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PubMed1983

The polypeptide profiles of strains of the Trypanosoma subgenera Schizotrypanum and Trypanozoon: peptideme characterization.

Examination, by SDS-PAGE, of the polypeptide profiles of 36 Brazilian strains of Trypanosoma (Schizotrypanum) cruzi has revealed five peptidemes (subpopulations having similar polypeptide profiles) recognizing differences not apparent from zymodeme analysis. T. cruzi zymodeme (Z)1 has been subdivided into peptidemes 3, 4 and 5 (one example of Z2 was included in peptideme 5). Peptideme 1 consisted mostly of Z2 strains except for one example each of Z1 and Z3. One strain of Z2 (Tc 003) was sufficiently dissimilar to merit separation into peptideme 2. Peptideme characterization was not possible with the Trypanozoon trypanosomes since there were no significant differences in the polypeptide profiles of 56 strains from Africa and South America; their profiles could only be compared in the molecular weight ranges 94,000 to 70,000 and below 36,000 because of distortion resulting from the variant specific surface glycoproteins. It was possible to differentiate between eight VATs of T. (Trypanozoon) brucei (BruTat 2 to 9) by isoelectric focusing of their soluble proteins.

Animals↗
PubMed1992

Variability in alkaloid profiles in neotropical poison frogs (Dendrobatidae): genetic versus environmental determinants.

Dendrobatid frogs produce a diverse set of alkaloids, whose profiles appear characteristic of frogs of each species or, in the case of variable species, of each population. In the case of one widespread species, Dendrobates auratus, alkaloid profiles in extracts of skin are markedly different in three populations, one from a Pacific island, Isla Taboga, Panama, one from central mountains in Panama, and the third from the Caribbean coast in Costa Rica. The first contains three major classes of dendrobatid alkaloids, the histrionicotoxins, the pumiliotoxin-A class and the decahydroquinolines. The second contains mainly histrionicotoxins, pumiliotoxin-A class alkaloids and one indolizidine. The third contains histrionicotoxins, a homopumiliotoxin, one decahydroquinoline, and a variety of indolizidines, quinolizidines and pyrrolizidines. Frogs from Isla Taboga or a nearby island were introduced into the Manoa Valley, Oahu, Hawaii, in 1932. Remarkably, although alkaloids of the pumiliotoxin-A class and one decahydroquinoline are still major constituents in skin extracts of Hawaiian frogs descended from the 1932 founding population, histrionicotoxins are absent and a novel tricyclic alkaloid is present. Offspring of wild-caught parents from Hawaii, Panama or Costa Rica raised in indoor terrariums on a diet of crickets and fruit flies do not contain detectable amounts of skin alkaloids. Offspring raised in large outside terrariums in Hawaii and fed mainly wild-caught termites and fruit flies do contain the same profile of alkaloids as their wild-caught parents in Hawaii, but at reduced levels. The genetic, environmental and dietary determinants of alkaloid profiles in dendrobatid frogs remain obscure, in particular the underlying cause for total absence in terrarium-reared frogs.

Alkaloids↗
PubMed1993

Molecular weight and biochemical profile of a chemically modified heparin derivative, Suleparoide.

Recently, a new chemically modified derivative of heparin (Suleparoide, Syntex Laboratories Buenos Aires, Argentina) was introduced for the prophylaxis of thrombosis and treatment of vascular disorders. This agent is claimed to contain a depolymerized, chemically modified, heparin derivative with similar biologic actions as heparan sulfate. To study the pharmacologic profile of this agent, we have defined its molecular weight distribution profile, utilizing a computerized gel permeation chromatographic system equipped with ultraviolet and refractive index detectors. Suleparoide exhibited a normal molecular distribution profile with no contaminants. It exhibited a weight average of 9.3 K DA and an apparent peak MW of 8.0 K DA. Approximately 50% of the molecular components were < 5.0 K DA and 40% > 5.0 K DA. The results from these studies on the mechanisms show that Suleparoide has anticoagulant activity primarily mediated through Heparin Cofactor-II (HC-II) and because of its novel mechanism of action, further investigations on the biochemical profile of Suleparoide are carried out. Global clotting tests such as Activated Partial Thromboplastin Time (APTT), Heptest and Thrombin Time (TT) revealed a concentration dependent effect in all assays. Plasma samples supplemented with Suleparoide exhibited no significant anti-Xa and anti-IIa activities. However, in the HC-II mediated inhibitory assay for IIa, Suleparoide exhibited significant activity. In contrast, the Antithrombin-III (AT-III) mediated inhibition of IIa was much weaker.

