Prevention of Chemography in Prestained Epoxy Autoradiographs by an Intervening Carbon Film

Evaporation of a carbon layer over toluidine blue stained epoxy sections prior to applying emulsion eliminates or significantly reduces chemography that would otherwise be present in autoradiographs. This simple procedure permits routine proceasing of large numbers of slides without the limitations of the impermeable membranes currently recammended for light microscopic autoradiography following prestaining. The method permits “before and after” microphotography and use of simple staining procedures for sections to be studied autoradiographically.     

A technique for quantifying the amount of macromolecule injected into cells of the early mouse embryo

A simple technique for the quantification of the volume injected into an individual mouse egg or blastomere is described. The method does not seem to have deleterious effects on development, allows the progeny of the injected cell to be identified and permits the measurement of the injected volume to be made up to 48 h after the time of injection.     

A simple method of protein determination in polyacrylamide gel using silver staining

A simple and relatively rapid method is elaborated for development of electrophoregram in PAAG by silver binding directly with protein. This permits avoiding the gel staining, considerably improves the quality of staining and promotes better reproducibility of the results. Sensitivity of the method permits detecting 1 ng of protein in the band.     

When alcohol is the answer: Trapping,identifying and quantifying simple alkylating species in aqueous environments

Alkylating agents are a significant class of environmental carcinogens as well as commonly used anticancer therapeutics. Traditional alkylating activity assays have utilized the colorimetric reagent 4-(4-nitrobenzyl)pyridine (4NBP). However, 4NBP based assays have a relatively low sensitivity towards harder, more oxophilic alkylating species and are not well suited for the identification of the trapped alkyl moiety due to adduct instability. Herein we describe a method using water as the trapping agent which permits the trapping of simple alkylating electrophiles with a comparatively wide range of softness/hardness and permits the identification of donated simple alkyl moieties.     

A simple way to look at DNA

A method is presented for embedding nucleotide sequence data in a simple metric space. Computer graphical examination of spatially-represented sequences permits rapid searches for canonical patterns or interesting structures. Sequence comparisons are facilitated by plots of distance measures for homologous sequences, and the large-scale structure of the genetic code can be studied by measures such as fractal dimensionality.     

Complementation Analysis of Simian Virus 40 Mutants

Seventy six new temperature-sensitive mutants of simian virus 40 have been isolated. A simple modification of the standard plaquing technique permits complementation analyses to be performed readily. By using this technique the new mutants have been divided into four complementation groups.     

Simple Modification to Improve Usefulness of the Bacti-Cinerator

A simple inoculating loop support is described which frees both hands for other operations or permits the use of two loops.     

Prediction of primary structure deamidation rates of asparaginyl and glutaminyl peptides through steric and catalytic effects.

The primary sequence dependence of deamidation has been quantitatively explained on the basis of a simple steric and catalytic model. Application to the known deamidation rates of peptides produces a table of coefficients that permits calculation of the known deamidation rates and prediction of deamidation rates for peptide sequences that have not yet been measured. This work permits a better understanding of deamidation, provides a prediction procedure for protein engineering, and facilitates improved computation of peptide and protein primary, secondary, tertiary, and quaternary structure deamidation rates.     

Differentiation of the sibling species Biomphalaria occidentalis and Biomphalaria tenagophila by the electrophoretic patterns of their hemoglobin

A simple and rapid method for differentiating the sibling species Biomphalaria tenagophila and Biomphalaria occidentalis by agarose gel electrophoresis (AGE) is described. Snail hemolymph is used as the test sample and the red coloration of the hemoglobin fraction permits visualization of the migration patterns without resorting to specific stains. Moreover, hemolymph samples may be obtained without killing the snail, thus permitting its use for other studies or for breeding.     

Discriminant-analytic structure-effect relationship of qualitative biological data. Virostatic effect of isatin-beta-isothiosemicarbazones]

"Yes/No" results from the plaque-diffusion inhibition test concerning the virostatic activity of substituted isatin-beta-isothiosemicarbazones against mengo- and vaccinia-viruses can be described discriminant analytically by means of simple substituent constants. The discriminant analysis permits quantitative structure-activity analysis of qualitative and semi-quantitative test data, thus offering a chance for theoretical synthesis optimization already at the level of rough screening.     

