Adequate Purity Research Articles

Study of different factors affecting arginine-vasopressinradioimmunoassay

Since Robertson et al’s description of a radioimmunoassay (RIA) method [l] for the deter~nation of ar~nine-vasopressin (AVP) in human plasma, there have been several reports on the same subject. Some of the methods are not sensitive enough [2-81 for the detection of low levels of AVP in plasma, while others, although sensitive enough to detect these levels [9-161, use extraction methods which are too laborious. In addition, there is no general agreement on the stability of the samples ]7,9,10,13]. In this paper, we describe a sensitive method for plasma AVP measurement using a commercial antiserum and a simple method for extraction [7]. To obtain a labelled hormone with adequate specific activity and purity, most of the experimental work was dedicated to a detailed study of the purification procedure. The consequences of using metabisulphite in the iodination are discussed. We also report the results of a study on stability of AVP values in freeze-dried samples.

Alpha-Amylase determination using maltopentaose as substrate.

The rationale of choosing a NADP-coupled continuous method, with the substrate maltopentaose, as a method for the determination of alpha-amylase (EC 3.2.1.1) activity is investigated. The method presented is investigated with respect to all reaction parameters, including possible influence of protein, and shows zero order reaction kinetics after a 5-6 minute lag phase. The blank reaction from maltopentaose substrate is constant and is 13% of the upper limit of the reference interval for serum. The course of the blank reaction can be used to check that the maltopentaose is of adequate purity for use in the assay. Km for maltopentaose is 0.48 mmol/l. There is no interference from endogenous glucose when the total NADP turnover is less than 0.25 mmol/l. Data for sensitivity, linearity and long term precision over an eighteen month period are given, together with reference intervals for serum and for urine. The method is recommended for consideration as a reference method.

A method for culturing chick melanocytes: the effect of BRL-3A cell conditioning and related additives.

A method for growing chick embryo melanocytes is described that utilizes medium conditioned by Buffalo Rat liver (BRL-3A) cells. The dissected trunk region of each 72 h (Stages 14 to 19) embryo produces approximately 200,000 melanocytes (purity, 80%) when processed and cultured for 8 d. Thus, a typical experiment involving 20 embryos would produce a total of 4 x 10(6) melanocytes. Choice of serum, serum concentration, and cell density were determined experimentally. Partially purified multiplication stimulating activity (MSA) from BRL-3A cells and insulin were also tested as medium additives. MSA was not stimulatory, whereas insulin gave a positive response in 2% but not 10 or 0% serum. The final protocol used a modified F12 medium with 10% bovine calf serum conditioned by BRL-3A cells. Cultures were fed every other day. Small colonies of cells became evident by culture Day 3 and increased rapidly to Day 5 when pigmentation became obvious. Colony size continued to increase but more slowly from Days 5 to 8, whereas pigmentation increased rapidly and maximized on Day 8. There is a factor, or factors, present in BRL-3A conditioned medium that stimulates embryonic chick melanocytes to divide preferentially over contaminating cell types. This results in cultures that can provide adequate numbers and purity for biochemical studies.

A Shorter Synthesis of Muscimol

Abstract The naturally occurring zwitterionic alkaloid muscimol 3 1 has been of considerable pharmacological interest in recent years, it being the best example of an in vivo active mimetic of the neurotransmitter γ-aminobutyric acid (GABA).2 A number of syntheses of this compound have been reported over the past fourteen years, culminating in the recent report of Jager and Frey who prepared 1 in three steps and 30% overall yield.3 These latter authors suggested the shorter two step route depicted in Equation 1 but were apparently unable to synthesize the requisite hydroxamic acid 2 in adequate yield and purity to complete the synthesis. The original preparation of this hydroxamic acid had been reported by Hines and Stammer in 1977′ from dimethyl acetylenedicarboxylate and hydroxylamine. This procedure also gave a relatively crude and low melting product.

Directions for preparing aqueous solutions of primary odorants to diagnose eight types of specific anosmia

Practical information is summarized, which should be helpful for researchers who wish to set up standardized tests for eight well-defined varieties of specific anosmia in humans. Sources for odorants of adequate purity are listed, and directions are given for conveniently achieving the diagnostic dilutions in water.

Production and separation of thallium-201 suitable for clinical myocardial imaging.

SUMMARY Australia's only cyclotron was used to test the feasibility of producing Thallium-201 with adequate purity and in quantities suitable for general clinical application. Maximum beam energy of 26 MeV at 40μ A yielded an achievable production rate of 4mCi per hour thallium-201 (2 patient doses). This could be increased by an order of magnitude if a positive ion source were fitted to the cyclotron but the present radiation shielding would be inadequate for this manoeuvre. The final separated product proved to be compatible in purity with the only other published data and its efficacy as a myocardial imaging agent was successfully demonstrated in animals. Liaison with A.A.E.C. at Lucas Heights has begun with a view to satisfying locally the growing demand for this nuclide.

