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At least 1,549 records · Page 86Linked to original sources
PubMed1994

Quantitative analysis of the compound muscle action potential in early acute inflammatory demyelinating polyneuropathy.

We quantitated the size and configuration of compound muscle action potentials (CMAPs) in 266 nerves (66 median, 67 ulnar, 71 tibial and 62 peroneal) of 72 patients with acute inflammatory demyelinating polyneuropathy (AIDP) initially studied within 19 days of symptom onset. Results were compared with criteria for CMAP abnormalities, including criteria for abnormal negative peak duration and desynchronisation, derived from a control population of 50 median, ulnar, tibial and peroneal nerves. Other motor conduction abnormalities including minimal F response latency were also examined. We also analysed patterns of CMAP abnormality, peak disability and outcome for AIDP patients who had at least 3 motor nerves evaluated at first electrophysiologic study. Amongst AIDP nerves, low amplitude of the distal CMAP, usually with prolonged distal latency, was much more common than an abnormal fall in CMAP amplitude between stimulus sites. Using our CMAP criteria more than half of these low amplitude distal responses showed prolonged negative peak duration of desynchronisation or both, consistent with demyelination. Of the 47 AIDP patients who had 3 or more nerves initially studied, 37 (78.7%) had at least 1 motor nerve with a distal CMAP showing evidence of temporal dispersion. In addition, those with at least 75% of motor nerves showing a pattern of low amplitude of the distal CMAP without a further significant fall in amplitude between stimulus sites had greater peak disability and a poorer outcome. Assessment of temporal dispersion of the distal CMAP should be included in electrophysiologic criteria for acute demyelination. In addition, for some patients with AIDP patterns of CMAP amplitude abnormality amongst motor nerves are present early in the illness and may provide prognostic information.

Action Potentials↗
PubMed1977

Erythromycin series. V. Quantitative analysis of cladinose and methylcladinoside by densitometry of thin-layer chromatograms.

A direct, quantitative, thin-layer chromatographic method is described for the determination of sugar cladinose and methylcladinoside in the presence of other acid-degradation products of the antibiotics erythromycin oxime and erythromycyl-amine. Cladinose and methylcladinoside are separated from compounds which cause interference on pre-coated silica gel F254 plates, and are measured directly on the thin-layer plate using a densitometer. Standard graphs obtained for cladinose and methylcladinoside show a linear relation between the square root of the peak area and the logarithm of the amount of substance present in the spot, as well as between the square of the area and the logarithm of the amount. This method is very successful in stability studies on the antibiotics erythromycin oxime and erythromycylamine in an acid medium. The technique seems to be particularly useful in instances in which the usual analytical methods either cannot be applied or can be applied only with difficulty.

Chromatography, Thin Layer↗
PubMed1999

Quantitative analysis of human cruciate ligament insertions.

The objective of this study was to provide quantitative data on the insertion sites of the cruciate ligaments. In the first part of the study, we determined the shapes and sizes of the insertions of the anterior and posterior cruciate ligaments (ACL and PCL), and further compared these data with the midsubstance cross-sectional areas of the ligaments. The cross-sectional area of the ACL and PCL midsubstance of 5 human knees was measured using a laser micrometer system. The insertion sites of each ligament were then digitized and the 2-dimensional insertion site areas were determined. Relative to the ligament midsubstance, the PCL tibial and femoral insertions were approximately 3 times larger, whereas those of the ACL were over 3.5 times larger. In the second part of the study, the ACLs and PCLs of 10 knees were each divided into their 2 components and the areas of each insertion were determined. Each component was approximately 50% of the total ligament insertion area and no significant difference between the 2 could be shown.

Aged↗
PubMed2001

Quantitative analysis of the electroencephalogram during cranial electrotherapy stimulation.