Antithrombin III↗
PubMed1983

Prediction of melting profiles and local helix stability for sequenced DNA.

The utility and limits of the current theory of helix-coil transition of DNA were intensively studied. Comparison of calculated and observed melting profiles affords solid criteria of a theoretical model and parameter values. Our model differs from others in that heterogeneity in stacking interactions is taken into consideration (Section II). The parameter values were estimated by fitting calculated to observed profiles for several known-sequenced DNA fragments (Section III). Calculated profiles agree quite well with observed, not only for DNAs used for the fitting but also for those not used. Such good agreement was never obtained with traditional two-term (A X T and G X C) stability assignment. It was shown that the all-or-none approximation for local melting transition (Azbel's model) provides informative but somewhat erroneous estimates of local stability. The stabilities of 10 kinds of stacking doublets estimated by the fitting accord well with known properties of DNA double helix (Subsection III-4); three-dimensional structure, calculated stacking energies, and binding specificity of some intercalative drugs are all consistent with the estimated order of stacking stabilities. Relationship between triplet stability and genetic code was discussed. The mechanisms of ionic-strength dependence of melting profiles were discussed in Section IV. Four different mechanisms were proposed and their relative contributions in various salt ranges were considered. It was suggested that at low ionic strengths melting processes deviate significantly from equilibrium, which fixes a limit to the applicability of the present theoretical mode. Locally unstable regions and frequently opening regions were located on several natural DNAs by calculating probabilities of individual base-pair doublets being in an unstacked state. With few exceptions, origins of DNA replication on various DNAs fall on frequently opening regions, indicating their functional importance. Positive correlations were also obtained between frequently opening regions and transcriptional promoters, terminators and gene boundaries (Section V).

Base Composition↗
PubMed1977

Carbon dioxide urethral pressure profiles in males.

Carbon dioxide urethral pressure profiles were obtained in a group of continent and incontinent male patients. Cystometry, needle electromyography of the striated urinary sphincter, and cystourethroscopy were also performed in most patients. A characteristic reproducible urethral pressure profile can be obtained in the continent, obstructed, and incontinent groups. The results also showed that the urethral pressure profile is influenced by the activity of the periurethral striated muscle. The urethral profile when performed with other established urodynamic procedures is a useful test in delineating normal and abnormal urinary sphincter function.

Adolescent↗
PubMed1983

Testosterone plasma profiles, as a function of age in young bulls from the bovine double-muscled Belgian white blue breed a preliminary report.

Plasma testosterone (T) 10 hour-profiles were determined at 10-day intervals in 29 young double-muscled bulls from the BBB-V breed between the ages 130 days and 190 days. Age at onset of T pulsatile profiles allowed to distinguish 3 groups of animals: We hypothesize that early appearance of pulsatile T profiles might mean precocity in onset of male puberty and sexual maturity. If this assumption is true, determination of T plasma profiles at a well specified age, might allow early selection of sexually precocious and capable BBB-V males.

Journal Article↗
PubMed1983

Seasonal LH profile in ovariectomized cattle.

Two experiments were conducted to examine seasonal changes in circulating LH concentrations in ovariectomized heifers. In experiment 1, four Holstein heifers were ovariectomized in April 1977 during middiestrus. Blood samples were collected daily for 30 days surrounding each equinox and solstice for one year to examine changes in plasma LH levels at the time of seasonal photoperiod changes. The LH concentrations were highest during the winter solstice period and lowest during the summer solstice period. In addition, samples taken at two-week intervals indicated a distinct LH profile with maximal LH concentrations during November-April and minimal concentrations during May-October. In experiment 2, eight Holstein heifers were ovariectomized in June-July, 1979 and given an estradiol or a control implant in October. A distinct LH profile for the interval extending from January, 1980 to February, 1981 was found in the heifers that were not treated with estradiol. Concentrations were maximal during December-April and minimal during May-November. The LH profile followed a similar pattern in the estradiol-treated heifers; however, the overall profile was at a higher level. These data indicate that underlying seasonal reproductive mechanisms are present in cattle even though the species ovulates and breeds throughout the year.