Crystal-controlled pump signal source for an experimental parametric acoustic receiving array

In the Parametric Acoustic Receiving Array (PARRAY), a locally generated, high-frequency carrier (or pump) wave is modulated in the water by a low-frequency acoustic wave. The information in the low-frequency signal appears as low-level modulation side bands of the pump wave; therefore, the side-band noise of the pump-signal source is an important PARRAY system parameter. Since commercial oscillators with adequate spectral purity were not available, a program was initiated to develop a 65-kHz crystal-controlled oscillator with sufficient spectral purity for use as the pump-signal source in an experimental PARRAY. Application of state-of-the-art techniques and components has enabled the design and construction of a crystal-controlled oscillator with spectral purity previously unattainable in this frequency region. Spectral purity of this oscillator is approximately four orders of magnitude better than commercially available oscillators in the 65-kHz frequency region. Measurements performed on the oscillator show that the spectrum level side-band noise referenced to the carrier level is better than −170 dB for frequencies greater than 100 Hz away from the carrier. The oscillator design is described in detail and side-band noise test data are presented and discussed. [This research was supported by the Advanced Research Projects Agency of the Department of Defense and was monitored by the Naval Electronics Systems Command under Contract NO0039-76-C-0231.]

Physicochemical and serological characteristics of respiratory virus fluorescein-isothiocyanate conjugates for fluorescent-antibody diagnosis

Fluorescein-isothiocyanate (FITC) conjugates were prepared by improved methods from standard reference antisera to influenza A and B, mumps, parainfluenza 1, 2, 3, and 4, herpesvirus, respiratory syncytial virus, and adenovirus hexon. The antisera, prepared in a variety of animals, were fractionated three times with selected optimal concentrations of ammonium sulfate and yielded gamma globulins of adequate purity for conjugation with FITC. Conjugates containing optimal fluorescein-to-protein ratios of between 5 and 10 were produced in 2 h by dialysis labeling. Serological titers of each antiserum and conjugate were determined by complement fixation, hemagglutination-inhibition, serum neutralization, and indirect hemagglutination tests where appropriate. When corrected for dilution, the serological titers of the FITC conjugates were identical to those of the starting antisera. The fluorescent-antibody staining titers correlated well with one of the serological parameters of the original serum. The conjugates stained homologous antigens specifically and were free of nonspecific staining at the working dilution. Undesired staining of host cells which was a problem with some of the conjugates produced from sera containing cellular antibodies was removed by absorption with packed cells. These physicochemical and serological findings were then used as a guide in preparing high quality reagents for fluorescent-antibody identification of respiratory viruses.

Isolation of lymphocytes from peripheral blood of dogs

Previous methods for the isolation of canine peripheral lymphocytes have not consistently produced cells of adequate purity. By means of centrifugation over a layer of Ficoll-sodium diatizoate of appropriate density, followed by passage through a simple column using nylon fibers, relatively pure lymphocyte fractions were isolated from canine peripheral blood. This simple and rapid technique requires no special equipment. Sixty percent of the total lymphocyte population was recovered. The fractions were composed of 96% normal small lymphocytes with a viability of 98%. The lymphocytes thus obtained were suitable for a lymphocytotoxicity assay.

Analyses of thermochemical errors and systematics in sublimation of lanthanide trifluorides

The measurements of the vapour pressures and associated thermochemical properties of inorganic substances at high temperatures has been plagued for decades with errors and nonreproducibilities. Errors as large as several kcal/mole in enthalpies and factors of two in vapour pressures are frequently encountered. To resolve some of these non-reproducibilities, at least four items are needed: 1. repetition of experimentation to test for reproducibiliity, 2. precision measurements so that some sources of errors can be eliminated, 3. statistical analyses which are more extensive and sophisticated than those usually performed and which are more applicable to small samplings, and 4. criteria which are beyond. the usual random statistics. Since the errors may be systematic and can be chemical in origin, it is productive to study systematic chemical effects concurrently with a study of errors. For this purpose, the investigation of the sublimation of the lanthanide trifluorides is useful. All of them are readily available with adequate purity. A sketch of the apparatus used to measure simultaneously mass-effusion and mass-spectrometric intensities of the species in the effusate is displayed in Figure 1 (3). The vacuum balance used is an Ainsworth semimicro Model

An improved fractionation system for pronase on CM-sephadex.

