometry. Lens autofluorescence in the eyes that underwent vitrectomy was significantly higher than in the contralateral eyes that were not operated on (P = .0003). The increase of autofluorescence was correlated significantly with the age at time of vitrectomy (P = .0008). There was no correlation between the increase in autofluorescence and the length of postoperative follow-up or the use of air during vitrectomy. Based on these results, we believe that oxidation of lens proteins intraoperatively may be one of the causes of development of nuclear cataract after vitrectomy.

Adolescent↗
PubMed2003

Qualitative and quantitative analysis of human herpesviruses in chronic and acute B cell lymphocytic leukemia and in multiple myeloma.

Real-time quantitative polymerase chain reaction (qPCR) was used to quantify viral loads of human herpesviruses (HHVs) at diagnosis in 61 samples of malignant B cells: 21 chronic lymphocytic leukemia (B-CLL), 29 acute lymphoblastic leukemia (B-ALL) and 11 multiple myeloma (MM); control samples were blasts from 16 acute myeloid leukemia (AML) and 24 blood or bone marrow samples from healthy donors. The majority of samples from healthy donors and patients (B-ALL, B-CLL or AML, but not MM) was positive for EBV and contained <100 ebv copies/100 ng dna. ebv loads were occasionally high (>500 copies/100 ng DNA) in B-ALL (2/16) and in B-CLL (2/21) samples. The fractions of samples positive for HHV-8 and HHV-6A, less than 10% for MM patients, were high for adults with B-ALL (18.8% HHV-8+, 43.8% HHV-6A+) or B-CLL (28.6% HHV-8+, 52.4% HHV-6A+). B-ALL, B-CLL and MM samples were rarely positive for HHV-6B and HHV-7. Lastly, 75% of B-ALL samples were positive for CMV, and CMV loads were significantly higher in B-ALL samples than in MM, B-CLL or AML samples. We also used PCR with consensus-degenerate hybrid oligonucleotide primers (CODEHOP) to look for novel HHVs in B cell samples: no sequence indicative of a new HHV was detected. Altogether, the data indicate that the presence of multiple HHVs, including EBV and CMV at high loads, is not rare in B-ALL and B-CLL cell samples. Future prospective studies should determine whether patients with high EBV/CMV loads at diagnosis in tumor samples face a higher risk of delayed hematological recovery, virus-related complications or relapse.

Adolescent↗
PubMed2006

Magnetic resonance images of the globus pallidus in patients with idiopathic portal hypertension: a quantitative analysis of the relationship between signal intensity and the grade of portosystemic shunt.

BACKGROUND AND AIM: To elucidate a quantitative relationship between hyperintensity of the globus pallidus on T1-weighted magnetic resonance images (MRI) and portosystemic shunt (PSS) in portal hypertension. METHODS: Fifteen patients with idiopathic portal hypertension (IPH) and 44 patients with liver cirrhosis (LC) underwent brain MRI to asses signal intensity at the globus pallidus and Doppler sonography to examine the blood flow volume of PSS. Blood manganese (Mn) levels were examined in 36 patients and neuropsychological tests were performed in 15 patients without overt hepatic encephalopathy. RESULTS: Pallidal hyperintensity on MRI was more prominent in patients with IPH than in patients with LC. There was no correlation between MRI pallidal hyperintensity and the severity of liver dysfunction or hepatic encephalopathy. The grade of hyperintensity correlated well with the grade of PSS. The correlation was stronger in patients with IPH than in patients with LC. The plasma ammonia level and whole blood Mn level significantly correlated with MRI pallidal hyperintensity, but blood Mn level showed a stronger correlation than plasma ammonia. CONCLUSION: Hyperintensity of the globus pallidus on T1-weighted MRI correlated with the development of PSS independent of liver cell function. This brain image should be an index of the grade of PSS rather than a landmark of chronic liver failure.

Globus Pallidus↗
PubMed1993

A quantitative analysis of illusion magnitude predicted by several averaging theories of the Müller-Lyer illusion.

This article describes a quantitative method to evaluate several averaging (i.e., confusion and assimilation) theories by comparing predictions of the absolute magnitude of the Müller-Lyer (ML) illusion with results of previous studies of the composite ML figure. The magnitude of illusion was best predicted by Davies and Spencer's (1977) theory and by integrative field theory (Pressey & Pressey, 1992). Furthermore, when the ML figure was at the point of subject equality, the average of shaft and intertip distances, and the configural dimensions proposed by Davies and Spencer, were most frequently closest to being equal in the apex-in ML and apex-out ML. Results indicate that a comparison of predicted and reported absolute magnitudes of the ML illusion can provide quantitative criteria to distinguish and evaluate averaging theories of the ML illusion.

Adult↗