Journal Article↗
PubMed1995

Plasmid profile and phage type of Salmonella typhimurium strains encountered in different regions of India.

A total of 190 Salmonella typhimurium strains encountered in different parts of India were characterized on the basis of plasmid profile, phage type and antimicrobial resistance pattern. Recent trends in the epidemiology of R-plasmids were also studied. The majority of S. typhimurium strains (90.5%) were untypable by phage typing. Only 18 strains (9.5%) were phage typable. The phage untypable strains isolated from northern (57) central (65), and southern (50) regions of India could be subgrouped into 24, 12 and 16 different plasmid profiles respectively. Heterogeneity was the prominent feature although most of the plasmid profiles were related among strains isolated from particular place. A great diversity among small plasmids (2.7-8.3 kb) made subgrouping of majority strains (71%) with R-pattern ApCmKmSmSuTcTp possible. Conjugation studies and plasmid profile analysis of transconjugants revealed all the strains to harbour non conjugative non-auto transmissible plasmids with the exception of 7.2 and 2.7 kb plasmids which were not mobilizable.

Bacteriophage Typing↗
PubMed1991

Methods for studying the conductance changes associated with synaptic activation of forebrain slices: the interpretation of field potentials using CSD profiles.

In this report the cortical slice preparation and an array electrode that instantaneously records laminar field potentials are used to evaluate issues related to the interpretation of cortical CSD profiles. The major issues are: (1) what cell types are responsible for producing the source/sink pairs seen in CSD profiles; (2) what neurotransmitters are responsible for producing the sinks/sources seen in the CSD profile and do the sinks/sources reflect activation of receptors that produce inward currents, outward currents, or both; (3) can active and passive currents be distinguished; (4) do action potentials contribute to the CSD profile; and (5) can synaptic population with different kinetics and onset latencies be distinguished? Methods for analyzing neuronal circuits and analyzing CSDs quantitatively are discussed.

Animals↗
PubMed1996

Computer aided data acquisition and analysis of acetlycholinesterase velocity sedimentation profiles.

Acetylcholinesterase (AChE) is an enzyme that appears in several molecular forms. Individual AChE molecular forms can be isolated and identified on the basis of their velocity sedimentation profiles. We have improved an existing method for analyzing AChE sedimentation profiles with a computer aided data acquisition and analysis system. The software facilitates measurements of AChE activity of individual molecular forms and comparison among AChE velocity sedimentation profiles. In practice, our program increased precision and reduced the time of AChE velocity sedimentation profile analysis. The software can also be applied to velocity sedimentation analysis of other proteins. We plan to upgrade the program by making it compatible with Microsoft Windows.

Acetylcholinesterase↗
PubMed1992

beta-Lactamase substrate profiles of coagulase-negative skin staphylococci from orthopaedic inpatients and staff members.

Three different beta-lactamase substrate profiles were identified in 95 isolates of coagulase-negative staphylococci (CNS), of 57 different phenotypes, from 16 orthopaedic inpatients and staff members in one ward, by applying a bacterial whole-cell assay based on the hydrolysis of cefazolin, cephaloridine and nitrocefin. The typability of the assay was 93%, and 91% of the CNS isolates could be classified. To assess the discrimination between the beta-lactamase profiles obtained in the whole-cell assay, beta-lactamase extracts from 19 of the CNS isolates were used for estimation of their relative beta-lactamase substrate affinity index (RSAI). The RSAI assay was able to type previously unclassifiable or nontypable isolates. Two of the profiles obtained with the whole-cell assay were similar to those of the Staphylococcus aureus controls producing A or D and B or C beta-lactamases respectively. The distribution of beta-lactamase substrate profiles among the CNS isolates indicated an efficient spread of these drug resistance genes.