OBJECTIVE: Normal individuals were used to quantitate electroencephalographic (EEG) changes during concurrent administration of 0.5 and 100 Hz cranial electrotherapy stimulation (CES). METHODS: Twelve normal, right-handed males were used in a randomized, double-blind crossover design study. A 3 amplifier system incorporating noise-cancellation was used to collect one channel of EEG (O1-Cz configuration) for 30 min. Either 0.5, 100 Hz, or sham CES treatment was administered for 20 min of each session. Statistical analyses were applied to time- and frequency-domain EEG variables. RESULTS: Relative to sham control, 0.5 and 100 Hz CES caused the alpha band mean frequency to shift downward. Additionally, 100 Hz CES also caused a decrease of the alpha band median frequency and beta band power fraction. CONCLUSIONS: Both 0.5 and 100 Hz CES provide frequency distribution shifts that suggest beneficial changes in mental state. However, compared to 0.5 Hz CES, 100 Hz CES effected a greater overall change. It is suggested that similar tests be performed on individuals with various behavioral and neurological disorders to determine if comparable EEG changes can be realized and correlated with beneficial effects of CES therapy.

Adult↗
PubMed2004

Quantitative analysis of tooth pulp afferent terminals in the rat brain stem.

This study analyzed quantitatively the ultrastructural features of tooth pulp afferent terminals and their presynaptic axonal endings (p-endings) in the trigeminal principal (Vp), dorsomedial oral (Vdm), and caudal nuclei (Vc). Mitochondrial volume, active zone area, apposed surface area, and vesicle number were highly correlated with afferent bouton volume. The afferent bouton volume varied widely in Vp, compared to that in Vdm and Vc. The values of all parameters of p-endings were within a narrow range, and were smaller than those of afferent boutons. The afferent bouton volume correlated with the number of postsynaptic dendrites and p-endings. These results suggest that pulpal afferent information is regulated in a unique manner in the each trigeminal sensory nucleus.

Afferent Pathways↗
PubMed2003

Quantitative analysis of sinoatrial node using Doppler tissue images.

A method has been developed to quantitatively analyze sinoatrial nodes (SAN) using Doppler tissue images (DTI). Doppler tissue images of SAN are acquired using an intracardiac catheter via the superior vena cava in an in vivo experiment. A sequence of DTI images of a SAN is obtained, and a complete cycle of the SAN excitation is observed. The tissue acceleration of the SAN is extracted and quantitatively analyzed. The estimated time-acceleration curve of the SAN exhibits remarkable similarity to the electrocardiogram curve. This is the first report on such finding. The experimental results show that the tissue movement of the SAN correlates with electrical cardiac activities and closely associates with the different phases of the cardiac cycle. This method has great potential in characterizing the local cardiac activities through the study of the conduct pathway.

Acceleration↗
PubMed1997

Quantitative analysis of firing properties of pyramidal neurons from layer 5 of rat sensorimotor cortex.

Quantitative aspects of repetitive firing evoked by injected current steps and ramps were studied in layer 5 pyramidal neurons in brain slices of rat sensorimotor cortex to answer the following questions. Do the tonic firing properties of burst-firing and regular-spiking (nonbursting) neurons differ significantly? Does burst firing denote a discrete class of neurons or represent a continuum of firing properties? Is firing rate during the burst of action potentials related to stimulus amplitude? What aspect of the stimulus might the initial firing rate code? How stable are a neuron's firing properties over time? All recorded neurons fired tonically to a long-lasting current above a minimum value, and the tonic firing properties of most neurons were quite similar irrespective of their initial response to a current step. Only a group of high-resistance neurons had significantly different tonic firing properties. When slow current ramps (rising between 0.5 and approximately 20 nA/s) were applied, the relation between firing rate and current during the ramp was very similar to the relation between tonic firing rate and current obtained from long-lasting current steps. Low-resistance cells exhibited three distinct initial responses to a current step: fast adaptation, high-threshold bursts, and low-threshold bursts, observed in 54, 28, and 10% of recorded cells, respectively. High-resistance cells exhibited a distinctive slow adaptation of firing rate. Slowly adapting, fast-adapting (FA), and high-threshold burster (HTB) neurons exhibited no adaptation near the minimum current that evoked repetitive firing (I(o)). FA and HTB cells exhibited two-spike adaptation to a fina tonic firing rate during currents up to 1.6 times I(o). Only a higher current (2.1 times I(o)) evoked a burst in HTB cells, whereas a burst was evoked at I(o) in the low-threshold burster cells. In most cells analyzed, the initial firing rate, whatever its nature, increased monotonically with current step amplitude. The response to fast current ramps indicated that firing rate during adaptation or bursting may code rate of change of current. Repeated measurements during long-duration impalements indicated that both transient and tonic firing properties are stable over time. We discuss how the different tonic firing properties of large and small pyramidal neurons could be more important functionally than the different transient responses (burst/nonburst) of the large neurons. We conclude that the large neurons would perform a better linear transduction of time-varying synaptic current that reaches their somata. We compare the responses evoked by somatically injected current with those evoked by dendritic glutamate iontophoresis in previous studies.