An efficient, single-column preparative-scale fractionation of pronase on CM-Sephadex using a linear gradient of pyridine-acetate, pH 5.0, has been developed. Under these conditions excellent resolution and minimal autolysis of the component proteolytic enzymes occurs. Only three major endopeptidases with caseinolytic activity are found. Streptomyces griseus trypsin (S.G.T.) is recovered in adequate purity for amino acid sequence studies. Streptomyces griseus Protease A and Protease B have been shown to correspond to PNPase I and II previously described by Wählby. Two aminopeptidases and a carboxypeptidase have also been demonstrated. Pronase appears to be a less complex mixture of proteolytic enzymes than had previously been appreciated.

Isolation and Purification of Metabolites Found in the Urine of Male Rats Fed Aldrin and Dieldrin

Abstract A procedure for the isolation and purification of aldrin and dieldrin metabolites derived from rat urine is described. The procedure yields enough material of adequate purity to enable the determination of the chemical structure of the metabolites.

The generic nature of the absolute-retardation method of photoelasticity

The method of absolute-retardation measurements does not depend upon the use of any specific interferometer. Any one of the many extended field interferometers can be employed, including the Series, Michelson, Mach-Zehnder and Fizeau types. Where adequate monochromatic purity of light source is available, reflections from the two surfaces of the model can form the interferogram, thus dispensing with the necessity of any separate optical interferometer.

Metabolic Activity of Purified Suspensions of Rickettsia rickettsi

THE independent metabolic activities of some of the obligate intracellular bacteria, such as rickettsiae and chlamydiae1, have been extensively investigated2. Such work has rarely included Rickettsia rickettsi, the agent of Rocky Mountain spotted fever, because of the difficulty of obtaining sufficient material of adequate purity and stability. The only data on respiration of R. rickettsi are those given in a preliminary report by Price3, who carried out his experiments with the collection from several thousand infected yolk sacs and tested the micro-organisms immediately after the final step of purification.

Acrylonitrile from Propylene, Ammonia, and Atmospheric Oxygen

AbstractAcrylonitrile was produced in pilot plant from propylene, ammonia, and atmospheric oxygen in a fixed‐bed reactor in the presence of Bi/Mo/Si oxide shell catalyst. The propylene conversion, which can amount to about 70% under optimal conditions, was studied as a function of structural properties and the chemical composition of the catalyst, and of the composition of the starting mixture. Acrylonitrile of adequate purity for use in polymerizations could be obtained by multi‐stage processing of the crude product.

Rare earth dibenzoylmethides preparation, dehydration and thermal stability

BS>A thermogravimetric study was made on the rare earth dibenzoylmethides in an inert atmosphere at atmospheric pressure. A general synthetic procedure by which most of the lanthanide dibenzoylmethide hydrates can be prepared in adequate yield and purity is described. The slow addition of aqueous ammonia to an ethanol-water mixture containing rare earth chloride, which is kept saturated with excess solid dibenzoylmethane, precipitates the compounds as hydrates. Thermogravimetric curves for hydrated rare earth dibenzoylmethides heated in an argon atmosphere are presented. (P.C.H.)

A simple monochromator

An easily constructed apparatus, giving illumination by light of any chosen colour, and of adequate purity in a narrow spectral region, has been made and found satisfactory in the determination of the optical properties of crystals.Light of high intensity is focused on an adjustable slit, rendered approximately parallel by means of a lens, and passed through two hollow prisms containing alpha-monochloronaphthalene. In the widely divergent spectral beams the microscope moves along a calibrated arc and any desired wave-band of reasonable purity may be selected. The apparatus is illustrated in the accompanying diagram (fig. 1) and photograph (fig. 2).A small carbon arc (A) using direct or alternating current gives adequate intensity, allowing for a narrow setting of the slit, with corresponding purity of the monochromatic beam.

Development and Operation of a Line-Screen Color Kinescope

A color-television receiver employing a single kinescope of the line-screen type has been developed. The kinescope screen consists of many hundred narrow parallel phosphor strips of the three primary colors, arranged cyclically. In the method investigated in greatest detail, the raster scanning lines are parallel to the phosphor strips. Circuit means are provided to cause the scanning lines to coincide with the phosphor strips of a single color. The beam is then deflected by a "stair-step" wave to the adjacent lines of the two remaining colors to generate color-dot areas in synchronism with the received color signal. The required registration of scanning lines with the screen elements is obtained by means of a servo circuit deriving control information from secondary-emission-signal areas on the kinescope screen. Various alternatives to this arrangement have also been investigated. Kinescopes of 16-inch envelope diameter have been employed to give color pictures of high horizontal definition and adequate color purity.

Standard Quality of Photographic Chemicals

Photographic Processing inherently involves chemical operations which require adequate purity of the chemicals to attain a high standard of photographic quality. As a result, it has been found desirable to set up standards of purity for “photographic grade” chemicals to meet the requirements of the various sensitive materials and processes. These chemicals fall into groups according to their use or chemical nature : developing agents, alkalies, sulfites, restrainers and antifoggants, fixing agents, acids, hardeners, and a group of miscellaneous chemicals.