Coagulase↗
PubMed1986

Profile planning based on alterations in the positions of the bases of the facial thirds.

To analyze the profile properly, the size and position of the bases of the facial thirds must be known. In this study an average face was created by standard cephalometrics. The bases of the facial thirds were then moved in the horizontal or vertical direction, and the soft tissue profile was drawn to correspond to the skeletal changes. The results show how underlying skeletal abnormalities influence the profile. The terms used to describe the size and position of the bases serve as an aid in profile planning.

Cephalometry↗
PubMed1990

Effects of transducer beam geometry and flow velocity profile on the Doppler power spectrum: a theoretical study.

A theoretical model is used to show how the Doppler spectrum for various axisymmetric velocity profiles is affected by beam misalignment and incomplete insonation. Results are presented for both circular and square beam geometries. Moreover, a closed-form expression is derived for the power spectral density received by an on-axis transducer with a Gaussian beam profile. It is shown that the error incurred in measuring the mean Doppler frequency with such a profile will generally be bounded by the results for the circular and square beam geometries. The effects of an ideal high-pass filter on the mean Doppler frequency and the backscattered Doppler power are examined. It is shown that such a filter can introduce large differences in the measured systolic to diastolic power ratios. Finally, theoretical expressions and results are presented for the spectral broadening index (SBI), normalized spectral variance (NSV), coefficient of kurtosis (CK), the coefficient of skewness (CS) as functions of the axisymmetric velocity profile shape assuming complete uniform insonation.

Blood Flow Velocity↗
PubMed1987

Characterisation of rotavirus isolates from sub-clinically infected calves by genome profile analysis.

Rotaviruses isolated from 43 sub-clinically infected calves from a single farm were analysed by genome profile analysis. The isolates showed genomic variation and eight different profiles were observed, including one which was atypical for Group A rotaviruses. The 3' terminal labelling method for the analysis of genome profiles used in this study required only 1 ng of viral RNA, an increase of 1000-fold in sensitivity over ethidium bromide staining for detecting all rotavirus genome segments. However, dual infections involving two rotaviruses with distinct profiles could not be detected if the concentrations of the viruses differed by greater than 10-fold.

Animals↗
PubMed1990

Slice profile improvement for a clinical MRI system.

Optimal control methods have been recently introduced to improve the design of selective radio frequency pulses and several optimized selective pulses that can produce excellent slice profiles have been reported. These pulses usually require high peak rf amplitudes to implement and thus can not be widely utilized because of the limitations of the specific absorption rate and the rf power amplifier of a clinical system. We have a Siemens 1.5 T MRI clinical system. Several pulse files which consist of the bandwidth matched 90 degrees and 180 degrees selective pulses are provided. Some of these can produce excellent slice profiles. However, they can only be used in the pulse sequences with the pulse length of 5.12 msec. The purpose of this paper is to improve the slice profiles produced by the pulse file in the pulse sequences with the shorter 2.56 msec pulse length. A pulse file optimized by the conjugate gradient method is proposed to substitute the 2.56 msec Siemens pulse file. Our experimental results confirm that the slice profiles and images are improved by the optimized pulse file with a lower peak voltage. The proposed pulse file can also be applied in other clinical MRI systems.

Magnetic Resonance Imaging↗
PubMed1992

Calculation of atrioventricular compliance from the mitral flow profile: analytic and in vitro study.