Quantitation of oxypurines and allopurinol metabolites in biological fluids by cation-exchange chromatography

Chromatography of urine, cerebrospinal fluid, and deproteinized serum on 30 × 0.9 cm columns of AG 50 permits the convenient separation of hypoxanthine, xanthine, allopurinol, and its metabolites. Quantitation by determination of absorbance at 250 mμ is accurate and can be automated. Column preparation is simple, and the columns can be regenerated and used daily for several months with no loss of resolution.     

A device for discrete information input into the Elektronika DZ-28 microcomputer

A simple matching device destined for the connection of electrophysiological plant with micro-computer "Electronics DZ-28" has been described. The device permits to carry out straight input of information concerning neurones impulsive activity.     

A simple device for harvesting biological fluids at the microscopic level

A simple aspirating device is described which permits repeated samples of biological materials to be taken near or at the microscopic level. It features an inner coaxial tube which delivers a harvesting fluid into the very tip of the collecting needle, permitting metabolic activity in the sample to be quenched immediately. The device is easily constructed from common laboratory material.     

Amniotic Fluid Crystallization Test for Ruptured Membranes

A simple and inexpensive test is described which permits positive identification of amniotic fluid by its fern-type crystallization. It permits a rapid and certain differential diagnosis between leukorrhea, hydrorrhea, urinary incontinence and spontaneous amniotomy. The crystallization test was shown to be most reliable and the few sources of error are easily avoided. The test is inhibited by cellular debris or blood when it is in a concentration greater than 1:10. Centrifugation permits the reappearance of fern-leaf crystallization. The typical image resembles that of the crystallization of cervical mucus. However, amniotic fluid crystallizes on the entire smear, whereas mucus crystallizes in a linear fashion. Cervical mucus crystallization is normally absent during pregnancy. It may occur in cases of threatened abortion. The authors have performed the test in combination with a nitrazin paper test in a series of 192 patients. In their hands it has given nearly perfect results.     

An anesthetic system for small laboratory animals.

A non-rebreathing anesthetic system for administering volatile anesthetic mixtures to small laboratory animals was designed. The device is easily constructed and simple to operate, yet permits the anesthetic management of small animals by technics similar to those used for man and larger species.     

Significant enhancement of fluorescence on hybridization of a molecular beacon to a target DNA in the presence of a site-specific DNA nickase

We have developed a simple isothermal (55 degrees C) reaction that permits detection of DNA targets using only two components: a molecular beacon and a site-specific DNA nickase without deoxyribonucleotide triphosphates and primers. The loop sequence of the molecular beacon should contain a DNA nickase recognition site. The nickase-molecular beacon (NMB) combination permits a 100-fold increase in fluorescent signal. The applications of the NMB assay for enhancement of fluorescent signal in some isothermal methods are discussed.     

Spectrophotometric quantitation of silver grains eluted from autoradiograms

Autoradiograms or fluorograms can be quantified by eluting the silver grains from the developed film with 1 M NaOH and measuring the absorbance of the eluate in a conventional spectrometer. In contrast to direct scanning of the film, the present method is rapid, requires only simple equipment, and permits accurate quantitation of even heavily exposed bands.     

Determination of DNA base composition by small scale acrylamide-CsCl gradient centrifugation

In this paper we describe a simple and rapid protocol for DNA base composition determination by CsCl gradient in the presence of acrylamide. This method permits the determination of GC content in microgram amounts of DNA, and results are easily documented in photographs or graphs. The protocol was applied to the characterization of nematode DNA, but can be used for other organisms. Analyzing several experiments the mean standard deviation observed in the calculated GC content is near 1.3%.     

A New and Simple Method for Studying the Microanatomy of Nephrons and Collecting Tubules

A simple procedure for studying the microanatomy of the kidney by light microscopy is described. Specimens are dried by the critical-point method and later impregnated with a mounting medium. The retention of air within the lumen of nephrons and collecting tubules permits their visualization. The method allows the observation of renal microanatomy without the distortions produced by microdissection or the loss of structural relationships among different kidney components. It also permits observation of the same specimen by both light and scanning electron microscopy.     

Detection of human blood by cloth-based enzyme immunoassay of immunoglobulin G

A specific and sensitive assay for the detection of human blood was developed using polyester cloth coated with goat anti-human IgG antibody to capture human IgG, an abundant and stable protein in blood. The captured IgG was detected by the reaction between goat anti-human IgG antibody-peroxidase conjugate and a chromogenic peroxidase substrate. Because the assay is simple and rapid, and permits simultaneous analysis of multiple samples, it has the potential to be used as a forensic test for human blood.