Animals↗
PubMed1995

Quantitative analysis of repeat adenovirus-mediated gene transfer into injured canine femoral arteries.

We quantitatively evaluated the effectiveness of a repeat administration of a recombinant adenoviral vector expressing bacterial Escherichia coli lacZ into the same arterial site of a relatively large animal, the dog. The replication-defective adenoviral vector was introduced percutaneously into balloon-injured femoral arteries through a double-balloon catheter. After a single dose of adenoviral vector, up to 90% of surface (73 +/- 16%, n = 7) and smooth muscle cells in multiple layers of the media showed transgene expression as evaluated by 5-bromo-4-chloro-3-indoyl beta-D-galactopyranoside histostaining without extralocal expression, as assessed by polymerase chain reaction. High-level expression (measured as beta-galactosidase activity) peaked 7 days after transfer and was transient, although it was retained for a month. Second does of the same adenovirus to the same arterial site were given 1, 2, 5, or 8 weeks after the first administration. At 1 week the second dose significantly enhanced lacZ expression. At 2, 5, or 8 weeks the second dose reinduced lacZ expression at 25% to 30% of the full expression. lacZ expression was also detected in preimmuned dogs, although the expression levels correlated inversely to the titer of neutralizing antibodies in their serum. These results demonstrate that arterial gene expression can be enhanced by a second administration of the same adenovirus after a short interval and that a repeat dose after a long interval partially but significantly reinduces gene expression despite the presence of an immune response. These data may provide an additional scientific foundation for the use of adenovirus-mediated arterial gene transfer in future clinical practice.

Adenoviridae↗
PubMed2003

Quantitative analysis of the polyphenols of the aerial parts of rock samphire--Crithmum maritimum L.

Quantitative spectrometric analyses of the contents of flavonoids, tannins and total polyphenols in the aerial parts of rock samphire--Crithmum maritimum L., collected from three separated geographic locations along the Adriatic coast of Croatia in different growth stages, are reported. The results point to variability of the analyte content as a function of the growing site and growth stage. The content of flavonoids was found to be 0.08-0.42%. The highest content of flavonoids was found in the samples collected before flowering. The content of tannins ranged from 0.10 to 2.65%, while the content of total polyphenols varied from 4.72 to 9.48%. The highest contents of tannins and total polyphenols were found in the samples collected before flowering and at the beginning of flowering.

Apiaceae↗
PubMed1978

[Studies on diarrhea of young calves. 1. Quantitative analysis of the gastrointestinal flora in clinically healthy calves and in calves with diarrhea].

Quantitative composition of gastro-intestinal-flora was determined in 23 clinically healthy calves and the course of germ spreading was followed up. In comparison with these healthy animals in 25 diarrhoea affected calves at the age of 4 to 17 days there could be observed signigicant differences only in few parts of the gastro-intestinal-tract concerning the quantitative composition of germ flora. Only in 3 animals enterotoxin producing E coli strains could be detected.

Animals↗
PubMedDate not supplied

[Quantitative analysis of the changes in the nuclear apparatus of thyrocytes in experimental thyroid hyperfunction].

Quantitative ultrastructural characteristics (volume, surface area, volume fraction and surface density) of the nucleus, nucleolus and cell were studied in albino rats after long-term (5, 10, 15, 20 days) melanotropin (MSH) administration. The experiments showed that enhanced functional activity of thyroid cells induced by MSH administration was accompanied by an increase in the volume, surface area of the nucleus, nucleolus and the cell proper, as well as by an increased nuclear pore diameter. Consequently, the nucleus-cytoplasm ratio in thyroid cells rises.

Animals↗
PubMedDate not supplied

Phenolic acids from Ginkgo biloba L. Part II. Quantitative analysis of free and liberated by hydrolysis phenolic acids.