The quantitative assessment of ventricular diastolic function is an important goal of Doppler echocardiography. Hydrodynamic analysis predicts that the net compliance (Cn) of the left atrium and ventricle can be quantitatively predicted from the deceleration rate (dv/dt) of the mitral velocity profile by the simple expression: Cn = - A/rho dv/dt, where A is effective mitral valve area and rho is blood density. This formula was validated using an in vitro model of transmitral filling where mitral valve area ranged from 0.5 to 2.5 cm2 and net compliance from 0.012 to 0.023 cm3/(dynes/cm2) (15 to 30 cm3/mm Hg). In 34 experiments in which compliance was held constant throughout the filling period, net atrioventricular compliance was accurately calculated from the E wave downslope and mitral valve area (r = 0.95, p less than 0.0001). In a second group of experiments, chamber compliance was allowed to vary as a function of chamber pressure. When net compliance decreased during diastole (as when the ventricle moved to a steeper portion of its pressure-volume curve), the transorifice velocity profile was concave downward, whereas when net compliance increased, the velocity profile was concave upward. Application of the preceding formula to these curved profiles allowed instantaneous compliance to be calculated throughout the filling period (r = 0.93, p less than 0.001). Numeric application of a mathematic model of mitral filling demonstrated the accuracy of this approach in both restrictive and nonrestrictive orifices.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Function↗
PubMed1994

Estimation of regurgitant flow volume based on centerline velocity/distance profiles using digital color M-Q Doppler: application to orifices of different shapes.

OBJECTIVES: In this study we investigated the centerline velocity profile method for flow computation as applied to noncircular, as well as circular, orifices using digital color flow data. BACKGROUND: Recently it has been suggested that flow volume through an orifice can be estimated more accurately by computing the axial "centerline" flow velocity/distance profile proximal to the orifice. METHODS: A total of seven different orifices were mounted in a constant-flow model: four circular orifices, two rectangular orifices with a major/minor axis ratio of 4:1 and 8:1 and an ovoid orifice having a major/minor axis ratio of 2:1. Three different flow rates were examined (1.68, 3.48 and 6.48 liters/min). Digital measurements of flow velocity at discrete positions along the centerline progressing toward the orifice were analyzed to yield complete flow velocity profiles for each orifice at each flow rate. RESULTS: A clear separation of the flow profiles for the three different flow rates was observed independent of orifice size for all of the circular orifices. The velocity/distance acceleration curves showed highly significant correlations using multiplicative regression fits (y = ax-b, r = 0.94 to 0.99, all p < 0.0001). An equation for quantitatively correlating the a and b coefficients from the multiplicative regression fits with flow rates was derived from stepwise regression analysis: Flow rate = 23a + 3.3b - 1.5 (r = 0.97, p < 0.0001, SEE 0.46 liter/min). CONCLUSIONS: In view of the various sizes and shapes encountered clinically for regurgitant orifices, the simplicity of this method for the estimation of the severity of regurgitant lesions might be of importance for clinical applications of this method.

Blood Flow Velocity↗
PubMed1994

Two-dimensional mitral flow velocity profiles in pig models using epicardial Doppler echocardiography.

OBJECTIVES: This study investigated the velocity distribution across the natural mitral valve. BACKGROUND: Information about the blood velocity distribution across the mitral valve is of interest in basic fluid dynamic studies of the natural mitral valve and is needed for precise cardiac output estimates by Doppler echocardiography. METHODS: The velocity distribution across the mitral valve was measured by epicardial Doppler echocardiography in ten 90-kg anesthetized pigs. By rotating the ultrasound transducer in 30 degrees intervals from the apical position, we constructed two-dimensional velocity profiles across the left ventricular inflow tract from diameters from each rotation arranged around a reference point. The time-averaged mitral velocity profile was calculated to estimate the error in cardiac output calculations that may occur with pulsed Doppler ultrasound when a single sample volume is used to record the mean velocity across the mitral orifice. RESULTS: The time-averaged diastolic cross-sectional mitral velocity profiles at the level of the mitral annulus and leaflet tips were variably skewed because of the development of a large anterior vortex in the left ventricle during the deceleration of early diastolic inflow and atrial systole. The ratio of the time-velocity integral of the center sample volume to the spatially averaged time-velocity integral was 1.13 +/- 0.15 (mean +/- SD) (range 0.80 to 1.32). Using regression analysis, we found a correlation between the degree of nonuniformity of the cross-sectional velocity distribution and the peak velocity of the anterior vortex (r = 0.65, p < 0.01). CONCLUSIONS: The assumption of a flat mean velocity profile across the mitral valve can introduce errors of +13 +/- 15% (mean +/- SD) in cardiac output measured with pulsed Doppler ultrasound when one is interrogating a single center sample volume.

Animals↗