HPLC was applied to the quantitative assay of seven free phenolic acids from the leaves, roots and seed testas of Ginkgo biloba L. (Ginkgoaceae). The concentration of the free phenolic acids amounted to: 19.693 micrograms/g of fresh leaves, 345.321 micrograms/g of roots and 2.708 micrograms/g of testas: protocatechuic acid is a dominant one. The concentration of the phenolic acids liberated by acid-mediated and alkaline hydrolysis was determined as well.

Chromatography, High Pressure Liquid↗
PubMed1994

Decomposition of clozapine N-oxide in the qualitative and quantitative analysis of clozapine and its metabolites.

Pooled plasma from healthy volunteers was spiked with pure, synthetic clozapine or clozapine N-oxide and then made alkaline with either sodium hydroxide or sodium carbonate. The alkalized samples were allowed to stand at room temperature for various time intervals before extraction with organic solvent and then analyzed by high-performance liquid chromatography. It was found that clozapine N-oxide was reduced to clozapine in plasma made alkaline with sodium hydroxide, but such reduction was negligible in the plasma made alkaline with sodium carbonate. The amount of clozapine produced from clozapine N-oxide depended upon both the strength of the alkali added to the plasma and the duration of exposure of the plasma proteins plus clozapine N-oxide to the alkali. The reduction appears to take place through reducing equivalents generated by the action of strong alkali on plasma proteins. The thermal lability of clozapine N-oxide during gas chromatography-mass spectrometric analysis was also investigated. It was found that clozapine N-oxide was quantitatively decomposed to clozapine during gas chromatography-mass spectrometric analysis.

Chemistry Techniques, Analytical↗
PubMed1979

Quantitative analysis of corticosteroids in adrenal cell cultures by capillary column gas chromatography combined with mass spectrometry.

A quantitative method using glass capillary column gas-liquid chromatography (GLC) has been established for the analysis of corticosteroids in small biological samples such as a few milliliters of medium from steroidogenic cultured cells. The steroid extract is separated in three main thin-layer chromatographic fractions. The steroids assayed in these fractions are: less polar fraction (C21O2) steroids), 20 alpha-dihydroprogesterone, pregnenolone and 20 alpha-dihydro-pregnenolone; intermediate fraction (C21O3 steroids), deoxycorticosterone, 11-oxo- and several hydroxy-20 alpha-dihydroprogesterones; corticosteroid fraction (C21O4 steroids), corticosterone and 18-hydroxydeoxycorticosterone. The method has been assessed by characterizing the steroid structures and checking the purity of GLC effluents through direct coupling of the capillary column to the electron-impact or chemical-ionization source of a computerized mass spectrometer. Applications to the quantitative evaluation of the endocrinological status of newborn rat adrenocortical cell cultures under various conditions of development, hormonal stimulation or specific inhibition by drugs are described.

Adrenal Cortex Hormones↗
PubMed2006

Quantitative analysis of anti-inflammatory and radical scavenging triterpenoid esters in evening primrose seeds.

Lipophilic triterpenoidal esters with radical scavenging and cyclooxygenase inhibitory properties were recently found in cold-pressed, nonraffinated evening primrose oil (EPO). A quantitative assay for the analysis of 3-O-trans-caffeoyl derivatives of betulinic, morolic, and oleanolic acid in evening primrose seeds was developed and validated. Extraction efficiency >99% was achieved by means of pressurized liquid extraction with two extraction cycles and 80% (v/v) ethanol at 120 degrees C. Analysis of esters was by normal-phase high-performance liquid chromatography on a Diol column and hexane/ethyl acetate (containing 0.1% formic acid) (65:35) as the eluent. The analytes were determined without further prepurification. Seeds from defined cultures of Oenothera biennis, Oenothera lamarckiana, and Oenothera ammophila, grown under identical conditions, were analyzed. The cultures originated from seeds from eight collections in the wild and from selections from five cultivars. The content of total triterpenoidal esters in seeds varied between 1.34 and 2.78 mg/g. Three types of qualitative patterns were observed for the triterpenoidal esters. The influence of different harvest times and plant treatments was studied with the cultivar Anothera. Variations between 1.5 and 2.3 mg/g were found.

Anti-Inflammatory Agents↗